Studies On The Accumulation Pattern Of Fatty Acid In Cottonseed Kernel And The Effect Of Fatty Acid On Cotton Fiber Differentiation And Development

As a kind of seed fiber, cotton fiber was differentiated by epidermal cells of the seed, and adhered to seed surface. The development and quality of the cotton fiber are influenced by many factors, the yield and quality of cotton fiber have a direct impact on our country’s textile industry and it also has important influence to the national economy and people’s livelihood. Cotton kernel was rich in fat, protein and other ingredients. However, whether these ingredients affect the differentiation and development of cotton fiber, subsequently influence the yield and quality is becoming a hot topic in the related research area of cotton fiber differentiation and development, as well as regulation to production and quality formation.In this research the upland cotton standard system TM-1and island cotton standard system3-79were taken as experimental material, which were cultivated in Zijingang experimental farm of Zhejiang University in May2012. The different development stages of cotton bolls and separation were collected, then using soxhlet extraction method and gas chromatography to determinate fat content and fat composition in all stages of development respectively. In order to enrich regulation theory of differentiation development of cotton fiber and offer a new direction for improving the cotton yield and quality, the cotton ovule culture technology combined with electron microscope of fiber differentiation development status were carried out, then further research on the effects of the different kinds and concentration of fatty acids on differentiation and development of cotton fiber were done.The main results are shown as follows:(1) Oil content of TM-1and3-79cottonseed have reached more than20%of the dry weight of the cottonseed at20days after anthesis(DAA). As the extension of the development period, the relative content of cottonseed oil will also increase, cottonseed oil content change is most obvious about30DAA, until fully mature boll development it reached the maximum content. But cottonseed oil development trend of Upland cotton standard system TM-1and island cotton standard system3-79is not entirely the same. The TM-1cottonseed oil content growth rate is faster in the period of20to30DAA, and oil content has reached the highest relative content at30DAA. But when it is the35th day after anthesis, cottonseed oil relative content of upland cotton material decreased, then increased, until mature it’s relative content is basically the same of30DAA. And cottonseed oil of island cotton standard system3-79growth speed is slow during the stage of20to30DAA, but increase rapidly in the period30to40DAA, then gradually increase slower, it’s oil content is maximum until fully mature.(2) The overall change trend of the content of all kinds of fatty acid in cotton kernel of upland cotton standard system TM-1and island cotton standard system3-79is basically the same in the process of cottonseed development:In the whole process of cottonseed development, content of oleic acid is the highest and54%～63%of total content, palmitic acid and oleic acid content is16%～22%and15%～22%respectively, the sum of the three levels of the mature is about95%of the total fatty acid content in cottonseed and the main components of fatty acid in cottonseed. But other types fatty acids content, such as stearic acid, palmitic acid, nutmeg acid and linolenic acid content are low, the relative content of the after three kinds is no more than1%. Palmitic acid, stearic acid and oleic acid content is along with the cottonseed development slowly increase, long chain fatty acids as nutmeg acid, palmitic acid, linoleic acid and linolenic acid and polyunsaturated fatty acid content is reduced along with the development of cottonseed, But linolenic acid of TM-1has relative content is higher from0to about25DAA, its relative content quickly reduce along with the development to the fully mature. In mature stage, unsaturated fatty acids of TM-1and3-79is about75%,76%of fat acids respectively.(3) Using cotton ovule in vitro culture techniques and SEM, the results showed that it is more obviously to promote the differentiation, development and elongation of cotton fiber when vitro culture medium is added5.0umol/L palmitic acid (C16:0). Wood wax acid (C24:0) also show a certain role in promoting the elongation of cotton fiber; qalmitic acid of5.0μmol/L had a remarkable effect on differentiation and development of cotton fiber through the cultivation of cotton ovule. But through the observation can be speculated that excessive concentrations (25μmol/L,30μmol/L) may inhibit the production and the elongation of cotton fiber.