Influence of light and nitrogen on the photosynthetic efficiency in the C 4 plant Miscanthus 3 giganteus
Influence of light and nitrogen on the photosynthetic efficiency in the C 4 plant Miscanthus 3 giganteus
复制标题
光氮对C 4 植物芒草光合效率的影响
DOI：
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发表时间：
2017
影响因子：
3.7
通讯作者：
Asaph B. Cousins
中科院分区：
文献类型：
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作者：
Jian-Ying Ma;Wei Sun;Nuria K. Koteyeva;Elena Voznesenskaya;Samantha S. Stutz;Anthony G;in;Andreia M. Smith-Moritz;Joshua L. Heazlewood;Asaph B. Cousins
有许多研究描述了生长条件如何影响C4光合作用的效率。然而，目前尚不清楚生化能力与叶片解剖结构的变化如何推动这种适应。因此，本研究的目的是确定如何生长光和氮供应量的影响叶片解剖，生化和效率的CO2浓缩机制芒。有一个增加的叶肉细胞壁surrface面积，但没有细胞壁厚度在高光（HL）相比，低光（LL）生长的植物，表明在HL植物叶肉电导率较高，这也有更大的光合能力。此外，HL植物有更大的表面积和厚度的鞘细胞壁相比，LL植物，表明有限的差异鞘CO2传导，因为增加的面积被抵消较厚的细胞壁。磷酸烯醇式丙酮酸羧化酶（PEPc）活性的气体交换估计值显着低于在体外PEPc活性，表明有限的底物在叶中的可用性，由于叶肉CO2电导低。最后，泄漏在所有生长条件下是相似的，并且在不同的测量光条件下通常没有变化。然而，叶片材料的稳定同位素组成的差异并没有与泄漏，表明干物质同位素测量是不是一个很好的代理泄漏。综上所述，这些数据表明芒属植物的CO2浓缩机制在低光照和有限的氮生长条件下是稳健的，并且观察到的叶解剖学和生物化学的变化可能有助于保持这种效率。
There are numerous studies describing how growth conditions influence the efficiency of C 4 photosynthesis. However, it remains unclear how changes in the biochemical capacity versus leaf anatomy drives this acclimation. Therefore, the aim of this study was to determine how growth light and nitrogen availability influence leaf anatomy, biochemistry and the efficiency of the CO 2 concentrating mechanism in Miscanthus 9 giganteus. There was an increase in the mesophyll cell wall surrface area but not cell well thickness in the high-light (HL) compared to the low-light (LL) grown plants suggesting a higher mesophyll conductance in the HL plants, which also had greater photosynthetic capacity. Additionally, the HL plants had greater surface area and thickness of bundle-sheath cell walls compared to LL plants, suggesting limited differences in bundle-sheath CO 2 conductance because the increased area was offset by thicker cell walls. The gas exchange estimates of phosphoenolpyruvate carboxylase (PEPc) activity were significantly less than the in vitro PEPc activity, suggesting limited substrate availability in the leaf due to low mesophyll CO 2 conductance. Finally, leakiness was similar across all growth conditions and generally did not change under the different measurement light conditions. However, differences in the stable isotope composition of leaf material did not correlate with leakiness indicating that dry matter isotope measurements are not a good proxy for leakiness. Taken together, these data suggest that the CO2 concentrating mechanism in Miscanthus is robust under low-light and limited nitrogen growth conditions, and that the observed changes in leaf anatomy and biochemistry likely help to maintain this efficiency.