小麦叶片叶绿素荧光参数与反射光谱特征的关系

以宁麦9号(低蛋白质含量)、淮麦20(中蛋白质含量)和豫麦34(高蛋白质含量)为试材，设0~300 kg hm^-2不同施氮水平，经2003—2004年和2004—2005年田间试验，对小麦顶部4张叶片叶绿素荧光参数和反射光谱特征的变化规律及其相互关系进行了分析。结果表明，小麦叶片叶绿素荧光参数F_v/F_m和F_v/F_o随施氮水平提高呈上升趋势，同时叶片光谱反射率在不同施氮水平、叶位和生育期均有明显差异。小麦植株顶1叶和顶2叶反射光谱在可见光区（520~680 nm）和近红外区（750~850 nm）与叶绿素荧光参数稳定相关。顶端2张叶片的植被指数DVI(750, 550)、DVI(735, 690)和TVI(750, 670, 550)与荧光参数F_o、F_m、F_v、F_v/F_m、F_v/F_o、F_s、F_m’、F_o’、F_v’、F_v’/F_m’的相关性均较好，其中DVI(750, 550)的相关性最好，且回归系数在不同品种和不同生育期之间没有显著差异。表明利用小麦叶片反射光谱监测其叶绿素荧光参数是可行的。

Relationship between Chlorophyll Fluorescence Parameters and Spectral Reflectance Characteristics in Wheat Leaves

It is of significant importance for using leaf spectral reflectance characteristics to estimate leaf chlorophyll fluorescence parameters in crop plants.We carried out two filed experiments in Nanjing to investigate the relationships between chlorophyll fluorescence parameters and spectral reflectance characteristics in top four leaves under different nitrogen levels in wheat(Triticum aestivum L.)cultivars Ningmai 9(low protein content),Huaimai 20(medium protein content),and Yumai 34(high protein content).Experiment one was conducted with Ningmai 9 and Huaimai 20 and five nitrogen application levels of 0,75,150,225,and 300 kg ha-1 in 2003 to 2004.Experiment two was designed for Ningmai 9 and Yumai 34 with three nitrogen application levels of 0,90,and 270 kg ha-1 in 2004 to 2005.The dynamic change patterns and interrelationships between chlorophyll fluorescence parameters and spectral reflectance in top four leaves of wheat cultivars under different nitrogen levels in two years were analyzed.The results indicated that the leaf chlorophyll fluorescence parameters Fv/Fm and Fv/Fo in wheat increased with increasing nitrogen rates,whereas the leaf spectral reflectance varied distinctly with nitrogen rates,leaf positions,and growth process.The correlations between chlorophyll fluorescence parameters and spectral reflectance in the top 1st and 2nd leaves were stabilized in the ranges of visible light(520-680nm)and near infrared light(750-850 nm).The leaf reflectance spectral indices DVI(750,550),DVI(735,690)and TVI(750,670,550)were all highly correlated with the leaf chlorophyll fluorescence parameters Fo,Fm,Fv,Fv/Fm,Fv/Fo,Fs,F'm,F'o,F'v,and F'v/F'm in top two leaves,and the DVI(750,550)had the best correlation.In addition,there were no obvious differences on regression coefficients among different cultivars and growth stages.These results suggested that it is feasible to monitor leaf chlorophyll fluorescence parameters by leaf reflectance spectra in wheat.