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N. 1. VAVILOV. IMMUNITY OF PLANTS TO INFECTIOUS
DISEASES.
Resume.
INTRODUCTION.
The study of the problem of immunity of plants to infectious diseases
(fungi and bacteria) has till now made not much headway in comparison
with investigations and great discoveries in the region of immunity to
diseases of man and animals.
The fundamental cause of this backwardness—are the specific pecu
liarities of the immunity of plants. _
There are two kinds of immunity: the n a t u r a 1 immunity specific
to this or that disease in different species of plants and animals. Man is
for instance, immune to cattle plague, wheat is immune to oat smut and
rust, etc. Another kind is the a c q u i r e d immunity, which appears
as a result of internal changes in the constitution of the organism e. g. after
some disease (in man after small pox and after spotted, typhus), or after in
jection of some substance, etc.
'
The basis of progress made in immunity of animals is the study ol
a c q u i r e d immunity, as a result of vaccination, injection of different
substances. The greatest discoveries have been made in this direction.
In the plant world a c q u i r e d immunity has but little signifi
cance. Here we have to do only with n a t u r a l immunity, which wo
cannot change and which we have to make use of, such as it is. Besides,
the natural susceptibility of plants to diseases changes but little.
The possibility of inducing a c q u i r e d immunity among plants
is theoretically not improbable (see e! g. N o e l B o r н а г d, B o a u-
v e r i e, R a y). Attempts have been made to inject different salt solutions
into plants to reduce their susceptibility to fungous and bacterial diseases
(S h e v у r e v, M о к r j e z к i, N o г t о n). Different manures are
also recommended (e. g. phosphates) for diminution of susceptibility to
diseases.
.
The majority of these attempts proved to be unsuccesful. In practice
even in the case ol their success they are o f little value and are available
perhaps only in very intensive culture (e. g. fruit-growing).
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