To concentrate or ventilate? Carbon acquisition, isotope discrimination and physiological ecology of early land plant life
To concentrate or ventilate? Carbon acquisition, isotope discrimination and physiological ecology of early land plant life
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DOI：
10.1098/rstb.2008.0039
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发表时间：
2008-08-27
影响因子：
6.3
通讯作者：
Griffiths, Howard
中科院分区：
文献类型：
--
作者：
Meyer, Moritz;Seibt, Ulli;Griffiths, Howard
本文对现代短角藻与近缘藻类的光合生理生态和碳同位素鉴别特征进行了比较研究。首先，与更先进的陆地植物群相比，考虑了branite分布和多样化的程度。其次，在干燥循环过程中的瞬时碳同位素歧视（D），光合CO2同化和电子传递速率的测量进行了比较。表面扩散限制的程度（润湿时），内部电导和水分利用效率（WUE）在最佳组织含水量（TWC）来自地钱和金鱼藻从对比的栖息地和不同程度的叶状体通风（作为内叶状体腔和内部空气空间）。我们还探讨了如何操作的生物物理的碳浓缩机制（CCM）回火同位素歧视的特点，在其他两个金鱼藻，以及绿色藻类Coleochaete orbicularis和衣藻reinhardtii。D的大小进行了比较，为每个生命形式的干燥曲线，并用于获得表面液相电导（润湿时）和内部电导（在最佳TWC）。外部和内部电导的大小，和WUE，是较高的通风，与不通风，地钱和金鱼藻相比，但各组内的值是相似的，这表明这两个因素已被优化为每个生命形式。对于金鱼藻而言，巨角蕨和金鱼藻的CCM渗漏率最高。眼轮匝肌（约30%），C. reinhardtii生长在环境CO2浓度下。最后，CCM在藻类和金鱼藻的操作的证据被认为是在叶绿体蛋白核的可能的作用，作为这个神秘的细胞器的起源，结构和功能的陆地植物的进化过程中进行了探索。
A comparative study has been made of the photosynthetic physiological ecology and carbon isotope discrimination characteristics for modern-day bryophytes and closely related algal groups. Firstly, the extent of bryophyte distribution and diversification as compared with more advanced land plant groups is considered. Secondly, measurements of instantaneous carbon isotope discrimination ( D), photosynthetic CO2 assimilation and electron transport rates were compared during the drying cycles. The extent of surface diffusion limitation ( when wetted), internal conductance and water use efficiency ( WUE) at optimal tissue water content (TWC) were derived for liverworts and a hornwort from contrasting habitats and with differing degrees of thallus ventilation ( as intra-thalline cavities and internal airspaces). We also explore how the operation of a biophysical carbon-concentrating mechanism (CCM) tempers isotope discrimination characteristics in two other hornworts, as well as the green algae Coleochaete orbicularis and Chlamydomonas reinhardtii. The magnitude of D was compared for each life form over a drying curve and used to derive the surface liquid-phase conductance ( when wetted) and internal conductance ( at optimal TWC). The magnitude of external and internal conductances, and WUE, was higher for ventilated, compared with non-ventilated, liverworts and hornworts, but the values were similar within each group, suggesting that both factors have been optimized for each life form. For the hornworts, leakiness of the CCM was highest for Megaceros vincentianus and C. orbicularis (approx. 30%) and, at 5%, lowest in C. reinhardtii grown under ambient CO2 concentrations. Finally, evidence for the operation of a CCM in algae and hornworts is considered in terms of the probable role of the chloroplast pyrenoid, as the origins, structure and function of this enigmatic organelle are explored during the evolution of land plants.