不同施磷水平下接种菌根玉米营养状况及光谱特征分析
Hyperspectral characterization and nutrition condition of maize inoculated with arbuscular mycorrhiza in different phosphorus levels
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摘要: 利用高光谱遥感技术来监测不同施磷水平下接种菌根对植物生长的影响规律。在较低施磷水平0和30 mg/kg下接种丛枝菌根能显著促进玉米植株对磷的吸收,植株生物量和叶绿素含量均高于相应对照组,而在较高施磷水平60和120 mg/kg下,接种丛枝菌根未促进植物生长和磷吸收,而对其有一定抑制作用。获取接菌对玉米叶绿素含量影响较为敏感的光谱响应信息,在不同施磷水平下,接菌组玉米的绿峰幅值均低于相应对照组,且绿峰幅值随着施磷水平的增加而减小,低磷条件下接菌组和对照组玉米光谱的蓝边斜率、黄边斜率、红边斜率差异最为明显。以不同处理玉米叶绿素含量差异的光谱特征参数作为自变量,构建以玉米叶绿素含量为因变量的线性或非线性回归模型。接菌玉米叶绿素含量的所有反演模型中,以REP为变量所构建线性模型具有较高的拟合精度和较好的反演效果,其拟合度达到了0.839,检验R~2为0.753,对照处理的玉米叶绿素含量的所有反演模型中,以R_G为变量所构建的指数模型稳定性最好,其拟合度达0.927,检验R~2为0.834。Abstract: This study is to monitor the impact of inoculation mycorrhizal on the growth of maize plants under different phosphorus(P) levels using hyperspectral remote sensing technology. At low P levels(0 and 30 mg / kg),inoculations significantly promoted the P absorption,plant biomass and chlorophyll content as compared with uninoculated control, while at higher P levels(60 and 120 mg / kg),inoculations effects somewhat inhibited,rather than promoted the growth and P uptake. Based on the sensitive spectral information on the response of chlorophyll content to the inoculation,un- der different P levels,the green peaks in inoculated plants were lower than those of uninoculated controls,and reduced as P application increased. In the low P conditions,the differences between the inoculated and uninoculated plants in the slopes of blue,yellow and red edges were the most remarkable. The spectral characteristic parameters that measure the difference in chlorophyll content in different treatments were used as independent variables to construct linear or nonlinear regression model using the chlorophyll content as the dependent variables. In all the inversion models that used the chlorophyll content,the linear model with REP as variables had higher fitting precision and better inversion outcomes,with a fitting value of 0. 839 and R2 of 0. 753. When the chlorophyll contents in the control were used in the inversion models,the most stable model was exponential with RG as variable. Its degree of fitting was 0. 927 with R2 of 0. 834.