不同施氮水平对小麦旗叶氮素代谢相关酶活性的影响

Effects of Nitrogen Application Rate on Nitrogen Metabolism and Related Enzyme Activities of Wheat

选用新冬18号小麦品种,进行3个施氮水平的土壤施肥处理,再选取不同水平处理下的小麦旗叶作为供试材料,分别测定小麦旗叶中的谷氨酰胺合成酶、硝酸还原酶、内肽酶,氨肽酶、羧肽酶这5种氮素代谢关键酶的酶活力。研究结果显示,在小麦开花之后14 d,施氮水平为240 kg/hm2可有效增加小麦旗叶中可溶性蛋白质含量和主要氮代谢相关酶的活性。在此水平下,旗叶中可溶性蛋白质含量与谷氨酰胺合成酶及硝酸还原酶活性变化趋势相同,相比施氮水平为350,180 kg/hm2更能减缓小麦开花之后14 d的蛋白质水解,可进一步促进蛋白质的合成。与此同时,在开花之后第21天,高水平施氮量处理下的小麦旗叶中可溶性蛋白质含量则与内肽酶、氨肽酶等水解酶活性变化趋势相反。说明在240 kg/hm2施氮水平下,开花后期其施氮量能有效促进氮素分解代谢相关酶活性,旗叶可溶性蛋白含量降低,进而为小麦植株中氮素的再分配和利用起到了协助调节作用,提高后期小麦籽粒蛋白质的品质。

The enzyme activities of 5 kinds of N application such as glutamine synthetase,nitrate reductase,endopeptidase,aminopeptidase and carboxypeptidase by using 3 treatments with soil N application,taking the flag leaf of winter wheat Xinjiang 18 as tested materials. The result showed that the soluble protein content and nitrogen related enzyme activity were promoted in contitions of nitrogen level of 240 kg /hm2 after 14 d of wheat flowering. In this condition,soluble protein content,glutamine synthetase and nitrate reductase activity had the same change trends. Compared nitrogen level of 350 kg /hm2 and 180 kg /hm2,the 240 kg/hm2 nitrogen level slowed down the wheat blossom and promoted the synthesis of protein. After flowering 21 d,the correlations between soluble protein content and AP,EP,CP enzyme activity were negatived. It suggested that in the conditions of application N of 240 kg /hm2,application N at the flowering later stage can promote related enzyme activity of N catabolism,reduce the soluble protein content of flag leaf,and the promote N regulation of wheat plant and increase the quality of wheat kernel protein.