Growth Characteristics Of Rice Root And Upper Land Plant With Increased Oxygen Supply

The experiment uses Oryza Sativa subsp. hsien: Xiang 24 and Xiang 11 ,and Oryza Sativa subsp. keng Yong 18 and Chunjiang 06 as raw materials. The rice was planted by adopting the methods of the watered- breeding and soiled-breeding. Effects of oxygen to the rice's roots and grain yield were studied by controlling the environment of oxygen density where the rice grew. The main results showed as follows:1. Oxygen concentration had influence on rice roots. The results showed that the length of rice roots became longer, the number of indeterminate roots and white roots became more and larger in rice planted in oxygen abundance condition. Besides, the roots were stronger under the oxygen treatment. But it also found that too much oxygen was harmful to the growth of roots. In the watered-experiment, the length of roots became longer significantly, while the amount of roots was significantly reduced, the roots were thin and small under saturated oxygen condition. Under the poor oxygen condition, the growth of roots was impaired significantly. The root length became shorter, the number of black roots was larger and the roots were weaker and so on.2. Oxygen concentration changed rice roots physiological activity. Compared to CK treatment, the capability of the rice roots to oxidantα^NA was more powerful under the sufficient oxygen condition, the absorbing area of the rice roots was larger and the roots bleeding intensity was high The SOD activity of roots decreased slowly, MDA content accumulated slowly. The roots activity was not only stronger but also lasting longer especially in grain-filling stage, which was advantageous to grain yield improvement.. Under the poor oxygen condition, the root activity was weak and the roots were early dead easily. 3. Oxygen affected the growth of the upper land plant of rice. Under the sufficient oxygen condition, the number of the effective branches increased; the individual plant became shorter, the dry material accumulation above land was increased. The chlorophyll content and SOD activity of the rice leaves decreased slowly, so the rice leaves senescence slowly. Under the poor oxygen condition, the rice grew small, the number of the healthy buds was little, and the dry material accumulation above land was decreased. The chlorophyll content and the SOD activity of the rice leaves decreased quickly, so the plant was apt to early senescence.4. Oxygen affected rice production. Abundant oxygen could accelerate the grain-filling rate of rice, and the contributions of filling matter to yield were high, so the seed rate and the weight of 1,000 grains were both higher than CK. Under the poor oxygen condition, the rice could not fill enough, the seed rate and the weight of 1,000 grains were low, so the production was very low. The order of the individual plant's productive ear which from the most to the least was: increasing aerobic treatment, compared treatment, decreasing treatment. Increasing oxygen could improve the number of effective branches, so it is benefit for the production.5. Oxygen changed soil oxidation-reduction potential. In soil fertilized CaO₂, the value of oxidation-reduction potential was between -100mv to 100mv, the change range was small and the value was relative stable. The soil oxidation-reduction potential of CK and CaO was similar, the value became smaller with watered time elongation, it reached the lowest (-340mv) in the mature period, and the range was also bigger. During the dried period, the oxidation-reduction ability was higher. Then after the elongation stage, chatter amplitude was bigger as the speed of accumulated water in the rice field became faster. As under the artificial joint oxygen situation, the oxidation-reduction ability was unsteadily. When in the CaO₂, the potential was higher. And it became lower when stopped the CaO₂.