水淹胁迫下枫杨(Pterocarya stenoptera C.DC.)幼苗叶片高光谱特征的研究

Hyperspectral Characteristics of Chinese Wingnut (Pterocarya stenoptera C.DC.) Leaves under Flooding Stress

测量了3个水淹深度（对照、根部水淹、全淹）条件下枫杨叶片的高光谱反射率、红边参数及对应的叶绿素总含量,对归一化植被指数与叶绿素总含量进行了相关分析.结果表明：①在水淹胁迫下,枫杨叶片的高光谱反射率呈现下降的趋势,且在蓝光波段（400~500 nm）和近红外波段（760~950 nm）表现为极显著差异;②随着水淹程度的加深,枫杨叶片叶绿素含量显著下降（p〈0.05）;③红边特征的分析显示,随着水淹程度的加深,叶片光谱出现了蓝移的现象,红边斜率呈现下降的趋势;④叶绿素总含量与归一化植被指数（R705/R750）呈正相关,相关系数为0.86（p〈0.01）.经回归分析,叶绿素总含量与归一化植被指数呈线性关系（R2=0.80,n=42）.认为枫杨叶片高光谱特征及归一化植被指数可较好地反映枫杨的叶绿素含量和水淹胁迫的程度.

In the experiment,three flooding-depth levels were set,i.e.control（T1）,below-ground submergence（T2） and complete submergence in water（T3）.The reflectance spectra of Chinese wingnut（Pterocarya stenoptera C.DC.） leaves,the red edge parameters and the corresponding chlorophyll content were measured,and the relationship between the normalized differential vegetation index（NDVI） and total chlorophyll concentration was analyzed.The results showed that the reflectance spectrum decreased under flooding stress,especially at the wavebands of 400-500 nm and 760-950 nm,with highly significant differences（p0.01）.With increasing depth of flooding,total chlorophyll content of P.stenoptera C.DC.leaves decreased significantly（p0.05）.The first derivative spectra were used to determine the wavelength of the red-edge,and the results showed that with the increase in depths of flooding the red edge position moved to short band and red amplitude tended to decrease.Construction of the NDVI index and the Chinese wingnut leaf chlorophyll content had a high degree of fitting（R2=0.80,n=42）,and was positively correlated（r=0.86,p0.01）.