ЭлБиб

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CHAPTER 3.

Immunity and Environment.

The predominant view met with in mycological literature is, that

physiological, as well as mechanical immunity of plants is changeable under

the influence о I environment. A variety immune to a certain disease in one

country may, according to this opinion, succumb to it in an other locality.

This view is endorsed in detail by C o m e s in his last hook (I. c.).

But few thoroughly experimental data are adduced to support tins generally

accepted view.

A rather opposite opinion on this subject is shared by E r i к s s о n,

M e n n i ng, К 1 e b a h n and G a s s n e r .

The author distinguishes the influence ol environment on mechanical

from that of physiological immunity. As to the first no doubt it may

be changed under different environment. E. g. immunity of cereals connected

with closed fIo\vering(in relation to infection by smut and ergot) is com

paratively changeable under the influence of different temperatures and

humidity at the time of flowering.

It is quite different with physiological immunity. There are more

data of extreme constancy of this kind of immunity, than on its mutability.

If one compares relations of definite species and varieties ol cultivated

plants to definite species of parasitic fungi in different countries one finds

many examples of the constancy of immunity. So the behaviour ol diffe

rent varieties of roses in relation to

Phragmidiurn subcorttcium

and

Sphaerotheca pannosa

is the same in England (B i I f e n 12), Germany

(L a u b e r t, 74) and in Russia (V o v i 1 о v). Varieties belonging to

Rosarugosa, R. polyanlha, R. lutca, R. pimpinellilolla

have proved to be

immune to rust and mildew in very different environments, in England and

N. Russia.

The varieties ol wheat, belonging to species of

Trilicum monococcum.

T. polonicum, T. durum

, and

T. turgidum

are characterised as immune

to brown and yellow rust

(Pnccinta iriliclna

and

P. glumariim)

by different

investigators in Australia (M a e A l p i n e , C o b b , F a i t e r), India

(H о w a r d), N. America (С a r 1e t о n, F r e e ni a n),

Sweden

( E r i k s s o n , H e n n i n g ) , France (V i l m o r i n, F o e x), Ger

many (К о e r n i с к e, W e r n e r , K i r c h n o r), England (B i I-

i e n, V a v i 1 о v), Russia (L i t v i n о v,

V a v i 1о v),

Africa

( S c o f i e l d , T r a b u t).

«Persian wheats—

T. vuhjare var. Juliginosum

Al, absolutely immune

Eryslphe granuhis

in Russia has proved to be absolutely immune also in

England (Cambridge) ( V a v i l o v , S p i n k s ) . The ordinary races of

Avena brevis

and

A. sirigosa

characterised by R e e d as immune to

Ustilago avenae

in America, harm proved to be also absolutely immune

in the author’s experiments in Russia.

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