Studies On Tissue Culture And Plant Regeneration Of Three Genus Of Crassulaceae

The micropropagation and plantlet regeneration of Echeveria cv.Huthspinke and Graptoveria Titubans and Pachyveria Pachytoides were studied and found out an efficient way to commercial production. The leaves as explants, the system including explants sterilization, initial differentiation, bud induction, rooting and acclimatization, was estabilished. By the microscopic observation of somatic embryo, the mechanism of somatic embryogenesis was elucidated to lay the foundation for the large-scale production.The main results as follows:1. The micropropagation estabilishment of Echeveria cv.Huthspinke and Graptoveria Titubans and Pachyveria PachytoidesThe adventitious buds induction:The leaves as explants, sterilized 15 mins, the combination of 6-BA, NAA and ZT, the results showed that the optimum medium for adventitious buds induction was MS+6-BA3.0mg/L+NAA1.0mg/L+ZT1.0mg/L.The buds proliferation:Supplemented with 6-BA and NAA, the suitable medium for buds proliferation was MS+6-BA5.0mg/L+NAAl.Omg/L.Plantlet in vitro rooting:1/2MS and MS were taken as rooting medium with AC and NAA, the results showed that The optimum medium for Echeveria cv.Huthspinke and Graptoveria Titubans rooting was MS+AC3.0mg/L+NAA0.1mg/L, and Pachyveria Pachytoides is MS+AC3.0mg/L+ NAA0.1mg/L, respectively.Plantlet in vitro transplanting:Peat moss, sand, vermiculite and perlite were used for rooting. The results showed that the optimum transplanting medium was peat moss.2 Somatic embryogenesis of Echeveria cv.Huthspinke and Graptoveria Titubans and Pachyveria Pachytoides.Histological analysis showed that somatic embryo of Echeveria cv.Huthspinke and Graptoveria Titubans and Pachyveria Pachytoides were formed from the leaves base cultured in MS+6-BA3.0mg/L+NAA1.0mg/L+ZT1.0mg/L. The morphology and histology of somatic embryogenesis were observed by stereomicroscope and Paraffin technology, and the somatic embryos originated from axilaryparenchymal cells with large nucleoli, cytoplasmic dense and arranged closely, which were through five stages of globular, shield-shaped, heart, torpedo and single-cotyledon embryo. The development of Echeveria cv.Huthspinke somatic embryo was the fastest, Pachyveria Pachytoides, second, and Graptoveria Titubans was most slowly, respectively.The protocorm-like bodies was developed from middle of leaves, which were originated from epidermal and subepidermal cells, and then developed matured protocorm-like bodies, further forming secondary PLB repeatedly and developing a single plant, finally. The protocorm-like bodies development process is similar to somatic embryo’s. The somatic embryo has polarity of buds pole and root pole, but the protocorm-like bodies only has unipolarity of buds pole.