Responses Of Corn To Different Irrigation Treatments

The growth and physiological characteristics, yield and water use efficiency of corn in greenhouse were studied under different irrigation methods. The main results were outlined as follows:Different irrigation treatments have certain influences in growth of corn plants. The plant height of corn under full irrigation(FI) increased more than the other treatments. Although consuming the same water amount, the plant height increases of the corn under PRD75% treatment are more than that of the corn under DI75% treatment during late growth stages.Different irrigation treatments have a significant effect on above-ground accumulation of biomass and dry matter. The plant of the corn under FI treatment was maintaining the maximum biomass, from the seedling stage, (more than that under DI75% and PRD75%). After shooting stage, the above-ground accumulation of biomass under PRD treatments increased more than that under DI when assuming same amount of water.When compared with root dry matter and root/shoot ratio of plants under different irrigation treatments, plants under FI treatments owned the lowest of them , and then came the DI75%, DI50% treatments , while the PRD75%, PRD50% treatments maintained higher level.The contents of free proline of leaves increased as the water supply was declined. With the same water consumption treatment, the content of free proline under PRD treatment was more than that of which under DI treatment. The accumulation of the free proline contents under 50% and 30% water supply increased significantly more than the other treatments, from beginning of water stress until resuming water supply. During the early stage of water stress, SOD activity of plants under FI treatment was more effective than the others, which showed good performance on scavenging free radicals. At the beginning of water stress, SOD activity was increasing. During 5-day stress, SOD activity under DI75%,PRD75%,DI50%,PRD50% treatments increased of 64.52%, 59.95%, 42.87%, 41.04%, while the activity under FI treatment varied gently. After 7-day stress, SOD activity under DI30%, PRD30% decreased of 10.61%, 3.15%.SOD activities of all treatments decreased after resuming water supply. It is showed that SOD activity had response to the accumulation of reactive Oxygen as water condition changed. DI75%, PRD75%, DI50%, PRD50% treatments had more effective performance.POD activities of all treatments showed the similar tendency with SOD activities, except DI30% treatment. The activity under FI treatment was increasing until resuming water supply. While it was up under DI50%, PRD50%, PRD30% treatments at the early stress period and down during 5-7 days stress. Especially the plants under DI30% treatment, POD activity was always declined from the beginning of water stress.The plants under PRD75% treatment provided the maximum ear dry weight, which was not consciously different with that under FI treatment. The ear dry weight under DI50% and PRD50% were lighter than others. The difference of seeds dry weight was significantly under all irrigation treatments. (FIï¹¥PRD75%ï¹¥DI75%ï¹¥DI50%ï¹¥PRD50%)Of all the yield components, only the seeds dry weight under PRD75% was somewhat less than that under FI treatment. The difference of the other parts of yield components between the tow irrigation treatments was not conspicuous. Different irrigation treatments had the most significant effect on the ear dry weight of yield components.Although the difference of yield was inconspicuous between PRD75% and FI treatments, the water consumption of PRD75% treatment was decreased 25% than that of FI treatment. Therefore, the yield and water use efficiency of the plants under PRD75% treatment were much higher than that under DI75% and FI treatments.