The Evolutionary Concept of the Morphology of Endosperm

抄録

A critical review of the existing theories of endosperm morphology has been attempted.
In accordance with a reconsideration of endosperm phylogeny, an evolutionary concept has been suggested to explain the various aspects of the development of endosperm. Evolutionary trends have been discussed on three main lines: 1. Increasing complexity in chromosomal constitution; 2. Gradual transposition in relation to fertilization; and 3. Dominance of mitotic inertia and demand for stimulation. Consideration of these guiding tendencies coupled with the existence in apomictic plants of an autonomous endosperm, has resulted in the formulation of the theory of the “pre-destined” nature of the endosperm.
It is shown that the endosperm in angiosperms is a tissue sui generis which should not be classified in rigorous chromosomal categories.
The role of physiologico-evolutionary modifications is shown to be reinforced by a purely physiological coincidence, the fusion of the second male nucleus with the proendospermatic cell.