【作者】 赵光武；

【导师】 王建华；

【作者基本信息】 中国农业大学 ， 作物遗传育种， 2004， 硕士

【摘要】 采用方差分析和相关分析研究来自西北、华北、华南、华中、华东等五个地区的18种不同类型甜玉米种子的健康状况、活力状况及其相互关系，建立评估甜玉米种子活力的有效方法和体系，同时对改善甜玉米种子活力的有效方法及其机理进行了探索。本研究获得了以下结果： 1．种子健康研究表明：京科甜115、绿色超人、华甜1号和蜜玉8号等种子的健康状况较差，外部带菌量118.0cfu／粒～320.7cfu／粒，内部带菌率98.0％～100.0％；而鲁甜9号、西星甜玉1号、超甜2000和京科甜116等种子的健康状况较好，外部0.2cfu／粒～6.7cfu／粒，内部8.5％～51.3％。加强甜和超甜玉米种子带菌差异显著，前者带菌较少，外部29.9cfu／粒，内部62.0％；后者带菌较多，外部86.2cfu／粒，内部79.2％。五个地区种子带菌差异显著，西北带菌较少，外部0.6cfu／粒，内部14.3％；华中带菌较多，外部135.2cfu／粒，内部95.9％。检验方法不同也会影响实验结果，与吸水纸检验相比，PDA检验可以检出在吸水纸上检测不到的真菌，如曲霉、白地霉和毛壳菌等，更能反映种子真实的带菌情况。种子外部健康状况对种子活力影响不大，而种子内部健康状况却直接影响田间出苗。种子外部和内部均以镰刀菌分离最多，外部66.1％，内部67.4％，内部镰刀菌分离频率与田间出苗率呈显著负相关。 2．种子活力研究表明：甜单8号、甜单10号、蜜玉8号和苏甜8号等种子活力较差，田间出苗率38.9％～47.2％；而鲁甜9号、京科甜116、超甜2000和扬甜1号等种子活力较好，田间出苗率71.3％～80.6％。脱氢酶活性、种子浸出液电导率和可溶性糖含量、挥发性醛含量以及穿纸发芽率等均与田间出苗率显著相关，可以作为评估种子活力的重要指标；而且种子浸出液电导率和可溶性糖含量以及脱氢酶活性还与田间出苗速率显著相关，它们是评估甜玉米种子活力的最佳指标。而标准发芽率和抗冷发芽率，与田间出苗率和出苗速率的相关关系均不显著，说明它们均不能较好地评估种子的活力状况。 3．同时对改善甜玉米种子活力的方法进行了探索，沙引发显著地改善了超甜玉米种子活力。引发后的种子比未处理种子出苗提前约4d，出苗率提高27.5％～36.5％，电导率下降27.2％～43.3％。播种12d后幼苗增高16.1％～29.0％，鲜重提高22.2％～39.8％，SOD活性提高5.9％～10.5％，CAT活性提高7.8％～21.1％。组合处理与单一处理差异不明显。其中以沙引发(核黄素)效果最好。但沙引发(核黄素)与沙引发(水)之间差异不显著，鉴于简单经济原则，沙引发(水)为最佳选择。 4．甜玉米种子活力机理的进一步研究表明：沙引发具有修复膜系统，使膜的完整性得到恢复，减少种子内含物质渗漏的功能，而尤以核黄素处理的种子细胞膜完整性恢复最佳；沙引发提高了幼苗SOD和CAT活性，并减缓了它们在低温胁迫下的下降；引发种子种胚蛋白在萌发前期(0-4d)降解速度明显快于未引发种子。更多还原

【Abstract】 Variance analysis and correlation analysis were used to studies on seed health, seed vigor and their relation in 18 species of sweet corn (Zea mays L. saccharata Sturt) collected from Northwest China, North China, South China, Central China and East China. Efficient methods and systems for seed vigor evaluation of sweet corn were established. At the same time, efficient methods of sweet corn seed vigor improvement and their mechanisms were investigated. Research results were showed as follows:1. The research into seed health showed that sugar enhanced corn "Lutian9", "Xixingtianl", "jingketian116" and super sweet corn "Chaotian2000" were more healthy than sugar enhanced corn "Jingketian115" and super sweet corn "Green superman", "Huatianl", "Mitian8". The number of fungi on seed surfaces and percentage of internally infected seeds of former four species was 0.2 cfu per seed ~ 6.7 cfu per seed and 8.5%~51.3%, and later four ones 118.0 cfu per seed - 320.7 cfu per seed and 98.0%~ 100.0%, respectively. Significant differences existed among species type. Sugar enhanced corn (The number of fungi on seed surfaces 29.9 cfu per seed and percentage of internally infected seeds 62.0%) were less infected than super sweet corn (86.2 cfu per seed and 79.2%, respectively) . There were also significant differences among five locations. Samples from Northwest China (0.6 cfu per seed and 14.3%, respectively) were least infected while those from Central China(135.2 cfu per seed and 95.9%, respectively) more infected. Different methods of seed health testing had an effect on experiment results. More fungi were deteced from PDA than from blotter, such as Aspergillus, Geotrichum, Chaetominm and so on. So, PDA testing could refect seed health status more efficiently. Health status of seed surfaces had no significant impact on seed vigor while fungi inside seeds had great impact. Further research showed that Fusariwn was the most frequently isolated fungus whose incidence on seed sufaces was 66.1% and 67.4% in seeds and had the most drastic impact on seedling emergence. Percentage of Fusarium in seeds had a significant negative correlation with seedling emergence rate.2. The research into seed vigor showed that seed vigor of sugar enhanced corn "Tiandan8", "Tiandan10", "Sutian8" and super sweet corn "Mitian8" were significantly lower than those of sugar enhanced corn "Lutian9", "Jingketian116" and super sweet corn "Chaotian2000", "Yangtian1". Seedling emergence rate of former four species was 38.9%~47.2% and later four ones 71.3%~80.6%. Correlation analysis showed that there was a significant correlation between seedling emergence rate and dehydrogenase activity, electrical conductivity, the content of soluble sugar, the content of microscale formaldehyde, or germination rate through paper while there was no significant correlation between seedling emergence rate and standard germination rate or germination rate of cold resistance. Furthermore, there was also a significant correlation between seedling emergence velocity and electrical conductivity, the content of soluble sugar or dehydrogenase activity. The three vigor indexes were the best ones evaluating seed vigor.3. At the same time, methods of sweet corn seed vigor improvement were investigated. Results suggested that sand priming significantly enhanced seed vigor of super sweet corn. After primed, seedling emerged earlier for about 4d and seedling emergence rate was promoted by 27.5%~36.5%. Electrical conductivity was deseased by 27.2%~43.3%. On the twelfth days since sowed, seedling was heightened by 16.1%~29.0 %, seedling fresh weight was promoted by 22.2%~39.8%, SOD and CAT activities were inseased by 5.9%~10.5% and 7.8%~21.1%, respectively. There was no significant difference between single treatment and combined one. Sand priming (riboflavin) played most significant role. However, there was no significant difference between it and sand priming(water) . Given simpleness and economy, the later was best.4. Further reseach into seed vigor mechanisms on更多还原