PHYSIOLOGICAL INVESTIGATIONS ON BED RASPBERRY PLANTS
INOCULATED WITH BED RASPBERRY MOSAIC

A th e s is
P re se n te d to th e Graduate School o f
M ichigan S ta te C ollege i n p a r t i a l f u lf ilm e n t
of th e re q u irem en ts f o r th e degree of
D octor of P hilosophy

By

eK

B uford H. G rigsby

Department of Botany
Ju n e, 1937

ProQuest Number: 10008318

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T able o f C ontents
In tro d u c tio n

Page
1

M a te ria ls and Methods

2

C arbohydrate S tu d ie s

3

Enzyme S tu d ie s

10

P h o to sy n th e sis and R e s p ira tio n S tu d ie s

16

T r a n s p ira tio n

25

C h lo ro p h y ll

31

L eaf Ash S tu d ie s

3^

D iscu ssio n
Summary

39

L i t e r a t u r e C ite d

lj-1

ACKNOWLEDGMENT
The w r i te r w ishes to ex p ress h is a p p r e c ia tio n f o r
th e h e lp f u l a d v ic e and c r itic is m g iven d u rin g th e co u rse of
th e se in v e s tig a tio n s by D r, R, P , H ibbard, u nder whose
d i r e c tio n t h i s work was done*

V aluable c r i tic is m of th e

m anuscript was a ls o given by Dr, E» A, Bessey and D r, J , H,
Munci e»

PHYSIOLOGICAL INVESTIGATION ON BED BASPBEBBY PLANTS
INOCULATED WITH BED BASFBEBBV MOSAIC

I,

I n tro d u c tio n

V iru s d ise a se s o f th e ra sp b e rry were f i r s t reco g n ized in 1895
by Green (17) a lth o u g h i t i s s a id t h a t Detmers (12) in I 89I d e s c rib e d
a d is e a s e t h a t was v e ry l i k e l y m osaic b u t was th en a s c rib e d to b a c t e r i a .
In 1922 Rankin and Hockey (28) d iv id ed th e v ir u s d is e a s e s in to two
g ro u p s, " c u rl" and "m osaic",

B ennett (3 ) in a more re c e n t stu d y has

r e p o rte d a t l e a s t f iv e d i s t i n c t v ir u s d is e a s e s of th e r a s p b e r ry .

They

a r e , re d ra sp b e rry m osaic, m ild m osaic, yellow m osaic, c u r l and s tr e a k .
The f i r s t i s th e one d e a l t w ith i n th e se s tu d ie s ,
B ennett ( 3) a ls o s ta t e s th a t tem p eratu re has a v e ry d ecid ed
in flu e n c e in masking symptoms of re d ra sp b e rry mosaic and m ild m osaic,
0
At tem p e ra tu re s h ig h e r th an 28 C„ no symptoms of m o ttlin g a r e shown.
P la n ts w ith symptoms masked were th e r e fo r e e a s i ly o b tain ed when d esired #
Numerous p u b l ic a tio n s , summarized by Sm ith (3 3 ) deeding w ith
Symptoms, methods o f d iss e m in a tio n and tra n s m is s io n , and o th e r p atho­
l o g i c a l p h a se s have appeared b u t th e w r i te r has found v e ry l i t t l e in
th e l i t e r a t u r e on th e e f f e c t of red ra sp b e rry mosaic v ir u s on p h y s io lo g i­
c a l a c t i v i t i e s of th e h o s t. I t appeared w orth w h ile th e n to make comparati v e s tu d ie s of h e a lth y and mosaic p la n ts and a ls o p l a n ts in which the
symptoms o f re d r a s p b e r ry m osaic had been masked.

M osaics a re re sp o n s ib le

f o r th e so c a lle d "ru n n in g out" of s e v e ra l v a r i e t i e s many of which have
been abandoned.

P urtherm ore such tro u b le s n ot only cause s e rio u s r e ­

d u c tio n i n y ie ld s and q u a lity of f r u i t b u t account f o r c o n s id e ra b le d e c lin e
in a c re a g e .

II,

M a te ria ls and Methods

In a l l o f th e s e s tu d ie s th e Latham v a r ie ty was u s e d .

H ealthy

p l a n t s of t h i s v a r i e t y were in o c u la te d w ith the v ir u s re s p o n s ib le f o r
th e d is e a s e d e sc rib e d by B en n ett (3) a s re d ra s p b e rry mosaic an d by
Cooley (8) a s g reen m o ttle m osaic.

The symptoms produced v ary c o n sid e r­

a b ly w ith th e v a r ie ty an d w ith th e environm ental c o n d itio n s .

The le a v e s

p r e s e n t a ty p ic a l m osaic m o ttlin g c h a ra c te riz e d by y e llo w ish g re e n a re a s
a l t e r n a t i n g w ith r a is e d d a rk green a r e a s , when th e p la n ts a re grown a t
a r e l a t i v e l y cool te m p e ra tu re .
in f ig u r e s 1 and 2 ,

T y p ic a l le a v e s of t h i s s o r t a r e shown

Under o rd in a ry summer tem perature in M ichigan th e

M o sa ic -in fe c te d p la n ts show no symptoms and th e d is e a s e i s s a id to be
masked.
In th e f a l l o f 1932 tw e n ty -fiv e Latham p l a n t s in o c u la te d w ith
red ra s p b e rry mosaic were re c e iv e d from D r, W, H* Rankin of th e New York
A g r ic u ltu r a l Experim ent S ta tio n a t Geneva,

These p la n ts were grown in

th e greenhouse d u rin g th e w in te r and tr a n s f e r r e d to th e f i e l d in th e
fo llo w in g s p rin g .

While i n th e f i e l d th ey were covered w ith w h ite m uslin

cages to p re v e n t any p o s s ib le in f e c tio n from o th e r s o u rc e s.

A d d itio n a l

d ise a se d p l a n t s were secu red through th e use of b a rk g r a f t in g , a method
su g g ested to th e w r i te r by H a rris of th e E ast M ailin g R esearch S ta tio n ,
England,

S ince th e r e s u l t s w ith t h i s method have y ie ld e d more than

n in e ty p e r c en t i n f e c tio n th e w r ite r e a r ly gave up a tte m p ts to tra n s m it
th e d is e a s e by in s e c t v e c to r s .

During t h i s tim e many methods were t r i e d ,

a s in s e c t v e c to rs were d i f f i c u l t to f in d d u rin g th e e a r l i e r p e rio d s o f
t h i s stu d y .

T h is d i f f i c u l t y was due to th e h o t, dry w eather and o th e r

en v iro n m en tal c o n d itio n s .

V arious in o c u la tio n methods f o r v ir u s tr a n s ­

m issio n were g iv en a t r i a l e s p e c ia lly th e carborundum method.
a tte m p t in t h i s d ir e c tio n f a i l e d .

Every

I t has been su g g ested th a t th e v iru s

i s d e stro y e d by o x id a tio n when ju i c e from in f e c te d p la n ts i s u sed f o r
in o c u la tio n #
The symptoms of th e d is e a s e do n o t appear in th e g r a f te d p l a n t s
u n t i l a new s e t o f canes i s s e n t up from th e r o o ts .

In a c o n p a ra tiv e ly

s h o rt tim e th e s e w ill a p p e a r when th e p l a n t i s cu t b ad e.

D r. H arris#

i n a l e t t e r to D r. H ibbard, s t a t e s t h a t in England symptoms do n o t appear
on th e g r a f te d p l a n t s t i l l th e y e a r a f t e r g r a f tin g , b u t th a t i n St#
C a th e rin e s , O n ta rio , where he (H a rris) had made many g r a f t s d u rin g 193^*
re d ra s p b e rry mosaic appeared w ith in two months a f t e r g r a f t i n g .

No

ex p la n a tio n was g iv en to account f o r the d iff e r e n c e o b tain ed in th e
Canadian m a te r ia l.

P la n ts f o r t h i s stu d y , i n w hich th e symptoms were

masked, were secu red by s e le c tin g d is e a s e d p la n ts and exposing them to
p ro p e r tem p eratu re co n d itio n s#
I I I . Carbohydrate S tu d ie s
D iffe re n c e s i n the b iochem ical re a c tio n s in th e h e a lth y , m osaic,
and masked p l a n t s m ight b e ex p ected .

I n o th e r p la n ts such a s to b acco ,

p o ta to , tom ato, p e ac h e s, e t c . , in v e s tig a to r s have n o ted d iff e r e n c e s in
carb o h y d rate and n itro g e n r e la tio n s h ip s b e sid e s a number of o th e r
fe a tu re s .

The f i r s t s tu d ie s made w ith r a s p b e r r ie s were th o se on carbo­

h y d ra te s .

Leaves of ap p ro x im ately th e same age were secu red from h e a lth y ,

mosaic and masked p l a n t s .

Two s e r ie s o f experim ents were conducted, one

in th e greenhouse and one in th e f i e l d .

The le a v e s were g a th e re d l a t e in

-li­
th e morning and d r ie d i n th e oven a t 100° C ., f o r one hour and th e n
a t 60° C ., u n t i l c o n s ta n t w eight was reach ed .

The sam ples were th e n

ground to p a s s a *K) mesh screen and f u r th e r tre a tm e n ts made a c c o rd in g
to th e r o u tin e su g g ested by th e committee on chem ical methods of the
A. S. P . P . ( 3 0 ).

B e r tr a n d 's (H) perm anganate t i t r a t i o n method was

s u b s t i t u t e d in th e p la c e of t h a t o f S h a ffe r and Hartman*
The r e s u l t s o f th e s e a n a ly se s a r e shown i n T able I .

A lthough

th e t o t a l c a rb o h y d rates i n the le a v e s of m o sa ic -in fe c te d p la n ts v a r ie d
l i t t l e o r none from th o s e in h e a lth y o n es, masked p l a n ts under f i e l d
c o n d itio n s , showed l e s s c arb o h y d rates th a n p l a n t s from the g reen h o u se.
Much l e s s em phasis i s c e n te re d on th e s e t o t a l carb o h y d rate v a lu e s th an
on th e f ig u r e s f o r th e d i f f e r e n t caro b h y d rate f r a c t i o n s .
I t may be s a i d , however, t h a t th e re i s l i t t l e unanim ity of
r e s u l t s a s shown by v a rio u s in v e s tig a to r s #

Dunlap (15) o b tain ed an

in c re a s e i n t o t a l carb o h y d rates in two y e a r ra s p b e rry canes b u t a de­
c re a se in one y e a r c an e s.

He does n o t s t a t e what form of carb o h y d rate

i s re s p o n s ib le f o r th e In c re a se or the d ecrease th a t he fin d s in th e
two c a s e s .

He d id n o t a n aly ze h is m a te r ia l in to th e v a rio u s carb o h y d rate

fra c tio n s .

Among a number of o th e r m o sa ic -in fe c te d p la n ts such a s

to b acco , sq u ash , to m ato , p e p p e r, cucumber, e t c . , he found a d ecrease of
c a rb o h y d ra te s.

Rosa (32) re p o rte d an in c re a se of carb o h y d rates in

yellow b lig h te d to m ato es.

True and Hawkins ( 38) found an in c r e a s e of

ca rb o h y d rate s in b lig h te d spinach le a v e s .

Brew er, K endricks and

G ardner ( 7) o b ta in e d a d e crease in carb o h y d rates in tom ato m osaic.
B a ile y (2) found a d e c re a se in s ta r c h and s o lu b le carb o h y d rates in

-5 -

Table I
P erc e n ta g e of C arbohydrates in le a v e s o f h e a lth y p l a n t s , m o sa ic -in fe c te d
p la n t s and p l a n t s i n which symptoms were masked*

Hour

Date

P la n t and H a b ita t

J u ly 20 10 A.M.
H

H ealthy

greenhouse

Su Bar .
Simple Sucrose

T o ta l
Sugar

S oluble

S ta rc h
I n s o l.

T o ta l

O.Sk

0.7*4

1.3 S

1.00

•73

1 .7 3

20 10

it

H

H

.6 k

♦73

1 .3 7

♦95

.71

1.66

Aug. 21 10

11

M

H

.6 9

1 .1 9

1.88

.5 2

.9 7

1 .M9

II

.6*4

1 .1 9

1 .8 2

.5 0

•92

1 .U 2

.70

1.22

1 .9 2

1 .0 7

•68

1 .7 5

n

21 10

11

11

H

21 10

H

11

II

21 10

11

11

u

.67

1.22

1.89

1.07

.7 0

1 .7 7

H

26 10

N

it

N

•65

1 .3 9

2.0*4

♦37

.5 6

.9 3

10

II

11

H

.6*4

1 .U 3

2 .0 7

♦38

.5 5

.9 3

J u ly 20 10

n

♦59

1.20

1 .7 9

.50

.85

1 .3 5

•60

1 .1 8

1 .7 S

•50

.85

1 .3 5

♦57

1 .7 2

2.29

•**■7

.8 7

1 .3 *

♦57

1 .7 5

2.32

.5 0

.86

1 .36

♦75

1.29

2.0*4

.65

.79

i .k k

♦75

1 .2 9

2.0*4

.65

.8 0

1 .U 5

♦57

1.^ 5

2.02

.* 7

•59

1.06

♦57

I.U 5

2.02

.*7

.67

l.l*

"

26

M osaic, greenhouse

20 10

it

H

Aug. 21 10

11

n
11

11

fie ld

11

21 10

H

n

21 10

n

ti

21 10

H

11

11

26 10

11

11

11

26 10

n

ti

H

fie ld
N

Masked, greenhouse
M
fie ld
11

-6 -

d is e a s e d m a te r ia l o f to b ac co , tomato and p etu n ia*

B unzel secured l e s s

c arb o h y d ra te s in s u g a r-b e e t le a v e s in f e c te d w ith c u rly to p , a cco rd in g to
Dunlap* s (15) i n t e r p r e t a t i o n b u t Brewer e t a l (7) i n t e r p r e t th e s e f in d ­
in g s a s showing l i t t l e or no e f f e c t on carbohydrates*
T urning now to a c o n s id e ra tio n of t o t a l su g ars we f in d accord­
in g to th e ta b le th a t th e s e a r e h ig h e r in fie ld -g ro w n p la n t s th an i n
th o se grown i n th e greenhouse*

This was to be expected*

In th e f i e l d ,

m o sa ic -in fe c te d p la n ts produced more su g a rs than any o th e r group, masked
p la n ts were in te rm e d ia te , and h e a lth y ones co n tain ed th e le a s t*

A

f u r t h e r stu d y of th e t a b l e r e v e a ls th e f a c t t h a t g lu co se i s more abundant
in greenhouse p la n ts th an in f i e l d grown ones, w hile su cro se i s more
p re v a le n t in f i e l d grown p l a n ts th an in th o se grown i n the greenhouse.
H ealthy p la n ts c o n ta in g r e a t e r amounts o f g lu co se th a n e i th e r m osaicin f e c te d o r masked p la n ts *

Sucrose on th e o th e r hand i s more abundant

in m o sa ic -in fe c te d and masked p la n ts*

These r e s u l t s a r e in agreem ent

w ith th o se o f a few o th e r in v e s tig a to r s working w ith o th e r p la n ts *

F or

example B arton-W right and MeBain (1) found la r g e r amounts of su cro se than
g lu co se i n th e c r in k le - in f e c te d p o ta to .

The a u th o rs suggested a slow ­

in g up o f tr a n s lo c a tio n due to an accum ulation of sucrose*
were reduced t h i s n a tu r a lly was the form tr a n s lo c a te d .
t r a n s lo c a te d .

As th e hexoses

Sucrose was n o t

True and Hawkins (38) r e p o rte d a re d u c tio n i n hexoses and

an accum ulation of su cro se in th e le a v e s of b lig h te d sp in ach p l a n t s .
Dunlap (15) a l s o found l e s s hexoses in th e le a v e s of m o sa ic -in fe c te d
tobacco p l a n t s .

The w r ite r* s ta b le s show a ls o a d e c rease in g lu co se in

m o sa ic -in fe c te d ra s p b e rrie s *

In re g a rd to s ta r c h th e ta b le re v e a ls th e fo llo w in g f a c t s .
H ealthy p l a n t s show h ig h e r v alu e s th an do masked or m o sa ic -in fe c te d
p l a n t s , th e r e f o r e th e d is e a s e d c o n d itio n shows a d e c rease in s ta r c h .
Though th e r e i s n o t much d iffe re n c e in s ta r c h v a lu e s "between green­
house and f i e l d specim ens th e l a t t e r a r e u s u a lly lo w er.

B oth masked

and m o sa ic -in fe c te d p la n ts in the f i e l d show a d ecrease in th e s o lu b le
f r a c t i o n a s w ell a s th e in s o lu b le form when compared w ith h e a lth y
p la n ts .

However, th e g r e a te r lo s s e s a r e r e g is te r e d in th e s o lu b le

a n y lo d e x trin f r a c t i o n th a n in th e a n y lo c e llu lo s e

o r In s o lu b le form .

T his re d u c tio n in th e amount of s ta r c h in th e d is e a s e d p la n t i s a ls o
in agreem ent w ith th e f in d in g s of o th e r w orkers.

Brewer e t a l (7)

found a d e cre ase in su cro se and s ta r c h in m o sa ic -in fe c te d to m ato es.
Cook (8) re p o rte d an in v e rs e r e la tio n s h ip between s ta r c h and th e
s e v e r ity o f su g a r cane m osaic.

B olas and Bewley (5) observed a de­

c re a se i n s ta r c h fo rm a tio n in th e y ello w mosaic o f th e tomato when
th e p la n t had been in f e c te d f o r some tim e b u t n o t in th e e a r ly s ta g e s .
One i s tem pted to c r i t i c i z e experim ents of t h i s ty p e t h a t
a re conducted in th e greenhouse because of th e d i f f e r e n t environm ental
c o n d itio n s to which th e p la n ts a re s u b je c te d .

However, th e r e s u l t s

in d ic a te d in th e ta b le show good agreem ent when a conparison of
d ise a se d and h e a lth y p la n ts i s made w hether in th e greenhouse o r in
th e f i e l d .

The w r i te r f e e l s th a t as th e se o b s e rv a tio n s a r e th e f i r s t

of t h e i r k in d a s f a r a s th e ra sp b e rry i s concerned, s im ila r s tu d ie s
o f a more d e ta ile d n a tu r e , p erh ap s, should be conducted over a p e r io d
of y e a r s .

F u r th e r , th e d a ta found in ta b le I were o b tain ed from an

a n a ly s is o f le a v e s from many p la n ts s e le c te d on th e p a r t i c u l a r d a te s
in d ic a te d *

These were mixed to g e th e r a f t e r drying and two-gram samples

tak en f o r carb o h y d ra te a n a ly s is .

An a l t e r n a t iv e method c o n s is ts in

a n a ly z in g th e le a v e s in th e s e p a ra te s e t o r groups and then f in d in g the
a v e ra g e s .

The d a ta th e n , a r e capable of s t a t i s t i c a l tre a tm e n t and th e

d eg rees o f s ig n if ic a n c e determ ined.
The c a rb o h y d ra te m etabolism i n th e m o sa ic -in fe c te d p l a n t s , a s
in d ic a te d in th e p ro c ee d in g acco u n t, has been a t t r i b u t e d by most w orkers
to th e in te r f e r e n c e i n tra n s p o r t r a t h e r th an to i n a b i l i t y to produce
c a rb o h y d ra te s .

In p l a n t s where one e f f e c t of th e v ir u s i s to cause a

y ello w in g o f th e p h o to s y n th e tic t is s u e i t i s q u ite p robable th a t carbon
a s s im ila tio n i s reduced b u t f o r many of th e mosaic d is e a s e s t h i s explana­
tio n i s n o t v a l i d , f o r in many p la n ts th e re i s v e ry l i t t l e y e llo w c o lo re d
t i s s u e w h ile in some c ase s th e green c o lo r i s more in te n s e .

I t was

tho u g h t t h a t a stu d y of th e carb o h y d rate changes in a ra sp b e rry p la n t
d u rin g a tw e n ty -fo u r hour p e rio d might g iv e in fo rm atio n a s to w hether
p ro d u c tio n o r tr a n s p o r t was b eing checked.
F o r t h i s experim ent f i e l d grown p la n ts were used and sam ples o f
le a v e s were c o lle c te d e a r ly in th e morning b e fo re s u n ris e and a g a in the
same day j u s t b e fo re d a rk .

The sam ples were s e le c te d i n such a way th a t

m a te ria l from th e same p l a n ts m s b e in g an aly zed in each c a s e .

The

f o u r th and f i f t h le a v e s back from th e t i p a re u s u a lly f u l l y expanded
and in t h i s case w ere c o n sid e red m ature.

By ta k in g , th e n , the f o u r th

l e a f of one cane and th e f i f t h le a f of a n o th er cane in th e morning i t
i s p o s s ib le t o secu re a sample in th e evening from th e same canes w hich

-9 -

i s com parable in every r e s p e c t to th o se taken p re v io u sly *

The sam ples

were a n aly ze d by the same method in d ic a te d above and th e r e s u l t s a re
g iv en i n t a b le II*
The v a lu e s shown i n th e column headed P* M. a r e f o r th e samples
secu red b e fo re s u n r is e and r e p re s e n t th e carbohydrate f r a c t i o n s in th e
le a v e s a f t e r a p e r io d of e lev en hours d u rin g w hich no p h o to sy n th e s is
had tak en p la ce *

O bviously th e se changes a re c h ie f ly r e l a te d to tr a n s ­

l o c a tio n and u t i l i z a t i o n *

The f ig u r e s in d ic a te d in th e column headed

A* M* a re f o r th e sam ples g a th e re d in th e evening and r e p re s e n t th e
carb o h y d rate f r a c t i o n s i n th e le a v e s as th e r e s u l t , c h ie f ly , o f photo­
sy n th e sis*
A study o f th e ta b le shows th a t h e a lth y p la n ts produce more
sim ple su g ars d u rin g th e day time than e i t h e r th e masked o r m osaicin f e c te d p l a n t s .

T his in d ic a te s a g r e a te r e f f ic ie n c y in sugar production*

D uring the n ig h t th e r e i s a g r e a te r lo s s of th e se su g ars in h e a lth y
p la n ts thali i n th e d is e a s e d ones in d ic a tin g e f f i c i e n t tr a n s p o r t and more
r a p id tra n sfo rm a tio n *

When th e su cro se f ig u r e s a r e co n sid ered a l l

groups o f p la n ts show s im ila r amounts, w ith s l i g h t l y more o c c u rrin g in
th e m o sa ic -in fe c te d p l a n t s in th e d a y lig h t period*

From t h i s i t may

be concluded t h a t su c ro se i s m ain tain ed a t a f a i r l y c o n s ta n t le v e l*

Dur­

in g th e n ig h t, how ever, th e sucrose co n ten t in c r e a s e s in a l l g ro u p s, w ith
th e g r e a t e s t in c r e a s e s o c c u rrin g in th e d is e a s e d p la n ts*

One can see in

th e se r e s u l t s on sim ple su g a r and th e d is a c c h a rid e sucrose evidence of
f u r t h e r su p p o rt to th e th eo ry t h a t g lu co se i s th e f i r s t su g ar formed
and t h a t su cro se i s d e riv e d from th e hexoses an d fu rth erm o re i s th e
su g ar o f tra n s p o rt*

-1 0 -

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-1 1 -

S o lu b le s ta r c h i s more abundant d u rin g th e daytim e p e rio d in
th e m o s a ic -in fe c te d p la n ts *

During th e n ig h t i t i s somewhat lower*

In a l l th re e groups th e s o lu b le s ta r c h has decreased d u rin g th e n ig h t
showing t h a t i t has b een u t i l i z e d in some biochem ical re a c tio n *

The

in s o lu b le s ta r c h f r a c t i o n in th e m o sa ic -in fe c te d p la n ts i s the same f o r
day and n ig h t p erio d *

The h e a lth y and masked p la n t s show s ig n i f i c a n t

d iff e r e n c e s between day and n ig h t p erio d s*
To summarize* i t i s r e a d ily seen th a t su cro se rem ains q u ite
c o n s ta n t d u rin g th e day, and th a t a l s o , as i s shown in ta b le I , th e
d is e a s e d p la n ts c o n ta in more o f t h i s su g ar th an th e h e a lth y ones*
The in c re a s e in su cro se d u rin g th e n ig h t i s in p a r t a t the
expense of th e sim ple s u g a rs •

The P* M. v alu e s f o r sim ple su g ar a r e

c o n s id e ra b ly low er th an th e A* M* v alu e s w hile th e P* M. v a lu e s o f
su cro se a r e h ig h e r th an th e A* M* values*

For th e m o sa ic -in fe c te d

p la n ts t h i s a cco u n ts f o r approxim ately h a lf o f th e in c re a s e in sucrose*
The o th e r h a l f i s accounted f o r by th e tra n sfo rm a tio n of th e s o lu b le
s ta r c h f r a c t i o n ( d e x tr in ) in to su cro se f o r as may be seen i n th e ta b le
th e P* M. v a lu e s of s o lu b le s ta r c h a re th a t much l e s s than th e A* M*
v alu es*

A s im ila r l i n e o f agrument i s a p p lic a b le in th e case of th e

h e a lth y and masked p la n ts *

The d a ta in th e column headed in s o lu b le

s ta r c h a r e d i f f i c u l t to in te r p r e t*

Had the v a lu e s been h ig h e r in th e

n ig h t tim e f o r h e a lth y p la n ts and th e same or low er f o r th e masked and
m o sa ic -in fe c te d p l a n t s , i t would seem to prove th a t the d is e a s e d p la n ts
were i n e f f i c i e n t in tra n sfo rm in g th e sugars and s o lu b le s ta r c h e s in to
perm anent s t r u c t u r e .

F u r th e r study i s contem plated alo n g t h i s lin e *

The r e s u l t s should be reg ard ed a s in tro d u c to ry to f u r th e r work of a

-1 3 -

more d e t a i l e d n atu re*
S upport f o r th e id e a t h a t su cro se i s in c re a se d a t th e expense
o f g lu c o se an d s ta r c h i s found i n th e s tu d ie s of B arton-W right and
McBain (1 ) who a t t r i b u t e d th e in c re a s e of su cro se in p o ta to c r in k le mosaic
to a l o s s o f hexoses and sta rc h e s*

They showed a l s o t h a t th e su cro se

was produced from g lu c o se and f ru c to s e (hexoses)*

The r e s u l t s re p o rte d

h ere i n t a b l e s I and I I do n o t su p p o rt th e id e a of checked o r r e ta rd e d
t r a n s lo c a tio n s in c e a c o n s id e ra b le In c re a s e in su cro se o ccu rred in the
h e a lth y p l a n t s a s w ell*

Cook (8) a ls o found no in te r f e r e n c e in translocac­

tio n i n th e m o sa ic -in fe c te d su g ar cane*
IV* Ensyme S tu d ie s
E xperim ental p ro ced u res in enzyme e x tr a c tiv e p u r if i c a t i o n , and
t e s t s f o r a c t i v i t y , have been very g r e a tly m odified in th e p a s t few y e a rs
a s f a r a s work on anim al t i s s u e s i s concerned*
e x tr a c ts h as re c e iv e d b u t l i t t l e a t t e n t i o n .

The work on p la n t t i s s u e

P re s e n t la b o ra to ry methods

a r e th o se of te n o r f i f t e e n y e a rs ago and can be co n sid e re d only roughly
q u a n tita tiv e *

B e tte r methods of e x tr a c tio n , time of sam pling, p u rific a p ­

t i o n , c o n d itio n s n e c e ssa ry f o r optimum a c t i v i t y and b e t t e r c o n tro l of
th e pH o f th e r e a c tin g medium, e t c . , sh o u ld be c a r e f u lly considered*
has been fo u n d , f o r exam ple, t h a t

It

d ia s ta s e n o t only i s a m ixture of

enzymes, b u t t h a t th e r e a r e d i f f i c u l t i e s in s e p a ra tin g them*

A gain, th re e

methods of d e term in in g d i a s t a t i c a c t i v i t y have been suggested b u t u s u a lly
only one i s taken*

In th e th re e methods however th e changes do n o t always

tak e p la c e i n th e same o rd e r o r a t the same r a t e and u n le s s a com parison
by means of th e th r e e methods i s made the degree of a c t i v i t y by any one

method might n o t r e p r e s e n t a c tu a l c o n d itio n s*

Sometimes th e r e i s a

ra p id l i q u i f i c a t i o n of s ta r c h p a r a l l e l e d by a slow m altose fo rm a tio n :
a t o th e r tim es th e r e i s a very ra p id fo rm atio n of m altose b u t a slow
d isa p p e a ra n c e of p ro d u c ts which g iv e a b lu e c o lo r w ith iodine*
The d if f e r e n c e s i n carbohydrate m etabolism betw een th e h e a lth y
and d is e a s e d p la n ts su g g ested a p o s s ib le connection w ith enzyme a c t i v i t y
o r in a c t i v i t y *

Only q u a l i t a t i v e o r rough q u a n tit a tiv e t e s t s were

p o s s ib le i n th e two ex p erim ents conducted a t two d if f e r e n t seasons*
Enzyme e x t r a c t s were sec u re d from le a v e s of s im ila r age s e le c te d from
th e th re e d i f f e r e n t groups of p la n ts*
e x tr a c tio n method was used*
p erio d *

In one s e r i e s th e u s u a l w ater

The le a v e s were g a th e re d in th e l a t e morning

In th e second experim ent th e enzymes were e x tr a c te d by a method

d e s c rib e d by True and Hawkins (38) in which g ly c e rin e was th e e x tr a c t­
in g medium*

In b o th experim ents a p re lim in a ry g r in d in g of th e tis s u e s

w ith c le a n q u a rtz sand was necessary*

The g ly c e rin e e x tr a c tio n was

co n tin u ed f o r 2b h ours and a t a tem p eratu re o f 10° C.

The e x t r a c t was

th e n squeezed th ro u g h c h e e se c lo th and made up t o mark in a 250 cubic
c e n tim e te r v o lu m e tric f la s k *

A one p e r c en t L intner* s s ta r c h s o lu tio n

was made up f r e s h each tim e a t e s t was conducted*

A t e s t c o n s is te d in

p la c in g v a ry in g c o n c e n tra tio n s of the enzyme s o lu tio n in a s e r i e s o f
t e s t tu b e s and th en ad d in g 5 cu b ic ce n tim e te rs o f a one p e r c e n t s ta r c h
so lu tio n *
tube*

O ne-half a cu b ic c e n tim e te r of to lu o l was p la c e d in each

The tu b e s were c lo se d w ith a s to p p e r, shaken, and p la c e d in an

in c u b a to r a t 37° C .f f o r US hours*

At th e end of t h i s tim e th e tu b e s

were removed from th e in c u b a to r and immersed in co ld w ater and to each
was added te n cu b ic c e n tim e te rs of cold d i s t i l l e d w ater and o n e -te n th

-lU c u b ic c e n tim e te r of a one p e r c en t io d in e s o lu tio n *

The tu b e s were

then shaken and th e enzym atic a c t i v i t y determ ined by th e o b se rv a tio n
of changes i n color*

The d a ta may be found in ta b le I I I *

T hat tube c o n ta in in g th e lo w est d i l u t i o n o f enzyme, in which
no b lu e c o lo r was fo u n d , on tre a tm e n t w ith io d in e was a r b i t r a r i l y tak en
a s zero*

Then th e tu b e i n t o which a sm all q u a n tity of b o ile d enzyme

had been in tro d u c e d and which on tre atm e n t w ith io d in e showed th e b lu e
c o lo r was tak en to r e p re s e n t th e o th e r end of th e s c a le o r 100*

The

o th e r tu b e s were g rad ed acco rd in g to c o lo r on a p ercen tag e b a s is *
From the ta b le i t i s obvious t h a t the

d i a s t a t i c a c t i v i t y of the le a v e s

of m o sa ic -in fe c te d p l a n t s was g r e a t e r th an t h a t of th e masked or h e a lth y
ones*

When co n sid e re d w ith the carbohydrate changes a lre a d y d e s c rib e d

above th e in c re a s e d d i a s t a t i c a c t i v i t y e x p la in s why th e re was such a
sm all amount o f s o lu b le s ta r c h o r d e x tr in and why th e re was an in c re a se d
amount o f su cro se i n th e m o sa ic -in fe c te d p la n ts*

In th e case of th e

••masked" p la n ts i t ap p ears th a t d i a s t a t i c a c t i v i t y h as n o t been m odified*
Masking e f f e c t s in th e ra s p b e rry may be in th e some phases comparable to
th e e f f e c t s of a l a t e n t v iru s in th e m etabolism o f th e p o tato *

B arto n -

W right (2 ) re p o rte d t h a t p o ta to e s c o n ta in in g a l a t e n t v ir u s had in no
way m odified carb o h y d rate metabolism*
a c tio n would be ex p e c te d .

In th a t case no changes In enzyme

These experim ents w i l l be re p e a te d on a

q u a n t i ta t i v e b a s is and d e f i n ite con clu sio n s must be re s e rv e d , f o r th e
f u t u r e , b u t o u t p r e s e n t r e s u l t s in d ic a te a s ig n i f i c a n t d iffe re n c e *
P ro o f t h a t d i a s t a t i c a c t i v i t y i s in c re a s e d in mosaic in fe c te d
tobacco has been shown by Dunlap (15)*

S reenivasaya (3*0 found th a t

th e d i a s t a t i c a c t i v i t y o f spiked le a v e s of sandal was much g r e a te r than

15-

T able I I I .
D i a s ta ti c a c t i v i t y of e x tr a c ts from leav es of h e a lth y , masked
and m o s a ic -in fe c te d p la n ts a s determ ined by th e c o lo r produced by
th e a d d itio n o f io d in e to a s ta r c h s u b s tra te *
i

Zero in d ic a te s

g r e a t e s t a c t i v i t y and 100 in d ic a te s no a c tiv ity *

P la n t

0*5e c .

Q u an tity of enzyme ex t r a c t
0.4cc* 0 *3cc* 0 *2cc* 0 * lcc

C ontrol

H ealth y

20

to

60

SO

100

100

H ealth y

20

to

6o

SO

100

100

Masked

20

to

60

SO

100

100

Masked

20

to

60

80

100

100

Mosaic

0

20

50

6o

100

100

M osaic

0

20

50

6o

100

100

- 16 -

th a t o f th e h e a lth y l e a v e s .

True and Hawkins ( 3S) however were unable

t o d e te c t any d if f e r e n c e between the d i a s t a t i c a c t i v i t y of th e le a v e s
of h e a lth y and d is e a s e d sp in a c h .

R asp b e rrie s th e n ap p ear to be n o t un­

l i k e o th e r p la n ts in f e c te d w ith mosaic in t h e i r power to q u ic k ly conv e r t s ta r c h and a ls o g lu co se in to s u c ro s e .
V.

P h o to sy n th e sis and R e s p ira tio n S tu d ie s

The r a te o f p h o to sy n th e s is in le a v e s , o r t h e i r e f f ic ie n c y in
th e fo o d m an u factu rin g p r o c e s s , has been determ ined f o r many ty p e s of
p l a n t s u n d e r v ary in g c lim a tic c o n d itio n s , ex p erim en tal p ro ced u res e t c .
I t h as been shown th a t n o t only do e x te r n a l c o n d itio n s modify t h i s
p r o c e s s , b u t i n t e r n a l c o n d itio n s a ls o , such a s w ater and c h lo ro p h y ll
c o n te n t, a g e , v a r i a t io n s in th e a b i l i t y to r e a c t (p ro to p lasm ic f a t i g u e ) ,
im proper n u t r i e n t c o n d itio n s , tr a n s lo c a tio n and u t i l i z a t i o n of a s s im ila t­
ed m a t e r ia ls .

In s p it e o f a l l th e se m odifying c o n d itio n s i t i s n o t

im p o ssib le to o b ta in a f a i r approxim ation of a normal l e a f ’ s e f f ic i e n c y .
The o b je c t o f t h i s work was to compare th e p h o to sy n th e tic e f f ic ie n c y of
h e a lth y ra s p b e rry le a v e s and th o se in f e c te d w ith m osaic.

The method of

H einicke and Hoffman (19) as a p p lie d to ap p le le a v e s was s e le c te d a s a
g u id e f o r th e s e s tu d ie s .

In p r in c ip le i t i s l i k e many o th e rs d a tin g

back even to th e tim e of K re u s s le r’ s work in 1885, b u t i t has th e ad­
v an tag e o f b e in g u s e f u l in cases where th e le a v e s a r e s t i l l a tta c h e d to
th e p l a n t .

These a u th o rs have a ls o been v ery e x p l i c i t in t h e i r des­

c r i p ti o n s of th e method, an d in p o in tin g out th e v a rio u s s te p s and the
need f o r c a re and p r a c t i c e in developing tec h n iq u e .

T his i s im p o rtan t

as i t i s th e n p o s s ib le to d u p lic a te p ro ce d u re s, a s t a t e o f a f f a i r s
which has u s u a lly been im possible to accom plish in experim ents o f t h i s

The r e p o r t t h a t fo llo w s d e a ls w ith p la n ts grown in th e green­
house*

R e s u lts o b ta in e d in t h i s way a re comparable t o th o se found in

f i e l d p la n ts *

The carb o h y d rate s tu d ie s re p o rte d above have shown

th a t norm al h e a lth y p l a n t s e x h ib it th e same g e n e ra l ty p e of m etabolism
in th e greenhouse a s i n th e f ie ld *

The f i e l d p l a n t s , however, p ro ­

duce ap p ro x im a tely tw ice as much m a te ria l*

S im ila r s tu d ie s by o th e r

w orkers have a ls o been conducted in greenhouses and no marked v a r ia ­
tio n in th e ty p e o f carb o h y d rate m etabolism has been thus f a r r e p o rt­
ed*

F i r s t s tu d ie s a r e n a tu r a lly made where experim ental f a c i l i t i e s

a r e a v a i l a b l e and where co m p licated a p p a ra tu s can be s e t up w ith o u t
f e a r of m istreatm ent*

Arrangements f o r f i e l d study have a lre a d y

been made f o r th e coming growing season*
were c a r r i e d through*

Three s e r ie s of experim ents

One in the s p rin g of 1936 , a second in th e

summer o f th e same y e a r and th e l a s t in th e s p rin g of 1937*
P h o to s y n th e tic e f f ic ie n c y was e stim a te d by d eterm in in g th e
d iff e r e n c e in Cog c o n te n t between a continuous stream o f normal a i r
an d a s im ila r stream of a i r th a t had p assed over l e a f tis s u e co n fin ed
i n a s p e c i a l ly c o n s tru c te d p h o to s y n th e tic chamber*

The p h o to s y n th e tic

chambers were in th e form of c y lin d e rs made of c e l l u l o i d as shown in
f ig u r e 3*
b e r ry cane*

They were la r g e enough to en clo se th e e n t i r e end o f a rasp ­
Thus a c o n s id e ra b le amount of p h o to sy n th e tic t is s u e can

be u sed and crow ding of le a v e s avoided*

There was a ls o a minimum o f

tem p eratu re v a r i a t io n so p re v a le n t in experim ents where s in g le le a v e s
o r p o r tio n s of le a v e s a r e used in cup chambers or o th e r sm all c o n ta in e rs*

-1 8 -

The c y l i n d r i c a l chambers were 20 in ch es hig h and 30 in ch es
i n circum ference*

A c e l l u l o i d cover was cemented to one end w ith a

m ix tu re o f c e l l u l o i d i n acetone*
tig h t*

A ll j o i n t s a t t h i s end were se a le d

At th e o th e r end th e c y lin d e r was a tta c h e d to a m etal rim to

which was f a s te n e d a lo n g m etal ro d th a t could b e used f o r a su p p o rt
when s tu c k in th e ground*

C ellophane f a s te n e d to t h i s rim by an

e l a s t i c b an d , and lo o s e ly t i e d around th e e x it and i n l e t a i r tu b e s and
stem , c lo s e d up th e chamber*

The a b s o rp tio n u n i t s w ith s l i g h t m odifi­

c a tio n were th e same a s th o se p ic tu r e d and d e s c rib e d by H einicke and
Hoffman ( 19) on page f o u r of t h e i r p u b lic a tio n .

T h e ir g e n e ra l method

o f p ro ced u re as to c a l i b r a t io n : ta k in g of sam ples, r e g u la tin g a i r
su p p ly , t i t r a t i o n s , e t c . , was followed*

The running tim e of an ex p eri­

ment was alw ays f o r f o u r h ours a s t h i s was a convenient tim e i n t e r v a l
f o r th e o p e ra to r and was of s u f f i c i e n t le n g th to produce re c o g n iz a b le
q u a n t i t i e s of Cog •

S im ila r ru n s f o r th e same tim e p e rio d s were made

i n darkened chambers o r d u rin g th e n ig h t in r e g u la r chambers f o r
in fo rm a tio n on r e s p ir a to r y a c t i v i t y in leaves*
L eaf a r e a s had to be determ ined and t h i s was accom plished w ith­
o u t i n ju r y to th e l e a f o r p la n t by means of a s im p lif ie d and p o r ta b le
p h o to e le c tr ic d ev ice d e sc rib e d by H ibbard, Grigsby and Keck (21)*

T his

d ev ice h as been used f o r th re e y e a rs and has a few s p e c ia l f e a tu r e s n o t
y e t n o te d in th e d e s c r ip tio n s of s e v e ra l devices re c e n tly p u b lis h e d .
I t i s o p e ra te d on a 6 v o l t b a t t e r y , has a m u ltip le p o in t, low i n te n s ity
l i g h t s o u rc e , and a s p e c ia lly c o n s tru c te d cone shaped l i g h t chamber and
needs no c o r re c tio n f o r tra n sm issio n of l i g h t th ro u g h th e t e s t le a f*

The d e v ic e can he made p o r ta b le and an autom obile b a tte r y can be used
a s t h e so u rce o f pow er.

F ig u re H i s from a photograph of th e ap p ara­

tu s .
The d a ta f o r p h o to sy n th e s is and r e s p ir a tio n may be found in
t a b l e s IV, V, and V I.

The f ig u r e s given f o r p h o to sy n th e s is a r e a c tu a l­

l y , a p p a re n t p h o to s y n th e s is , and re p re s e n t th e m illig ram s o f Co2 p e r
100 sq u are c e n tim e te rs of s u rfa c e p e r h o u r, over an d above th e q u a n tity
o f Co^ l i b e r a t e d th ro u g h the o p e ra tio n of r e s p ir a t io n and o th e r meta­
b o lic p ro c e s s e s o f th e p l a n t .
ed A. M.

These f ig u r e s a r e below th e column head­

The f ig u r e s below th e column headed P . M, a r e f o r th e q u a n tity

o f Co^ l i b e r a t e d p e r 100 square c e n tim e te rs p e r h o u r, d u rin g runs a t
n ig h t o r i n b la c k hooded cham bers.

These f ig u r e s re p re s e n t r e s p ir a tio n .

Greenhouse tem p era tu res between n ig h t and day a r e u s u a lly of wide
v a r i a t io n b u t a system of r e g u la tio n was p o s s ib le and in th e se ex p eri­
ments th e g r e a t e s t v a r i a t i o n in te n p e r a tu re s were n o t more th an 5 ° V.
The canes u sed were in t h e i r f i r s t season of grow th.

A stu d y o f a l l

th re e t a b l e s shows th a t th e a p p a re n t p h o to sy n th e sis i s reduced in th e
m osaic p l a n t s .

In o th e r words th e d is e a s e d p la n ts a r e l e s s e f f i c i e n t

i n p h o to sy n th e s is th a n th e h e a lth y ones and t h e i r r a te of a c t i v i t y
i s red u c ed .

R e s p ira tio n on th e o th e r hand showed a g r e a te r a c t i v i t y

in th e m o sa ic -in fe c te d p l a n t s .

The r e s p ir a to r y a c t i v i t y of th e masked

p lg n ts i s in te rm e d ia te , l e s s than th e d ise a se d b u t more than th e
h e a lth y .
A f u r t h e r stu d y o f th e ta b le s shows th a t p h o to sy n th e tic
a c t i v i t y v a r ie s w ith th e tim e of th e y e a r .
a r e low er th an th e sunnier v a lu e s .

The s p rin g or May v a lu e s

Two ex p lan atio n s a r e p o s s ib le .

20-

Table IV
A pparent p h o to sy n th e s is and r e s p ir a tio n o f h e a lth y and m osaioin f e c te d p la n ts i n th e sp rin g of 193&* expressed a s m illig ram s of Co
2
p e r 100 s q . cm. p e r h o u r. Average of U-hour 6cT<zjrmmations d u rin g
th e day o r n ig h t.

R atio
Day

N ight

Day

N ight

6.50

K js

100

100

^.1 5

5 .28

63

110

11

H ealthy 1*7*79

5.23

100

100

11

Mosaic

9*97

6.07

77

115

13

H ealthy L5.31

^ .62

100

100

13

Mosaic

9*09

6.10

59

132

15

H ealthy

6.52

2 .7 s

100

100

15

Mosaic

3.82

3 .5 6

58

128

D ate

P la n t

toy U H ealthy
k

Mosaic

-2 1 -

T able V.
A pparent p h o to sy n th e s is and r e s p i r a t i o n o f h e a lth y , m o s a ic -in fe c t­
ed and masked p l a n t s e x p ressed a s m illig ram s of COg , p e r 100 sq* cm*,
p e r h o u r.

Average of 4 -h o u r d e te rm in a tio n s d a rin g day or n ig h t*

Summer

o f 1936*

Date

P la n t

J u ly 8

Day
A.M.

P a tio
P.M.

Day Av.

N ight

Day

N ight

H ealthy

11,70

10.75

11.22

4.06

100

100

8

Masked

13.09

11.79

12.44

4 .6 l

110

113

8

Mosaic

10.50

9.69

10.09

5.05

89

121

9

H ealthy

8*08

8.08

8.08

4 .4 i

100

100

9

Masked

S.U5

7.71

8.08

4.07

100

92

9

Mosaic

7.70

6.81

7.25

4.47

88

101

10

H ealthy

12.12

13.22

12.67

4.07

100

100

10

Masked

12*13

12.13

12.13

4.03

95

99

10

Mosaic

11.62

12.07

11.84

4.53

93

111

14

B aa lth y

31.64

24.90

28.27

4.60

100

100

14

Masked

29.10

22.44

25.77

5.46

91

118

14

Mosaic

27.49

19.49

23.49

6.06

S3

131

15

H ealthy

17.22

15.68

16.45

5 .5 4

100

100

15

Masked

1 7 .9 4

17.37

17.60

7.46

107

134

15

Mosaic

1 3 .24

12.10

12.67

S.97

77

161

16

H ealthy

16.71

18.02

17.36

7.19

100

100

16

Masked

20.02

19**6

19.94

8 .54

114

110

16

Mosaic

16.51

17.14

16.82

12.07

96

167

17

H ealth y

16.90

15.94

16.42

6 .4 i

100

100

17

Masked

20.07

17.40

1S.73

7.55

114

117

■22-

T able V (co n tin u ed )

D ate

P la n t

Day
A* M#

P.M.

Day Av.

N ight

Day

R atio
N ight

J u ly 17

Mosaic

15.00

lKS2

lU .91

S.90

Sh

13S

Aug. IS

H ealthy

17.32

15.50

l6 .H l

5 .^

100

100

IS

Masked

17.^3

17.17

17.50

S.02

106

1U6

IS

Mosaic

15.96

15.00

15.U8

9.2H

9U

16s

23

H ealthy

13.H9

12.37

12.93

KSk

100

100

23

Masked

12.16

12.16

12.16

1+.6H

9U

100

23

Mosaic

1 1 .3 s

10.73

11.05

5.00

25

107

—23"*

Table 7 1 .
A pparent p h o to sy n th e s is and r e s p ir a t io n of h e a lth y and m osaicin f e c te d p la n ts in e a r ly s p rin g , 1937*
of Cog , p e r sq . cm ., p e r h o u r.

R e s u lts ex p ressed a s m illig ram s

Average of H-hour d e te rm in a tio n s d u r ­

in g day o r n ig h t#
Rfitio
lig h t

A. M.

P . M.

Day Av.

R ight

Pay

5 . 51*

S.9 2

7 .2 3

3 .0 0

100

100

29 Mosaic

2.U3

5 .2 1

3 .8 2

H.H3

52

lHH

30 H ealthy

H.17

H.17

1 .3 2

100

100

30 Mosaic

1 .3 8

1 . 3S

2 .7 3

33

206

D ate

P la n t

March 29 H ealthy

H ealthy

7 .9 1

5 . 5H

6.72

3 . Hi

100

100

1

Mosaic

H.19

2 .8 6

3 .5 2

3*58

52

105

2

H ealthy

5 .5 0

5 .5 0

5 .5 0

1 .1 7

100

100

2

Mosaic

H.23

H.H9

H.36

1 .3 5

79

115

A p r il 1

-2 U -

F i r s t , i t m ight h e a case o f d if f e r e n c e i n v ig o r, th e summer p la n ts
b ein g th e most v ig o ro u s o r , se c o n d ly , i t m ight b e a group o f e x te rn a l
c o n d itio n s , c h i e f l y l i g h t and temperature* t h a t cause the d iffe re n c e *
The fo rm er e x p la n a tio n does n o t a p p e a r to be a s reaso n ab le a s th e
l a t t e r , s in c e th e ty p e of grow th in th e ra sp b e rry i s in d e te rm in a te ,
and th e groups o f le a v e s on th e ends of the canes a r e in s im ila r
grow th sta g e s*

S easonal v a r ia t io n s in p h o to s y n th e tic r a t e do occur

a c c o rd in g to D astu r and D esai (10)*
(19) v a r ia tio n s from day to day*

H einicke and Hoffman re p o rte d

B olas and M e lv ille ( 6) observed a

s e a so n a l v a r i a t i o n , th e r a t e of p h o to sy n th e s is b ein g h ig h in summer
and th e n d e c lin in g tow ards w inter*

V a ria tio n i s th e r u le r a t h e r

th a n th e exception*
Stone ( 36) working w ith m o sa ic -in fe c te d p o ta to e s found a r e ­
d u c tio n i n p h o to s y n th e tic e f f ic ie n c y , b u t n o ted t h a t th e s e v e rity of
th e d is e a s e had l i t t l e e f f e c t upon th e degree of red u ctio n *
( lh ) claim ed th a t m osaic in h ib ite d p h o to sy n th e tic e f f ic ie n c y .

Dufrenoy
B arto n -

W right ( 2) fo und t h a t in young p o ta to p la n ts s u ff e rin g from mosaic
th e r e was no d if f e r e n c e in carb o h y d rate m etabolism o r th e a b i l i t y to
make c a rb o h y d ra te s, b u t a s th e p la n ts grew o ld e r th e re was a d e c lin e
in th e amount of c arb o h y d ra te s formed*

There seems to be no doubt

in th e c a se of th e ra sp b e rry of a decrease in a c tiv ity *

As to a

r e l a t io n s h i p betw een s e v e r ity o f the d is e a s e and p h o to s y n th e tic ac­
t i v i t y i t would a p p e a r th a t th e r e i s one*

The degree o f re d u c tio n

o r d e c re a se o f a c t i v i t y seems to be p ro p o rtio n a l to symptom expression*
In th e masked p la n ts th e re d u c tio n i s not so g r e a t a s in th e m osaic-

-2 5 -

i n f e c te d ones*

W hitehead ()J0) o b tain ed s im ila r r e s u l t s in p o ta to

p l a n t s in f e c te d w ith l e a f r o ll*

Dunlap (15) g iv e s d a ta th a t show in ­

c re a se d r a t e o f r e s p i r a t i o n in young ra sp b e rry p l a n t s and a d ecrease
in o ld e r ones*

H is r e s u l t s a r e b ased on Co 3. evolved p e r hour in an

av erag e s iz e d l e a f , th e a r e a of which was unknown*
VI* T ra n s p ira tio n
A com parative stu d y of th e tr a n s p ir a tio n r a t e of h e a lth y ,
d ise a se d and masked p l a n t s was u n dertaken i n th e greenhouse*

A ll re c o rd s

h e re were o b ta in ed by th e s ta n d a rd iz e d hygrom etric p ap er method*

T his

was f i r s t su g g ested by S ta h l (35) and l a t e r was s ta n d a rd iz e d by
L iv in g sto n and h is co-w orkers ( 23)*

There have been some m o d ific a tio n s

by L iv in g s to n h im se lf and by o th e r workers in t h i s f i e l d in more re c e n t
tim es*

The m o d ific a tio n s by Meyers (25) were fo llo w ed in th e main*

By

u s in g t h i s method th e le a v e s d id n o t have to be detached from th e p la n t
and one can make t e s t s on le a v e s under d if f e r e n t c o n d itio n s w h ile th e y
a re grow ing n a t u r a l ly in benches or p o ts in the greenhouse*

The method

of o b ta in in g r e s u l t s i s more sim ple and q u ic k e r than experim ents w ith
p o to m ete rs o r w a te r c u ltu r e set-u p *

I t i s p r e f e r a b le , e s p e c ia lly in

experim ents of a p re lim in a ry n a tu r e , to th e more e la b o ra te methods
w hich have been d escrib ed *

The w r ite r b e lie v e s th a t much more inform a­

tio n sh o u ld b e c o lle c te d n o t on ly from p la n ts in th e greenhouse b u t
from f i e l d specimens*

These re p o rte d f ig u r e s , however, a re in d ic a tiv e

of th e e f f e c t o f a v ir u s on p la n t tra n s p ir a tio n *

Up to the p r e s e n t,

few s tu d ie s of t h i s k in d have been made and none a t a l l on th e ra s p b e rry .
R e s u lts , shown in ta b le V II, a r e reco rd ed a s grams of w ater

- 26-

T able VII
Grams of w a te r vapor tr a n s p ir e d from le a v e s of healthy* and
masked p l a n t s p e r horn* p e r 100 sq u are c e n tim e te rs o f l e a f area*

H ealth y (H)
Bench
P ot

Time
March 13

Masked (M)
Bench P o t

D
D iseased (D) R atio TT
Bench P o t
Bench P o t

R atio
Bench

M
H
Pot

1 .9 5

-

1.95

1.08

2.03

1 . 1H

10U

-

100

55

2*01

1.08

2.00

O.7 6

1U5

-

1U5

78

N

20

1.37

-

H

21

-

-

' -

1.30

1.7S

1.11

166

-

-

122

U

31

1*01

-

-

•S3

1.77

.95

176

-

m

82

1*55

a*

1*67

1.57

•95

101

-

120

107

-

I .63

1.25

1*10

—

*•

—

A p ril 8
H

12

-

-

1*87
-

-2 7 -

vapor l o s t i n one hour p e r 100 sq u are c e n tim e te rs of l e a f area*

The

r e l a t i o n "between th e c o lo r o f th e hygrom etric p ap e r and th e amount
o f w a te r ta k e n up i s determ ined in th e fo llo w in g way*

The time* in

sec o n d s, n e c e ssa ry

f o r a d e f i n it e a r e a of pap er p re ss e d on th e l e a f

su rfa c e , to a tta in

th e same p in k c o lo r a s a s im ila r p ie c e of p ap er

in a s a tu r a te d atm osphere a n d u sed a s a re fe re n c e s ta n d a rd , was found*
Now, by u s in g th e fo rm u la G m (0*0678^- * 3^0Q)
th e amount of
T
w a te r v ap o r can he determ ined* The c a lib r a tio n of th e re fe re n c e
s ta n d a rd showed t h a t th e p in k c o lo r was e q u iv a le n t to th e a b s o rp tio n
o f 0*0678 grams o f w a te r vapor p e r 100 sq u are c e n tim e te rs of p ap er
su rface*

Thus th e

c o lo r was a measure of w ater c o n te n t of th e p ap er

and t h i s was r e l a t e d to th e tim e*

In th e eq u atio n G eq u als th e grams

of w a te r vapor l o s t p e r hour and T i s th e tim e o f c o lo r change in
seconds*

The number o f seconds in one hour i s 36OO, the f ig u r e in d ic a t—

ed i n th e num erator o f th e e q u atio n above*
The f ig u r e s in th e ta b le show th a t the m o sa ic -in fe c te d p la n ts
have a g r e a t e r t r a n s p i r a t io n r a t e than th e h e a lth y ones and th a t th e
r e s u l t s from th e masked p la n ts a r e in term ed iate*

Heuberger and Norton

( 20) observed a g r e a t e r r a t e of tr a n s p ir a tio n in m o sa ic -in fe c te d tomato
p la n ts .

H arriso n (16) re p o rte d no in c re a se d tr a n s p ir a t io n in m osaic-

in f e c te d bean le a v e s b u t w ater lo s s e s from the pods of d ise a se d p la n ts
were g r e a t e r th an from th o se of h e a lth y p la n ts*
The d a ta a ls o show t h a t th e lo s s of w ater vapor i s more ra p id
in p l a n t s growing i n th e s o il in an open bench where th e s o i l i s two
f e e t d e e p , th an i n p o ts where th e s o i l mass i s r e s t r i c t e d and n o t more

-2 6 -

th a n f o u r o r f i v e in c h e s deep*

In the l a t t e r th e supply of m o istu re

i s l e s s th a n in th e "bench and th e p la n t r o o ts q u ic k ly u s e up th e supply*
When p l a n t 8 have grown in p o ts f o r some tim e th e m a jo rity o f the r o o ts
grow n e a r th e s id e s o f th e p o t and on th e o u ts id e of th e s o i l mass*
The w a te r h e re i s soon u sed up and a d ecrease in tr a n s p ir a tio n occurs*
A f te r i t had "been determ ined t h a t the tr a n s p i r a tio n r a te in
d is e a s e d p l a n t s was g r e a t e r than i n th e h e a lth y an ex p lan atio n was
sought in th e d i s t r i b u t i o n and number of stom ata on th e le a v e s of th e
d i f f e r e n t ty p e s o f p la n ts *

The ra s p b e rry lam ina i s of a d e lic a te

s t r u c t u r e , i t s s u rfa c e i s of a convoluted o r wavy n a tu re and i t s only
su p p o rt a r e th e prom inent v eins*

To a s s i s t in m a in ta in in g i t s r i g i d i t y

th e s u rf a c e i s im pregnated w ith s ilic o n *
a b le amounts o f s i l i c o n a r e found*

When le a v e s a r e ashed c o n sid e r­

There was g r e a t d i f f i c u l t y th e r e fo r e

in s t r i p p i n g o f f s u ita b le p ie c e s of epiderm is f o r th e purpose of f ix in g
th e sto m ata on th e l e a f in a b s o lu te a lc o h o l so th a t sto m atal s tu d ie s
co u ld be made la te r *

The c o llo d io n f ilm method f i r s t suggested by

N ew irth (26) and l a t e r improved by Long and Clements (2^4-) was n o t success­
f u l*

The c h ie f th in g t h a t m il ita te d a g a in s t th e s e methods was th e f a c t

t h a t th e s u rf a c e o f th e l e a f was covered by a mat of lo n g , tenuous i n t e r ­
lo c k in g h a ir s *

I t was d i f f i c u l t a ls o to see th e stom ata because of the

d e n se, d a rk , c e l l co n ten ts*

The stom ata a r e sm all and th e r e fo r e q u ite

numerous and some method had to be devided to a v o id th e se d i f f i c u l t i e s *
F i r s t i t seemed n e c essary to u se some c le a r in g agent*

A la c tic -

a c id -p h e n o l p re p a ra tio n a s re p o rte d by Davis (11) proved very good*

The

method o f c o u n tin g and s tu d y in g stom ata c o n s is te d f i r s t i n s e le c tin g
s u ita b le com parable le a v e s , d etach in g them from the p a re n t p la n t and

-2 9 -

im m erslng th an in a b s o lu te a lc o h o l to k i l l and f i x them in th e form
i n which th ey were gath ered*

The le a v e s were n e x t immersed in th e

c le a r in g f l u i d in which th e y rem ained f o r tw en ty -fo u r hours and a f t e r
c le a r in g were washed w ith w ater so a s to be f r e e of c le a r in g f lu id *
The t i s s u e was s ta in e d w ith an aqueous s o lu tio n of io d in e in po­
ta ssiu m iodid e*

T h is re a g e n t tu rn e d th e s ta r c h i n th e guard c e l l a

d ark b lu e c o lo r and i t was n o t d i f f i c u l t then to f in d th e sto m ata and
count them*

S lid e s were made and s tu d ie d under hig h m a g n ific a tio n o f

th e m icroscope*

Stom ata were found only on the low er fa c e of th e

l e a f and on th e m argin of th e l e a f , th ey occur in l a r g e r numbers than
in th e c e n te r p o r tio n of th e le a f*
t a b le V I I I .

Stom atal co u n ts a re found in

They were c a lc u la te d on the b a s is of so many p e r square

m illim e te r o f l e a f area*

Counts were tak en a t random in d i f f e r e n t

re g io n s of th e b la d e , some n e a r th e m id -rib , o th e rs n e a r th e t i p of
th e l e a f , some a t th e b a se and o th e rs on th e m argin, etc* Counts on
te n d i f f e r e n t m icro sco p ic f i e l d s were u s u a lly obtained*
A com parison was made of o ld le a v e s and young leaves*
The number of sto m ata i s d if f e r e n t f o r th e two ty p es in d ic a te d *

The

younger le a v e s p o s se s s p e r u n it a r e a a g r e a te r number of stom ata than
o ld e r o n es, w hether one c o n sid e rs th e h e a lth y o r m o sa ic -in fe c te d
p la n ts * . The d is e a s e d le a v e s have tw ice a s many a s th e h ealth y *

A

d e te rm in a tio n of th e s iz e of th e opening between the guard c e l l s was
atte m p ted b u t because o f the uneveness of th e su rfa c e and the
abundance o f h a ir s p r e s e n t on th e s u rfa c e of th e l e a f no s a ti s f a c to r y
r e s u l t s w ere obtained*

T his in fo rm a tio n i s needed because i t w il l

T a b le VIII

Number o f sto m ata p e r sq« mm* of l e a f a re a in h e a lth y and m osaici

in f e c te d p l a n t s .
H ealthy
Bandom Counts
>ia told did young

margin
o ld

Mosaic
; landom Counts
o ld o ld

11

10
22

21

11
21
11

10

11

12
12

Average 9**J 9*7

9.g

26. g

25*5

m argin
old

-3 1 -

h e lp to d e cid e th e q u e stio n of w hether o r n ot th e g r e a t e r r a t e o f
t r a n s p i r a t i o n i s due to th e g r e a te r number o f stom ata*

H arriso n (12)

r e p o rte d in th e c a se of bean mosaic th a t th e re was a re d u c tio n in
t r a n s p i r a t i o n , and acco u n ted f o r t h i s re d u c tio n by d em o n stratin g a
d e c re a se i n th e number of fu n c tio n in g stomata*

In f a c t he found many

sto m ata c lo s e d , a lth o u g h th e number d id not vary in th e two s o r t s of
p la n ts *

The in c re a s e d number of stom ata on th e ra sp b e rry m osaic-

in f e c te d l e a f may be accounted f o r by the f a c t th a t th e l e a f i s sm a lle r
th a n a h e a lth y one and th e r e fo r e more stom ata a r e c o lle c te d in a u n i t
o f a r e a th a n on a w e ll expanded h e a lth y le a f*

I t i s a w ell known f a c t

t h a t the d is e a s e d le a v e s a r e somewhat dwarfed*
V II.

C hlorophyll

A com parative stu d y of th e c h lo ro p h y ll c o n te n t of th e le a v e s
o f th e th r e e s o r t s o f p l a n ts was made*

In appearance, the d ise a se d

c o n d itio n i s accompanied w ith m o ttlin g of th e leav es*
b lis te re d

There a re

a re a s in which th e t i s s u e i s a d a rk e r green than th e normal

and th e r e a r e o th e r a r e a s in which th e t i s s u e s a r e a p a le g re e n .
th e s e s tu d ie d the e n t i r e l e a f was taken*

In

To s e p a ra te th e g reen p o r tio n s

from th e p a le g reen in any one l e a f was u n c a lle d f o r a t t h i s time*
The masked p l a n t s , on c a s u a l o b s e rv a tio n , d id n o t lo o k very d if f e r e n t
from th e h e a lth y b u t a s one can see from th e ta b le they c o n tain ed more
c h lo ro p h y ll*
P e te rs o n (27) in 1931 found a re d u c tio n of c h lo ro p h y ll in m osaicin f e c te d to b acco .

C h lo ro p la sts in le a v e s of m o sa ic -in fe c te d p la n ts

have been s tu d ie d and th e changes noted b u t l i t t l e o r no knowledge i s

-3 2 -

o b ta in a b le on th e c h lo ro p h y ll c o n te n t and i t s p o s s ib le v a r ia tio n
i n d is e a s e d and h e a lth y p l a n t s .

In connection w ith th e d ise a se d

p l a n t 's reduced p h o to s y n th e tic a c t i v i t y , one m ight expect a re ­
d u c tio n i n c h lo ro p h y ll c o n te n t.

However, reduced p h o to s y n th e tic

a c t i v i t y might j u s t a s w ell b e due to accum ulation of p ro d u c ts o r
some o th e r c o n d itio n .
The c h lo ro p h y ll c o n te n t o f le a v e s was determ ined by th e
method d e s c rib e d by U lv in (39)*

The c o lo r im e tr ic method of ch lo ro ­

p h y ll d e te rm in a tio n was s e le c te d .

The r e s u l t s a r e g iv en in m i l l i ­

grams of c h lo ro p h y ll p e r 100 sq u are c e n tim e te rs of l e a f a re a and
a r e n o te d in t a b le IX.
A stu d y o f t h i s ta b le shows th a t the m o sa ic -in fe c te d le a v e s
c o n ta in e d ap p ro x im ately 12 p e r c e n t more c h lo ro p h y ll than th e healthy*
The le a v e s of th e masked p la n ts a ls o p o ssessed about 11 p e r cen t
more c h lo r o p h y ll.

These r e s u l t s do not ag ree w ith th o se of P e te rso n

(27) and were unex p ected and a l i t t l e s u r p r is in g .

The experim ents

were re p e a te d in a d i f f e r e n t season and th e same g e n e ra l r e s u l t s
were o b ta in e d .
c a n t.

The p e rc e n ta g e in c re a s e i s n o t g r e a t b u t i s s i g n i f i ­

A p o s s ib le e x p la n a tio n i s advanced a s a r e s u l t o f some c y to lo g i-

c a l s tu d ie s of d is e a s e d le a f t i s s u e .

The m o sa ic -in fe c te d le a v e s have

a p a le g reen c o lo r and in some sp o ts a r e alm ost y ello w , b u t a l t e r n a t ­
in g w ith th e se a r e a s a r e o th e r numerous, r a is e d o r b l i s t e r e d a re a s
t h a t a r e v ery d ark g ree n in c o lo r .

A m icro sco p ical study of s e c tio n s

in th e se b l i s t e r e d a re a s show two o r th re e e x tr a la y e r s of p a lis a d e
c e l l s , a l l o f which c o n ta in numerous p l a s t i d s .

These e x tr a c e l l s

a r e a p p a re n tly p l e n t i f u l enough to g iv e the d is e a s e d le a v e s more

-3 3 -

T able IX
F re sh w e ig h t, t o t a l c h lo ro p h y ll and c h lo ro p h y ll p e r 100 sq .
cm. in le a v e s of h e a lth y masked and m o sa ic -in fe c te d p la n ts*

P la n t

P re s h
Wt. Gm*

Area
Cm.^

* d 100

C hlorophyll C hlorophyll
100 Cm5
mg.

H ealthy

8.127

32k

2*$k

S .9U

2.76

H ealthy

5-132

322

1.60

7-96

2 .^7

Masked

H.152

20k

2*07

6.30

3-15

Masked

iuoi&

196

2.02

5-59

2.79

Mosaic

3-301

2.20

U.7S

3-1S

Mosaic

3-35S

2.09

U.78

2.98

162

Average
«
C h io r/100 Cm

R atio

2.61

100

2.97

111

3-08

112

-3 ^

c h lo ro p h y ll th a n h e a lth y o n es.

B ennett ( 3) s t a t e s th a t th e s e v e re ly

a f f e c te d v a r i e t i e s o f re d r a s p b e r r ie s “show a f in e - g r a in e d p a tt e r n o f
m o ttlin g c o n s is tin g o f sm all yellow sp o ts stir rounded hy t i s s u e of
d eep er g ree n c o lo r .

Leaves in g e n e ra l a r e d eep er green th an a re

le a v e s o f h e a lth y p la n t s . ** U n til f u r t h e r work i s done no d e f i n it e
c o n c lu s io n , p e rh a p s , should be drawn though th e two t e s t s a re in d ic a ­
t i v e o f a sm all in c r e a s e in c h lo ro p h y ll in th e m o sa ic -in fe c te d le a v e s .
V I II .

Leaf Ash S tu d ie s

Rao and S re e n iv a ssa y a (29) made a study o f th e a s h of h e a lth y
and “ sp ik e d 1* san d al and found l e s s calcium and potassium in “spiked**
t i s s u e th an in h e a lth y , b u t th e w r ite r has been unable to f in d any
f u r t h e r l i t e r a t u r e on a s h a n a ly s is in h e a lth y and m o sa ic -in fe c te d
tis s u e s .

Only one s e t o f t e s t s was made w ith ra sp b e rry p la n ts and

f u r t h e r work should be done to c le a r up d is c re p a n c ie s and e s ta b li s h
t e n t a t i v e c o n c lu s io n s .

Leaves of h e a lth y , masked, and m o sa ic -in fe c t­

ed re d ra s p b e rry p la n ts were c o lle c te d s e p a r a te ly and ash ed .
in g tem p eratu re was ap p ro x im ately 550° C.

The a sh ­

The same method was fo llo w ­

ed a s t h a t u sed s u c c e s s fu lly in a n o th e r p r o j e c t >n o t y e t r e p o rte d .
The elem ents (Ca, P e, My* P* and X) in the a s h were determ ined
by th e s p e c tro g ra p h ic method and th e t e s t s were made under th e d ir e c tio n
of P r o fe s s o r D. T. Ewing o f the Chem istry Department of t h i s I n s t i t u t i o n .
The d a ta may b e found in ta b le X.
th e d ry w eight b a s i s .

The p e r cen t o f a sh i s c a lc u la te d on

I t may be observed from a study of th e ta b le

th a t th e a fte rn o o n f ig u r e s a re low er than th e morning f ig u r e s , in d ic a t­
in g th a t p o s s ib ly a d iu rn a l v a r ia tio n in s a l t c o n te n t e x i s t s .

-3 5 -

f a b le X
Dry w eig h t, w eight of a s h , p e r c e n t ash and m in erals p re s e n t
in a sh of le a v e s from h e a lth y , masked and is o s a io in f e c te d p la n ts*

P la n t

Dry Wt.

H ealtby A.M.

0.463 gm 9.57

10.7$

4 .$

3.7$

3 . ¥ 16.056

1 5.6

6 .1

3 .6

2 .4

15.3

3.3^3

8. 1J0

Masked A.M.

2.716

.269

9.90

6 .3

4 .7

3 .0

3 .4

19.0

P.M.

3.117

♦284

9.11

2 .9

* .3

3 .1

2 .4

18.0

A.M.

3.111

.290

9 .3 2

1 0 .5

5 .0

5 .3

3 .7

17.3

P . M.

2.687

.232

s . 63

7 .2

3 .2

3 .5

2 .4

17.3

CVJ

P.M.

r< ~ \

^Element 100$ of. Ash
Mg.
F e.
Ua.

.

«

4 .8 3 4 gm*

Wt. Ash $ Ash

•

n
Mosaic
R

♦Large q u a n t i t i e s of s i l i c o n were found in a l l p l a n t s .

-3 6 -

P otassium i s more abundant than any o th e r elem ent and ir o n
i s th e l e a s t p l e n t i f u l *
abundant*

Calcium fo llo w s potassium a s th e n e x t most

When d is e a s e d and h e a lth y p la n ts a r e compared i t i s obvious

t h a t th e r e i s l e s s calcium and more potassium in m o sa ic -in fe c te d
leav es*

The d if f e r e n c e i s n o t g r e a t and may n o t be s ig n i f i c a n t b u t

i f p o tassiu m o r calcium p la y any im portant r o le s in p h o to sy n th e s is a s
some th in k ( th e se s tu d ie s do n o t b e a r out such conclusions*

One

would e x p e c t to f in d g r e a t e r q u a n titi e s of th e s e elem ents in p la n ts
where p h o to sy n th e s is o ccu rs most r a p id ly or in t h i s case in th e h e a lth y
p la n ts *

S in ce magnesium i s an i n te g r a l p a r t of th e c h lo ro p h y ll

m o lecu le, an d s in c e th e c h lo ro p h y ll c o n te n t of d ise a se d p la n ts i s
a p p re c ia b ly h ig h e r, one might a s p e c t a h ig h e r c o n te n t of magnesium,
b u t th e r e i s h a rd ly a d iffe re n c e betw een the h e a lth y and d ise a se d in
t h i s re s p e c t*

W o lf's (U3) numerous ta b le s do n o t in clu d e d a ta on

th e ra s p b e rry and th e w r i te r has n o t been su c c e ss fu l in fin d in g in
th e l i t e r a t u r e any f ig u r e s on th e elem ents p re s e n t i n th e re sp b e rry
p la n t*

An abundance o f s i l i c o n was found*

In f a c t i t i n t e r f e r r e d

a t f i r s t i n th e p r e p a r a tio n of sam ples f o r sp e c tro g ra p h ic a n a ly s is ,
b u t th e q u a n tity o b ta in e d was n o t determined*

More study should be

g iv en to th e a s h c o n te n t of th e ra sp b e rry l e a f and s e v e ra l t e s t s
should be conducted b e fo re d e f i n it e co n clu sio n s a r e drawn*
IX,

D iscu ssio n

I t has been known f o r many y e a rs th a t when a ra s p b e rry p la n t­
in g becomes in fe c te d w ith mosaic th e p la n ts g ra d u a lly d e c lin e in
p r o d u c tiv ity and th e p la n tin g i s u s u a lly d e sc rib e d a s having "run out"*

~ The d a ta p re s e n te d i n t h i s paper may be in te r p r e te d in th e main a s
o f f e r in g an e x p la n a tio n f o r th is "running out" o f p la n tin g s of
s u s c e p ta b le v a r i e t ie s *
I t i s shown th a t p ro d u c tio n of carb o h y d rates i s reduced by
th e p re se n c e of th e v i r u s and th a t i t s in flu e n c e upon p h o to sy n th e s is
i s ev id en t*

N a tu ra lly t h i s le a d s to a d ecrease in th e supply o f re ­

s e rv e s s to r e d i n th e ro o ts to be u sed in th e su cceeding crop of f r u i t
and new c a n e s .

P ro g re s s iv e dw arfing of the canes produced each y e a r

i n an in f e c te d p la n tin g b e a rs out th e s e o b serv atio n s*

The fo rm atio n

of f r u i t o f poor q u a l i t y and f la v o r i s a ls o a t t r i b u t a b l e to a reduc­
tio n i n p h o to sy n th e sis*

In a d d itio n to a re d u c tio n i n d ecrease in

c a rb o h y d rate m an u factu re, i t has a ls o been p o s s ib le to show th a t
r e s p i r a t i o n i s g r e a t l y in creased *

A high r e s p ir a to r y r a te in d ic a te s

t h a t th e p ro d u c ts of p h o to sy n th e s is a re b ein g used up much more rap id ­
l y i n th e m o sa ic -in fe c te d p la n ts*

The v i r u s ,p e rh a p s i s w a ste fu l of

th e s to r e d energy o f th e d ise a se d p la n t*

This ra p id r e le a s e of energy

to g e th e r w ith th e d e c re a se in r a t e of fo rm atio n of r e s p ir a b le m a te ria l
soon le a d s to s ta r v a t i o n and e v e n tu a lly death*

The s c a r c ity o f s ta r c h

in d is e a s e d le a v e s i s one in c id e n t a t l e a s t of s ta r v a tio n co n d itio n s#
S ta rc h may be co n sid e re d as one of the re se rv e forms of carb o h y d rate
and in t h i s case th e sim ple m a te r ia ls a r e not co n v erted in to s ta r c h
o r i f s ta r c h i s form ed i t i s soon hydrolyzed to produce r e s p ir a b le
sim ple su g a rs when s y n th e s is i s slowed up or in a c tiv e *

That some­

th in g o f t h i s s o r t has taken p la c e i s in d ic a te d by th e poor f r u i t i n g
h a b its of th e m o sa ic -in fe c te d p la n ts #

“ 3^"

The h ig h e r r a t e s of t r a n s p ir a tio n and th e in c re a se d number of
sto m ata p e r u n i t a r e a in d ise a se d le a v e s in d ic a te th a t th e w ater
r e l a t i o n s of th e p l a n t a r e s e r io u s ly a f f e c te d by th e p resen ce of th e
v iru s *

I t i s a w e ll known f a c t th a t th e f r u i t s from m o sa ic -in fe c te d

p la n ts a r e seed y , d ry and te n d to crumble when h arvested*

T his con­

d i t i o n may be b ro u g h t about by th e i n a b i l i t y of th e p la n ts to m ain tain
a p ro p e r w ate r balance*

Under fa v o ra b le c o n d itio n s , th e poor c o n tro l

of w a ter b a la n c e may n o t be e v id e n t n o r a c t as a d e trim e n ta l f a c t o r ,
b u t when s e a so n a l c o n d itio n s and tem p eratu res a re u n fav o rab le and th e
supply of m o istu re i s lim ite d , th en m o sa ic -in fe c te d p la n ts e x h ib it
t h e i r in e f f ic ie n c y in w ater c o n serv atio n by p roducing f r u i t o f poor
q u a lity *
The r e s u l t s g a th e re d so f a r in t h i s study b r in g t o o n e 's -■
a t t e n t i o n c e r t a i n im p o rtan t d if f e r e n c e s in th e physio lo g y of th e th re e
s o rts of p la n ts .

They c o n s titu te sig n p o s ts or g u id es in th e study

of th e cau ses u n d e rly in g th e se d iff e r e n c e s and p o s s ib ly p o in t o u t a
method o f c o rre c tio n o r c o n tr o l.

Enzymatic a c t i v i t y o r i n a c t i v i t y

seem to" p la y th e m ajor r o le and th is phase i s to be s tr e s s e d in f u tu r e
work*
No method of c o n tr o llin g mosaic d is e a s e s o th e r than roguing o r producing d i s e a s e - r e s i s t a n t form s has been found.

B roadly speak­

in g , once a p l a n t i s in f e c te d i t can n o t be c u red .

Claims have been

made t h a t p l a n t s o c c a s io n a lly re c o v e r from a tta c k .

S to rey (2) r e p o rt­

ed rec o v e ry of sugar cane from th e s tr e a k d is e a s e and Robbins (31)
has d e s c rib e d th e rec o v e ry of s u g a r-b e e ts from m osaic.

In many of

-39-

th e s e r e p o rte d c a s e s , i t has heen shown t h a t th e cu re was an in s ta n c e
o f a m asking of th e symptoms.

W ilhrink (^2) h as d e s c rib e d a method

o f c u re f o r d is e a s e d su g ar-can e c u ttin g s by tre a tm e n t w ith h ot water*
Kunkel ( 22) found t h a t a h e a t tre a tm e n t was a cu re f o r c e r ta in v ir u s
d is e a s e o f th e p e a c h .

Masking in th e ra sp b e rry i s r e la te d to th e

tem p era tu re a t which th e p la n ts a re grown, and a study of th e p o s s i­
b i l i t y of c u rin g re d ra sp b e rry mosaic by a h e a t tre a tm e n t might w ell
b e made*

Summary
T h is p ap er r e p o r ts th e r e s u l t s of in v e s tig a tio n s d e a lin g
w ith th e p h y s io lo g ic a l a c t i v i t i e s of h e a lth y , masked, and m osaicin f e c te d r a s p b e r r i e s .

The s tu d ie s were confined to th e Latham

v a r i e t y i n f e c te d w ith th e re d ra s p b e rry mosaic*
A nalyses of th e le a v e s f o r v a rio u s carb o h y d rate f r a c tio n s
were made.

A d e c re a se i n sim ple sugars and s ta rc h e s occurs in th e

mosaic an d masked p l a n t s .

Sucrose occu rred in in c re a s e d amounts in

m o sa ic -in fe c te d p la n ts *
D i a s ta ti c a c t i v i t y was s tu d ie d and appears to be a c c e le r a te d
in p l a n t s e x h ib itin g th e m osaic symptoms*
P h o to s y n th e tic a c t i v i t y and r e s p ir a to r y r a t e were determ ined
by th e C o ^ ,a b so rp tio n m ethod.

P h o to sy n th e sis was decreased in p l a n ts

showing marked symptoms o f d isease*
R e s p ira tio n p ro ceed s a t a h ig h e r r a te in d ise a se d tis s u e
r e g a r d le s s of w hether th e symptoms a re masked o r evident*

-H oln ex p erim en ts where s ta n d a rd iz e d hygrom etric p ap er was used
to d eterm in e th e q u a n tity o f t r a n s p i r a t io n , i t was found th a t a h ig h e r
r a t e o f w a te r l o s s was e x h ib ite d by th e le a v e s of m o sa ic -in fe c te d
p la n ts *
An in c r e a s e in th e number of stom ata p e r u n i t a r e a of l e a f
t i s s u e p ro b a b ly acco u n ts f o r th e h ig h e r r a t e of t r a n s p i r a tio n in th e
d is e a s e d le a f *
C h lo ro p h y ll d e te rm in a tio n s show a g r e a te r amount of c h lo ro p h y ll
p e r -unit a r e a o f l e a f in th e m o sa ic -in fe c te d p la n ts*
Ash a n a ly s e s o f th e le a v e s of th e d if f e r e n t p la n t s were made
by th e s p e c tro g ra p h ic method*

T his one t e s t in d ic a te d a h ig h amount

o f s i l i c o n , a g r e a t e r p e r c e n t of ash i n th e morning m a te ria l th an
t h a t in th e m a te ria l g a th e re d in th e even in g , a low er calcium c o n te n t
and a s l i g h t l y h ig h e r p e r c en t of potassium in th e d ise a se d tis s u e s *

- H l-

L l t e ra tu re C ited
1*

B arto n —W right, E*, and Alan McBain.
th e v i r u s d is e a s e s of th e p o ta to :

S tu d ie s in th e p h y sio lo g y of
A Comparison of th e C arbohydrate

m etabolism o f normal w ith t h a t of c r in k le p o ta to e s to g e th e r w ith
some o b s e rv a tio n s on carb o h y d rate metabolism in a c a r r i e r v a rie ty *
Ann. Appl* B i o l . 20:
2*

B a rto n -W rig h t, E,

526- 51*8 .

Recent Advances in B otany.

and C o ., I n c ., P h ila d e lp h ia .
3* B e n n e tt, C. W.

1933.
P , B la k is to n ’ s Son

1932.

V iru s d is e a s e s of r a s p b e r r ie s .

Mich. Agr. Exp*

S t a . , Tech. B u i. SO. 1927.
H.

B e rtra n d , 0 . Le dosage des su c re s re d u c te u rs .
s e r. 3.

5*

1285-1299*

1906*

B o la s , B ernard and W. P . Bewley.
to m ato.

A n o te on m etabolism .

6* B o la s , B. D. and R. M e lv ille .

Aucuba o r y ello w mosaic of th e
N ature 126: *+71.

7.

193° ♦

The in flu e n c e of environm ent on th e

grow th and m etabolism o f th e tom ato p l a n t .
and p re lim in a iy r e s u l t s .

B u ll. Soc. Chim*,

Ann. B o t.

I

Methods, tech n iq u e

673- 688.

1933*

B rew er, P . H ., James B. K endrick and Max W. G ardner.

E f f e c t of

m osaic on carb o h y d rate and n itro g e n c o n te n t of th e tomato p l a n t .
P h y to p ath 16: 8H3- 851.
g.

Cook, M. T.

1926*

P h o to sy n th e s is of th e sugar cane mosaic p l a n t .

D ept. A g r., P o rto Rico 10: 239-2^2.
9.
10*

C ooley, L. M.
HH-55. 1936.

1926,

The i d e n t i t y of ra sp b e rry m osaic.

D a s tu r, R. H. and B. L. D esai.

Jour*

P h y to p ath . 26:

The r e la tio n between w ater c o n te n t,

c h lo ro p h y ll c o n te n t and th e r a t e of p h o to sy n th e sis in some t r o p i c a l
p la n ts a t d i f f e r e n t te m p e ra tu re s.

Ann. B o t.

69- 88.

1933*

-H a ­
il.

D av is, W. H.

12.

D etm ers, P .

L aeto p h en o l.

B o t. Gaz. ]]± 3H3- 3UH.

D ise ase s o f th e ra sp b e rry and b la c k b e rry .

Exp. S ta . Ann. B p t. 10: 128-129*
13*

D ickson, B. T .

lH .

D nfrenay, J e a n .

S tu d ie s on m osaic.

P hytopath 11: HH6-H58.

Bev. P a th . Compt*

1931.

The t o t a l n itro g e n and carb o h y d ra te s and th e r e l a t iv e

r a t e s o f r e s p i r a t i o n in v iru s a f f e c te d p l a n t s .

16.

3H8-357.

_______________ •

Green S . B.

C arbohydrate v a r ia tio n accompanying th e m osaic
Amer. J o u r. B o t. 12s

N. Y. S ta te A gr.

1935*

H e in ick e, A. G. an d M. B. Hoffman.

The r a te of p h o to sy n th e s is o f

th e ap p le u n d er n a t u r a l c o n d itio n s .

C ornell A gr. Exp. S ta . B u l l.

577.
20.

1931*

1895*

H a rris o n , A rth u r L. The p h y sio lo g y of bean m osaic.
Exp. S ta . Tech. B u i. 235.

19.

328- 336.

Cane r u s t of r a s p b e r rie s (a n th racn o se) Minn. A g ric .

Exp. Sta* Ann. R e p t. IS9H: 230.
18.

Amer. J o u r. Bot*

1930.

d is e a s e o f to b ac co .
17.

1933.

H euberger, J . W. and J . B. S. N orton.

The mosaic d is e a s e s o f

to m ato es. Md. A gr. Exp. S ta . B u i. 3H5 S P a r t I , HH7-H86.
21.

H ib b ard , R. P .,B u fo rd H.G rigsby and G. W. Keck.

K unkle, L. 0 .
p ea ch .

1933*

A low l i g h t i n t e n s i t y

p h o to e le c tr ic d e v ic e f o r th e d e te rm in a tio n of l e a f a r e a s .
22.

1921.

La r e te n tio n de l 'e a u p a r l a c e l l u l e v e g e ta le s

e t Hyg. Gen. 3 1 : 212-223.
19* D unlap, A. A.

Ohio A g ric.

1891.

M aladies d'hypotom e e t m aladies d ’hypertom ie.

11s

I 92H.

(In p r in t.)

Heat tre atm e n t f o r th e c u re of yellow and r o s e t t e o f

P h y to p ath I , 25:

2H.

1935*

23*

L iv in g s to n , B. E* and E. B. Sh r eve.

Improvements in th e method

f o r d eterm in in g th e tr a n s p ir in g power o f p l a n t s u rfa c e s by
h y g ro m etrlc p a p e r.
2U,

Long, F . L , and P , E. Clem ents,
f o r sto m ato ,

25*

P la n t World l ^ j 287- 309.

Amer,

Meyer, B ern ard S ,

The method o f c o llo d io n film s

J o u r. B o t, 21: 7-17*

26,

502-591*

N euw irth, F ,
Z e its c h ,

27,

The measurement o f th e r a t e of w ater-v ap o r
Amer, J o u r. B o t,

1927.
B e itr a g zur K enntnis des Ohefl&che d e r Rttbe.

Z u ck erin d .

P e te rs o n , P . D,

Czech,

Republ.

^

j 3U I-3U9 .

28,

119*

P h y to p ath

1951#

R ankin, W, H. and J , P . Hockey,
o f th e c u ltiv a te d r a s p b e rry .

29*

1929-30,

P l a s t i d pigm ent and c h lo ro p h y lla se c o n te n ts

of tobacco a s in flu e n c e d by th re e types of m osaic.
21:

'

1931*,

l o s s from le a v e s under sta n d a rd c o n d itio n s ,
lb :

1916,

Mosaic and l e a f c u r l (yellow s)

Phytopath 12:

Bao, D. A, Roma and M. G reenivasaya.
of Spike D isease of S andal.

253-26ty,

1922*

C o n trib u tio n s to th e stu d y

P art I? .

Chemical com position o f

h e a lth y and sp ik ed sandal stem s, Jour* In d ia n I n s t , S c i. 11A;
2U I-2U3.
30.

1928,

(Authors* summary in B io l. A b s ts, H: 3^1*

R eport o f th e Committee on Methods of Chemical A n aly sis f o r th e
American S o c ie ty o f P la n t P h y s io lo g is ts .
195 - 20K 297-b02.

31.

R obbins, W. W.
3U9- 365.

32.

1930*)

P I . P h y s io l. 2:

91-97*

1927*

Mosaic d is e a s e s of sugar b e e t s .

Phytopath* 11:

1921,

Rosa, J . T,

Chemical changes accompanying th e w estern y ello w

b l i g h t of tom ato,

P I . P h y s io l. 2:

163- 169.

1927*

-4 4 -

33*

S m ith, Kenneth M.

R ecent advances in th e stu d y of p la n t v ir u s e s .

P . B la k is to n * s Son and C o., P h ila d e lp h ia ,
34*

S re e n iv a sa y a , M.
album .

35•

Masking of sp ik e d ise a se symptoms in Santalum

N ature 126?

S t a h l , E.

1934*

957,

(1930)

E in ig e Yersuche u b e r T ra n s p ira tio n und A s s im ila tio n ,

B o t. Z e i t . 5 2 :

117-146.

36* S to n e, Winona E.

1S94.

Growth, chem ical com position and e f f ic ie n c y of

norm al and m osaic p o ta to p la n ts in the f i e l d .

J o u r.

A gr. R es.

295-309. 1936.
37* S to re y , H. H.
38.

( i n B arton-W right (2) )

T ru e, R. H. and L. A. Hawkins.
and b lig h te d s p in a c h .

39*

U lv in , Geo. B.
c o n d itio n s .

40. W hitehead, T.

W ilcox, R. B.

P I . P h y s io l.

1918.

59-82.

1934*

R e s p ira tio n o f h e a lth y and l e a f r o l l p o ta to e s .
1931.

O b serv atio n s on masking of ra s p b e rry m osaic by

h ig h te m p e ra tu re .
4 2 . W ilt;rin k , G.

J o u r . A gr. R es. 15? 381-384.

C hlorophyll p ro d u c tio n under v a rio u s environm ental

N atu re 128: 967.
41.

C arbohydrate p ro d u ctio n in h e a lth y

P hy topath 16:

SO.

1926.

Warmwaterbehandlung van stekken a l s geneesm iddel

teg en de s e rc h z ie k te van h e t s u i k e r r i e t . A rch. S u ik e rin d u s.
N ederland - I n d i8 , Meded. P r o e f s t. Ja v a S u ik e rin d u s. JL: 1 - 15. 1923*
43.

W olf, E. V.

A schenanalysen von la n d w irts c h a ftlic h e n Produkten

usw. B e r lin : P . P arey I T e il 1871. I I . T e il 1SS0.

F ig u re 1*

T y p ic a l l e a f of th e Latham v a r ie ty in f e c te d w ith

re d ra s p b e rry m osaic.

F ig u re 2»

H ealthy and mosaic in f e c te d le a v e s of th e Latham v a rie ty *

A. Mosaic in fe c te d *

B. H ealthy

F ig u re 3*
o p e r a tio n .

A b so rp tio n u n i t and a s s im ila tio n chambers a s s e t up f o r
A* C e llu lo id a s s im ila tio n chamber*

F ig u re

P h o to e le c tr ic l e a f a re a ap paratus*

m

\