不同供氮水平下小麦品种的氮效率差异及其氮代谢特征

【目的】明确不同氮肥生理利用率小麦品种的氮代谢差异,为小麦高产及合理施肥提供理论依据,实现小麦节氮增产。【方法】采用大田试验方法,从16个小麦品种中筛选出氮素利用效率差异显著的低氮高效型小麦品种漯麦18、豫麦49-198和低氮低效型品种西农509、豫农202。然后进一步分析两类品种在N0(CK),N120(120 kg·hm-2)和N225(225 kg·hm-2)3个供氮水平下各小麦品种的产量、叶片GS活性、可溶性蛋白、游离氨基酸、NO3-及全氮含量等氮代谢指标的差异。【结果】不同供氮水平下,氮肥生理利用率、产量、地上部及籽粒氮素积累量和叶片的GS活性、硝态氮含量、游离氨基酸含量、可溶性蛋白含量、全氮含量等均表现为低氮高效品种漯麦18、豫麦49-198显著高于低氮低效品种西农509、豫农202。增加供氮量,两类品种的产量、地上部及籽粒氮素积累量和叶片GS活性等氮代谢同化物指标均增加,而氮肥生理利用率降低。但两类品种对供氮水平响应不同,与N0相比,增加供氮量,低氮低效品种西农509、豫农202地上部及籽粒氮积累量、叶片的GS活性、硝态氮含量、游离氨基酸含量、可溶性蛋白含量、全氮含量的增幅均高于低氮高效品种漯麦18、豫麦49-198,但是,产量的增幅却显著低于低氮高效品种;氮肥生理利用率的降幅则以低氮高效品种显著高于低氮低效品种。【结论】低氮高效品种漯麦18、豫麦49-198相对于低氮低效品种西农509、豫农202具有更高的产量及氮素利用效率是因为其具有较高的GS活性,从而促进了植株对氮素的吸收与同化,使整个氮代谢过程利用效率提高,获得更高产量。低氮高效品种耐低氮能力较强,增产潜力较大;低氮低效品种对氮肥反应较为敏感,但是其氮素分配利用能力较低。

Differences in Nitrogen Efficiency and Nitrogen Metabolism of Wheat Varieties Under Different Nitrogen Levels

【Objective】This study aims to clarify the difference in nitrogen metabolism of wheat varieties with different nitrogen use efficiencies and to achieve optimization of nitrogen application and high-yield.【Method】In this study, Luomai 18 and Yumai 49-198(LH), Xinong 509 and Yunong 202 (LL) were selected from 16 wheat varieties in yield conditions, and GS activity, soluble protein, free amino acids, NO₃^- and total nitrogen content of leaves were detected under nitrogen levels of N0 (0, CK), N120 (120 kg·hm^-2) and N225 (225 kg·hm^-2). 【Result】The results showed that GS activity, soluble protein, free amino acids, NO₃^- and total nitrogen content in leaf, N accumulation of aboveground and grain, yield and NPE of Luomai 18 and Yumai 49-198 (LH) were significantly higher than that of Xinong 509 and Yunong 202 (LL). GS activity, soluble protein, free amino acids, NO₃^- and total nitrogen content in leaf, N accumulation of above ground and grain, yield increased with the increasing of nitrogen level, and the NPE reduced. But the response of the two types of varieties to nitrogen levels was different, compared with N0, the growing rate of GS activity, soluble protein, free amino acids, NO₃^- and total nitrogen content in leaf, N accumulation of above-ground of Xinong 509 and Yunong 202 (LL) were significantly higher than that of Luomai 18 and Yumai 49-198(LH), however, the growing rate of yield of Xinong 509 and Yunong 202 (LL) were significantly lower than that of Luomai 18 and Yumai 49-198(LH); the decreasing range of NPE of Luomai 18 and Yumai 49-198 (LH) was significantly higher than that of Xinong 509 and Yunong 202 (LL). 【Conclusion】Compared with Xinong 509 and Yunong 202 (LL), the reason that Luomai 18 and Yumai49-198 (LH) had higher yields and nitrogen use efficiency was that they had higher GS activities. Therefore the ability of nitrogen uptake and assimilation were improved, the nitrogen physiological efficiency in the whole nitrogen metabolism process was increased and better yields were obtained. Increasing the supply of nitrogen, yields of Luomai 18 and Yumai49-198 (LH) were significantly promoted. Luomai 18 and Yumai49-198 (LH) have a stronger tolerance to low nitrogen stress and the potential of yield is greater; Xinong 509 and Yunong 202 (LL) are more sensitive to nitrogen, but their ability in distribution of N is lower.