冬小麦冠层高光谱对低温胁迫的响应特征

Response of Winter Wheat(Triticum aestivum L.)Hyperspectral Characteristics to Low Temperature Stress

在全球范围内,低温冻害已经成为了冬小麦减产的主要灾害之一,而高光谱遥感技术已成为一种有效的监测与预防手段。为了探究拔节期冬小麦冠层高光谱对低温胁迫的响应规律,通过低温胁迫试验,对同一品种拔节期冬小麦在-2,-4和-6℃等3个温度梯度下处理12h,并测定其冠层光谱反射率,提取红边参数,从而研究低温胁迫对冬小麦冠层光谱特征的影响。结果表明,冬小麦在遭受低温胁迫后,在近红外波段冠层光谱反射率随着低温胁迫程度的加大而升高,而在可见光波段则降低,并出现"绿峰"减弱,"红谷"抬升的现象。另外,对原始光谱进行一阶微分处理后,其一阶微分光谱随低温胁迫程度的加剧,出现向短波方向移动,红边位置也出现"蓝移"现象,红边面积与红边幅值也出现逐渐增大的趋势。研究表明冬小麦在拔节期遭受低温胁迫以后,其冠层光谱对其响应敏感,利用高光谱技术可以实现冬小麦冻害的有效监测。

The simple winter wheat variety was conducted under the low temperature treatment at-2,-4,and-6 ℃,the canopy reflectance was measured and the red edge parameters were extracted to study the winter wheat canopy spectral characteristics effected by the low temperature stress and the hyperspectral response to the low temperature stress of winter wheat at jointing stage.The results showed that the canopy reflectance decreased in visible region and increases at near infrared band with the high intensively low temperature stress,and 'green peak' was weakened and'red well'was not distinctive.Moreover,the derivate spectrum had the trend of shift to short wavelength direction with the strengthening of low temperature stress and the red edge presented the blue shift.The area of red edge and red edge amplitude exhibit increase.It indicated that the canopy spectrum of winter wheat is sensitive to the low temperature stress,and the hyperspectral technology can be used to monitor the low temperature stress of winter wheat at jointing stage.