Steady-state and dynamic photosynthetic performance and nitrogen partitioning in the shade-demanding plant Panax notoginseng under different levels of growth irradiance
Steady-state and dynamic photosynthetic performance and nitrogen partitioning in the shade-demanding plant Panax notoginseng under different levels of growth irradiance
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不同生长辐照度下喜荫植物三七稳态和动态光合性能及氮分配
DOI：
10.1007/s11738-014-1614-9
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发表时间：
2014-09-01
影响因子：
2.6
通讯作者：
Yang, Sheng-Chao
中科院分区：
文献类型：
--
作者：
Chen, Jun-Wen;Kuang, Shuang-Bian;Yang, Sheng-Chao
在这项研究中，我们研究了稳态和动态的光合性能和叶片氮（N）分配的典型遮荫要求的草药三七种植沿着光梯度。在低光照条件下，叶片面积的气体交换量显著降低，叶片质量的气体交换量达到最大值，然后沿着光梯度降低。比叶面积随光照强度的降低而显著增加（P0.001），羧化效率随光照强度的降低而降低（P0.001）.此外，降低生长光照水平导致的最大羧化速率（Vcmax）和最大电子传递速率（Jmax）的下降，虽然Vcmax/质量和Jmax/质量的影响相对小于Vcmax/面积和Jmax/面积。缓慢的光合反应，以模拟sunflourism下观察到低水平的生长辐照度，气孔限制只在低光照条件下生长的叶片中检测到。叶绿素含量随光照强度的降低而显著增加。氮含量在叶质量基础上明显增加，而氮含量在叶面积基础上明显下降。叶片氮分配到捕光组件的分数显着增加，而羧化和生物能量分配的分数显着降低生长光照水平。作为一种适应生长光照的策略，我们得出结论，在典型的遮荫要求的物种，如三七，在比叶面积的调整可能比叶片生理和生化的变化更重要。
In this study, we examined steady-state and dynamic photosynthetic performance and leaf nitrogen (N) partitioning in the typical shade-demanding herb Panax notoginseng grown along a light gradient. Gas exchange on a leaf area basis was significantly reduced under low irradiance, with gas exchange on a leaf mass basis reaching a maximum value and then decreasing along the light gradient. Specific leaf area significantly increased with decreasing irradiance levels (P < 0.001), whereas carboxylation efficiency was decreased (P < 0.001). In addition, decreasing growth irradiance levels led to declines in maximum carboxylation rate (Vcmax) and maximum electron transport rate (Jmax), although Vcmax/mass and Jmax/mass were relatively less affected than Vcmax/area and Jmax/area. Slow photosynthetic response to simulated sunflecks was observed under low levels of growth irradiance, with stomatal limitations only detected in leaves grown under low-light conditions. Chlorophyll content increased significantly with decreasing irradiance levels. N content on a leaf mass basis apparently increased, while N content on a leaf area basis markedly decreased. The fraction of leaf N allocated to light-harvesting components increased significantly with decreasing growth irradiance levels, whereas the fraction allocated to carboxylation and bioenergetics was significantly reduced. As an adaptation strategy to growth irradiance, we conclude that adjustments in specific leaf area may be more important than changes in leaf physiology and biochemistry in typical shade-demanding species such as P. notoginseng.