小麦不同近缘种籽粒蛋白质积累及其关键酶活性的研究

Dynamic Accumulation of Grain Protein and Its Key Regulatory Enzymes in Different Wheat Related Species

为明确小麦不同近缘种籽粒蛋白质积累的演进规律,以二倍体野生一粒小麦(T.boeoticum)、栽培一粒小麦(T.monococcum)、节节麦(Ae.tauschii)和黑麦(S.cereale),四倍体野生二粒小麦(T.dicoccoides)、栽培二粒小麦(T.dicoccum)和硬粒小麦(T.durum),六倍体普通小麦(T.aestivum)扬麦9号、豫麦34和扬麦158为材料,采用盆栽试验研究了小麦不同近缘种籽粒蛋白质积累的动态变化及相关酶活性的差异。结果表明,与六倍体普通小麦相比,二倍体和四倍体材料籽粒产量和蛋白质产量低,但蛋白质含量高,其灌浆初期氮代谢能力比较强,硝酸还原酶(NR)、谷氨酰胺合成酶(GS)和谷氨酸丙酮酸转氨酶(GPT)活性较高,蛋白质积累速度快;除黑麦外,其他二倍体和四倍体材料蛋白质合成关键酶活性下降早而快,在灌浆中后期低于普通小麦,蛋白质积累的功能期较短。因此,普通小麦灌浆后期较高的氮代谢酶活性和较长的持续期是提高籽粒产量和蛋白质合成的重要生理原因。

Understanding of genetic difference in protein accumulation dynamics among different wheat genotypes evolved from diploid to hexaploid is important to provide valuable information for breeding progress and reasonable cultivation.The pot experiment was carried out during 2005-2006 using ten wheat genotypes including four diploid species of T.boeoticum,T.monococcum,Ae.tauschii and S.cereale,three tetraploid species of T.dicoccoides,T.dicoccum and T.durum,three hexaploid cultivars of Yangmai 158,Yumai34 and Yangmai 9 to investigate the evolution patterns in protein dynamic accumulation and its key regulatory enzymes.The results showed that grain yield and protein yield were lower while protein content were higher for diploid and tetraploid wheat than that of hexaploid wheat.Furthermore,protein accumulation rate of diploid and tetraploid wheat were higher than that of hexaploid wheat during early period of grain filling.The reason for this phenomenon was that diploid and tetraploid had higher nitrate reductase（NR） and glutamine synthetase（GS） activities in flag leaves,and higher glutamate pyruvic aminotransferase（GPT） activity in grains during early filling stages.However,except for S.cereale,the activities of NR,GS and GPT of diploid and tetraploid wheat declined more quickly and became lower than that of hexaploid species during late grain filling stage.The results suggested that higher enzyme activities and longer duration of nitrogen metabolism during late grain filling stage were the key physiological basis for hexaploid species to enhance grain yield and protein synthesis.