巴西橡胶树花药体胚发生类型及其培养条件的改良

摘要

橡胶树花药培养体胚发生率低及植株再生频率低是制约其组培苗工厂化生产的瓶颈.以热研7-33-97品系花药为外植体,研究橡胶树花药体细胞胚发育过程并对其体细胞胚进行系统分类,同时改良其培养条件.结果表明,完整的体胚发育过程是球形胚-心形胚-鱼雷胚-子叶胚,但有些心形胚不能进一步发育成鱼雷胚,在后继培养中会分化成畸形胚；体胚发生不具同步性,在鱼雷胚旁又长出次生胚.胶树花药体细胞胚共分9种类型,发现胶树花药体胚发生过程中产生连体胚现象,该类胚能正常发育成植株.不同胚状体培养条件对植株再生率的影响说明,暗培养诱导胚状体2个月后再转移至500 lx弱光照条件下培养10～15 d,然后再转移至出苗培养基培养,能够显著提高植株再生率.在诱导胚胎发生培养基中添加不同浓度的稀土,结果表明,稀土具有提高橡胶树花药体胚发生率的效果,其中以添加1 mg/L稀土培养效果最佳.%The low frequency of somatic embryogenesis and plantlet regeneration is the bottleneck preventing the large scale applications of juvenile-type clones in anther culture of Hevea brasilliensis. Using the anthers of Reyan7-33-97 as the explants, developmental process and embryo classification and improved cultural conditions of somatic embryogenesis were studied, which could improve anther culture of rubber trees. The results showed the whole developmental process of somatic embryos could be divided into four phases: ball-shaped embryos, heart-shaped embryos, torpedo-shaped embryos, double-cotyledon embryos. The further growth of some heart-shaped embryos was hampered and they ultimately turned into abnormal ones. Some secondary embryos arose near the torpedo-shaped embryos, indicating somatic embryogenesis was out of sync. Nine types of somatic embryos were systematically classified and the connected embryos regenerated could form normal plantlets. Cultural conditions of somatic embryogenesis were improved too. Embryoids transferred in weak light of 500 lx for 10 to 15 d after cultured for 2 months in the dark significantly improved plantlet regeneration. The induction embryogenic media supplemented with 1 mgL-1 rare earth could enhance somatic embryogenesis.