Changes in the carbohydrates, proteins and nucleic acids in the ovules of Zephyranthes lancasteri at different stages of maturation

Abstract

The major changes in the levels of soluble and insoluble carbohydrates, nitrogenous compounds and nucleic acids were investigated at different stages of seed development in Zephyranthes lancasteri. The activities of amylases, glutamic-alanine transaminase, ribonuclease and deoxyribonuclease were also studied. The alcohol-soluble nitrogen and carbohydrates attain their maximal levels prior to the elongation ofthe cotyledon. Both of these decrease markedly during further maturation of the seed. The accumulation of total nitrogen in the ovule follows a sigmoid pattern. The glutamic-alanine transaminase activity appears to be exclusively localized in the endosperm and is absent from the embryo. The embryo seems to derive its organic nitrogen fromthe endosperm. The peak in the level of DNA per ovule is attainedprior to the elongation of the cotyledon while that of RNA is foundsoon after.