Regulation Effects Of Plant Growth Regulators On The Waterlogging Stress Of Peanut

Rain is frequent during the period of peanut cultivation in southern China, especially during the early and middle growth stage, which usually leads to severe waterlogging stress. In order to decrease the loss of peanut caused by waterlogging disasters, this experiment chose waterlogging-tolerant cultivar XiangHua2008, waterlogging-sensitive cultivar ZhongHua-4as experimental material, simulated the process of waterlogging stress suffered by peanut in the late vegetative growth stage (south rainy reason), then sprayed three kinds of plant growth regulator-GA3, ETH and PP333, respectively set5kinds of spraying concentration. Observed peanut s growth and development situation at the period of flowering pegging, bearing pod stage, full fruiting after spraying; measured the following indicators:accumulation of dry matter, photosynthesis, content of chlorophyll, activity of protective enzyme, damaging degree of cytomembrane, metabolism of anaerobic respiration, yield, quality et al; compared the function of different plant growth regulators on promoting restorative growth, alleviating waterlogging disaster of peanut. Provided disaster relief measures and theoretical basis for alleviating waterlogging disaster of peanut, stabilizing its yield and quality. Results indicated that:(1) Growth and Development For waterlogging-tolerant varieties, each treatment increased the dry matter of underground part of peanut compared with no spraying of chemical control agents. The differences was:Every concentration of GA3promoted the growth peanut, but ETH and PP333restrained plant height, the growth of branch, and the dry matter of underground part. For waterlogging-sensitive varieties, each treatment inhibited branch number and the shoot dry weight. The differences was:GA3and ETH promoted plant height and the growth of branch, but decreased branch number, PP333inhibited plant height and branch length.(2) Photosynthetic Physiology For waterlogging-tolerant varieties, each treatment increased the chlorophyll content at flowering pegging stage, but decreased at full fruiting stage.GA3decreased Ci and Gs, increased Pn and Tr of peanut; ETH decreased Ci and Gs, increased Pn, but promoted or inhibited Tr, which showed that the treatment of GA3and ETH promoted photosynthesis, and the stoma did not restrain this effects. PP333decreased Ci, promoted or inhibited Gs, significantly increased Pn and Tr. For waterlogging-sensitive varieties, each treatment decreased the chlorophyll content at flowering pegging stage, but increased at full fruiting stage. GA3decreased Ci, increased Gs, inhibited Pn, promoted Tr, which indicated that non-stomata limitation was the dominant factor of photosynthetic restrictions. ETH decreased Ci and Gs, inhibited Pn, which indicated that stomata limitation was the dominant factor of photosynthetic restrictions, however promoted or inhibited Tr. PP333promoted or inhibited Ci and Pn, increased Gs and Tr, which indicated that non-stomata limitation was the dominant factor of photosynthetic restrictions.(3) Resistant Indicators For waterlogging-tolerant varieties sprayed various concentrations of three kinds of plant growth regulator in the flowering stage and the similar effects of those treatments were:Increased the activity of ADH (key enzyme of anaerobic respiration) and root activity, increased the content of soluble protein of leaves of different stages after treatment. The differences was:GA3of each concentration inhibited the activity of SOD、CAT and POD, but GA3of low concentration promoted the activity of MDA and GA3of high concentration inhibited. ETH inhibited the activity of SOD and CAT, promoted or inhibited the activity of POD, decreased the content of MDA. PP333inhibited the activity of CAT, POD, promoted or inhibited the activity of SOD and the content of MDA. For waterlogging-sensitive varieties, three kinds of plant growth regulator all inhibited the activity of ADH, but increased the content of soluble protein. Treatment of GA3and ETH increased the activity of roots.PP333of low concentration inhibited the activity of roots and PP333of high concentration promoted. As for protective enzyme system, three kinds of plant growth regulator all increased the activity of SOD and POD, decreased the content of MDA. The differences were:GA3and PP333increased CAT; ETH promoted or inhibited the activity of CAT.(4) Yield and Quality For waterlogging-tolerant varieties, sprayed various concentrations of plant growth regulator and the similar effects of those treatments on the yield formation and quality component was:Increased total pod number, full pod number, full pod rate and full kernel rate, decreased blighted pod number, hundred-pod weight, hundred-kernel weight and shelling rate, decreased the content of protein, increased the content of fat, but had different influence on the O/L value-GA3increased the value,PP333decreased, ETH sometimes increased or decreased. Three kinds of regulator all increased the yield, and the effect was GA3>ETH>PP333, the treatment of150mg/L GA3showed a yield increase of24.9%. For waterlogging-sensitive varieties, various kinds of plant growth regulator all increased total pod number, full pod number, blighted pod number, hundred-pod weight, hundred-kernel weight, shelling rate, but decreased the full pod rate, full kernel rate. Each treatment increased the yield of pod, and each concentration of GA3significantly increased the yield.100mg/L GA3had the highest yield, showed an increase of45.3%, followed by ETH, showed an increase of11.7%-26.6%, PP333showed an increase of4.7%-24.2%.GA3and ETH all increased the content of protein, decreased the content of fat, PP333had an opposite effect. All treatments decreased the O/L value.In brief, plant growth regulators had evidently better effect on the waterlogging-sensitive varieties than on waterlogging-tolerant varieties. That was to say, it would be better to conduct chemical regulation before suffering from waterlogging for waterlogging-sensitive varieties to make up for the inherent shortage. Waterlogging-tolerant varieties could resist the waterlogging-hazards depending on their inherent genetic characteristics, which indicated that it was important to carry out ecological breeding of waterlogging tolerance. Utilizing chemical regulators could not only increased the yield, but also decreased the material and labor cost.