江淮地区一季稻高温热害指标及其特征研究

High Temperature Damage Indexes and Characteristics of Single-season Rice in Jianghuai Area

[目的]确立江淮地区一季稻高温热害的指标,并对该地区一季稻高温热害的特征进行研究。[方法]结合实际观测资料,分析江淮地区一季稻高温热害的产生时期,确立高温热害的衡量指标,并对指标进行验证,最后讨论高温热害的产生原因,提出预防对策。[结果]江淮地区一季稻高温热害多发生在7月下旬～8月上旬,以8月上旬危害最为严重;经验证,确立的高温热害指标准确可靠;高温热害的发生与江淮地区的气候及种植品种和种植制度有关;在满足基本生育积温条件下,防御一季稻高温热害要适期早播早栽或迟播迟栽,选用耐高温品种。[结论]该研究可为减轻安徽省江淮地区一季稻高温热害的危害提供参考。

High temperature damage refers to the injury of high temperature to the growth and yield of plant（biology）,and it usually occurs when the environment temperature exceeds the upperlimit temperature of plant growth.High temperature has effect and damage to crops,especially more obvious effect on rice.Jianghuai area is a main productive region for single-season rice in Anhui Province.Recently,single-season rice in Jianghuai area frequently suffer from high temperature damage so that rice production is damaged seriously. Based on the meteorological observation records data from representative sites in Jianghuai area,the high temperature damage of single-season rice in Jianghuai area was studied by using agrometeorological and farmland microclimate principle.Measurement indexes of high temperature damage were determined and verified,and the causing reason of high temperature damage was discussed.Preventive measures were proposed finally. The single-season rice in Jianghuai area enters into booting-heading stage in early August.Jianghuai area of Anhui Province is controlled by subtropical high easily,and high-temperature and clear weather usually appear.If single-season rice stays at heading-blooming stage in this case,high temperature damage occurs easily. High temperature damage indexes of single-season rice during blooming and filling stage in Jianghuai area were as followed：①the daily maximum temperature was equal to or more than 35 ℃,or daily mean temperature was equal to or more than 30 ℃ for sustainable 3 days;②the temperature was near to 29 ℃ at 20：00 in the same period;③the relative humidity of rice canopy decreased from about 80% to 60%.Seven varieties like Zhongxian 898,Teyou 559,Xieyou 559, Zhongxian 2503,II You 128,Xieyou 52 and Wandao 153 which were largely planted in Jianghuai area by farmers were used to verify high temperature damage indexes.Results show that the determined high temperature damage indexes in Jianghuai area were accurate and reliable,and it provided realistic directive significance for how to largely plant single-season rice varieties in Jianghuai area. The occurrence of high temperature damage was related to planted varieties,cropping system and the climate of Jianghuai area.The distribution of high temperature damage in Jianghuai area was basically identical with atmospheric circulation background from late June to early August except that it was related to heat-resistance difference of single-season rice varieties.The high temperature damage caused by local microclimate factors also appeared usually.The single-season rice under different sowing and transplanting progress in the same region suffered from different degrees of high temperature damage.Different single-season rice varieties had obviously different tolerance to high temperature damage.Besides,the degree of high temperature damage was also related to seedling quality,plant growth,cultivation conditions and management level. From the cropping system and planting habit of single-season rice in Jianghuai area,if the basic accumulated temperature was satisfied,early sowing and early planting or late sowing and late planting should be used to control the high temperature damage of single-season rice so as to aviod to meet high temperature weather in heading-blooming period.Besides,if high temperature weather appeared under the given other growth conditions during heading-blooming stage of single-season rice,single-season rice during blooming stage should be treated with some meaesures like shallow water and continuous irrigation,daytime irrigation,night emission and real-time dry set so as to promote root haleness and high temperature resistance-enhanced of single-season rice. With the increase of occurrence probability of extreme weather in recent years,the frequency of high temperature damage of single-season rice in Jianghuai area also increased.Single-season rice in Jianghuai area were also planted after rape and winter wheat,so strong chilling resistance during rice seedling stage and high temperature resistance after heading should be promised.From variety types to see,medium variety was suitable to plant in Jianghuai area. The rsearch provides reference for reducing the high temperature damage of single-season rice in Jianghuai area.However,it is poorly described that whether high temperature damage is dominated by physical damage or physiological injury or both of them,as well as the previous physiological indexes to rapidly and effectively detect high temperature damage.Therefore,the physiological and biochemical mechanism of rice injury by high temperature stress should be studied, and high temperature resistance mechanism of rice should be found out so as to screen and cultivate high temperature resistance varieties.Meanwhile,the present defensive measures of high temperature damage of rice should be furtherly imporved so as to reduce the rice loss caused by high temperature damage.