Response of leaf photosynthesis to vapor pressure difference in rice (Oryza sativa L) varieties in relation to stomatal and leaf internal conductance
Response of leaf photosynthesis to vapor pressure difference in rice (Oryza sativa L) varieties in relation to stomatal and leaf internal conductance
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DOI：
10.1626/pps.11.184
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发表时间：
2008-04-01
影响因子：
2.5
通讯作者：
Shiraiwa, Tatsuhiko
中科院分区：
文献类型：
--
作者：
Ohsumi, Akihiro;Hamasaki, Akihiro;Shiraiwa, Tatsuhiko
午后空气湿度降低，灌溉条件下水稻叶片光合速率（P-n）往往下降。为了阐明P-n对湿度响应的基因型差异，我们测量了不同遗传背景、不同蒸汽压差（VPD）和发育阶段9个水稻品种的P-n和气孔导度（g(s)）。在1.0 ~ 2.3 kPa VPD范围内，各品种的P-n和g(s)随VPD的增加而减小。在低VPD条件下，高g(s)的品种随着VPD的增加，g(s)的下降幅度大于低g(s)的品种，但在改变VPD条件下，高田cv的g(s)最高。在不同发育阶段，P-n与g(s)呈显著的对数关系，表明g(s)是决定P-n及其对VPD变化响应的主要因素。为了解释g(s)降低对P-n的影响，我们利用前人研究中准确估计低VPD下P-n基因型差异随g(s)和单位叶面积叶片含氮量的模型分析了两者之间的关系。假设叶片内部电导g(w)不变的模型很好地解释了高VPD下P-n仅随g(s)的变化而下降。分析还表明，在高VPD下g(w)和羧基化能力是恒定的。结果表明，高VPD环境下P-n降低的基因型差异主要是由g(s)降低带来的，高g(s)的品种在高或低VPD环境下的g(s)都较高，因此P-n也较高。
In the afternoon when air humidity decreases, leaf photosynthetic rate (P-n) often declines in rice grown under irrigated conditions. To clarify the genotypic difference of P-n in response to humidity, we measured P-n and stomatal conductance (g(s)) for nine rice varieties with diverse genetic backgrounds, at various vapor pressure differences (VPD) and developmental stages. P-n and g(s) of all the varieties decreased with VPD increase from 1.0 to 2.3 kPa of VPD. The variety with high g(s) at low VPD exhibited a greater decline of g(s) with VPD increase than the variety with low g(s), but cv Takanari showed the highest g(s) under altered VPD conditions. Significant logarithmic relations were found between the decreased P-n and g(s) at the respective developmental stages, suggesting that g(s) is the dominant factor determining P-n and its response to VPD change. To explicate the effect of decreased g(s) on P-n, we analyzed the relations by using the model that accurately estimated the (genotypic difference in P-n at a low VPD with g(s) and leaf nitrogen content per unit leaf area in the previous study The model assuming that leaf internal conductance (g(w)) remains unchanged well explained the decreased P-n at high VPDs by g(s) change alone. The analysis also suggested the constancy of g(w) and carboxylation capacity at high VPD. It is concluded that the genotypic difference in the decrease of P-n at a high VPD is brought mainly by that in decreased g(s), and the varieties with a high g(s) always exhibit a high P-n owing to their relatively high g(s) at either high or low VPD environments.