The Situation in Biological Science , pp. 587-588 (1948)
Removing Endosperm
I. I. Prezent

I shall take the liberty of stating briefly here that, working experimentally on this subject, I have come to the conclusion that double fertilization has a biological significance similar to that of fertilization in general. Thanks to double fertilization, nourishment of a special kind is obtained, in which is included a wealth of specific adaptation. Double fertilization, like fertilization generally, has the effect of broadening the adaptive potentialities of the organism, of widening the amplitude of its connections with external conditions, while at the same time the developing organism is morphologically less dependent upon fluctuations of its external environment. This is precisely that general enhancement of vitality which Academician A. N. Severtsov defined as "aromorphosis." The effect of this type of aromorphosis is the opposite of inbreeding. And when we, in our experiments, removed the product of the double fertilization, that is, the endosperm, and grew the plant from embryos isolated from the endosperm, we obtained something analogous to inbreeding: the plants of stable equalized strains proved to be extremely diverse, with changed characters, even with changes of variety. This is true both of non-hybrid, and even more of hybrid forms. As to the latter, I shall here reply to another assertion of Academician Zhukovsky, namely, that he knows of no exceptions to the Mendelian rules. He would be much closer to the truth if he said that he knows of no corroboration of these rules. As to the exceptions, permit me to exhibit this. (Exhibit.) You said, Academician Zhukovsky, that the Mendelian rules were firmly established.

P. M. Zhukovsky. For annual self-pollinators.

I. I. Prezent. Permit me to exhibit hybrid wheat plants obtained from crossing an awnless pubescent variety with an awned glabrous variety. As you see, this is a self-pollinator and, moreover, an annual. Well, be good enough to tell me, which generation is this? According to you, and according to Mendel, this cannot be the first, for here we have in one and the same generation awned and awnless forms, pubescent and glabrous. But this is the first generation. And in order to obtain such a "segregation," it was sufficient to grow the hybrid plants of the first generation from embryos isolated from the endosperm, to deprive them of hybrid nourishment.