【作者】 林彰文；

【导师】 欧阳西荣；

【作者基本信息】 湖南农业大学 ， 作物耕作与栽培学， 2003， 硕士

【摘要】 以PEG、6-BA浸种及老化处理改善或降低玉米种子活力，并通过SOD、α-淀粉酶活性等多项生理生化指标的测定，对种子处理对玉米种子萌发及幼苗期生理生化的影响，对PEG、6-BA浸种及老化处理改善或降低玉米种子活力的机制等方面有了更深入的了解。主要研究结果概述如下： 1．不同浓度6-BA对玉米种子萌发有不同影响，太低对种子萌发促进作用不明显，而超过一定浓度会抑制种子萌发。实验表明6-BA以1.0×10^-8mol/L浓度25℃浸种18 h处理玉米种子的效果较佳，表现发芽率高，幼苗健壮，根粗壮，叶色深，植株高，干物质积累多。PEG处理种子也能提高种子活力，但主要是提高了种子的萌发率，萌发速度和幼苗的整齐度。 2．实验采用45℃，100％RH的处理方法对种子进行人工老化，发现老化1 d的种子活力下降不大，各项生理生化指标与对照没有明显差异；而老化2 d的种子活力下降明显，表现为种子发芽率和幼苗生长势的明显下降，生理生化指标差异明显，而且出现了畸形苗。 3．用PEG和6-BA处理的玉米种子，其α-淀粉酶活性都较高，而人工老化1 d的种子α-淀粉酶变化不大，人工老化2 d的种子的酶活性显著降低。PEG和6-BA处理有可能促进了萌发启动物质的产生和积累，从而促进萌发。 4．以浓度为1.0×10^-6和1.0×10^-8mol/L的6-BA处理玉米种子，其萌发的幼苗叶片叶绿素含量都较对照显著提高，人工老化2 d及自然老化的种子萌发幼苗的叶绿素含量都较对照低。尽管1.0×10^-6 mol/L 6-BA处理对提高玉米种子活力的作用不大，但也能较明显地提高玉米幼苗叶片叶绿素含量，表明6-BA可在一定程度上提高叶片叶绿素含量，增强幼苗光合作用。 5．对幼苗的抗逆性进行分析发现，在10℃的冷环境中，6-BA处理的玉米种子的幼苗SOD酶活性、可溶性蛋白含量都较高，而MDA含量较低。PEG处理的玉米种子的幼苗SOD酶活性和MDA含量较低，而可溶性蛋白含量较对照略高。人工老化2 d的种子幼苗叶片中SOD酶活性较对照下降明显，其可溶性蛋白含量变化幅度最大，且含量也低，MDA含量高。试验结果表明高活力种子的幼苗抗逆性较强。 6．从发芽率、幼苗生长势、简化活力指数等一系列生理生化指标的测定和比较，发现玉米种子处理改变了种子活力，而种子活力在很大程度上决定其萌发及幼苗期生理生化特征。但同时也发现活力相同，生理生化表现也不一定相同。种子内部的生理生化是相互影响，互相作用的，单独某个生理生化指标的大小不能用来衡量种子活力的大小。更多还原

【Abstract】 Improving and reducing maize seed vigor were obtained by PEG, 6-BA treatments and artificial ageing, and a lot of physiological and biochemical characteristics were tested, such as SOD and α-amylase activities. The results can help us to get better understanding for the effects of seed treatment on the physiology and biochemistry during seed germination and in seedlings of maize (Zea mays L.). And the mechanism of the seed vigor change by the treatments was analyzed. The main results of the present study were as follows:1. The concentration of 6-BA affects maize seeds vigor. Low density of 6-BA did not show effect to seed germination, and too high density inhibited seed germination. The results of present study showed that the 6-BA density of 1 .0× 10-8 mol/L was the best to improve maize seed vigor, the treated seeds by this concentration showed higher germination percentage, more vigorous seedlings, stronger root and thicker leaf color. PEG also improved seeds vigor, but it mainly accelerated seeds germination, higher germination percentage and the seedlings come out evenly.2. Maize seeds were artificially aged in the environment of 45 ℃ , 100% RH. One day ageing declined maize seed vigor little, but two day ageing declined the seed vigor significantly, the seed germination percentage was declined and the seedling growth were stunted, weaker seedling and deformity seedlings were appeared.3. The a-amylase activity of the maize seeds treated by PEG and 1.0×10-8 mol/L 6-BA was higher than the untreated seeds. The a-amylase activity of the seeds aged for 1 d changed little, and of the seeds aged for 2 d was declined significantly. PEG and 6-BA treatments might actuate to produce the material for seed germination starting.4. The chlorophyll content in the seedling leaves of maize seeds were treated by 1.0× 10-6 and 1.0×10-8 mol/L 6-BA was significantly higher than CK, and that of the seeds naturally aged or artificially aged for 2 d was lower. Though 1.0×10-6 mol/L 6-BA treatment did not enhance seed vigor, but it also increased the chlorophyll content of seedling leaves. It may show that 6-BA can increase leaf chlorophyll content and improve their photosynthesis.5. For high vigor seeds, their seedlings showed stronger resistance to adverse circumstances. For the seeds treated by 1 .0×10-8 mol/L 6-BA, whenthe seedlings were growing in 10℃ cold environment, their SOD activity and soluble protein content were higher and their MDA content was lower. And for the seeds treated by PEG, the SOD activity and MDA content of the seedlings were lower and their soluble protein content was higher than the CK. For the seeds aged 2 d, their seedlings showed lower SOD activity, higher MDA content, and significantly lower soluble protein content.6. From sorts of seeds physiological and biochemical characteristics, such as germination rate, seedlings growth, simper vigor index, we could get a conclusion that seed treatment could change seed vigor, their physiological and biochemical characteristics were mainly decided by seeds vigor. In the other hand, even with the same vigor, there were still differences for their physiological and biochemical characteristics. There were interaction among all the seed physiological and biochemical characteristics can affect each other. It is not suitable to use only one physiological and biochemical characteristic to judge seed vigor.更多还原