Effect Of High Temperature At Vegetative Stage On Chilling Tolerance Of Rice During Reproductive Period

Caused by low temperature chilling injury of rice production in recent years,increasingly become the important factors affecting the development of rice security in the world.According as the decreasing of rural labor force,machine planting at the beginning of the reaches of the changjiang river was popular,but the adoption of rootstocks ripe in late japonica rice varieties in jiangsu province machine plug,harvest is usually put off until October20-during November 10,stage,a significantly increased risk for low temperature.At the same time,because of global warming,the Yangtze river downstream in the vegetative growth stage of rice often encounter the weather heat stress.So the vegetative growth stage of research on the influence of high temperature on rice growth,the influence of low temperature on rice growth and yield and vegetative high temperature stage,the impact of the cold resistance of rice has important practical significance.This test is to ning japonica 1,Yang rice as the material,6 by pot and field experiments,using artificial high temperature,low temperature and natural low temperature above problem is studied.The main results were as follows:1.Vegetative heat treatment promoted the growth of rice,by raising temperature processing,testing varieties of plant height,stem tillers number,leaf area,aboveground dry matter weight were significantly increased,but the leaf age,leaf chlorophyll content does not take place obvious change,including indica rice varieties Yang rice 6 is affected by high temperature.The increase of leaf area ratio is experimental varieties and the accumulation of dry matter weight of the main reasons for the increased significantly.2.Delayed sowing of rice slow growth,plant height,leaf area on three declined.Delayed sowing of rice seed setting rate,grain number decreased significantly,resulting in rice production.Sowing delay reduced dry matter accumulation of rice maturity,changing the weight distribution ratio of dry matter.From the physical analysis of temperature stress postpone sowing harm caused to the cell membrane,so that MDA were significantly increased antioxidant enzyme activity was significantly decreased.3.The high temperature stress during vegetative growth stage leads to the increase of nitrogen content and reduced tendency of phosphorus contentin rice shoot;Under cold stress,rice maintained higher SOD and POD activities,leading to a higherMDA ansolubleprotein content to a certain extentCompared to the cold-sensitive varieties"Yangdao6",cold-tolerant cultivar "Ningjingl" maintained higher SOD and POD activities and soluble protein content,lower membrane lipid peroxidationcontent.The cultivars experienced high temperature during vegetative growth have increased MDA accumulation and more obvious rising trend,reduced SOD,POD activity and soluble protein content with slowed upward trend,significant lower setting rate and yield under cold stress in the booting stage and heading stage.All the cultivars experienced high temperature during vegetative growth were more cold-sensitive during reproductive stage than that under the control.With higher MDA content,lower SOD,POD activity.and soluble protein,[Conclusions]the high temperature during vegetative growth has an adverse impact on rice cold tolerance in reproductive period.