用高光谱植被指数估算水稻乳熟后叶片和穗的色素含量

 分析测定了大田条件下2个水稻品种在3个氮素水平下的剑叶和穗从乳熟期至收割的光谱反射率(350~2500 nm)及对应剑叶和穗的叶绿素（Chl）、类胡萝卜素（Car）含量,并利用相关分析研究了11个植被指数与剑叶、穗的叶绿素含量之间的关系。mSR705、mND705在试验范围各叶绿素含量水平下，都表现极显著的相关性。mSR705、mND705与叶片、穗叶绿素含量进行线性回归，两者拟合R2分别为0.9319和0.9488（n＝48）。植被指数与类胡萝卜素、Car/Chl间的相关性分析表明，光化学反射指数（PRI）与剑叶、穗Car/Chl都有很好的负相关（R2=0.7745，n=48）, 可以用来预测不同植被结构的Car/Chl;R760/R500与剑叶Car/Chl和穗Car含量也具有较好的相关性。结果表明，mSR705、mND705和PRI等指数可用于估算叶片、穗的色素含量，作为水稻成熟度的监测指标。

Estimation Pigment contents in Leaves and Panicles of Rice after Milky Pipening by Hyperspectral Vegetation Indices

A field experiment was carried out to investigate the relationships between the hyperspectral reflectance and pigment(chlorophyll a,b and carotenoids) contents in flag leaf and panicle of two rice cultivars under three nitrogen levels from milky to harvest.Eleven vegetation indices were correlated with the pigment contents in flag leaves and panicles.As a result,the mSR_(705) and mND_(705)indices were significantly related to the chlorophyll contents,with R~(2)=0.9319(n=48) for leaves and R~(2)=0.9488(n=48) for panicles,respectively.Photochemical reflectance index(PRI) was negatively significantly correlated with the Car/Chl ratio in both flag leaves and panicles(R~(2)=0.7745,n=48),indicating that PRI could be used to predict Car/Chl across different vegetation structures.R_(760)/R_(500) was also significantly(P=0.05) correlated with Car/Chl in leaves,and carotenoids contents in panicles.It was suggested that mSR_(705),mND_(705) and PRI could be used to estimate pigment contents in leaves or panicles of rice,and applied as spectral parameters in rice maturation monitoring.