The Effects Of Seed Treatment On The Physiology And Biochemistry During Seed Germination And In Seedlings Of Maize(Zea Mays L.)

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.