Study On Physio-Biochemical Characteristics In The Developing Boll Of Sea Island Cotton (Gossypium Barbadense L.) Under The Condition Of Drip Irrigation Under Plastic Mulch In Southern Xinjiang

To study the dynamic changes and physio-biochemical characteristics in different parts of bolls at different developing stages, field experiments were conducted in Alaer, Xinjiang Province in 2006-2008 by using two Sea Island Cotton varieties. It should offer a theory basis for the high and regular yield and cultivating new varieties of cotton.In this experimental conditions, the fiber length, uniformity and gouge strength of YX-193 and XH-28 had on differences. However, their elongation and micronaire were significantly different. It was explained the effect of sowing dates to influence Sea Island Cotton bolls was more important, so early sowing time would be helpful to improve the quality of the fiber.The results showed that analysis of the dry matter accumulation showed an"S"type-curve and could be simulated with a Logistic equation. The length of time for all the boll parts to reach their maximum accumulation showed an order as: fiber > cotton seed > boll shell. Varity Youxi 193 reached the maximum accumulation 5 to 10 days later than variety Xinhai 28. With the development of boll, the assimilation in boll shell redistributed its assimilates and the ratio of boll shell to boll became higher. But the ratio of seeds to boll, the economic coefficient, and the ratio of seed cotton to boll shell weight became lower with the maturation of bolls. As for the contribution of boll shell to the weight of seed-cotton. The number of ovules, seeds and the percentage of seed weight correlated with the blooming time. Bolls of Youxi 193 were smaller than those of Xinhai 28 in terms of ovule and seed number per boll. However, its seed fertility was lower than that of Xinhai 28.The results suggested that on the aspect of physiological property, the chlorophyll content in boll shells of YX-193 and XH-28 was more and more rich by the florescences passed, it was explained that the ability of photosynthetic capacity and delaying senescence was stronger. The soluble protein content in boll shells of YX-193 and XH-28 was lower gradually, the soluble protein content in seeds was higher than other organs, it was explained that the nutrient was transported into seeds and fiber by boll shells. The catalase activity and peroxidase activity in boll shells and seeds of YX-193 and XH-28 , it was explained that the resistance of these two varieties was stronger. The ascorbic acid content in seeds was higher than other organs, it could stable the membrane's structure strongly. The invertase activity in fiber of Sea Island Cotton YX-193 and XH-28 was better than boll shells and seeds, it was proved that the load and unload ability in fiber was stronger, had advantages to fiber developing.The starch content in boll shells was lower, in seeds of Sea Island Cotton YX-193 and XH-28 was higher than other organs, it was explained that the accumulated carbohydrates could provide energy and more carbon skeleton for seeds and fiber.