摘要
对影响棉花体细胞胚胎发生和植株再生的基因型、外植体及培养基中的碳源、氮源、固化剂、外源激素、pH值等方面的因素进行了综述,并讨论了存在的问题及今后的研究方向。
Today plant tissue culture is an important tool in basic and applied studies, as well as in commercial application. Efficient tissue culture procedures have been successfully developed in many crops, such as carrot, tobacco, rice and some horticultural crops. However, compared to other crops, cotton tissue culture has lagged behind. In vitro cultured cotton, cells had been induced to produce somatic embryogenesis in some laboratories using varied strategies . However, there were many factors affecting somatic embryogenesis and plant regeneration of cotton. First, somatic embryogenesis and plant regeneration of cotton are genotype-dependent. Only a few of varieties were regenerated through somatic embryogenesis, such as Coker312, Coker201, Lumian6hao, Jihe 321,etc. The feasibility of somatic embryogenesis of cotton was dissimilar among different Gossypium species and different varieties in the same Gossypium species. Second, the effect was different when different kinds of explants were used. The immature tissues production was easier than mature one. Callus initiated from hypocotyls was common. Inclusion of medium was the third important factor affecting somatic embryogenesis and plant regeneration of cotton. There were several kinds of media in plant tissues culture. However, modified MS was the basic medium. Glucose instead of sucrose was generally adopted. Various genotypes, however, had different responses on various sugar sources. The change of nitrogen source maybe an important, but not the key factor. A medium solidified with Gelrite or phytagel was better than that with agar, which was normally used in plant tissues culture, in somatic embryogenesis and plant regeneration of cotton. Adding appropriate type and appropriate concentration of auxin and cytokinin such as 2,4-dichlorophenoxyacetic acid, kinetin could promote callus proliferation in subcultures. Various genotypes, however, had different responses on exogenous hormones. And the concentration should decrease in subculture. Germinating somatic embryos were placed on MS medium with hormones free. The pH value of medium would make for initiation and proliferation of callus. The best range of pH was 5.8～6.2.The culture mode, temperature, light intensity, timely manipulations were also the factors that effected the somatic embryogenesis and plant regeneration of cotton. There were two kinds of culture mode, one was suspension and the other was solid culture without a liquid step. The method of suspension culture was advantageous over proliferation of embryo process, but many abnormal embryos were produced. Therefore, most researchers applied solid culture without a liquid step. However, some researchers still believed that the liquid step not only decreased the culture time but also increased the number of embryos per gram of cultured tissue. Explants were incubated at room temperature (28±1℃) under a 14-hour photoperiod of 2,000 lx. The period of subculture depended on the speed of callus growth. Some different methods were applied to maintain embryonic callus according to various genotypes. Adding an appropriate amount of Vitamin C, PVP, active carbon and AgNO_3 could promote callus proliferation in a subculture. Plantlets were acclimatized on new produced root or grafted before replanted to the greenhouse. Furthermore, there were other factors effecting somatic embryogenesis and plant regeneration of cotton, for example, the status of callus. Over the past 20 years, A great deal of progress was made. However, there were still some problems to be solved. There was a need to broaden the number of regenerable cotton species. The common strategies to get somatic embryogenesis of various cotton species should be improved to adapt to any laboratory. In addition, the mechanism of physiology, biochemistry and genetics in somatic cell and tissue culture should be investigated successively.
出处
《棉花学报》
CSCD
北大核心
2004年第1期55-61,共7页
Cotton Science
基金
河北农业大学重点科技项目(9816)
