| Cite this article: | Mounkaila Hamani Abdoul Kader,申孝军,陈津赛,等.水盐胁迫下棉花叶片光合的气孔限制与非气孔限制[J].灌溉排水学报,0,():-. |
| Mounkaila Hamani Abdoul KADER,SHEN Xiaojun,CHEN Jinsai,et al.水盐胁迫下棉花叶片光合的气孔限制与非气孔限制[J].灌溉排水学报,0,():-. |
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| Stomatal and non-stomatal limitation of leaf photosynthesis for cotton seedling under water and salinity stress |
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Mounkaila Hamani Abdoul KADER, SHEN Xiaojun, CHEN Jinsai, WANG Guangshuai, GAO Yang
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Farmland Irrigation Research Institute,Chinese Academy of Agricultural Sciences
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| Abstract: |
| 【Background】Drought and salt stress are the main abiotic stress on crop production in arid and semi-arid regions as well as high-salt areas. The elevated concentration of salt in the soil is the most violent abiotic stress, restricting plant productivity for about 20% of irrigated lands worldwide. NaCl-induced salinity has currently gained a keen interesting concern in the field of abiotic stress research on non-halophytic plants. NaCl stress lead to numerous variations in plants metabolism such as ion toxicity and low water potential. Cotton as largest fiber source for textiles worldwide is classified as a medium salt-tolerant crop, while its growth and development are still dramatically decreased under high saline conditions, particularly at the seedling stage. Photosynthesis is a process in which plants use light energy to fix CO2 in the atmosphere to synthesize organic matter, but it is often inhibited by biotic and abiotic stress. Leaf photosynthesis is the most important phenomena in response to salinity stress. At present, the evidence remains controversial in whether stomatal restriction or non-stomatal restriction is the main factor to inhibit the photosynthetic rate of plant leaves under water and salt stress, and some studies believe that it is the result of the combined action of stomatal factors and non-stomatal factors. Therefore, understanding the limiting factors of water and salt stress on cotton leaf photosynthesis is of great theoretical and practical significance to reveal the stress resistance mechanism of cotton and ensure the high and stable yield of cotton.【Objective】The objective is to understand the limitation mechanism of water and salinity stress to leaf photosynthesis in plants.【Method】Pot experiments were conducted in a phytotron to investigate effects of different treatments of water and salinity stress on stomatal characteristics and pigment content, leaf photosynthesis rate and chlorophyll fluorescence. The experiments were comprised with four treatments, i.e. T1-without stress of water and salinity, T2- water stress, T3- salinity stress, T4- water and salinity stress.【Result】Compared with T1, the water stress in T2 decreased the stomatal length and width of cotton seedling leaves insignificantly, while markedly reduced the stomatal density. Stomatal characteristics (length, width and density) of cotton seedling leaves in T3 and T4 were decreased significantly, whereas the difference between T3 and T4 was not significant. Leaf pigment content (chlorophyll a and b, and carotenoid) of cotton seedling in difference treatments of stress was significantly reduced compared with T1, while the difference in carotenoid between T3 and T4 was significant. Different stress treatments markedly decreased leaf photosynthesis rate of cotton seedlings. Leaf photosynthesis of cotton seedling in T1 was mainly limited by biochemical characteristics. The average value of stomatal and mesophyll limitation to leaf photosynthesis in T2, T3 and T4 was 0.38 and 0.35, respectively, indicating that decline of leaf photosynthesis rate was primarily controlled by stomatal and mesophyll limitation. When leaf photosynthesis was inhibited, the cotton seedlings dissipated the excess energy by heat dissipation principally. 【Conclusion】Under the condition of water and salinity stress, the cotton leaf photosynthesis was inhibited both by stomatal and mesophyll limitation. |
| Key words: salinity stress; water stress; photosynthesis rate; stomatal limitation; non-stomatal limitation |
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