Lessons from relatives: C4 photosynthesis enhances CO 2 assimilation during the low-light phase of fluctuations
Lessons from relatives: C4 photosynthesis enhances CO 2 assimilation during the low-light phase of fluctuations
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亲戚的经验教训：C4光合作用在波动的弱光阶段增强CO 2 同化
DOI：
10.1101/2023.04.03.535443
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Arce Cubas L
中科院分区：
文献类型：
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作者：
Arce Cubas L
尽管具有c4光合作用的物种具有全球重要性，但对于波动光下的c4表现缺乏共识。对比假设和实验证据表明，c4光合作用在波动光下固定碳的效率低于或高于原始的c3形式。已经确定了可能缺乏共识的两个主要问题：忽略了选定的c3和c4物种之间的进化距离，以及使用对比波动光处理。为了避免这些问题，我们在3个独立的系统发育控制的比较中测量了malloteropsis，Flaveria和cleomegenera的c3和c4物种在21%和2% O2下对波动光的光合反应。叶片受到光强（800和100µmol m−2s−1光子通量密度）的重复逐步变化，有3种不同的持续时间：6、30和300 s。这些实验与之前的研究结果一致，并表明(1)在低光照阶段，c4物种对co2同化的刺激比c3物种更强、更持久；（ii）高光期co2同化模式可能与物种或c4亚型差异有关，而非光合途径；(3)波动状态中每个轻步的持续时间对实验结果有很大影响。
Despite the global importance of species with C4photosynthesis, there is a lack of consensus regarding C4performance under fluctuating light. Contrasting hypotheses and experimental evidence suggest that C4photosynthesis is either less or more efficient in fixing carbon under fluctuating light than the ancestral C3form. Two main issues have been identified that may underly the lack of consensus: neglect of evolutionary distance between selected C3and C4species and use of contrasting fluctuating light treatments. To circumvent these issues, we measured photosynthetic responses to fluctuating light across 3 independent phylogenetically controlled comparisons between C3and C4species fromAlloteropsis,Flaveria, andCleomegenera under 21% and 2% O2. Leaves were subjected to repetitive stepwise changes in light intensity (800 and 100µmol m−2s−1photon flux density) with 3 contrasting durations: 6, 30, and 300 s. These experiments reconciled the opposing results found across previous studies and showed that (i) stimulation of CO2assimilation in C4species during the low-light phase was both stronger and more sustained than in C3species; (ii) CO2assimilation patterns during the high-light phase could be attributable to species or C4subtype differences rather than photosynthetic pathway; and (iii) the duration of each light step in the fluctuation regime can strongly influence experimental outcomes.