THE HYDROCYANIC ACID CONTENT
OF SUDAN GRASS

Thesis for the Degree of M. 5.
Lawrence. C. Walker
1935

 

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THE HYDROCYAKIC ACID CONTENT

O F SUD.” If C-RAS S

.A Thesis Submitted to

the Faculty of

I‘IICIITGAIT TATE COLLEGE
OF

AGRICULTURE AND APPLIED SCEHCE

in Partial Fulfillment of the Requirements

for the Degree 0; Master of Science

LAWRENCE C. WALKER

M

September, 1955

 

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appreolation to Prozess r C. D. Ball, whos

dance and helpful SlaVGStiOHS have made

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the completion 0? th‘s work, anfl to Ir. C.

. 1‘“

and 7“. C. F. Huffman, who so kindly ooope

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furnlsnlng the mateylal useu in this proge

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e able
poss’ble
R. Iogee

rated in

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INTRODUCTION

HISTORICAL

EXPERITEITZ L
Study of Iethods

Study of Effect of

tudy of Second Cro

Effect of Stage of
Diurnal Variations

Hybrids

COILESIT

"I

Stare 0: Growth
L)

tudy of Diurnal Variations

tudy of Some Hybrids

" .

. J— .1 "
Won aha may

Growth

Second Growth and Hay

CO rTCLUS IO NS

LITERATURE CITED

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(Uh)
(DUI

 

 

INTRODUCTION

It has long been known in countries where Sorghums are
grown as forage that this crOp frequently causes the death
of cattle when they are allowed to eat it under certain
conditions. The Sorghuns have been studied extensively
and considerable work has been done on Sudan grass. There
is some confusion regarding the nomenclature of Sudan grass.
It has been given various names by different authors. It
is regarded by some botanists (l) as a separate species
under the name Sorghug sudanense, Stapf., while others (2)
consider it only a variety of Johnson grass and give it the
name S, halgpgnse var. sudananse. Hitchcock (5) in his
recent publication gives it the name S. vulgang var. sudan-
gage (Piper) Hitchc. There is also some confusion in the
reports of the work done on Sudan grass due to the fact
that most of it is reported merely as done on Sudan grass
(4, 5, 6). Some Australian workers (2) contend that pure
Sudan grass is non-poisonous but that the various Sorghum-
Sudan hybrids are poisonous. This paper will consider in
particular the poisonous properties of the commercial Sudan
grass as grown at Michigan State College. The seed for
this material was produced in Texas and obtained by the

college from the Michigan Farm Bureau.

 

HISTORICAL

Prussic acid poisoning by the various sorghums has been
studied extensively since tae early part of this century.
Poisoning by Sudan grass has been studied by comparatively
few men over a much shorter time. In considering the
history of this subject it is therefore desirable to con-
sider essentially the history of Prussic acid poisoning by
the Sorghums.

The first report of any great loss from Prussic acid
poisoning was made by Pease (7) who reported that great
numbers of cattle died from eating Sorghum in India in 1877.
The year 1877 was one of extreme drought and was followed by
the dry years of 1887 and 1895, which were also marked by
the deaths of a considerable number of cattle from the same
cause. Pease made a chemical study of the Sorghums in 1895
and came to the conclusion that the poison responsible was
nitrate of potash present in some stems to the extent of
25% and eSpecially abundant at the nodes. This observation
was contradicted in 1900 by Hiltner (8) of hebraska, who
found that in most if not all cases there is not sufficient
potassium nitrate present to produce the observed effects.
He failed, however, to find the Prussic acid and came to the
conclusion that the toxic effect which manifested itself at
times was not due to a chemical poison inherent in the plant.

The fact that Prussic acid is present in the Sorghuns

 

 

was first reported in 1902 by Dunstan and Henry (9). In the
same year Slade (10) suggested that a highly poisonous
chemical compound might be produced by the action of an
enzyme on a glycoside formed in a plant through a process

of abnormal growth. Slade actually isolated Prussic acid
from a sample of Sorghum late in 1002. Further work by
Avery and Peters (11) conclusively proved that Prussic acid
was the direct cause of Sorghum poisoning.

That Prussic acid poisoning is common in practically
all Sorghum producing countries is evidenced by reports
from Australia, Africa, Italy, China, Japan, Java, India,
the West Indies, the Phillipines, EurOpe, and America.
Actual accurate figures as to the number of deaths are not
ayailable, but Eiltner (8) states that 144 fatal cases were
reported in a single year but unquestionably this represents
only a small proportion.

Investigations by other workers have since established
the presence of the Prussic acid principle in other plants
belonging to the Sorghum family. Crawford (12) in 1906
reported it in Johnson grass. Francis (15) in 1915 reported
it in Oklahoma-grown Sudan grass. The wide-spread occurrence
of hydrocyanic acid in nature is illustrated by two papers
by Rosenthaler (14) in which he lists 410 species, 148
genera, and 41 families as containing the poisonous principle.

The form in which the hydrocyanic acid occurs in the
plant has been the subject of research by many workers.

Slade (10) in 1901 suggested that the poisonous principle,

 

then unknown, was produced by the action of an enzyme on a
glycoside.

Avery (ll) concluded from his work that it was evident
that the hydrocyanic acid did not occur in a free state but
rather in a combined form, probably as a glycoside as
suggested by Slade. The conclusion of Avery was confirmed
by Dunstan and Henry (9) who isolated dhurin, a glucoside
readily hydrolized by the enzyme emulsin. The two English
workers and the Americans, Slade and Avery (11), and Dowell
(15) agree that the hydrocyanic acid occurs in the plant
only in the form of a glucoside which is hydrolized during
the early processes of digestion. Willaman (16), however,
contends that he Prussic acid occurs not only as a gluco-
side but also uncombined or in a loosely combined form.
Willaman has some support for this theory in the work of the

talians, Ravenna and Babini (6), who in 1909 reported the
occurrence of free hydrocyanic acid in the leaves of cherry
laurel, peach, and flax. The talians, however, qualified
their conclusions by indicating how readily a small amount
of free hydrocyanic acid could be produced by autolysis
during the progress of the experiment. Tuskunaga (17) in
1928 remarked that the amount of free hydrocyanic acid is
greater in young plants while that of combined hydrocyanic
acid becomes greater but decreases as the plant matures.
Swanson (5) in 1921 concluded that the hydrocyanic acid is

not present in the plant in the free state since it is not

 

 

Cfl

I. .9 ., J- .' A "' .- i - .1 .L' f5 -
IDVGS'l flcthS have revealed one iact

moisture, staec of lejuri ’ty, and ingury such as frost and

drought on Prussic acid content. Studies have also been

g
.

made to det-rtine the distribution of hydrocyanic acid in
the di{‘f erent parts of t;

'— ___ -. _ _O . J_ _O O - 1 1.. . r O . _' ,
‘he effect of 8011 fer ili‘y has oe;n studied by several

.‘.--

.74
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(I)
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v
b

in 1915 workir” n Sorghum

U

workers . Uillanan and

D

k

found that when grown on poor, inf rtile soil, added nitrogen

may slizhtly increase the amount of hydrocyanic acid in the

plant. With fertile so 1 and abundant nitrogen t
may not be produced. Brunnich (19), in 1905, an? Alway and
Trumbull (20), in 1909, concluded that, since fertilized
plants contained slightly more hydrocyanic acid than un-
fertil' zed plants, heavy nitrogenous soils and fa vorable
climatic conditions would increase the amount of acid.

There is some confusion in the literature regarding the
efiect of moisture on the hydrocyanic acid content of
Sorghuns. Some of t11e early work done on Sorghuns see1s to

show that Jca1t1y plow.1t s in the best growing condition con-

n 1902, came

‘0
Ho

tained the most hydroc: anic a.cid. Avery (11)
to the conclusion that stunted plants contained more Prussic
acid th«n the healthy plaz1cs. Brunnich (19), in 1905, A_wav

and Trumbull (20), in 1909, and Willanan and heat (18), in

 

1915, all reported that those plants stunted by a lack of
soil moisture conte ined less hydrocyanic acid than did the
green hea thy plants. Hilligan (21), in 1909, came to the
conclusion that atmospheric humia ity had a greater effect
on the Prussic acid content than did th soil moisture.
Swanson (5), in 1920, concluded from his data that healthy
green plwx ts contained r1ore hydrocy anic acid than hose
growing under dry conditions.

The effect of the stage of maturity has been the subject
of a great deal of researc ch and has led, as Vinall (6) says,
to almost complete agree went among farmers and chemists con-
cerning the effect of maturity on the hydrocyanic acid con- y
tent of Sorghum plants. The percentage of hydrocyanic acid
in the plants decreases steadily from the time they begin to
grow until they reach maturity if the growth is normal.
Vinall compiled in a table data from the work of Willaman,
in Minnesota, Menaul and Dowell, in Oklahoma, and Schroeder,
in Uruguay. This data illustrates very clearly the fact

‘

that the hydrocyanic acid percer tage varies 3 stated above.
Acharya (22) found, in 1955, however, that while the percent-
age decreases gradually, the total amount of hydrocyanic

increases and then rapidly

Cf

acid in the plant at firs

decreases toward maturit

‘4

The1e is a~n3arently a consensus of Opinion as to the

H

distribution of the hydrocyanic acid in Sorghum plants.

Willaman and West (18), and Breakwell (25) each came to the

rst three or four vecks the

H-

conclusion that during he f
hydrocyanic acid is concentrated in the stalk and from then
on it decreases ther but persists in decreasing percentages
in the leaves un 11 hiaturity. Swanson (5) reported 3 milar
work from which he concluded that the Prussic acid was almost
entirely in the leaves

The effect of injury on the Prussic acid content of the
Sorghums is of great interest and has been studied exten-
sively. Data presented by Vinall (6) and Acharya (22) con-
firmed the contention that there is considerable increase in
the Prussic acid content of the Sorghums due to injury or
drought. Acharya also cont-nds that too intense sunlight,
even in the presence of sufficient moisture, will fit znulste
the production of Prussic acid in the Sorghums.

Acharya, in 193 5, made a study of the variations in the
Prussic acid content of Cholam during the day. From his data
he concluded tie t the hydrocyanic acid content is least in
the morning and increases to a ma:<imum at about 2 p.m., after
which there is a gradual fall until 6 p.m. followed by
rapid decrease in the night. He adds further that tne
variation in Prussic acid content siiows a striking parallel-
131 to the variation in photo-synthetic activity and of

protein me tabolis ~1 in the plant and lends support to the

hypothesis that the formation of cyanogenic compounds is a

normal part of the protein metabolism of the plant. Henaul

and Dowell (4), in 1919, considered the subject and came to

the conclusion that the hydrocyanic acid content was higher
in the morning than in the afternoon.
0 ont en t

The qu-stion of the hydrocyanic acidAof the various
Sorghum-Sudan hybrids is of interest since there is often
considerable chance for the accidental production of such
hybrids. The work of hoodie, Ramsay and Finnemore and Cox
on this subject has been cited by meadly (2 ). Koodie (25),
in 1929, concluded that pure Sudan grass w‘s non-poisonous
and perfectly safe for feed at any stage of growth. he said
further that the Sorghum-Sudan hybrids may contain more
hydrocyanic acid than the Sorghum parent. Ramsay (26), in
1929, came to the conclusion that most hybrids were more
toxic than the Sorghum parent and that Sudan grass did not
contain enough Prussic acid to be dangerous. Finnemore and
Cox (27), in 1931, however, came to the conclusion that the
hybrids were lower in hydrocyanic acid content than the
majority of the Sorghums.

There has apparently been a consensus of Opinion that
second growth is of a higher hydrocyanic acid content than
the original growth. Menaul and Dowell (4), in 1919, pre-
sented data demonstrating this.

The effect of haying is of interest since if the Prussic
acid is removed or driven ff when the material is dried
much more Sorghum fodder can be used. Vinall (6) and Swanson

(5) agree that when Sudan grass is made into hay it is no

longer dangerous.

 

The amount of Sorghum or Sudan fodder which must be
eaten to produce fatal results varies greatly with the con-
ditions. That this is true is evident from the fact that
the hydrocyanic acid content varies greatly. It may be
influenced in varying degrees by any or all of the various
factors discussed above. The lethal dose of hydrocyanic acid
for a cow has been placed at 0.5 to 0.6 grams. On the basis
of this Vinall concludes from the data of several workers
that 7.6 pounds of green Sorghum or 18.9 pounds of fresh
Sudan grass would be necessary to produce fatal results.
This is on the basis of one hundred per cent liberation of
the hydrocyanic acid. Since a cow will eat 80 to 100 pounds
of fodder a day it is evident that Sorghum or Sudan grass of
.0164 per cent and .0066 per cent respectively, as given by
Vinall, would be extremely dangerous.

The methods of determining hydrocyanic acid have been
the subject of considerable investigation. Francis and
Connell (28), in 1915, made a comparative study of six
suggested methods:

1. The silver nitrate method in which silver cyanide is
determined gravimetrically was found to be applicable only
for amounts of l milligram or more of hydrocyanic acid.

2. The ferro ferricyanide method, in which the blue color

pared to a standard

developed is com: , was found to be appli-
cable only to amounts of more than .5 of a milligram.
5. & 4. The ammonia alum and lead acetate methods were found

to be applicable only when more than .12 of hydrocyanic acid

was present.

5. The mereurous nitrate method was purely a qualitative

method.

6. The thiocyanate colorimetric method was found to compare

favorably with the silver gravimetric method. By this

method the hydrocyanic acid is distilled into potassium

hydroxide. A portion of the distillate is treated with

ammonium sulfide, evaporated to dryness, acidified with

hydrocholoric acid, filtered and treated with ferric chloride;

the resultant cherry red color is compared with a standard.
Smith (29) is reporting the work of several collaborat-

ing chemists made the following conclusions:

1. The prussian blue colorimetric method was the longest

and most complicated of the three studied and offered the

most chance for error. It was applicable to material contain-

ing volatile halides.

2. The alkali titration method was the simplest in that it

consists in the titration of the distillate (in sodium

hydroxide) with standard silver nitrate to the first turbi-

dity. The end-point in the titration was rather difficult,

eSpecially in the presence of organic matter.

5. The acid titration method was found to be the most

accurate. I- this method the hydrocyanic acid is distilled

!

into standard silver nitrate, the silver cyanide filtered
off, and the excess silver nitrate is titrated with standard

pot ssiun thiocyanate. The end-point in this case was not

ideal but it was considerably better than that for the
alkali method.

Acharya (22 , in 1955, studied the three methods listed
above by Smith and came to the conclusion that the alkali
titration method was best suited for a routine analysis of
a large number of samples. Acharya used this method in his

work which will be quoted later.

{”1" 1".”‘Ifl“‘rl'\L

ax “Minnie“
The cxjeiLn,ltal pen
(1) a study of the suggested methods and a selec
of them, (2) a study of the effect of the stage of gro'tli
on the hydrocyanic acid content, (5) a study of the diurnal
variations in the hydrocyanic acid content, (4) a study of
the hydrocyanic acid content of some known hybrids, (5) a

c.

study of the hydrocyanic acid content of second growth and hay.

Study of hethods
The study of the methods resolves itself into two
iods of leteruinin

parts, (1) a study 0. the not the hydro-

cyanic acid itself, (2) a study of the application of the

J

00971flt mzter al.

rd

me thod
Three methods of determining hydrocyanic acid were
considered:

1. The Alkali Titration Lethod.

.‘M-vou- .- .

 

In this method the 1yorocyanic acid is distilled into

.‘

about 23 sodium hydroxide. The ris illate is then titrated
with 0.02 h silver nitrate until the first permanent turbi idity
appears. This method was found to be saimi factory wit

actorr when used with the distillate

U

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solutions, but unset i
from plant material. The distillate became dark colored when

titrated and this darkening made it impossible to determine

 

 

 

Under bfliS method the distillate is received in sodium

hydioxicm an“ made up to a definite volune. An alieuot por-

 

tion of the distillate is concentrated below 700 by means of
a vacuum pump and a condenser to 1 cc. or less. Freshly
prepared ferrous sulfate and a small amount of potassium
fluoride are added and the flash 9:: aus ed for 5-1OI11 nutes.
The mixture is acidified with 30% nitric acid and the blue
color develOped compared with a standard.

It was found that known amounts of potassium cyanide

could be determined accurately as shown by Table I.

TABLE I

A-LH-INAIIOE 0F HYDPOCX ’AIIC ACID BY PRUSSIAH BLLL’HETHOD

 

 

 

Trial hg_. ECIIEdggg;hw,H53 determined Per cent recovery
1 1.2506 1.2142 97.09
2 " 1.2856 102.79
3 u 1.1967 95.69
4 " .325 w 106.08
Average = 100.412

 

It was noticed that there were some variations in the
color and a considerable variation in the values determined
for the various sanples (see Table I). This method was not
used because there seemed to be considerable chance for
error and also because it is applicable only for amounts
of .5 milligram or more of hydrocyanic acid. In many cases
the amount of hydrocyanic acid in a reasonable sized sample

is considerably below .5 milligram.

 

-M-A‘ _-_..- .

5. The Acid Titration Kethod.

“

 

By his method the hydrocyanic acid is distilled into

standard silver nitrate. The distillate is filtered through

» s 3 o 17.1.: TD'+0{‘
a Goucn.cruciole and the excess Silver nitrate eAwith star dard
potassium thiocyanate usin3 ferric alum indicator.

It was found as is shown by Table II that known amounts

of potassium cyanide could be determined accurately.

TABLE II

DETE *TATION 0F HYDROCYAUIC ACID BY ACID TI TRAT' ION HETHOD

 

Trial V3 HON added M3. determined Per cent recovery

 

 

 

1 2.000 2.0035 100.11
2 " 1.9175 95.88
5 " 1.9385 96.92
4 " 1.9682 “_M98.4l

Average = 97.84

 

Since the P1 ussian blue metlod was not applicable to
amounts of less than .5 milligram the acid titration method
was tried with plant material. The material was produced in

he Botany green house by the courtesy of Ir. Beeskow.

Two methods of preparing the sample for distillation
were considered:

1. The Keghpd of Acharya (22).

 

By this method the sanple was cut up and ground in an

iron mortar and extracted with water until the volume of the

 

extract was 1000 cc. The pulp was then placed in a flask
and covere:l tith water and both were allowed to stand 24
hours. Then the pulp and 500 cc. of the extract were
distilled and the hydrocyanic acid content determined. The
second half of the extract was allowed to stand another 24
hours and then distilled. If this portion was found to give
a higher value that value was used and the total hydrocyanic
acid content of the sample calculated.

This method was checked and discarded since as Table
III shows there was no hydrocyanic acid left in the pulp

and there was practically no dif ence between the two

portions of the extract.

TABLE III
11:13 DHTT‘T'II'AT 01? T HCN BY TILT I13 TIIOD OF ACIIAR IA (22)

&

_— u.--” m

 

Sample hilligrans of HG?
PUlP 24 hour 43 hour
filtrate filtrate

 

1 - .864 .864
2 - .567 .562
5 - ' .657 .648
4 - .648 .621

From the results obtained it was decided that this
method of preparation was not necessary.

2. The hethod of the -ssoci iation of Of ic is 1 A3 ricultupal

Chemists (50L;

In this method it was suggested that the sample be

 

 

ground to p ss a 20—mesh sieve, placed in a Kjeldahl flask

with 100 cc. of water and macerated two hours at room

temperature. Another 100 cc. of water was then added and

the mixture was steam distilled into acidified silver nitrate.
Since there was such a discrepancy between the macer-

s a series of

(,3;

ation periods suggested by the two metho

_.._‘_._AA-

analyses at various intervals of time was made. For this
work dried material from one of the Dairy Department pasture

fields was used. The results are given in Table IV.

TABLE IV

THE DETERIIHATICH 0F HYDROCYAHIC ACID AFTER VARYING PERIODS
OF HACERATION.

 

 

Sample Time of Raceration M3. HON Determined
1 0 hrs. .615
2 2 .648
5 4 .657
4 6 .669
5 8 .675
6 12 .648
7 16 .652
8 20 .585
9 24 .702

 

 

fi‘.-- -- —.

This data indicated that the hydralysis was probably complete

od.

H-

after a two-hour maceration per

In orde to make a thorough check of the methods

selected a series of determinations was made in which
potassiumc cyanide was added to tie plant material and then

Table V.

I«

determined. The results oe6ained are presented

TABLE V

RECOVERY OF ADDED HYDROCET TIC ACID (AS KCK)

 

-‘a..-.-..~-a..—.—--.-.—.a-..-- --- - .o-d - - non.- «n--—-‘. ‘ ‘ ‘m‘-—.--”-—O . - -.-‘-—~.---.-—.—.—--.-

Trial M3. HON 1.13. in check Total in H3. Per Cent
added manple est sample recovered re overed

 

~..-... --o.m.-. - ‘U’--—.---—. --.~.'-—. .. o- 3-. -- no --_ -..---4 -- -. — on- ”v—Q—..~._. -.--~.—--- .— .— “c.

.7852 .756 1.1772 .4212 109.54

 

NH

.8586 1.2096 .5510 91.12

.9072 .5456 89.72

C4
CT]
I”)
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0)

I45
.Q
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0
+15
03
H
(n
gs.

1.5

Cw
C}
N)

O
«a -q
. (2]
' (Q
C)

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C )

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O
“5‘

 

5 .7704 .6264 1.4256 . 992 105.74
Average = 97 99

 

This data was considered sufficient to warrant the use

a ’ 0

nd tne meth d of the AsIociat ion 01

’63

Cid titration

O
“3
tr
go
{3

O

eial Agricultural Chemists in the rest of the work

reiorted here. The method of the Association of Official
lgricultural Chemists was weed with some slight variations.

‘

The sample was cut in small pieces and ground in an iron

mortar. A one liter round bottomed flask was used instead

3.

of a Kjeldahl and 500 cc. I mt ad of 200 cc. of water was

added to the sample.

Efiect of Stare of Growth
aterial lor the stuev of his subject was taken from

the first dairy p886ure field.

,3

 

 

A complete series of analvses was made from the time the
material was 5-5 inches tall until it was 50 inches tall and

headed out. All samples were taken at 10 a.3. The plants

ct-
iv!
,_2
CD

were cut close to the ground and tahen immediately to

‘
O

‘ _.‘ . ‘ w,- -v L VI' . L .2 fl -.n ,"q ‘\ .
where tnex were CUb up H16h sci-sore and n1

.J

laboratory ced.

l I

From this material samples to be distilled and for dry

weight were weighed out. Ten plants were also measured

and weighed aid th

(D

average taken. The samples for dry

‘

weight were dried to a constant weight at 100 degrees
centicrade in a vacuum oven. The data obtained is presented
in Table VI, and Fig. 1. The number of milligrams per 100

plants was calculated from the average weight per plant and

C4

the total number of milligrams in the sample use‘.

TABLE VI

EFFECT or STAGE or GROWTH

 

 

 

 

 

 

Material Age in Height Wt./plant % HCH 55cm 53. HCN/
days in inches in grams fresh wt. dry wt. 100 plants
Sudan 24 5-5 .12 .01502 .0699 1.565
Grass
H 26 505-505 0125 00:14:95 .0779 1.866

" 28 4-6 1.45 .01449 .0785 2.1

N 29 5.5 .15 .0125 .0555 1.

CO

9

.26 .0158

O

o
C)
E)
Ca
C)
(3
c:

8
” 55 8.5 .42 .01099 .0765 4.575
56 12 .7 .00859 .0542 6.02

" 59 16 1.4 .00605 .0427 8.45

 

eight)

dry w

(

“CH

Cent I

Per

.07

.05

 

 

 

 

HCH per 100 plants

8

C11

0

(a

 

 

so 5b 40 5'0 6'0 '70
June 24 Age in Days July 50
F i ( ' rr‘.

)5
0°

1 - EFFECT OF STfiGR OF

0301

'|
0...

H

” HON - Dry wt. basis

Iilligrans of Hydrocyanic Acid per 100 Plants

 

TABLE VI (Continued)

 

O-u-mwo‘ - __ ‘_.A____‘A_‘ -

 

o -- —‘.’ I 7 - o 1- 77
lght Wt./plant s new p sea Lg. ch/
inches in grams fresh cut dry out 100 plants

CD

fiaterial Age in E
days in

- __‘ ‘ A.~ A ‘ L‘ _- -- 4,-

 

Sudan 41 24 5.5 .00252 .0180 8.51
Grass
" 47 51.7 6 .oooee .00526 5.15
n 50 5]. 4:06 .00048 .OOZLV 1.1.2
" 55 56.7 7.5 .000542 .ooeos 2.5
" 57 47 15.4 .000121 .00069 1.64
" 60 50 16 .000112 .ooose 1.8

Diurnal Variations
In order to obtain information on the diurnal variations
. cgngterd: ‘ .
in the hydrocyanic a01cmof Sudan grass Six series of analyses
were made. The determinations were made at two-hour inter-
vals between 6 a.m. and 6 p.m. The procedure used was as

described under Effect of Stave 01 Growth. The data

8
obtained is presented in Table VII and F's. 2. The data for
July 5, 10 and 22 represents original growth from the south-
east portion of dairy field he. 1. Laterial from dairy field
No. 5 was used July 17 and 26. Second growth material from

field No. l was used August 12.

 

 

W (dry weight)

‘
1.

Per Cent HC

 

 

July
July
July

A ————— July

 

.07

2
J11]..:] (.46
Aug. 12

—i

 

\

.00 ”?T' 1

 

July 5

\
,.«*\\\ y/’
CW/ \

M”” " If fl§~~I

——4b-————._

L

I)

 

-nr--""'Ky

 

6 a.m. 5 16 12 a

Time of Day

Fig. 2 - DIUHYAL VARIATIOHS

p 03710

4

6

 

"F.M1A-~‘N ‘Ah. 5

. ._.___. “mu-Jud -c

 

.L It IDLE VI I

DIURIAL VAR IAI‘IOITS

—‘ - -.--.--.M-—o-a. --. “-o.‘n- .- ~.— --- c. -- “—9—“4-0 . - -- em

 

 

 

 

 

Per cert HCH (“rv weight
21251:... of 13.31:---9 5.11:3.-.8. -2-3 1.27.5534; 13:11.55.2.33;}...0’37} 7-3
Date Age in
days
July 5 56 .0507 .052 .0542 .0605 .0656 .0655 -

" 10 41 .0555 . 275 .015 .0200 .0256 .0272 .0205
" 17 57 .0405 .0250 .015~ .0152 .0066 .0125 .0252
" 22 55 .0012 .0015 .00205 .00149 ..0010 .00075 .00105
" 26 46 .00176 .00546 .00575 .00055 .00194 .00275 .00122

Aug.12 2nd. .00508 .00528 .00278 .00586 .00457 .00444 .00587

In an effort to obtain an explanation of 615 observed

as

\“

variations the weat11er data for the days involved r

obtained from the United States Weather Bureau at East

Lane 1 5. W.)le VIII pre 55 ents the hourly eexpe 6rature in
degrees Farenheit and the sunshine in percentage of the

total possible. The value 1 represents 100 per cer t sunshine.

T113311” VIII

WEAThSR 03 DAYS DIUHUAL V'RIATIOU WAS ST"DIL D

 

*- CI. -. ”-.*.o--‘—- -‘u.—.-.—. —.- - -

Date Time of Day 6 8 10 12 2 4 6

~.- .‘--“

 

 

 

July 5 Temp. 05 70 75 54 57 55 57 57
Sunshine .92 1.0 1.0 1.0 1.0 1.0 1.0
July 10 Temp. or 67 72 51 54 54 55 54
Sunshine .57 1.0 1.0 1.0 1.0 1.0 1.0
July 17 Temp. 05 61 60 51 5 52 52 51
Sunshine .77 1.0 1.0 1.0 1.0 1.0 1.0

 

- 21 -

TABLE VIII (Continued)

 

U
p:

tr
(D

*3
I...“
6

0

*5
U
93

C)
03
H
(D
}._l
03
t0
:9
0}

July 22 Temp. OF 70 74 55 54 55 55 52
Sunshine 0 .2 1.0 .4 1.0 . .9
July 26 Temp. or 65 e7 75 52 55 54 55
5111181111619 .65 1.0 1.0 1.0 1.0 1.0 1.0
Aug. 12 Temp. OF 2 77 57 55 57 54 79
Sunshine 1.3 1.0 1.0 1.0 1.0 1.0 1.0

l
o
I
i
I
O
I

The Hydrocyanic Acid Content of S me Hybrids.
A study of some Sorghum-Sudan hybrids was made in an
effort to determine the relative amounts of hydrocyanic acid

in known hybrids and the available Sudan grass and Early

-1

‘8 pre-

.L

}

Amber Sorghum. The material used and its source a

sented in Table IX.

TABLE IX

I'IYBRID IILTSRIAL AID ITS SOURCE

—‘ - A

m~—.—. ’~‘-—‘“ -

 

 

 

Haterial Source
Early Amber Sorghum C. M. 15550, hichigan State College

Sudan grass " II n n n

Sorghum x Sudan (tall) J. C. Ireland, Oklahoma A & M "

n u (short) n n n n n
Orange Sorgo x Sudan(F2) R. E. Karper, Texas Agr. Exp. Sta.
Leati F.C. 6610 X " " J. C. Stephens, U.S. Dept. Agr. Bu.

P 1 an t Indus .

 

 

p eviousl" described. Th1n material was Frown in the exper-
1.10'10'11 plots 0. the Far 1 Crepe Deprnt .ent. The data
obtained is presente: in Table X.
TAB E X
THE h_J f.OCYh IC ACID CO“TE'T OF SOIE IYBHIDS
fiaterial Age in Height 5 L a p HCI

days

in inches

resh cut

 

 

Early Amber Sorghum

'l I! I!

29

47

(n
“\

204:

-’)

L’J

.0421

.0105

 

Sudan x So rro (tall)

\J

I! ll 1!

g 4300.)].

.1144

 

 

 

 

” ” " 58 50 .0076 .0257
Sudan x Sorgo (short) - - - -
" " " 45 27.5 .0176 .1267
" ” " 57 57 .0037 .0264
Suda x Orarge Sorgo 20 12.5 237 .125
” " " 44 38 .0005 .09a6

II 1! II

0050

o
C)
'.J
O
}_J

 

.02 5
.0058

.0008

 

Sudan Grass
n u

I! ll

50

.6163
.0068
.0025

.1302
004305
.0117

 

 

The Hydrocyanic Acid Content of Second Growth & Hay

In order to obtain information in
analyses were made on material from the eXperinental plots
of the Departnert of Farm CrOps. A sample of the original
gr wth was taken July 9, when the plot vas being cut for
hay. Eleven days later the SOCOLQ growth and the hay were
analysed. The procedure was the same as described before.

The results are presented in Table XI.

TABLE XI

HYTROCYAVIC AICD COKTEIT 0F SECOKD GROWTH & HAY

‘
‘ I

 

I

Material Age in Days Hoi51t, inches pHCN (dry wt.)

Original growth 54 56 .0196
Second " 11 18.7 .0560

Hay 11 £36 .00118

 

DISCUSS ION

R

Hethods for Determining ME droc anic acid
The alkali titration methoa proved to be unsatisfactory.
It was possible to determine known amounts of potassium

cyanide 1n a cure solution, but the listillate from plant

.... $

3

material became dark colored when titr ted. Jhis dar-

(\

Smith (29) says was caused by the presence of organic matter
and made the titration practically impossible.
m

-he Prussian blue color 1 etric method proved to be

fai1 lv accurate in pure solutions as inFi cated in Table I.

1 C

re were, however, var]. iations in the colors 11111.11 made then

1—3
5‘
CD

fficult to match. This n1etlzod is long and comnlicated and

offers considerable cl1ance for error as indicatedb by the

H

variations in Table These results confirm the Opinion of
Smith (29).

11e acid titration method was found to be s ..pler than
the Prussian blue method and less subiect to error as indi-
cated by the m1all variati om1 in Table II. The end point,

ht be cesired. These results

0‘ 3‘- “. D o 5
1110.13, s ol 81.11.11.

Hethod for Preparing the sample

"n 4. ..-. 1.1, P n n n. - - - ,1. L1 .,-..
unen the Meonod oi acharya (22 ior precarino tne salple

1.- 1 1‘ ‘1

was co 1p: re d 1.15-1.11

1e As so ci-

(.3

ation of Official Aericultura Chemists (50) the former was
found to be unnecessarv as shoun bv Table III. Table IV

shous that the two-hour maceration perioa su

 

L

Elfect of Stage of Groweh
F1" 0 '0’. ° 0 T c“. 1 -11.} ”1760 1" f“ (1' 1'71 1" -? map ~711th
.Lne VL‘.P.L‘-A Lilono O 3;) -1 VL'-‘. (.xJ. xx -LO J a -J a I0..J.O- :1 ‘11 aul ~Je.-.‘d11
. o _ _o
seasonal variations.

v 3 "I“ ~~- ‘ I ‘ In 1‘ . 4‘
With other reports on “e SUejece o

Vinall (6) states that thsre is almost complete agreement

among farqers and chemists that the percentage of hydrocyanic
acid decreases stealilv 1ron the tine tre llant start‘ to

grow until it reaches maturity if the growth is no nal. The
data presented in Table VI and F's. 1, however, 1r die ates
that tne ercenta e of hydro vanie acid at firs t increases
and then gradually decreases toward maturity. There is
however, considerable diff2n1en e in the na‘erial used. In
the table given by Vinall, on the subfect, nest of the work
was started on material 50-41 days old and 8-36 inches high.

tions are not given. The material used in

3 the first month
growing cor d-itions were very poor. The normal rainfall for
Ju1e is 3.51 inches while the rainfall for June of this year

'~ !' O~ rh‘, _ .1. 9 O a p q “a . ..‘ I
v as 4.9..» inches. 111-3 nor-al suns-11 1e 1er the sa..-e 110111.11 lS

<1
{\3
L ~
1...:

o a -_ .° ,1 .. ”T, 1" -. ~ r1
111s tais year June received only 54p. Shis encess

rain and de ficient sunshine may be a factor causing tne
discrepancy, or the fa ct that younger material was studied
may be the explanm ion.

3 4 a

When the data oetained is calculated on the basis of

mill gra1s of hvdrocvanic acid per 100 plants as shown in

1“

column 6 01 Table VI and in Fig. l, i '3 shown that the

Cf“
f—o

total ago ou11t of hy drocvsr1e acid at first increases and than

- 25 _
gradually decreases to. lard maturity. This is in complete
agreement with the conclusions Acharya (22) who is the

only'vmnia31 to

#07

‘

A

8210 1'! t 1'1 a t Ni

O
Q

tend

the cor clusions

. ~ L . " I V
mentioned was

could not be repeated.

‘ Q‘ - ‘1-
tne «or».

U

work of

Dowell, however,

report on

iurnal va riatiors

th one excep

and data

for very young

of Acharva.) It
Henaul and Dow

-. ‘
is very

t‘ C

313 subject to date

“C

Diurnal Variati01s

in Table VII

tion th

to decrease

in exact

of Acharya (22). (ine exception

material and unfortunately

This one case ement with

is, howevei in agreelent with the

11 (4). The work of Renaul and

incomplete in that the data is only

for] I101: in; and afternoon of one date and txe tine of day
is not mentioned.

E0 hard and fast conclusions should be drawn fro 01 this
work on ‘iurnal variations until it has been repeated for
several years. The hydrocyanic acid content is small and
tlie variations are p: Oportionally small and there is con-

siderable chance for

impossible to obtain

The hydroc nic

given in Table X var

acnl the (301‘s

unerical Suda

4.

error due to the fact that it is

exactly uniform samples.

vv

nybri

C‘
Q

d

acid content of the hybrids studied as

ied between that of Early Amber Sor311un
n grass as grown here. iais is not

 

hr

5’

in a; ree3ent with the worg, cited by headly (2 ), oi mooaie

(25) or Ra_say (26), but confirns the concluss ions of Finne-

aore and Cox (27). There is, of course, no r ason to expe t
exact agreement, since the hybrids used are very likely not
the sa 3e.

The Australian workers Hoodie (25) and Ramsay (26) each
contend that iure Sudan grass is not dangerous at any stage
of growth. The data presented in able VI indicates th iat
the connerical Sudan grass as grown here this year would be
dangerous at lea st until it was 16 inches hich, at 3'Ihicl-‘3
time 18.3 pounds of green material contained about .5 .7 ’-

gram of hydrocyanic acid. This amount accorcin” to Vinall

(J
(6) would be sufficient to produce fatal results if it were

all liberated. This diiference of Opini03 as to the toxicity

a ‘ '. ""V w? a, - -/\ ‘ V
of Sudan grass here and in Australia had be elplained DJ a
v *' ’v J-‘ L O _. ‘ V
fact den4103ed W Winall. he saps tnat there 18 neon less

Prussic acid poisoninj r0301; ted in the southern than in the

I .J
i—Jo
(D
U]

3«

northern portion of the United States. All of Austral a

A

north of a degress sou h lati Jude thile Last Lansin

}_J
H.
03

bet.1een 42--3 degrees north a itude. The reason for this
Climatic variation would be a stal" of much interest.
Second Growth and Hay
The composition of the hay and resunt’ng second growth
as presented ’n Table XI shows that the hydrocyanic acid
conter.t of hay is considerably less than that of t3e original

.23 m ° 0 . , (*3. x r- - .. /‘
grox-Jtn. ihis is in ear 33.163116 nub.“ Swanson (o) and Vinall (o).

-.-r

 

A

A' ”h. 2.141mulb‘lzvan‘~-£‘-h A.‘ hfllflloai' ._.~_‘1 - I

 

(fir)

‘
r—jfl-‘y (‘1 ‘

 

 

 

 

 

iaele JLL alsx).i_ous Lani' tne Infirocgunfibe acixl conte1iz<if the
330 nd growth at the stage tthed nae i333r t‘rn that f
the original growth. Jhen, h ‘ever, th; 43 rocyanic acid
content of the second growth is cone red to that o? a sanple
of original "rouuh of cornauaule Size, fable "II, theie is
seen to be little differente. This contradicts the prev-
alent Opinion that secon“ ”r wt? is go:e t xic than the
01igina'l. This may be exp eined by the fact that the second
growth has not ’ can coapared with original growth of the
sane age.
E3 XII
A COI£P1313ISOZI OF C'ECOUD AITD ORICI—IITAL G; Olin-I
Sample and Source He’ght Per cent FOR

A “_ in inches ‘(drv wt.)
Second growth (3am eXI) 18.7 .0560
Original " ( " VI) 16 .0427

30 con013 si 13 shoulw be node n this subject until a
series 0: analyses has been made on both the original 1d
second (“Olub, taking eacn to the same stage of "renth.
It aLpears from the ava’lable data th :1t the sedond growtl
may be little if any more dangerms than the original
growth at the sane stage of growth.

 

 

I“ .. .rt $.25... I
.ll. ‘ .Iqu

In)
L')
I

COlICLUSIOlIS

The alkali titration netboi was found to be the most

H
O

satisfactor;.
/ ._ 1 r 1 o 0 w y _ 1,1, , 3 V g
2. ”be p;rcentabe of nyurocyanic aCia in uNG conne1clal

.'

(V ,‘ a L O o . 4“,
ouean grass CU first rises ana tje

‘5

_ gradually decreases to—

I»

ward laiil .

5. The conwcrcial Sudan crass as crown at Iichi an State
College this year corta iris su~
daaferous at least until it is 16 inches tall.

4. The tota>l awzoqwnt of hylrocya rlic acic nor plant at firnt

increases and then falls off toward 1aturic 3?.

'n ~nww‘n'l “‘°"*"r\“t "i“ 4"” r WY" ’" a I" r3 o‘i'Y” ( 1 l 'éji't l
1-- Q-‘L'\J... L3. l‘l- ._Vl Q) g) i—A LILAC ‘AIOL Lllnu L~n\1_ UVJILl-1LJ a.“ _(_J. O J n

6 The h"brifls tee ted contained more nVGrocycn 0 acid than
Sudan grass and less than the Early Amber Sorghum.

7. r"he sccona growth does not necessarily contain more

lrntro cyanic acid_t?arx 'fiie original {nmnfifll at the STIR? sta
of growtln

o p - . n 1- r n. 1 4-». V °
0. ligarinQ oaueee a vely aeCiaea oecrease in two rflr ocya IllC

acid content.
9. Due to the fact tlat this work covers only one season's
work the above conclm: iors should not be taken as final

until the H01 has been reoea.eJ during the course of several

 

I.F I. . '2 ~l,l... I

ii.

 

 

LTTicHV N‘CTcsD
.. 144L111. in; ....'_..J

s-fi C. L ’v q 9—. v"

1. Baron-Hey, G.K., Sliiot, n. G., Hoaaly, G. n. w.

Sudan Grass

C4

. Dept. Agr. Western Australia, Sert. (1934).

‘.

p. Xeadly, G. R. J., Sorghum, Sudan Grass a Johnson G ass
Poisoning

J. Dept. Agr. Western Australia. June (1934).

5. Hitchcock, A. S., fianual of The Grasses of The United

"7"

4. Renaul, P. and Dowell, C.i., Cyanogenesis in Sudan Grass

J. Agr. Res. 18:547-e50 (1919).

5. Sw.nson, C. 0., Hydroeyanic Acid in Sudan Grass

J. Agr. Res. 23:125 138 (1921)'

6. Vinall, H. 3., A Study of the Literature Concerning
Poisoning of Cattle by the Prussic Acid in Sorghum,
Sudan Grass, and Johnson Grass

J. Am. Soc. Aaron. 13:267-280 (1921).

7. Pease, H. T., Poisoning of Cattle by Andrapagan Sorghum

See Vinall (6).

J.

8. Kiltner, R. S., The Fatal Effect of Green Sorghum

Nebr. Agr. EXp. Sta. Bul. 65:71-84 (1900).

_.— . n . - - -
£-- « A. 14. .‘...2- - I ._

em--

.8".

L _“ MM“ '4

-

 

 

 

 

'AE it DIS.

9-

|. an!) I

 

(Q

10.

11.

12.

15.

0-, «y—

Dunstan, a. ;

f-V

. 7* , __ .. ., x -. _ . 9 .,.L
. and nonrur, i. .11., C"&ZlOCC¥-lGS-_S in Plants

,.\_

" - — V.'. ‘ ‘0“ “_' ‘ 1"
Part 2. She Grout nillet (Soriluw Vulbmre)

 

Proc. Roy. Soc. (London . 70:155 (1002).

Slade, H. 3., Prussic Acid in Sorghum

J. 11:71. (3110311. 300.. 25:55-59 (1903) 0

1‘ H 1‘ r- o l ' '3 - T 1‘ I .. , ) 7v 0 -. -.
Peters, A. 3., Slsue, n. 3. anl AVOIU o., P01sonin

Y n.

Cattle by Common Sorghum and Kai r Corn.

Iebr. Arr. EXp. Sta. Bul. 77:1-16 (1003).

\J

Crawford, A. C., The Pois nous Action of Johnson G‘ass
U.S. Dept. Agr. Bur. Plant Indus. Bul. 90, part 4
(1300).

Francis, C. K., The Poisoning of Live Stock unile T“aged--
ing on Plfilts of the Sorghum Group

kla. Agr. Exp. Sta. Cir. of Information 38:1-4 (1915

415 (1919)

C.A. 24:5796 (1030).

Dowell, C. T., Cyanogcnesis in Andrapo

'l‘v'fi a “#311 -1
s.‘. 00". L)“‘L L

Uillanan, J. J., The Estimation of Hydrocysnic Acid and
the Probable Form in Shich It occurs in Sorghum

N

J. Biol. Chen., 20 : lo. 1 35-56 (1017).

0"

- u-“e... I. 1".
. " 0 ‘ . .. -

'_ - .7 a"-..

J..—

”fl

 

II: v.
. .?,

,..,

 

.Pl.

17.

l .

2

CD

I"
,4
I.’ .

l.

T3‘~111“1‘-a3&. K., Prussic Acid in Sorghum

C.A. 22:1794 (1928).

J
' "1
0
(71‘
CO
(.3
O
:25
ct

Willaman, J. J. and W-st, n. g., so Hydro-

cyanic Acid Content of Sorghum

J. Agr. Hes., 4 : Io. 2 170-18 5 (1015 ).

‘V

Brunnich, J. C., Hydrocyanic “oil in bodder Plani

J. Ch... Soc. (London) 85. 78 s (1003)-

Alrrav, J. F. and "rum 111, ii. 8., 0n the Occurrence of

U

iun and Iaize

«M:
\J“

Pru.ssic Acil in Sor

‘w ,. \

Nebr. Agr. »np. Sta. 25rd Ann. Rep. 35-50 (1000).

Acharya, C. N., Investigations on the Develonveht of
Prussic Acid in Cha an (Sorghum vulgare)
Indian J. of figr. Sci. 5 (iant 5) : 851 (1033.
Breakwell, 3., 01a scs and Fodder Plants of New South

Sales

Smeibadly W”-

Koodie, A. W. S., Sorghum-Sudan Crass Hyorids

Agr. GaZ. u.S. Wales. Oct. (1020).

vv- 1 o

‘rarocyanic Acid Content of Sorghum-Sudan

 

J- D

27. Finnemore, I. and Cox, C. B., The Amount 01 Iydrocvanic

CO
CO

V

T.’

. - "a u-- I , a a 9 a. C‘ ~- "". - .
ACid in Sorbnun, Sudan grass ana Some agorids

" (1

Roy. Soc. L.u. Wales. Sept. (1051).

' ‘ ' "at
I

‘cis, C. K. and Connell, s. 3., ine Colorimetric

(L)

I.

nitn, 0., Report on the Determination of HCH in Glucosise

Lethod for Detertinin: H03 in nlants with Special

d-

.l 7'

'3 I- - — 7". -~‘~ a
nefsrence to mar r Corn

- I C" r7
.1. 11:11. Chen. Uoc., .35: (1010).

Bearing Iaterial.

J. Assoc. Official Agr. Chen. 16:187-189 (1965 .

‘cial and Tentative Iethods of Analysis of the

A I"

association of Ofiidal Agricultural Chezists.

 

._.‘... ‘—

ti} 1! f... no d

0 Hr .. x |..

.‘1

,ll-I.

 

(Var.
If»; H

‘Ug24'33 +3.6.

1 2 m
In 10 '58

NE F0 OVERDUE
mom aus-25. PER DA!

 

 

MICHIGAN STATE UNIVERSITY LIBRARIES
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