Studies On Rapid Propagation And Plant Regeneration Of Lagerstroemia Indica

Lagerstroemia indica as a garden ornamental plant, has its own unique beauty and appreciation. It blooms in summer with long bloom duration and colourful flowers. So it is an important landscape plant. Myrtle usually grows by seeding and cutting. And tissue culture has been to improved. Rapid propagation, seeds in vitro culture and the establishment of regeneration system could add new ways for propagation. At the same time genetic transformation on the basis of the regeneration system and rapid propagation cultivate more varieties of ornamental value to adapt to the needs of landscape, which has important meaning.The study mainly included rapid propagation, seed propagation and different explants regeneration in vitro. The research result can be listed as follows:1. Stem propagation:In spring stems with buds were sterilized 4min and stems with axillary buds were sterilized 8min better by 0.1% HgCl2. Sampling in summer germination rate was better than in spring and fall. Stems with axillary buds from summer were primarily cultured best on medium MS+6-BA1.0mg/L+NAA0.1mg/L. The germination rate was 72.3%. After the proliferation of four subcultures on the same medium it obtained the average number of adventitious buds up to 61. Proliferation coefficient was high. Plantlets on the medium supplemented without 0.3mg/L GA3 grew best. Rooting medium used 1/2MS+IBA0.5mg/L2. Sterile culture system of seeds:Mature seeds from crape myrtle were in-vitro cultured in order to propagation under sterile sprout conditions. Seeds (not cracking capsule) to 0.1% HgCl2 disinfection time controlled over 10min best. Mature seeds were better in disinfectant of 8min 0.1%HgCl2. The most appropriate sterile germination medium was the MS and sucrose content was 30g/l under 14h/10h of light and dark culture conditions. The best proliferation medium of plantlets was MS+6-BA1.0 mg/L+ NAAO.lmg/L. Average adventitious buds were up to 56. Rooting medium was 1/2MS+ IBA0.5mg/L and rooting rate was 61.6%.3. Establishment of regeneration system:Through different explants regeneration experiment, the results showed that:(1) The optimum combination of Myrtle’s immature embryos induced callus was MS+2,4-D2.0 mg/L+KT0.2 mg/L. The best differentiation medium for callus induction was MS+6-BA 2.0mg/L+NAA 0.2mg/L and shoots induction rate was 33.3%; (2)Cotyledon and hypocotyl could be induced callus. The best hormone combination of cotyledon induced callus was MS+6-BA1.0 mg/L+2,4-D0.5 mg/L. It was a better differentiation on MS+6-BA1.0mg/L+NAA0.2mg/L and regenerated plants grew well. Callus differentiation rate was 13.8%. The best medium for callus induction of hypocotyls was MS+6-BA1.0 mg/L+NAA0.1 mg/L; (3) For leaf regeneration studies, leaf facing up was conducive to callus induction; Light culture have some influence on leaf regeneration of crape myrtle. Callus grew fast under light. Under dark culture callus was less and light green. The optimum callus induction medium of leaf was MS+BA 0.5mg/L+2,4-D 0.5mg/L; Ratio of induced callus was 43.3%. (4) The best differentiation medium of stem callus was MS+6-BA1.0 mg/L+NAA 0.1mg/L. Shoot induction rate was 66% and the average number of shoot was 5.1.4. Proliferation and rooting of regenerated shoots:The shoots cultured on medium: MS+6-BA1.0mg/L+NAA0.1mg/L; Proliferation multiple was 3.2 and the shoots grew well. Continued to following subculture, there was the availability of a large number of multiple shoots. Rooting medium was 1/2MS+IBA0.5 mg/L and rooting rate was 52.7%.5. Hardening and transplanting:Transplanting substrate selected the sand:garden soil (1:2) and the survival rate was 70%.In summary, it is important that the propagation system for the preservation of germplasm. It was possible that sterile culture of seeds for the study of plants physiological and ecology in vitro conditions. And there was a new method to propagating. Establishment of regeneration system will be used to developing new varieties by genetic transformation in future, such as powdery mildew-resistant, larger flowers and more varieties.