The Mediterranean evergreen Quercus ilex and the semi-deciduous Cistus albidus differ in their leaf gas exchange regulation and acclimation to repeated drought and re-watering cycles.
The Mediterranean evergreen Quercus ilex and the semi-deciduous Cistus albidus differ in their leaf gas exchange regulation and acclimation to repeated drought and re-watering cycles.
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DOI：
10.1093/jxb/err233
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发表时间：
2011-10
影响因子：
6.9
通讯作者：
Flexas J
中科院分区：
文献类型：
--
作者：
Galle A;Florez-Sarasa I;Aououad HE;Flexas J
植物在经历干旱后可能表现出一定程度的适应，但对干旱和再浇水（恢复）连续循环的生理调节几乎没有研究。地中海常绿holm oak （Q. ilex）和半落叶岩玫瑰（C. albidus）在三个干旱周期（S1、S2和S3）的第一个周期后表现出一定程度的驯化。例如，在S2和S3期间，尽管叶片水势相似，但两种植物的叶片相对含水量均高于S1。然而，两种植物对重复干旱循环的光合适应表现出显著差异。在三个循环中，两种植物的光合作用下降幅度相似（为对照值的20-40%）。然而，在S1和S2处理后，由于气孔和叶肉对CO2的导度持续降低，霍尔木姆的光合作用仅恢复到对照值的80%。叶片内在水分利用效率（WUE）在整个试验过程中基本保持不变。相比之下，岩花的光合作用在每个干旱周期后几乎完全恢复（为对照值的90-100%），而用水效率在S1后大幅且永久地增加（根据天数不同，增加50-150%）。这是由于一种调节方法，即保持较低的gm（重新浇水后恢复到控制值的50-60%），同时保持较高的gm（重新浇水时甚至超过控制值）。虽然实现水分和二氧化碳在叶片中扩散的这种特殊调节的机制尚不清楚，但它显然代表了该物种在干旱周期后的独特驯化特征，这使得它在连续干旱事件中表现更好。因此，对重复干旱周期的光合适应差异可能对气候变化情景框架内不同地中海物种或生长形式的相对适合度产生重要影响。
Plants may exhibit some degree of acclimation after experiencing drought, but physiological adjustments to consecutive cycles of drought and re-watering (recovery) have scarcely been studied. The Mediterranean evergreen holm oak (Q. ilex) and the semi-deciduous rockrose (C. albidus) showed some degree of acclimation after the first of three drought cycles (S1, S2, and S3). For instance, during S2 and S3 both species retained higher relative leaf water contents than during S1, despite reaching similar leaf water potentials. However, both species showed remarkable differences in their photosynthetic acclimation to repeated drought cycles. Both species decreased photosynthesis to a similar extent during the three cycles (20–40% of control values). However, after S1 and S2, photosynthesis recovered only to 80% of control values in holm oak, due to persistently low stomatal (gs) and mesophyll (gm) conductances to CO2. Moreover, leaf intrinsic water use efficiency (WUE) was kept almost constant in this species during the entire experiment. By contrast, photosynthesis of rockrose recovered almost completely after each drought cycle (90–100% of control values), while the WUE was largely and permanently increased (by 50–150%, depending on the day) after S1. This was due to a regulation which consisted in keeping gs low (recovering to 50–60% of control values after re-watering) while maintaining a high gm (even exceeding control values during re-watering). While the mechanisms to achieve such particular regulation of water and CO2 diffusion in leaves are unknown, it clearly represents a unique acclimation feature of this species after a drought cycle, which allows it a much better performance during successive drought events. Thus, differences in the photosynthetic acclimation to repeated drought cycles can have important consequences on the relative fitness of different Mediterranean species or growth forms within the frame of climate change scenarios.
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影响因子：
6.4
作者：
Galmes, Jeroni;Abadia, Anunciacion;Flexas, Jaume
通讯作者：
Flexas, Jaume
影响因子：
9.4
作者：
Galmes, Jeroni;Medrano, Hipolito;Flexas, Jaume
通讯作者：
Flexas, Jaume
影响因子：
4.2
作者：
Flexas, J;Medrano, H
通讯作者：
Medrano, H
影响因子：
4.2
作者：
Chaves, MM;Pereira, JS;Pinheiro, C
通讯作者：
Pinheiro, C
影响因子：
7.4
作者：
HARLEY, PC;LORETO, F;SHARKEY, TD
通讯作者：
SHARKEY, TD