Creation Of Chinese Dwarf Cherry(Cerasus Humilis Bge.) Polyploid Germplasm Via In Vitro And Their Identification

Stem tips by tissue culture and seed embryos of Chinese dwarf cherry-"nongda 7" were used as experimental materials.The inoculation method and immersion method was adopted to deal with the material by colchicine at different concentration and different time. Suspected variant plants were identified by morphology, chromosome number, flow cytometer and physiological indexes. The main results were as follows:1.The seed embryos were inoculateed directly to MS culture medium containing different concentrations of colchicine. The embryo survival rate decreases gradually with increaseing of the concentration of colchicine, but suspected variation rate increased in the lower concentration of colchicine then decrease in the higher concentration of colchicine. When the concentration of colchicine at 80mg/L, the mutation rate was highest up to 30%.2.When the stem tips with colchicine soaking were inoculated directly to MS culture medium and vaccination,the death rate of stem tips increased wiht the increaseing of concentration of colchicine and the prolonging of soaking time, when treatment time was 48h±24h with 0.6% colchicines, the suspected variation rate was more. And when stem tips were inoculated directly to MS culture medium adding the concentration of colchicine at 80mg/L, the suspected mutation was highest up to 30%.3. The four tetraploid plantlets were found when 50 suspected variation plantlets were identified by flow cytometry. The four tetraploid plantlets were confirmed further by chromosomes preparation technology with the conditions including 0.002mol/L 8-HQ pretreatment 2.5h and HC1 about 60±1℃ dissociation 15 min. The chromosome number of variant plant was 2n=4x=32.4.The leaves area of variant plant were 3.46 fold bigger than normal leaves.Leaf color was daker. The differentiation ability and rooting ability of variant plants was both 2.1 fold stronger than the contrast group. Stoma area was 5.1 times bigger than contrast group. The ratio of stoma long diameter/short diameter was about 50% of the contrast group,and the number of stoma about 40% of the contrast group.5. One of four variant plant maybe came form stem tip, and the other three was from embryo by SSR Molecular markers.6.The characteristics of their physiological indexes were found that Photosynthetic plain of tetraploid was higher,but enzyme activity of SOD、POD、CAT and content of MDA was lower.