高温胁迫下水稻红边特征及SPAD和LAI的监测

Red edge characteristics and monitoring SPAD and LAI for rice with high temperature stress

为了促进高光谱遥感技术在水稻长势监测及其灾害评估中的作用,该文以扬稻6号与南粳43为试验对象,通过高温胁迫试验,测定孕穗期高温胁迫后2个品种在不同生育期冠层高光谱反射率、红边参数和叶片绿色度(SPAD)值及叶面积指数(LAI)。结果表明,2个水稻品种剑叶的SPAD值与LAI随生育期的进行呈先上升后下降的趋势,在开花期均达到最大值,在始穗期与蜡熟期时较低。随着高温胁迫的加剧,SPAD值和LAI不断减小。冠层光谱红边位置、红边幅值与红边面积在开花前呈"红移",开花后呈"蓝移"现象。随着胁迫温度的提高,3个红边参数也呈现"蓝移"现象。不同生育期剑叶SPAD值和LAI与红边特征参数均具有显著或极显著的相关关系。相对于红边幅值,以红边位置为参数所建的模型能更好地预测水稻剑叶的SPAD值和LAI。

For promoting the application of hyper-spectral technique on growth monitoring and disease evaluation in rice,the high-temperature stress experiments for two rice cultivars Yangdao 6 and Nanjing 43 were conducted in this paper,and canopy hyper-spectral reflectance,red edge parameters,soil and plant analyzer development（SPAD） value and leaf area index（LAI） of two rice cultivars at different growth stages were measured under high-temperature stress on booting stage. The results showed that SPAD value and LAI of two rice cultivars presented a tendency from rising to falling with development of growth stages,wherein both of them were up to peak value on flowering stage and turned lower value on early heading and ripening stages. The SPAD value and LAI would be reduced with the elevation of stress temperature. There were ‘red shift’ phenomena before flowering and ‘blue shift’ phenomena after flowering for the red edge position,red edge slope and red edge area of canopy spectrum. With the elevation of stress temperature,the ‘blue shift’ phenomena were also presented for those three red edge parameters. The SPAD value and LAI of rice flag leaves at different growth stages were significantly or very significantly correlative to the red edge feature variables. Therefore,the model based on red edge position could be more reliable for predicting SPAD value and LAI of rice flag leaves compared with red edge slope.