Diel leaf growth cycles in Clusia spp. are related to changes between C3 photosynthesis and crassulacean acid metabolism during development and during water stress.
Diel leaf growth cycles in Clusia spp. are related to changes between C3 photosynthesis and crassulacean acid metabolism during development and during water stress.
复制标题
Clusia spp 的昼夜生长周期。
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
B. Osmond
中科院分区：
文献类型：
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作者：
A. Walter;M. M. Christ;U. Rascher;U. Schurr;B. Osmond
这项研究报告的证据表明，叶子生长的时间对 Clusia spp 的发育和环境限制有反应。我们使用成像方法监测了兼性 C(3)-景天酸代谢 (CAM) 物种 Clusia minor 和假定专性 CAM 物种 Clusia alata 中叶片生长的昼夜模式，并跟踪了 CO2 交换和酸化的昼夜模式。浇水充足的 C.minor 发育中的叶子表现出类似 C3 的气体交换和生长模式，在夜间初期具有最大相对生长率 (RGR)。当停止浇水时，生长减慢，并伴有夜间 CO2 交换和 CAM 的二酸变化特征。当停止浇水时，最大叶片 RGR 从深夜转移到清晨。在浇水良好的 C. alata 中，随着叶子个体发育期间 CAM 的发育，叶子生长的昼夜模式也会发生类似的变化。我们假设，伴随着从 C3 光合作用向 CAM 转换的叶片生长周期的转变，主要是由于 CAM 对夜间 CO2 固定和酸合成的底物的主要需求，从而减少了叶片夜间生长所需的碳水化合物的可用性。尽管在光照下叶子生长的转变可能与碳水化合物的可用性、源库关系和 Clusia spp 幼叶中持续的昼夜酸水平有关。需要对生长过程进行进一步评估。
This study reports evidence that the timing of leaf growth responds to developmental and environmental constraints in Clusia spp. We monitored diel patterns of leaf growth in the facultative C(3)-crassulacean acid metabolism (CAM) species Clusia minor and in the supposedly obligate CAM species Clusia alata using imaging methods and followed diel patterns of CO2 exchange and acidification. Developing leaves of well-watered C. minor showed a C3-like diel pattern of gas exchange and growth, with maximum relative growth rate (RGR) in the early night period. Growth slowed when water was withheld, accompanied by nocturnal CO2 exchange and the diel acid change characteristic of CAM. Maximum leaf RGR shifted from early night to early in the day when water was withheld. In well-watered C. alata, similar changes in the diel pattern of leaf growth occurred with the development of CAM during leaf ontogeny. We hypothesize that the shift in leaf growth cycle that accompanies the switch from C3 photosynthesis to CAM is mainly caused by the primary demand of CAM for substrates for nocturnal CO2 fixation and acid synthesis, thus reducing the availability of carbohydrates for leaf growth at night. Although the shift to leaf growth early in the light is presumably associated with the availability of carbohydrates, source-sink relationships and sustained diurnal acid levels in young leaves of Clusia spp. need further evaluation in relation to growth processes.