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用咸水(不同浓度的Na Cl溶液)浇灌盆栽棉花植株,随后进行持续干旱处理.测定干旱处理期间棉花的生长情况、光合速率、叶绿素荧光等参数的变化,并对植株的相对含水量、水势、渗透势等水分状况和Na+、K+含量进行分析,探索环境Na+在棉花适应干旱胁迫中的作用.结果表明:干旱可以明显抑制植株的生长,降低叶片的净光合速率;用25~100mmol·L-1Na Cl溶液浇灌后进行持续干旱处理的棉花植株,其株高、生物量、净光合速率和Fv/Fm值均明显高于用水浇灌后进行持续干旱处理的植株.同时,前者的土壤和叶片相对含水量、细胞膨压、Na+含量也明显高于后者,但植株水势和组织渗透势则显著低于后者,且组织渗透势的降低与Na+含量具有显著相关性.上述结果说明,土壤适量Na+的存在能够提高土壤和植株的保水力、增加棉花对Na+的吸收和积累、降低组织渗透势,从而增强植株吸水力、保持较高的细胞膨压,维持相对较高的光合速率和生长速度.土壤中存在一定浓度的Na Cl可以有效缓解干旱对棉花的不利影响.
Potted cotton plants were drenched with saltwater (NaCl solution of different concentrations), followed by continuous drought treatment.The changes of cotton growth, photosynthetic rate, chlorophyll fluorescence and other parameters during the drought treatment were measured, and the relative water content, water potential , Osmotic potential and other water status and Na +, K + content were analyzed to explore the role of environmental Na + in cotton adaptation to drought stress.The results showed that: drought can significantly inhibit plant growth and reduce the net photosynthetic rate of leaves; with 25 ~ 100mmol·L The plant height, biomass, net photosynthetic rate and Fv / Fm of cotton plants that were droughted with -1Na Cl solution after watering were significantly higher than those of the plants treated with water after continuous watering.At the same time, the former soil and leaf Relative water content, cell turgor and Na + content were also significantly higher than the latter, but plant water potential and tissue osmotic potential were significantly lower than the latter, and tissue osmotic potential decreased significantly with the Na + content of the above results show that soil The presence of the proper amount of Na + can increase the water holding capacity of soil and plant, increase the cotton’s absorption and accumulation of Na +, reduce the tissue osmotic potential and enhance the water absorption of the plant , To maintain a high cell turgor pressure, maintaining a relatively high photosynthetic rate and growth rate. Certain concentration in the soil Na Cl can effectively alleviate the adverse effects of drought on cotton.