Study On Plant Regeneration And Polyploid Induction Of Pear Cultivars

Study of leaf regeneration system of pear and polyploid induction has important significance for screening resistance strain. The bud stem of Huangguan pear, Xuehua pear and Zhongliyihao pear were uesd as materials in this study to establish a rapid system. The leaves of Huangguan pear, Xuehua pear and Zhongliyihao pear test-tube plantlet were uesd as materials to establish leaf regeneration system. Induction of Huangguan pear, Xuehua pear and Zhongliyihao pear were researched by colchicine combined with tissue culture. The main results as follows:1.Mid-May was the best time for picking of Huangguan, Xuehuali and Zhongliyihao and had lower contamiation rates and browning rate. Through secondary culture, the results showed that MS+6-BA2.0mg/L+NAA0.2mg/L+GA30.5mg/L, MS+6-BA1.Omg/L+NAA0.15mg/L+GA30.5mg/L and 1/2MS+6-BA1.0mg/L+NAA0.2mg/L+GA30.5mg/L were the most suitable proliferation medium for Huangguan pear, Xuehua pear and Zhongliyihao pear respectively.2.Plant growth regulators that influenced adventitious buds from leaves of Huangguan pear, Xuehua pear and Zhongliyihao pear in vitro were studied. The results showed that the medium for leaf regeneration of Huangguan pear, Xuehua pear and Zhongliyihao pear was NN69+6-BA1.0mg/L+TDZ0.5mg/L+NAA0.1 mg/L, NN69+6-BA1.0mg/L+TDZ1.0mg/L+NAA0.15mg/L, NN69+6-BA2.0mg/L+TDZ0.5mg/L+NAA O.lmg/L respectively, and the leaf blade of regeneration frequency was 0.81、0.78、0.88 respectively, and the bud number of per leaf was 3.89,3.11,3.51 respectively. Through surfce analysis, the theory rgeneration frequency of Huangguan pear and Zhongliyihao pear can up to 100% which cultivated in the theory optimal medium NN69+6-BA1.0mg/L+NAA0.15mg/L. The rooting rate of Huangguan pear, Xuehua pear and Zhongliyihao pear were 63.3%,56.7% and 60.0% respectively on the medium of 1/2MS+IBA1.0mg/L.5 days of dark culture can obviously increase the rooting rate.3. Polyploid induction effect has significant relationship with treatent way, concenration and time of colchicine. The effect of mutagenesis on the soaking Huangguan pear leaf in 0.4% colchicine solution for 2 days was more efficient and regeneration buds were 1.45; The effect of mutagenesis on the soaking Xuehua pear leaf in 0.2% colchicine solution for 3 days was more efficient and regeneration buds were 1.67; The effect of mutagenesis on the soaking Zhongliyihao pear leaf in 0.2% colchicine solution for 2 days was more efficient and regeneration buds were 1.67. In the mixed culture experiment of fluid nutrient medium, the regeneration buds were 1.95 and 1.54 when Huangguan pear leaf were cultured on medium added 25mg/L and 50mg/L colchicine respectively; the regeneration buds were 1.67 when Xuehua pear leaf were cultured on medium added 25mg/L colchicine; the regeneration buds were 2.21 and 1.00 when Zhongliyihao pear leaf were cultured on medium added 25mg/L and 50mg/L colchicine respectively. In the mixed culture experiment of soild nutrient medium, the regeneration buds were 2.00 when Huangguan pear leaf were cultured on medium added 25mg/L colchicine; the regeneration buds were 1.71 when Xuehua pear leaf were cultured on medium added 25mg/L colchicine; the regeneration buds were 2.12 and 1.00 when Zhongliyihao pear leaf were cultured on medium added 25mg/L and 50mg/L colchicine respectively.