Responses Of Carbohydrate Metabolism In Upland Cotton Fibers To Water Deficit And Its Relationship With Fiber Elongation

In mid-July to mid-August, there will be midsummer drought in the Yangtze River cotton region, this time is in full bloom, water deficiency often leads to decreased fiber length, and low fiber quality. With A001 and A705 as materials, pot method, different soil moisture treatments(normal irrigation, drought), and observed cotton fiber elongation differences. The dynamic changes of cell osmotic adjustment substances(glucose, fructose,hexose, sucrose, starch, total sugar) and key enzymes(SS, SPS, VIN) in the cotton growing fiber was researched the difference between genotype and fiber elongation.The dynamic changes of osmotic regulation substance on the cotton stretch cottonseed was researched the relationship between the genotype differences and fiber elongation. Obtain the following main research results:1. With Logistic growth equation to the fiber length of the A001 and A705 forming process to simulating, which cotton fiber length was fitting equation dynamic growth and reaching a significant level. Soil drought made cotton fiber length to shorter, but there is have a different reaction for different genotypes. A001 fiber length were significantly different in different treatment, A705 was no significant difference among different treatments. A001 fiber elongation showed sensitive to drought stress, but A705 is not sensitive to drought stress.2. Compared with normal irrigation, the soil drought lead to cotton fiber soluble sugar(glucose, fructose, total sugar and sucrose) content drop, the fiber osmosis rise and the pressure drop, eventually fiber length change shorter during cotton fiber elongation stage.In different genotypes fiber, which soluble of total sugar content changes to soil drought stress responses are different. In boll 12 d, 15 d, 18 d, 21 d, 24 d, 27 d and 30 d, A001 fiber soluble sugar content were significantly or very significantly lower than the normal irrigation under the soil drought.In boll 12 d, 18 d and 21 d, A705 fiber total soluble sugar content were significantly lower than the normal irrigation. The results support the A001 fiber elongation is sensitive to drought stress, A705 insensitive response to drought stress.3. Compared with normal irrigation, soil drought caused key enzymes activities of carbon metabolism(VIN, SS, SPS) decreased in the cotton fiber elongation stage. Acid invertase and sucrose enzymes decomposed one molecule of sucrose into hexose or which its derivative. As to, two enzyme activities under drought conditions may decreased,solute concentration decreased, the fiber osmosis rise and the pressure drop, eventually inhibiting fiber elongation. Different genotypes fiber metabolism enzyme activity in response to drought stress is different. In boll 6d, 12 d, 15 d and 18 d, A001 fiber vacuolar acid invertase activities(VIN) were significantly or very significantly lower than the control under drought treatment. Except for boll 24 d, other boll age of A705 which VIN enzymes activity were not significantly differences between treatments. In the boll 3d, 15 d,21d and 24 d, A001 fiber that SS enzymes activity were significantly or very significantly lower than the control under drought stress; Except for boll 6d, other boll age of A705 which fiber SS enzymes activities had no significant difference between treatments. The results support that the A001 fiber elongation is sensitive to drought stress, A705 insensitive response to drought stress.