TRANSMISSIBLE VARIATIONS IN THE CYTOPLASM WITHIN SPECIES OF HIGHER PLANTS

Abstract

Transmissible variations in the cytoplasm of maize and other green plants occur and persist indefinitely in combination with different genotypes. Cytoplasmic differences are usually expressed in vital processes such as germ-cell formation and chlorophyll production but are also visible in morphological characters. Several cytoplasmic conditions which affect pollen production have been identified in maize. Three of these cytoplasmic conditions, designated "normal,""S,"and "T"types, have been shown to be different in their responses to given genotypes and in their effect on the free amino acid content of anthers at certain stages of development. Their expression is subject to genic control, but the cytoplasmic condition is not permanently altered by the genic environment. Cytoplasmic pollen abortion in maize may be accompanied by a precocious accumulation of alanine and other amino acids, as shown by chromatographic studies.[long dash]Auth. summ.