Study On Induction And In Vitro Plant Regeneration Of Tetraploid Robinia Pseudoacacia L

Locust tree is one of the most important fast-growing timber trees. Planting of locust tree can not only abate the problem of lumber shortage of China, but also improve the ecological environment. Tetraploid locust tree is a fine feed tree and of high economic value. In this paper, two kinds of tetraploid plants of locust tree were obtained and two in vitro regeneration systems were established with the injuried tissues of Robinia bella-rosea and the seeds of Robinia pseudoacacia L. by the method of cochicum-induced injuried tissues. The conclusions are as follows:(1) Among the different ways, the concentrations of colchicum were particularly significant for the induction of tetraploids of Robinia bella-rosea and Robinia pseudoacacia L. trees.(2) The combined treatment of "33" (40 mg·L-1 colchicum+10 d treatment) is the best method in the tetraploid induction of Robinia bella-rosea, and the maximum of induction was 15.12%,while in the induction of Robinia pseudoacacia L., the maximum value of tetraploid locust of 25.71% was induced by the "47" combination of 60 mg·L-1 colchicum+2 d treatment. It is concluded that combinations 33 and 47 are suitable for tetraploid locust induction. The fited induction method of Robinia bella-rosea tree and Robinia pseudoacacia L. is the combination of low-temperature +injuried tissue impregnation and low-temperature+seed impregnation, respectively.(3) The cell chromosome appraisal indicates that the root point cell chromosome numbers of two locust tree's variation adult plant was 2 times of that of diploid plant (2 n= 4 x= 22). The DNA concentration of the single cell leaf of tetraploid locust tree was also 2 times of that of diploid plant.(4) Compared with the diploid plant, the leaf area, thickness, color and bristle increased; the amount and the density of leaf elevated and decreased, respectively; and the concentrations of malondialdehyde, protein, proline increased and the activity of POD decreased.(5) The investigation of in vitro plant regeneration conditions of two kinds of tetraploid plant with leaf, stem and leaf-stem shows that the leaf-stem was the most sutiable explant. The most sutiable induction culture medium of the injuried tissue, bud and root of tetraploid plant of Robinia Bella-rosea tree and Robinia pseudoacacia L. was MS+0.1 mg·L-1 IBA+5 mg·L-1-1 6-BA, MS+0.3 mg·L-1 IBA +5 mg·L-1 6-BA and 1/2MS+0.1 mg·L-1 NAA and MS+0.1mg·L-1 IBA+5 mg·L (?)6-BA,MS+0.5mg·L-1 IBA+5 mg·L-1 6-BA and 1/2MS,respectively.