Nature and Patterns of Proteins during Cotton Seed Development.

Patterns of accumulation and ontogenetic relationships among proteins of cotton (Gossypium hirsutum L.) seeds were examined between 10 days postanthesis and maturity (56 days). Total and extractable nitrogen contents were determined; alkali- and water-soluble proteins were assayed quantitatively and electrophoretically. Two alkali-soluble proteins present in the electrophoretogram of mature embryos first appeared at 21 days postanthesis; most of the final profile was established by 28 days. Except for minor changes centering around the 7th week of development, the pattern from 28 days to maturity was marked by intensification of bands. The quantity of water-soluble nitrogen increased through the first 21 days of development, then declined until 42 days, when it again began to increase; it reached its highest level at maturity. There was evidence of a high peptide content 7 weeks postanthesis.