Die voorkoms, verspreiding en vorming van sianogenetiese glukosiede by 'n aantal sorghum-soorte
Abstract
The occurrence of cyanogenetic glucosides is of
considerable economical importance because they render plants poisonous, and animals consuming this material
may _be poisoned. Methods for the utilization of these
plants to avoid poisoning have been proposed by several workers, namely Boyd (1938); Rose (1941) and Visser
(1956). These methods are based on the principle that
plants, as they mature, contain progressively less
cyanogenetic glucosides.
Certain individual plants and selections contain
a higher concentration of cyanogenetic glucosides than other plants of the same species, grown under the same conditions. Leeman (1935) and Visser (1958, unpublished) give an extensive account of plants containing these
substanies. In the present investigation six species of Sorghum and 24 selections of S. almum and S. verti
cilliflorum x S. sudanense were investigated.
The age and the part of the plant had a marked
effect on the cyanogenetic glucoside content. As the
plant matures, the glucosidal content decreases per
unit of dry weight. The same applies to the different
parts of the plant, namely the younger the part; the
higher the concentration of cyanogenetic glucosides.
Fertilization with nitrogenous fertilizers caused
an increase in the content of cyanogenetic glucosides
while phosphatic fertilizers counteracted this effect.
From the results it is evident that the application of
urea in all instances resulted in,a lower glucosidal
content as. was the case with the application of
sulphate of ammonia and calciumnitrate. The application of urea however, resulted in a quicker increase of
glucoside content.
A lack of moisture resulted in the plants containing
more cyanogenetic glucosides than where moisture was
available in adequate quantities. The possible explanation for this may be sought in the fact that
plants growing under conditions of moisture deficiency
remain for a longer period in a relatively young
physiological stage. ( Boyd et alia, 1938).
Immediately after frosting, an increase in glucosidal content occurs, but as the plants thaw and wilt,
a decrese in glucosides is observed. A condition that
frequently occurs is that after a frost, a spell of
hot weather prevails. This causes the plants to sprout
again and the young sprouts have a high glucosidal
content.