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棉 花 学 报 Cotton Science 2008，20(3)：203-206
Combined Effects of Waterlogging and Salinity on Plant Growth and Some Physiological Parameters in Cotton Seedling Leaves Abstract：Salinity and waterloging are two important abiotic stresses to agricultural production. Since the period of plant growth and development of cotton and the rainy season overlap, a combination of waterloging and salinity may occur in saline cotton field, but the effect of the combined stress on cotton is still not well documented. In attempt to investigate the single and the combined effects of waterlogging and salinity on cotton ( Gossypium hirsutum L.), two cotton varieties (SCRC17 and SCRC28) were cultured and treated with either fresh water (CK), salinity, waterlogging or a combination of both stresses at the 3 true-leaf stage in a greenhouse. The photosynthetic rate (Pn), chlorophyll fluorescence parameters, chlorophyll contents in seedling leaves and plant dry weight were examined at 14 d after stress. The results showed that salinity, waterlogging or the combination significantly reduced Pn and dry weight for both cultivars ， but the effect of waterlogging was significantly greater than that of salinity, and that of the combination of both stresses was greater than either stress alone. A significantly combined inhibitory effect on plants growth and leaf photosynthesis was observed in the combination treatment. The decreased Pn under salinity stress was greatly attributed to the decline of leaf chlorophyll contents, while the decreased Pn under waterlogging and a combination of both stresses might be attributed to the reduced stability of chloroplast and PS Ⅱ. It is suggested that improvement in irrigation and drainage in saline cotton field is a practical way to enhance cotton yield and fiber quality.
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