Abstract

Efforts were made to study whether zein accumulation in maize endosperms was controlled by the source activity or by endosperm genotypes. Analysis of F2 and F3 individual kernals from segregating ears derived from crosses between maize cultivars ILP and IHP that differ in zein concentrations showed no quantitative segregation in zein. When the kernals of these cultivars were cultured in vitro, zein accumulation was greatly influenced by amino acid concentrations in the medium. In vitro labelling of developing kernals with radioactive amino acid results suggest that accumulation of zein in maize endosperms is determined by the source supply of nutrients rather than by the endosperm genotype.

中文摘要

本研究的目的在於探討胚乳zein蛋白之合成究竟是受控於胚乳基因或營養組之基質之來源，利用兩種玉米品種(IHP及ILP分別代表zein含量高及低的品種)為材料做交配，並分析F1、F2及F3子代的種子，發現在F2及F¬3子代均無zein含量之性狀分離。體外種子培養之結果，發現IHP與ILP種子合成zein之能力與培養基中之氨基酸濃度有密切關係。以放射性同位素測定胚乳對氨基酸之吸收，亦發現種子吸收氨基酸以合成zein之能力與外界基質之濃度有正相關之影響。這些實驗均證明胚乳中zein蛋白之合成量是部受胚乳基因之調控，相反的，營養組織之基質對於此蛋白之合成有密切影響。

Keyword: Amino acids, Sucrose, Maize, Sink, Source, Zein, Zea mays L.