亚热带常绿阔叶树种对模拟遮荫胁迫的高光谱响应

摘要

利用 ASD 地物光谱仪，测定不同梯度遮荫胁迫条件下4种亚热带常绿阔叶树种的光谱反射率，应用微分技术处理其反射光谱，并结合 SPAD-502测定的叶绿素相对含量进行分析，研究其在遮荫胁迫情况下的高光谱特征。结果表明：4种树种都具有一定的耐荫性，遮荫处理会影响树种的叶绿素含量，透光率85％的遮荫处理下的叶绿素含量最大；透光率85％的遮荫处理下红边位置发生“红移”现象，但过高的遮荫处理会抑制其生长，出现红边位置“蓝移”现象。不同遮荫梯度下，红边位置对应窄波段范围内的平均一阶微分光谱与叶绿素含量间的相关性较高，R 2大于0．61，相关性显著。本研究通过分析4种亚热带常绿阔叶树种在不同遮荫梯度下的光谱变化特征，以及红边位置对应窄波段范围内平均一阶微分光谱与叶绿素含量的相关性，证明了遮荫影响4种树种的生长，红边位置的一阶微分光谱能有效地监测遮荫对树种的影响，为在大气气溶胶阳伞效应条件下森林植物的生长遥感监测提供了理论依据。%Using the ASD spectrometer to determine the spectral reflectance of four kinds of subtropical evergreen broad-leaved species in different gradient shading stress conditions,the differential technology to process their reflectance spectra,and combining the relative chlorophyll content of SPAD-502 for analysis,this paper studies spectral variation characteristics of four tree species in the shading stress conditions.The results showed that:four kinds of trees have a certain shade tolerance,tree shading will affect chlorophyll content,light transmission rate of 85% shade treatments has maximum chlorophyll content;the red edge position expressed as “red shift”in light transmission rate of 85% shade treatments condition,but excessive shading treatment will inhibit their growth,red edge position expressed as “blue shift”.The mean first derivative spectral of red edge position corresponds to a narrow wavelength rage and chlorophyll content has higher correlations,R 2 is more than 0.61.The correlation is significant.This study analyzed the spectral variation characteristics of four kinds of subtropical evergreen broad-leaved species in different gradient shade and the correlation between the red edge position corresponds to an mean of a narrow band within the first derivative spectra and chlorophyll content.It proves that shade effect the growth of four kinds of subtropical evergreen broad-leaved species.The red edge position of the first derivative spectra can effectively monitor the impact of shading on trees.It provides a theoretical basis for remote sensing monitoring the growth of forest plants in atmospheric aerosol parasol effect condition.