盐胁迫对不同基因型棉花苗期光合特性和养分吸收的影响

为探讨盐胁迫对苗期不同棉花品种光合作用和养分吸收的影响，以盐敏感型中棉所45和耐盐品种中棉所35为材料，通过盆栽试验研究盐胁迫对棉花光合特性与养分吸收的影响。结果表明，盐分胁迫显著降低了棉花根、茎、叶和整株的干物质质量积累以及光合特性，与CK相比，棉花整株的干物质质量、净光合速率、气孔导度和蒸腾速率分别下降了39.1%~40.1%、33.9%~41.1%、34.3%~36.6%和27.7%~28.8%，耐盐品种降低幅度较盐敏感品种小。盐分胁迫也显著抑制棉花对N、P、K养分的吸收积累，降低棉花叶中叶绿素含量。盐胁迫下，棉花苗期光合速率下降的原因是由非气孔限制引起，光合参数和养分吸收与基因型抗性密切相关。上述结果为棉花栽培管理、耐盐机制及盐碱地改良提供了理论依据。

Effects of Salt Stress on Root Morphology and Physiological Characteristics of Potted Cotton at Seedling Stage

In order to discuss the impact of salt stress on photosynthesis and nutrient uptake of different cotton varieties at seedling stage and providing a theoretical basis for cotton cultivation management, salt tolerance mechanism and saline land improvement, this paper took salt sensitive cultivar (CCRI45) and salt tolerant cultivar (CCRI35) as materials, and conducted pot experiments to investigate the effect of salt stress on cotton photosynthesis character and nutrient adsorption. Results showed that salt stress significantly decreased the dry matter accumulation of cotton root, stem, leaf, whole plant and photosynthesis characteristic. Compared with the CK, the dry matter weight of whole cotton plant, net photosynthetic rate, stomatal conductance and transpiration rate decreased by 39.1%~40.1%, 33.9%~41.1%, 34.3%~36.6% and 27.7%~28.8%, respectively. The decreasing range of salt tolerant varieties was smaller than that of the salt sensitive varieties. The salt stress also significantly inhibited the adsorption and accumulation of N, K and P nutrients, and reduced the content of chlorophyll SPAD in cotton leaves. The decrease of net photosynthetic rate under salt stress was caused by no-stomatal restriction. Photosynthetic parameters and nutrient uptake were closely correlated with the resistance of genotype.