Study On Polyploidy Induction Of Bougainvillea Seeds And Isolated Tissues

In this study,bougainvillea seeds and sterile seedling stems were used as materials,and colchicine was used to conduct an induction doubling test in order to obtain polyploidy and create new germplasm for Bougainvillea.1.Different concentrations of colchicine(250 mg/L,500 mg/L,1000 mg/L)were used to soak the seeds of Bougainvillea for 12 h,24h,36 h.Four mutant strains were obtained by flow cytometry,among which three were tetraploid and one was 2×/4×mixoploid;two tetraploid plants were obtained by colchicine concentration of 500 mg / L and soaking for 36 h,with the highest induction rate of 3.33%.After grafting the diploid,2×/4× mixoploid,and tetraploid branches of the same mutant plant,the morphology and cytology of the different ploidy plants were observed and compared,and it was found that the mutant plants had leaves compared with the diploid plants.The folds increase and thicken,the thorns become longer,and the number of branches decreases.In addition,plants with different ploidy have significant differences in guard cell length and width,stomata length and width,and the number of stomata per unit area.2.To establish a stable and effective in vitro regeneration protocol,in the present investigation,the seed hypocotyl of Bougainvillea glabra ‘Bouform 1’ was used as the explant,and the growth status of stages of induced differentiation,adventitious bud proliferation,sound seedling,rooting and so on was evaluated on MS medium supplemented with various plant growth regulators.The results showed that the optimal protocol was as follows: the medium for adventitious differentiation was MS + IBA 0.1 mg/L + 6-BA 2.0 mg/L,with the differentiation rate at 81.35 % and the differentiated buds at7.04 on average.The medium for adventitious bud proliferation was MS + NAA 0.05 mg/L+ 6-BA 3.0 mg/L,with the proliferation coefficient at 5.22.The seedling strength medium was MS + NAA 0.1 mg/L + 6-BA 1.0 mg/L and the average seedling height reached 5.59 cm.The rooting medium was 1/2 MS + NAA 0.2 mg /L,with the rooting rate at 82.54 %and 4.38 roots per seedling on average.3、The stem segments of sterile seedlings obtained from hypocotyl differentiation are explants,and they are inoculated into media containing different colchicine concentrations for induction doubling test.Six chimeric variants were obtained in the treatment with colchicine concentration of 25 mg/L,and the induction rate was 5%.