| Cotton is one of the most important economic crops, which play a pivotal role in agriculture and industrial production. Fiber is a special single-cell structure which differentiated from the epidermal of ovule. During the development of the cotton fibers, there are four periods, i.e. the initial differentiation of cotton fiber cells, fiber elongation, secondary wall formation and mature. It is a good model for the study of cell elongation and differentiation because of its development process without cell division. In recent years, cotton fiber culture in vitro seems to be a good method to study of the mechanisms of differentiation and development, so the establishment of an efficient culture system in vitro for cotton fiber is imminent, In this experiment, the different basic media, culture methods, hormones and their combinations, ovule age etc. were studied, using ZMS49as material, to establish a suitable system for fiber growth and development during cotton ovule culture in vitro, which may provide an experiment platform for the functional gene validation and mechanism of the growth and development of cotton fiber. The main results are as follows:1. MS, B5and BT medium were choosed in the experiment. The result indicted that BT medium was defined as the basic medium in which the fiber development was the best. Liquid culture was better than solid one although both of them could induce the fiber growth and development during the ovule culture.2. The fiber development were significantly different when7hormone added to the BT medium separately. GA and IAA can effectively promote the fiber growth in vitro. Meanewhile the effect of NAA, Ethylene and BR followed the GA and IAA. The role of ABA and KT were not obvious though low concentration can also induce fiber growth.3. Different combinations of hormone were also carried out during the ovule culture. The results showed that5.0μmol/L GA and5.0umol/L IAA was the optimum hormone combination. Furthermore, the combinations of NAA and GA, Ethylene and GA, BR and IAA can co-promote fiber growth as well, but not significantly. Otherwise the combination of GA and ABA, IAA and KT were mutually antagonistic, unfavorable for fibroblast growth. High concentrations of GA and IAA were able to reverse the inhibition of ABA and KT on fibroblast growth in vitro.4. According to the results, among the ovule ages of-1d,0d,1d and2d, the ovule of0d was the best material. However, whether ovules fertilized or not had a little effect on fibroblast growth as a result of ovules of different periods can be also induced.5. Based on the established experiment system, different genetypes of cotton ovule experiments were carried out. In the same culture conditions, the fiber development were distinctly different. And also the different genotypes required for different hormone combinations.6. There were significantly differences between the fiber development of ovule culture of cotton which have or have no pigment glands, which indicated that pigment glands and gossypol playing a facilitating role in fiber growth and development. The results also showed that foreign genes had some impacts in the coton ovule culture such as EPSP and Bt, although the difference were not obvious. With or without iaaM gene near-isogenic pair-wise comparison test showed that endogenous IAA content was increased in the transgenic plants, the fiber development was better than the corresponding near-isogenic lines, which extended that IAA was necessary for fiber development. |
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