分蘖和拔节期干旱对小麦植株氮素积累转运的影响

Effect of Water Deficit during Tillering and Jointing Stages on Nitrogen Accumulation and Translocation in Winter Wheat

为明确分蘖和拔节期干旱对小麦氮素积累转运的影响,采用盆栽试验,以扬麦13和扬麦16为材料,研究了小麦分蘖和拔节期轻度和重度干旱条件下产量、氮代谢相关酶活性、氮素积累和转运的特征。结果表明,分蘖和拔节期干旱对两个小麦品种植株氮素积累转运的影响基本一致,分蘖和拔节期轻度干旱对小麦籽粒产量和蛋白产量影响不显著,而重度干旱可显著降低籽粒产量和蛋白产量。两时期干旱处理均显著降低小麦叶片硝酸还原酶(NR)和谷氨酰胺合成酶(GS)活性,且重度干旱降幅更大;胁迫解除后,叶片NR和GS活性增强。分蘖期轻度干旱提高了分蘖-拔节、拔节-开花阶段植株氮素积累量,而拔节期轻度干旱提高了拔节-开花、开花-成熟阶段的氮积累量。分蘖期轻度干旱提高了花前氮素转运量及其对籽粒贡献率;拔节期轻度干旱提高了花后氮素积累量及其对籽粒氮贡献率,而降低花前氮素转运量。成熟期籽粒氮素积累量与籽粒产量和蛋白产量均呈显著正相关。分蘖期和拔节期轻度干旱解除后,植株氮代谢相关酶活性增强,有利于植株氮素积累,并协调花前和花后氮素积累对籽粒氮贡献,从而获得高籽粒产量和蛋白产量。

In order to investigate the effects of water deficit during tillering and jointing stages on nitrogen(N) accumulation and translocation in winter wheat, a pot experiment was conducted using winter wheat cultivars(Yangmai 13 and Yangmai 16) to analyse the characteristics of grain yield, nitrogen metabolic enzyme activity, nitrogen absorption and utilization under moderate and severe water deficit conditions. Effects of water deficit on nitrogen accumulation and translocation showed similar tendency in the two cultivars. Moderate water deficit during tillering(TM) and jointing(JM) had no effect on grain yield and protein yield, while severe water deficit significantly decreased grain yield and protein yield. Nitrate reductase(NR) and glutamine synthetase(GS) activity was decreased by water deficit and enhanced after stress relief. TM treatment increased the nitrogen accumulation from tillering to jointing and from jointing to anthesis. JM treatment enhanced the activity of NR and GS in flag leaves which attributed to higher nitrogen accumulation from jointing to anthesis and from anthesis to maturity. TM treatment increased nitrogen translocation amount and its contribution to grain N, and JM increased post-anthesis nitrogen accumulation and its contribution to grain N, but reduced nitrogen translocation amount. Nitrogen accumulation at maturity showed a significantly positive correlation with grain yield and protein yield. After stress relief, TM and JM enhanced the activity of NR and GS which was beneficial for higher nitrogen accumulation, and coordinated the contribution of pre-and post-anthesis nitrogen accumulation to protein yield, leading to high grain yield.