Studies On Accumulation Characteristics Of Tocopherol In Cottonseed Kernels And Its Effects On Differentiation And Development Of Cotton Fiber

Cotton fiber is definitely one of important product of cotton which is a kind of worldwide crop, while the growth and elongation of cotton fibers can be influenced by several internal and external factors. Therein, some content of tocochromanol (a kind of mixture of four tocopherols, four tocotrienols and esters) have been found in cottonseeds. In order to make clear the accumulation characteristics and possible effects of tocopherols on differentiation and development of cotton fibers, in this study, a HPLC method was established to measure the content and variety of tocopherols at different stages in cottonseed kernels. Meanwhile, by vitro culture technique, effects of tocopherols on growth of cotton fibers cultivated in BT with four isomers (α-, β-, γ-, and δ-T), respectively, were observed. Main results are as follows:1. A high performance liquid chromatography (HPLC) measuring method was established and optimized. For instance, after dissolved in ascorbic acid and ethanol, the analytes were ultrasonically extracted by n-hexane. Then, took n-hexane and isopropanol as the mobile phase(ratio being100/1), four types of tocopherol were isocratic eluted and separated using ZORBAX(?) RX-SIL C18column with the flowing rate of0.88mL/min, thereafter detected and quantified by ultraviolet detector (ex=300nm, em=330nm).2. At mature stage of cottonseed kernel, γ-T was the main isomer in most of cotton germplasms followed by α-T. While in some germplasms, the content of β-T and α-T were higher than γ-T and δ-T. Total tocopherol contents in cottonseed kernels varied significantly among different genotypes, morever the α-T content in cottonseed kernels of fiber germplasms were higher than fiberless ones. It meaned20～40days after flowered, the content of β-T was higher than α-T in Xuzhou142and Jiaoli Dahua, while in other5genotypes i.e. TM-1,n2, GZNn2-1,Ji150and fiberless Xuzhou142, the content of γ-T were higher than a-T, although both β-T and δ-T was with low contents. Also in this research, it was found that the accumulation of4kinds of tocopherols in different kinds of cottonseed represented2accumulation models:"S" and "U".3. Positive effects was found on differentiation and elongation of fibers in vitro culture of cotton ovules after added different tocopherols into BT, and α-T as well as γ-T were with significant influences. Simultaneously, based on the observation of ovules cultivated in vitro for3days through scanning electron microscope (SEM) and the measurement of final fiber length after finishing the45days culture, it showed that α-T increased the quantity of ovule epidermis cells, while γ-T accelerated the fiber elongation.4. Concentration effect of tocopherols on differentiation and elongation of fibers was measurably found out in vitro culture of cotton ovules. And,1μmol/L was the optimum concentration of a-T and y-T exogenously added into BT medium.