Study On Induction Autotetraploid Non-heading Chinese Cabbage With High Quality And Heat Resistance

In the study,the diploid plants of non-heading Chinese cabbage(Brassica campestris ssp.chinensis Makino,2x=2n=20)'Xia di' and 'Kao qing' were used as materials,induced by treating the growing point of seeding with 0.2%colchicine.The autotetraploid plants were selected and identified based on the characteristics of morphology,anatomic and cytology(DNA content determinated by flow cytometry instrument and chromosome ploidy identification).Then the agronomic characters and nutritional quality were determinated and compared between diploid and tetraploid.The purpose was to obtain the autotetraploid 'Xiadi' and 'Kaoqing' plants which were with high quality and heat resistance.The results were as follows:1.The non-heading Chinese cabbage 'Xia Di' were induced by treating the apical portion of their seedlings with 0.2%colchicine for 2,4 and 5 times.Then the tetraploid plants were selected and identified based on characteristics of morphology,anatomic and cytological observation.The results showed that the 4 times treatment in 0.2%colchicine could get 15 tetraploid plants,the rate of tetraploid at highest was 3.47%.Compared with the diploid,the tetraploid plants showed great sex in the bud,petal,legumen,they were increased respectively by 37.10%×58.06%;24.56%×37.35%;24.17%× 12.33%.The size of the tetraploid stomata and pollen grain were significantly increased than that of diploid,increased respectively by 32.93%×48.98%and 34.56%,but significantly lower in density,reduced by 50.30%.By the flow cytometry instrument identification,a peaks of diploid plant was in 200,while the tetraploid plants was in 400.The chromosomes number of the tetraploid was 40,two times of the diploids.The result of flow cytometry was the same as the chromosome analysis.2.The diploid plants of non-heading Chinese cabbage(Brassica campestris ssp.chinensis Makino,2x=2n=20)were induced by treating the growing point of seeding with 0.2%colchicine.The autotetra ploid plants were selected and identified based on the characteristics of morphology,anatomic and cytology.The purpose was to obtain high quality autotetraploid materials.The test results showed that the treatment with 0.2%colchicine for 4 times at the best effect and the autotetra tetraploid rate was 1.16%.Compared with the diploid plants 'Kaoqing'.the tetraploid plants showed significant differences in plants size,floral organ,legumen,stoma and pollen grain.The length of petals showed significantly differences,the width showed significantly difference,increased by 16.67%and 32.26%;The Stomatal length and width,the diameter of the pollen grains were increased by 31.56%×42.42%;40.06%,the density of stomata was significantly lower,reduced by 48.84%.By the flow cytometry identification,the DNA content of diploid had a signal peak at 200 while the tetraploid was at 400.The result of flow cytometry was the same as the chromosome analysis.3.Using diploid and tetraploid 'Kaoqing' and 'Xiadi' as experimental materials,they were determinated by agricultural characters and nutritional quality,the purpose was to obtain tetraploid plants which was with high quality and high yield.The result showed that the tetraploid 'kaoqing' plants showed better agronomic characters,leaf length,leaf width,single petiole weight,total leaf weight and the plant weight showed significance difference,respectively increased by 6.6%,52.2%,12.2%,25.8%,19.4%.The content of soluble sugar,soluble protein,vitamin C and dry matter in tetraploid plants increased significantly,increased by 25.98%,35.59%,26.39%and 19.92%respecttively;the content of nitrate nitrogen and organic acid were lower,reduced by 35.57%and 22.61%respectively.Compared with the diploid 'Xiadi',the leaf length,leaf width,single petiole weight,total leaf weight and the plant weight of the tetraploid 'Xiadi' showed significance difference.The content of soluble sugar,soluble protein,vitamin C and dry matter in tetraploid plants increased significantly,increased by 23.00%,44.38%,29.03%and 11.05%respecttively;the content of nitrate nitrogen and organic acid were lower than the diploids,reduced by 14.84%and 16.70%respectively.In the summer heat resistance test,the tetraploid 'Xiadi'and 'Kaoqing' were with great high yield.