玉米營養組織對zein蛋白合成的影響

Effects of Vegetative Source on Zein Synthesis in Maize

本研究的目的在於探討zein蛋白之合成究竟是受控於胚乳基因或營養組織基質之來源，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F3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氯基酸產生之吸收，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蛋白之合成量是不受胚乳基因之調控，相反的，營養組織之基質對於此蛋白之合成有密切影響。

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 kernels from segregating cars derived from crosses between maize cultivars ILP and IHP that differ in zein concentrations showed no quantitative segregation in zein. When the kernels of these cultivars were cultured in vitro, zein accumulation was greatly influenced by amino acid concentrations in the medium. In vitro labelling of developing kernels with radioactive amino acid indicated that the movement of glutamine into kernels followed a non-saturated kinetics. These results suggest that accumulation of zein in maize endosperms is determined by the source supply of nutrients rather than by the endosperm genotype.