研究土施、喷施2种施硫(Na2 SO4)方式及不同施硫时期对不结球白菜植株产量、营养指标及光合作用的影响,以明确其最佳施硫方式和最适施硫时期.结果表明,土施及喷施2种施硫方式可显著提高植株地上部的生物量和维生素C含量,硝酸盐累积量显著降低(P<0.05);2种施硫方式能显著提高叶片的叶绿素a含量、叶绿素b含量、叶绿素总量、净光合速率(Pn)、水分利用效率(P<0.05);播种当天施硫,植株地上部的生物量、维生素C含量相对最低,硝酸盐累积量相对最高;播种后15 d施硫的地上生物量相对最大,播种后10 d施硫的维生素C含量相对最高,播种后10～15 d施硫可使植株硝酸盐含量有显著降低(P<0.05);播种后5 d施用硫肥,不结球白菜的叶绿素a、叶绿素b含量相对最低,而播种后15 d施硫的叶绿素a、叶绿素b含量相对最高,多显著高于其他处理(P<0.05);播种当天施硫的叶片Pn、蒸腾系数(Tr)、叶片胞间CO2浓度(Ci)相对最低,播种后15 d施硫的相应值相对最高.土施及喷施硫肥均能显著促进不结球白菜的生长发育,两者之间各指标多差异不显著,而土施操作相对简便,应采用土施方式进行施硫;播种后15 d为不结球白菜最适施硫时期,可明显提高不结球白菜的单株产量、营养品质及光合作用.

Diploid plants of non-heading Chinese cabbage(Brassica campestris ssp. chinensis) were induced by treating the apical portion of seedlings with different solution of colchicine. After selecting and identification,dwarf and tight white petiole autotetraploid plants with high quality were selected and bred. The test result showed that treatment with 2. 0 mg·g-1for 6 times yielded doubled chromosomes at highest rates and doubling rate was 7. 02%. Compared with diploid plants,autotetraploid plants had significant differences on vegetative mass,stoma,floral organ and silique,with the plant height reduced,the leaf width increased,the petiole shorter,the plant expansion degrees decreased,showing a compact plant type with bright green leaves. Compared with diploid plants, soluble sugar,protein and vitamin C of autoterploid plants contents were significantly increased by 11. 14%,25. 98% and 11. 70%. After two generations of breeding,the tetraploid pure degree was 100% and the uniformity was 95%,the yield of plot was increased by 18. 10% more highly than the diploid,while it has good application prospects.

In order to study photosynthetic characteristics of the diploid and autotetraploid radish,the diploid radish and autotetraploid radish were measured using the LI-6400 portable photosynthesis system. The results showed that during the initial course of light induction treatment, net photosynthetic rate (Pn), stomatal conductance (Gs), CO2 concentrations (Ci) and transpiration rate (Tr) of autotetraploid were higher than diploid radish. The results also showed that the changes of Pn, Gs, Ci and Tr were same approximately in diploid and autotetraploid radish. There was a direct relationship between the high Pn and the high yield in autotetraploid radish.

15 crossing combinations are made by 4xMtCMS and 5 parents of pakchoi〔Brassica campestris L.ssp.chinensis(L.)Makino var.communis Tsen et Lee〕with the method of complete diallel cross(half mating design).The result shows that 16 agronomical characters are controlled by the additive gene effect,dominance effect and interaction effect.And among 6 parents 07P-10 is a best parent,as it has highest general combining ability.It is excellent parent materials for the most of traits.The sterile lines 07P-2 is a better parent for quality genetic improvement research in autotetraploid pakchoi.The analysis of SCA effects show that the SCA effects of different characters in the same parent are obviously different,so does the same character in different parents.According to the comprehensive performance of the SCA effects,07P-2×07P-7 and 07P-2×07P-10 have application of great value because they include sterile lines 07P-2.

The author studied the physiological and biochemical characteristics of the buds,flowers and flowering leaves at different growth and developmental stages of tetraploid MtCMS line and its maintainer line in Chinese cabbage.The results showed that the contents of soluble protein,soluble sugar and proline in the buds and flowers of tetraploid MtCMS line were significantly lower than those in its maintainer line,while the MDA content in tetraploid MtCMS line was 1.72 times of that in the maintainer line.The activity of SOD in the buds of tetraploid MtCMS line was higher than that in maintainer line.The activities of POD and CAT in the buds of tetraploid MtCMS line were significantly higher than those in its maintainer line,except that the activity of CAT in the large buds of tetraploid MtCMS line was significantly lower than that in its maintainer line.The contents of soluble protein,soluble sugar and proline in the flowering leaves of tetraploid MtCMS line had no significant differences from those in the maintainer line,while the MDA content and the activities of POD,SOD,CAT in tetraploid MtCMS line were lower than those in its maintainer line.There were eight different bands between tetraploid MtCMS line and its maintainer line in electrophoretic analysis of POD,SOD and EST isozymes,but there were more isozyme zymogram bands in the maintainer line.