白粉菌侵染后田间小麦叶绿素含量与冠层光谱反射率的关系

 本文对白粉菌侵染后田间小麦叶片叶绿素含量与光谱反射率的关系进行了研究。用不同浓度的药液控制田间病害的发生梯度,于灌浆期对不同严重度小麦冠层的光谱反射率进行了测量,同时测定小麦叶绿素含量并调查病情指数,分析叶绿素含量与病情指数、冠层光谱反射率的关系。结果表明,药剂对叶绿素含量无显著影响;受白粉病危害后,小麦叶片叶绿素含量明显降低,抗性不同的品种之间下降速度存在差异,与病情指数之间也有极显著的相关性。绿光波段与叶绿素含量之间的相关性达到了显著水平;基于多波段建立的模型要优于单波段,可以利用绿光、红光波段的反射率估计叶绿素含量。红边参数与叶绿素含量之间也有较好的相关性,其中以红边面积的相关系数最大。

Relationships between canopy reflectance and chlorophyll contents of wheat infected with powdery mildew in fields

Relationships between canopy reflectance and chlorophyll contents of wheat infected with powdery mildew in fields were investigated.Different disease epidemic patterns in each of the experimental plots were obtained by spraying fungicide at different concentrations and inoculating with Blumeria graminis f.sp.tritici.The canopy reflectance of wheat with different severity was measured at the stage of milk-filling,and chlorophyll content was also measured as well as disease index(DI) at the same time.Correlations between chlorophyll content and DI or canopy reflectance were calculated.The results showed that fungicide had no significant impact on chlorophyll content.When wheat was damaged by powdery mildew,chlorophyll content decreased significantly,however,rates of decreasing were different in varieties with different resistance levels.There was highly significant correlation between chlorophyll content and DI,and significant correlation between chlorophyll content and green band.Models of relationships between canopy reflectance and chlorophyll contents of wheat infected with powdery mildew were constructed,and the models based on multiple bands were better than that based on single band.We can estimate chlorophyll content by using reflectance in green and red band.Red edge parameters were also well correlated with chlorophyll content,and the area of red edge was higher than the others.