Influence of light and nitrogen on the photosynthetic efficiency in the C₄ plant Miscanthus × giganteus

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• 作者：Jian-Ying Ma ; Wei Sun ; Nuria K. Koteyeva ; Elena Voznesenskaya…
• 关键词：Carbon isotope discrimination ; C4 photosynthesis ; Miscanthus ; Nitrogen ; Light
• 刊名：Photosynthesis Research
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：131
• 期：1
• 页码：1-13
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Plant Sciences; Plant Physiology; Biochemistry, general; Plant Genetics & Genomics;
• 出版者：Springer Netherlands
• ISSN：1573-5079
• 卷排序：131

文摘

There are numerous studies describing how growth conditions influence the efficiency of C₄ 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 CO₂ concentrating mechanism in Miscanthus × giganteus. There was an increase in the mesophyll cell wall surface 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 CO₂ 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 CO₂ 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.