Effect of nitrogen-deficiency on midday photoinhibition in flag leaves of different rice (Oryza sativa L.) cultivars
Effect of nitrogen-deficiency on midday photoinhibition in flag leaves of different rice (Oryza sativa L.) cultivars
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DOI：
10.1007/s11099-009-0038-z
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发表时间：
2009-08
期刊：
影响因子：
2.7
通讯作者：
E. Kumagai;Takuya Araki;Osamu Ueno
中科院分区：
文献类型：
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作者：
E. Kumagai;Takuya Araki;Osamu Ueno
比较了氮素缺乏对两个粳稻品种旗叶正午光抑制的影响。shirrobeniya （SRB）和日本籼型高产中间型，cv。Akenohoshi (AKN)。两个品种分别在高氮和低氮条件下生长。正午时，低氮供应导致SRB的净光合速率、气孔导度、最大光系统II量子产量（PSII）和PSII电子传递量子产量的下降幅度大于AKN，表明在低氮条件下SRB比AKN受到更强烈的光抑制。正午时分，两个品种的低氮植株超氧化物歧化酶（SOD）活性均高于高氮植株。而在低氮（缺氮）条件下，抗坏血酸过氧化物酶（APX）活性在AKN中维持，而在SRB中显著降低。低氮条件下，SRB的过氧化氢（H2O2）含量显著增加，表明SRB低氮植株对正午光抑制的敏感性与H2O2积累增加有关。提示光合作用午间抑制可能是低氮植物氧化应激的结果，抗氧化能力不足以应对H2O2的产生。因此，h2o2清除能力可能是决定低氮条件下水稻旗叶正午光抑制差异的重要因素。
Effects of nitrogen (N)-deficiency on midday photoinhibition in flag leaves were compared between two contrastive Japanese rice cultivars, a traditionaljaponicacultivar with low yield, cv. Shirobeniya (SRB), and ajaponica-indicaintermediate type with high yield, cv. Akenohoshi (AKN). Both cultivars were grown under high-N and low-N conditions. At midday, low-N supply resulted in more intensive reductions in net photosynthetic rate, stomatal conductance, maximal quantum yield of photosystem II (PSII) and quantum yield of PSII electron transport in SRB than in AKN, indicating that SRB was more strongly photoinhibited than AKN under low-N condition. At midday, the low-N plants of two cultivars showed higher superoxide dismutase (SOD) activities than the high-N plants. However, ascorbate peroxidase (APX) activity was maintained in AKN but significantly decreased in SRB under low-N condition (N-deficiency). In contrast, hydrogen peroxide (H2O2) content in SRB significantly increased under low-N condition, indicating that the susceptibility to midday photoinhibition in the low-N plants of SRB is related to the increased H2O2accumulation. It is suggested that the midday depression in photosynthesis may be a result of oxidative stress occurring in the low-N plants in which antioxidant capacity is not enough to cope with the generation of H2O2. Therefore, H2O2-scavenging capacity could be an important factor in determining the cultivar difference of midday photoinhibition in flag leaves of rice under low-N condition.