Increases of chlorophyll a/b ratios during acclimation of tropical woody seedlings to nitrogen limitation and high light
Increases of chlorophyll a/b ratios during acclimation of tropical woody seedlings to nitrogen limitation and high light
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DOI：
10.1046/j.1365-3040.2003.01017.x
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发表时间：
2003-06-01
影响因子：
7.3
通讯作者：
Hogan, KP
中科院分区：
文献类型：
--
作者：
Kitajima, K;Hogan, KP
根据氮素在叶片中最佳分配的理论，叶绿素（Chl）a/B的比值预计将随着叶片氮含量的降低而增加。在这里，我们报告了这一预测的第一个实证支持。氮胁迫使紫葳科4种热带木本植物幼苗叶片和子叶中Chl a/B比值升高，Chl含量降低。所有四个物种的反应是在同一个方向，但不同的幅度。对于Tabebuia rosea，表现出最大的增加叶绿素a/B比（高达5.9的值）的物种，详细的光合特性进行了研究。光和氮的利用率与光饱和和CO2饱和的光合O-2释放速率、叶片羧化能力（V-cmax）和电子传递速率（V-j）呈正相关。严重的N限制和强光并没有引起慢性光抑制（即量子产率或暗驯化的F-v/F-m没有变化）。所观察到的V-cmax叶氮的比例在响应N的可用性的变化是一致的，可能的功能的原因在叶绿素a/B比的变化。叶绿素a/B比值的调整显然是适应强光和低氮条件的一个整体特征。
According to the theory of optimal nitrogen partitioning within a leaf, the chlorophyll (Chl) a/b ratio is expected to increase when leaf N content decreases. Here, we report the first empirical support for this prediction. The Chl a/b ratio increased while Chl content decreased in response to N limitation in photosynthetic cotyledons and leaves of seedlings of four tropical woody species in the Bignoniaceae. The responses of all four species were in the same direction, but differed in magnitude. For Tabebuia rosea , the species that exhibited the greatest increase in Chl a/b ratios (up to values of 5.9), detailed photosynthetic characteristics were also examined. Light and N availability were positively correlated with the light- and CO2-saturated photosynthetic O-2 evolution rate, as well as with leaf carboxylation capacity (V-cmax) and electron transport rate (V-j). Severe N limitation and high light did not cause chronic photo-inhibition (i.e. no change in quantum yield or in dark-acclimated F-v/F-m). The observed change in the ratio of V-cmax to leaf N in response to N availability was consistent with likely functional reasons for change in the Chl a/b ratio. Adjustment of the Chl a/b ratio was apparently an integral feature of acclimation to high light conditions and low N availability.