Photosynthetic acclimation and photoinhibition on exposure to high light in shade-developed leaves of Fagus crenata seedlings
Photosynthetic acclimation and photoinhibition on exposure to high light in shade-developed leaves of Fagus crenata seedlings
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DOI：
10.1016/j.flora.2005.04.008
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发表时间：
2006-01-01
期刊：
影响因子：
1.9
通讯作者：
Kakubari, Y
中科院分区：
文献类型：
--
作者：
Naramoto, M;Katahata, S;Kakubari, Y
研究了钝齿水青冈幼苗在弱光（L）下发育的叶片对不同强度强光（H：强光，M：中光）照射的生理反应。对毛茛林林下盆栽幼苗进行了测定。在夏季，将L中已长出叶片的幼苗转移到H（L-H）和M（L-M）中。在强光照射下，暗适应的PS Ⅱ光化学效率（F-v/F-m）立即下降，随后在L-H和L-M叶片中恢复。通过实验发现，L-H叶片的F-v/F-m平均值低于L-M叶片，说明L-H叶片的光抑制程度大于L-M叶片。转移后约1个月，L-H和L-M幼苗分别有37%和5%的叶子脱落。这一结果也表明L-H叶片中存在较大的光抑制。此外，L-H叶片的光合能力（P-Nmax）下降。相反，L-M叶片的P-Nmax增加，但P-Nmax低于M对照。叶黄素循环库（VAZ）的增加，表明光保护功能的增加，在L-H和L-M叶片中被发现。特别是在试验结束时，L-M叶片的VAZ库高于M叶片。与L-H叶片相比，L-M叶片可通过增加P-Nmax或VAZ库来减少过量光，从而有效地避免光抑制。因此，强光下的生理适应取决于强光的强度。由于过量光的差异，强光照射前后光强的变化是影响光合适应的重要因素。(c)2005年Elsevier GmbH。All rights reserved.
The physiological response of leaves developed in low light (L) on Fagus crenata seedlings exposed to different levels of high light (H: high light, M: medium light) was studied. Measurements were conducted on potted seedlings in the F crenata forest understory. The seedlings with leaves developed in L were transferred to H (L-H) and M (L-M) in summer. On exposure to high light, the photochemical efficiency of dark-adapted PSII (F-v/F-m) immediately decreased and was followed by a subsequent recovery in both L-H and L-M leaves. The mean value of F-v/F-m in L-H leaves was lower than that in L-M leaves through experiments, indicating that the degree of photoinhibition in L-H leaves was greater than that in L M leaves. About I month after transfer, 37% and 5% of leaves had fallen in L-H and L-M seedlings, respectively. This result also indicated the greater photoinhibition in L-H leaves. Moreover, the photosynthetic capacity (P-Nmax) of L H leaves decreased. In contrast, the P-Nmax of L-M leaves increased, although the P-Nmax was lower than that of M control leaves. An increase in the xanthophyll cycle pool (VAZ), indicating an increase of the photoprotective function, was found in both L-H and L-M leaves. Especially, the VAZ pool in L-M leaves was higher than that in M leaves by the end of experiments. L-M leaves may avoid photoinhibition effectively by the decrease in excess light with the increase of the P-Nmax or VAZ pool, compared to L-H leaves. Thus, the physiological acclimation on exposure to high light depended on the degree of high light. To achieve successful photosynthetic acclimation with slight photoinhibition, the variation of light intensity before and after exposure to high light would be an important factor because of the difference in excess light. (c) 2005 Elsevier GmbH. All rights reserved.