State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 83001, China; Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China; Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, Xinjiang, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 83001, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Plant Physiol Biochem. 2024 Sep;214:108911. doi: 10.1016/j.plaphy.2024.108911. Epub 2024 Jul 4.
Soil salinization effects plant photosynthesis in a number of global ecosystems. In this study, photosynthetic and physiological parameters were used to elucidate the impacts of saline-alkaline stress on Cyperus esculentus L. (C. esculentus) seedling photosynthesis. The results demonstrate that salt stress, alkali stress and mixed salt and alkali stress treatments all have similar bell-shaped influences on photosynthesis. At low concentrations (0-100 mmol L), saline-alkaline stress promoted net photosynthetic rate, transpiration rate and water use efficiency in C. esculentus. However, as the treatments increased in intensity (100-200 mmol L), plant photosynthetic parameters began to decline. We interpreted this as the capacity of C. esculentus to improve osmoregulatory capacity in low saline-alkaline stress treatments by accumulating photosynthetic pigment, proline and malondialdehyde to counterbalance the induced stress - an adaptive mechanism that failed once concentrations reached a critical threshold (100 mmol L). Stomatal conductance, maximum photosynthetic rate and actual photosynthetic rate all decreased with increasing concentration of the stress treatments, and intercellular carbon dioxide showed a decreasing and then increasing trend. These results indicated that when the saline-alkaline stress concentrations were low, C. esculentus seedlings showed obvious adaptive ability, but when the concentration increased further, the physiological processes of C. esculentus seedlings were significantly affected, with an obvious decrease in photosynthetic efficiency. This study provides a new understanding of the photosynthetic adaptation strategies of C. esculentus seedlings to varying concentrations of saline-alkaline stress.
土壤盐渍化对许多全球生态系统中的植物光合作用产生影响。本研究利用光合作用和生理参数阐明了盐碱性胁迫对香蒲（Cyperus esculentus L.）幼苗光合作用的影响。结果表明，盐胁迫、碱胁迫和混合盐碱性胁迫处理对光合作用均有相似的钟形影响。在低浓度（0-100mmol/L）下，盐碱性胁迫促进了香蒲的净光合速率、蒸腾速率和水分利用效率。然而，随着处理强度的增加（100-200mmol/L），植物的光合参数开始下降。我们将其解释为香蒲通过积累光合色素、脯氨酸和丙二醛来提高在低盐碱性胁迫处理中的渗透调节能力，以抵消诱导的胁迫——一旦浓度达到临界阈值（100mmol/L），这种适应机制就会失效。气孔导度、最大光合速率和实际光合速率均随胁迫处理浓度的增加而降低，胞间二氧化碳呈先降低后升高的趋势。这些结果表明，当盐碱性胁迫浓度较低时，香蒲幼苗表现出明显的适应能力，但当浓度进一步增加时，香蒲幼苗的生理过程受到明显影响，光合效率明显下降。本研究为了解香蒲幼苗对不同浓度盐碱性胁迫的光合作用适应策略提供了新的认识。
