Photosynthetic acclimation is important for post-submergence recovery of photosynthesis and growth in two riparian species
Photosynthetic acclimation is important for post-submergence recovery of photosynthesis and growth in two riparian species
复制标题
光合适应对于两种河岸物种的光合作用和生长的淹没后恢复很重要
DOI：
10.1093/aob/mcp257
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发表时间：
2009-12-01
期刊：
影响因子：
4.2
通讯作者：
Matsubara, Shizue
中科院分区：
文献类型：
--
作者：
Luo, Fang-Li;Nagel, Kerstin A.;Matsubara, Shizue
水淹时伴随的O-2和光照度的增加会对植物的光合器官造成光抑制和光氧化损伤。由于生长需要光合作用提供能量和碳水化合物，推测淹水后的生长恢复可能需要高效的光合作用适应增加的O2和光照，以最大限度地减少光氧化损害。这一假设在两个耐涝物种身上得到了验证：C-3草本植物--喜旱莲子草和C-4草本植物--高山牛鞭草。采用不同淹水处理与遮荫相结合的方法，研究了浑浊洪水中典型的低O-2和低光照条件对淹后恢复的影响。试验在淹水30d(淹水或淹水)期间进行，在生长条件下进行，恢复时间为20d。记录干质量、分枝/分蘖数、最长节间和主茎长度的变化以表征生长反应。根据叶绿素a荧光测定，测定了成熟叶片的光合作用参数(光系统II效率和非光化学猝灭)，在淹水处理结束后，物种的生长和光合作用都恢复了，光合作用的恢复(开始于去淹后不久)先于生长恢复(在第40-50天显著)。光系统II和非光化学猝灭的有效量子效率在淹水过程中降低，而在去淹过程中迅速增加。在所有遮荫植物中都发现了类似的变化，无论是否有洪水。沉水植物在整个恢复期内没有受到光抑制，但其生长恢复受到了延缓。在突然退水后，C-3植物水华和C-4植物高山松都能够通过快速适应变化的O-2和光条件来维持光合作用的功能。光合作用适应能力对于适应水位波动的湿地生境可能是必不可少的。
Concomitant increases in O-2 and irradiance upon de-submergence can cause photoinhibition and photo-oxidative damage to the photosynthetic apparatus of plants. As energy and carbohydrate supply from photosynthesis is needed for growth, it was hypothesized that post-submergence growth recovery may require efficient photosynthetic acclimation to increased O-2 and irradiance to minimize photo-oxidative damage. The hypothesis was tested in two flood-tolerant species: a C-3 herb, Alternanthera philoxeroides; and a C-4 grass, Hemarthria altissima. The impact of low O-2 and low light, typical conditions in turbid floodwater, on post-submergence recovery was assessed by different flooding treatments combined with shading.Experiments were conducted during 30 d of flooding (waterlogging or submergence) with or without shading and subsequent recovery of 20 d under growth conditions. Changes in dry mass, number of branches/tillers, and length of the longest internodes and main stems were recorded to characterize growth responses. Photosynthetic parameters (photosystem II efficiency and non-photochemical quenching) were determined in mature leaves based on chlorophyll a fluorescence measurements.In both species growth and photosynthesis recovered after the end of the submergence treatment, with recovery of photosynthesis (starting shortly after de-submergence) preceding recovery of growth (pronounced on days 40-50). The effective quantum yield of photosystem II and non-photochemical quenching were diminished during submergence but rapidly increased upon de-submergence. Similar changes were found in all shaded plants, with or without flooding. Submerged plants did not suffer from photoinhibition throughout the recovery period although their growth recovery was retarded.After sudden de-submergence the C-3 plant A. philoxeroides and the C-4 plant H. altissima were both able to maintain the functionality of the photosynthetic apparatus through rapid acclimation to changing O-2 and light conditions. The ability for photosynthetic acclimation may be essential for adaptation to wetland habitats in which water levels fluctuate.