| Melastoma dodecandrum Lour, is a kind of foliage and viewing flower. In this paper, a high-efficient rapid propagation system of Melastoma dodecandrum in vitro culture had been achieved successfully and chimerals plant of Melastoma dodecandrum was first obtained. The cytological, morphological and physiological characters of chimerals plants were also studied by comparing with the diploid . The main results were as follows:(1)The study of rapid propagation system in vitro cultureCluster buds was induced by using stem as a source of initial explants and a high-efficient rapid propagation system of Melastoma dodecandrum rapid propagation in vitro culture had been achieved and effects of different phytohormone, subculture time, sucrose, coconut ilk, illumination on multiplication and rooting of cluster buds had been studied. The medium MS + 6-BA1.0 mg·L-1 + NAA 0.1 mg·L-1 +sucrose 30 mg·L-1+agar 7 mg·L-1 was relatively appropriate to induction culture of cluster buds and inducement rate was 89.5%. The medium MS + 6-BA 0.2 mg·L-1 + NAA 0.1 mg·L-1 + sucrose 30 mg·L-1+agar 7 mg·L-1 was relatively appropriate to multiplication and growth of cluster buds and the medium 1/2 MS + NAA 0.5 mg·L-1 + IBA 0.2 mg·L-1 + sucrose 30 mg·L-1+agar 7 mg·L-1 to rooting. The multiplication rate was 10.2 and the rooting rate was 100%. The multiplication rate was increased and average height was decreased with increasing concentration of 6-BA. The effective buds were decreased with increasing subculture time. Coconut milk cultivation can promote growth of shoots and make effective rejuvenation by supplying coconut milk 8 g·L-1 to MS medium.(2)The study of chemical inducementCluster buds of Melastoma dodecandrum was mutated by adding 0.1%colchicines to the medium in tissue culture for 14 d. The mutated ratio was 28%. By observing the chromosomes of induced plants microscopically, the chromosome number of some cells was 2n=4x=56, others was 2n=2x=28. The fact that induced plants had two groups of cells with nuclear DNA content also suggested that these inducing plants were chimerals. Compared with the normal diploid plants, the chimerals had thicker and larger leaves, darker leaf color, and stronger stems with shorter length per stem stalk, larger stomata and fewer stomata per unit area. The chimerals had higher level of SOD activity, chlorophyll content, Proline content and CAT activity in leaves comparing with the diploid. |
