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棉 花 学 报 Cotton Science 2008，20(3)：212-216
Effect of Sand Priming on the NaCl Tolerance of Seed of Transgenic Insect Resistant Cotton ( Gossypium hirsutum L.) Abstract：The effect of seed priming with sand on the seed germination, seedling emergence, the characters of seeding growth and development of the transgenic insect resistant cotton stressed with different concentrations of NaCl was studied, using two extending transgenic insect resistant cotton cultivars, CCRI 41 and Z-905, as materials and their genetic background cultivar, CCRI 23, as check. The results indicated that it was harmful for the seed germination and field emergence of the upland cotton seeds when they were treated with different concentration of NaCl. The germination percentage and field emergence of the transgenic insect resistant cotton cultivars stressed by NaCl were much lower than those of their genetic background check. However, priming treatment with sand could alleviate the harm of the NaCl stress significantly. After the treatment of seed priming, the germination percentage and seedling emergence on the condition of NaCl stress were increased significantly, and the seed tolerance to the salt stress was enhanced greatly, especially for the transgenic insect resistant cotton cultivars. There were great differences in the effect of the seed priming treatments on the seed germination and field emergence, stressed by NaCl, between the transgenic insect resistant cotton and their genetic background one; and the formers, with weaker tolerance against NaCl stress, had a better effect than that of their genetic background one without exogenous insect resistant genes. The results of biochemical analysis showed that the activities of peroxidase (POD) and superoxide dismutase (SOD) in cotyledons and roots of cotton seedling increased significantly, but decreased dramatically for the content of malondialdehyde (MDA), when they were treated by seed priming with sand, comparing with the check. This experiment indicated that sand priming for cotton seed could enhance the salt tolerance of seedlings due to increasing the antioxidant enzyme activity and reducing the malondialdehyde (MDA) accumulating in the cotton seedlings, which suggested that sand priming may help to improve seedling establishment and enhance the ability of salt tolerance in cotton.
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