Qiu Nianwei, Lu Qingtao, Lu Congming
Photosynthesis Research Centre, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
New Phytol. 2003 Aug;159(2):479-486. doi: 10.1046/j.1469-8137.2003.00825.x.
• Here, the effects of salinity (0-400 mM NaCl) on photosynthesis, photosystem II (PSII) efficiency and the xanthophyll cycle were investigated in the halophyte Atriplex centralasiatica grown under outdoor conditions. • Leaf sodium and chloride in leaves increased considerably whereas CO assimilation rate decreased. PSII efficiency (Φ ) and the efficiency of excitation energy capture by open PSII reaction centres decreased whereas nonphotochemical quenching (NPQ) increased significantly. There was no change in photochemical quenching (q ) in salt-adapted plants. Salinity induced no changes in the maximum efficiency of PSII photochemistry (F /F ) measured either at midday or at predawn. However, F /F values were c. 20% lower at midday than at predawn. • Contents of chlorophyll (a + b), neoxanthin, lutein and β-carotene were unchanged with increasing salt concentration, but zeaxanthan increased significantly, at the expense of violaxanthin. There was a linear relationship between the de-epoxidation state of the xanthophyll cycle and Φ , , and NPQ. • Our results suggest that A. centralasiatica shows high tolerance to both high salinity and photoinhibition and that the xanthophyll cycle played an important role in protecting photosynthetic apparatus from photoinhibitory damage. Tolerance of PSII to salinity and photoinhibition can be viewed as an important strategy for A. centralasiatica to grow in very high saline soil during the summer season with high irradiance.
• 在此，研究了盐度（0 - 400 mM NaCl）对生长在户外条件下的盐生植物中亚滨藜光合作用、光系统II（PSII）效率和叶黄素循环的影响。• 叶片中的钠和氯含量显著增加，而CO同化率下降。PSII效率（Φ）和开放PSII反应中心捕获激发能的效率降低，而非光化学猝灭（NPQ）显著增加。适应盐环境的植物的光化学猝灭（q）没有变化。盐度对中午或黎明前测量的PSII光化学最大效率（F /F）没有影响。然而，中午的F /F值比黎明前低约20%。• 叶绿素（a + b）、新黄质、叶黄素和β - 胡萝卜素的含量不随盐浓度增加而变化，但玉米黄质显著增加，同时紫黄质减少。叶黄素循环的脱环氧化状态与Φ、、和NPQ之间存在线性关系。• 我们的结果表明，中亚滨藜对高盐度和光抑制均表现出高耐受性，并且叶黄素循环在保护光合机构免受光抑制损伤方面发挥了重要作用。PSII对盐度和光抑制的耐受性可视为中亚滨藜在夏季高光照下于高盐土壤中生长的重要策略。
