外源钙离子对小麦幼苗氮素代谢的影响  

Effects of exogenous Ca^(2+) on nitrogen metabolism in wheat seedlings

作　　者：王志强[1] 王春丽[1] 林同保[1] 

机构地区：[1]河南农业大学农学院/河南省作物生长发育调控重点实验室,郑州450002

出　　处：《生态学报》2008年第8期3662-3667,共6页Acta Ecologica Sinica

基　　金：国家粮食丰产科技工程资助项目(No.2006BAD02A07-2);河南省高校杰出科研人才创新工程资助项目(No.2007KYCX003);河南省重点农业攻关资助项目(No.072102170002)~~

摘　　要：以普通小麦豫麦34为材料,研究了不同浓度的外源Ca2+对小麦幼苗氮素代谢的影响。在小麦第一片叶完全展开后,开始外源Ca2+处理,设0(对照)、2、4 mmo.lL-1和8 mmo.lL-14个Ca2+浓度梯度。处理5d后,测定氮同化酶活性、氮同化量及其它相关代谢物含量。结果表明,小麦幼苗叶片中硝酸还原酶(NR)和谷氨酰胺合成酶(GS)在2 mmo.lL-1Ca2+处理下活性比对照有显著增加,4 mmo.lL-1Ca2+处理的NR活性增加明显,但GS活性增加不显著;8 mmo.lL-1Ca2+处理下NR和GS活性比对照均明显降低。谷氨酸脱氢酶(NADH-GDH)活性在2 mmo.lL-1Ca2+处理下活性增加不明显,而在4、8 mmo.lL-1Ca2+处理下活性显著增加。小麦幼苗氮同化量以4 mmo.lL-1处理最大,2 mmo.lL-1处理与4 mmo.lL-1之间差异不显著;Ca2+浓度为8mmo.lL-1时,氮素同化量明显降低。结果揭示了小麦幼苗不同氮同化途径对Ca2+的响应不同,GS途径比GDH途径对小麦氮素同化量的增加作用更大;4 mmo.lL-1对小麦幼苗的氮素利用可能是最有效的Ca2+浓度。The seedlings were material. Ca^2＋ exogenous calcium-induced effects on nitrogen assimilation enzymes and nitrogen use efficiency in wheat investigated hydroponically using an treatments with solutions containing ordinary wheat cultivar （Tritieum 0, 2, 4, and 8 mmol-L-1 Ca^2＋ aestivum L. cv. Yumai 34 ） as the were initiated immediately after the complete expansion of the first leaf. Wheat seedlings were sampled five days later to determine the activities of nitrate reductase（NR）, glutamine synthetase（GS） and NADH-dependent glutamate dehydrogenase （NADH-GDH） in leaves, as well as the amount of nitrogen assimilation. The results showed that Ca^2＋ had obvious effects on the ability of nitrogen assimilation in wheat seedlings, and ammonium assimilation enZymes responded variously to different Ca^2＋ concentrations. Significant increases in NR activity were found in plant leaves exposed to 2 and 4 mmol- L-1 Ca^2＋ concentrations, among which the former induced the highest activity, whereas 8 mmol·L·Ca^2＋ concentration significantly reduced NR activity. GS activity was markedly increased by 2 mmol·L-1 Ca^2＋ application, but further increase in the concentration reversed the above effect, even 8 mmol·L^-1 Ca^2＋ induced striking decrease in GS activity. Unlike NR and GS, NADH-GDH activity in leaves manifested pronounced increases with all Ca^2＋ concentrations in nutrient solution. High nitrogen content in leaves was found always together with Ca^2＋ concentration of 4 mmol·L^-1. All the above results suggested that GS activity was important for nitrogen assimilation, and 4 mmol· L^-1 Ca^2＋ was the most effective concentration to make wheat plants own high ability to assimilate nitrogen.

关 键 词：小麦 钙离子 氮素代谢 

分 类 号：S512.1[农业科学—作物学]