Does the photosynthetic light-acclimation need change in leaf anatomy?
Does the photosynthetic light-acclimation need change in leaf anatomy?
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DOI：
10.1046/j.1365-3040.2003.00981.x
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发表时间：
2003-04-01
影响因子：
7.3
通讯作者：
Hirose, T
中科院分区：
文献类型：
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作者：
Oguchi, R;Hikosaka, K;Hirose, T
叶片厚度与单位叶面积光饱和光合速率（P-max）之间有很强的相关性。然而，当叶片成熟后暴露于更高的光照强度时，P-max通常增加而不增加叶片厚度。为阐明藜成熟叶片P-max增加的机理，研究了藜成熟叶片从弱光到强光转换过程中的解剖和生理特性变化。与连续弱光处理的叶片（LL叶）相比，弱光转强光处理的叶片（LH叶）P-max显著增加。同时，叶绿体向胞间隙的面积（S-c）也增加，并保持了P-max与S-c之间的强相关性。LL叶片的叶肉细胞在细胞壁沿着有空隙，叶绿体缺失，这使得叶片在强光（LH）下能够增加P-max。然而，LH叶不够厚以允许P-max进一步增加到HH叶中的水平。因此，叶片厚度决定了从低光条件到高光条件变化的叶片P-max的上限。遮荫叶只有在有开放空间容纳叶绿体时才能增加P-max，叶绿体在光照条件改善后伸长。
There is a strong correlation between leaf thickness and the light-saturated rate of photosynthesis per unit leaf area (P-max). However, when leaves are exposed to higher light intensities after maturation, P-max often increases without increasing leaf thickness. To elucidate the mechanism with which mature leaves increase P-max, the change in anatomical and physiological characteristics of mature leaves of Chenopodium album, which was transferred from low to high light condition, were examined. When compared with leaves subjected to low light continuously (LL leaves), the leaves transferred from low to high light (LH leaves) significantly increased P-max. The transfer also increased the area of chloroplasts facing the intercellular space (S-c) and maintained a strong correlation between P-max and S-c. The mesophyll cells of LL leaves had open spaces along cell walls where chloroplasts were absent, which enabled the leaves to increase P-max when they were exposed to high light (LH). However, the LH leaves were not thick enough to allow further increase in P-max to the level in HH leaves. Thus leaf thickness determines an upper limit of P-max of leaves subjected to a change from low to high light conditions. Shade leaves would only increase P-max when they have open space to accommodate chloroplasts which elongate after light conditions improve.