氮胁迫条件下水稻理想株型基因ipa1对氮代谢的影响

利用水稻(Oryza sativa L.)近等基因系NIL-IPA1和NIL-ipa1,研究在施氮与不施氮条件下,理想株型调控基因ipa1在水稻快速分蘖期对氮代谢的影响。结果发现,在施氮条件下,相对于NIL-IPA1植株,NIL-ipa1水稻植株中谷氨酰胺合成酶(Glutamine synthetase,GS)、NADH谷氨酸合酶(NADH-glutamate synthase,NADH-GOGAT)的活性降低,叶片中游离氨基酸含量减少,但NADH谷氨酸脱氢酶(NADHglutamate dehydrogenase,NADH-GDH)、NAD+谷氨酸脱氢酶(NAD+-glutamate dehydrogenase,NAD+-GDH)活性升高,表明ipa1能够降低水稻植株氮素同化效率,同时提高氮素重复利用率。在不施氮条件下,NIL-IPA1和NIL-ipa1植株GS活性提高,NADH-GOGAT、NADH-GDH、NAD+-GDH活性降低,可溶性蛋白和游离氨基酸含量减少,同时发现在NIL-ipa1植株中GS、NADH-GOGAT活性变化相对较小,NAD+-GDH活性相对较低,游离氨基酸含量相对较高,表明ipa1能够降低氮胁迫对水稻植株氮同化效率的影响,提高水稻植株对低氮胁迫的抗性。

Effects of Ideal Plant Architecture Gene ipa1 on Nitrogen Metabolism under Nitrogen Stress Condition

In the present study,under nitrogen deficiency and fertilization conditions,the effects of ipa1 on nitrogen metabolism at rapid tillering stage of rice near-isogenic lines NIL-IPA1 and NIL-ipa1 were analyzed. Under nitrogen fertilization condition, although the activities of glutamine synthetase(GS),NADH-glutamate synthase (NADH-GOGAT) and the content of free amino acid were significantly reduced,the activities of NADH-glutamate dehydrogenase (NADH-GDH) and NAD +-glutamate dehydrogenase (NAD+-GDH) were increased in the NIL-ipa1 plants when compared with NIL-IPA1 plants. This result indicated that ipa1 improved the nitrogen recycling efficiency,although the efficiency of nitrogen assimilation was reduced in NIL-ipa1 plants. When the rice plants were cultivated under the nitrogen deficiency condition,the GS activity was increased,the activities of NADH-GOGAT,NADH-GDH and NAD+-GDH were reduced. Meanwhile,although the contents of soluble protein,free amino acid were decreased in NIL-IPA 1 and NIL-ipa1 plants,the change of GS,NADH-GOGAT activities were relatively limited,the NAD+-GDH activity was lower and the content of free amino acid was higher in NIL-ipa1 plants when compared with NIL-IPA1 plants. The result suggested that ipa1 gene could lighten the impact of nitrogen deficiency stress on the nitrogen assimilation ability of rice plants and enhance their resistance to nitrogen stress.