不同水稻生育期实测光谱与叶绿素相对含量的响应分析

Response Analysis of Measured Hyperspectral and Chlorophyll Relative Content in Rice During Multiple Growth Stages

为探索和研究水稻叶片不同生育期叶绿素相对含量(SPAD值)与实测水稻叶片光谱的变化规律和响应特征,通过采集研究区水稻发育关键期叶片光谱及叶绿素相对含量,研究探讨了随着生育期的推进,水稻叶片光谱特征变化及其与SPAD值变化的响应关系,分析比对了SPAD值与4个生育期水稻差值植被指数(DVI)、比值植被指数(RVI)、增强植被指数(EVI2)植被指数敏感波段。结果表明:随着生育期推进,SPAD值逐渐减少,可见光(红光)范围光谱反射率呈一致的逐步增加趋势;孕穗期近红外波段对SPAD值敏感,抽穗期、灌浆期和成熟期可见光波段对SPAD值敏感;不同植被指数与SPAD值显著相关,DVI对孕穗期、成熟期的SPAD值敏感,RVI对抽穗期的SPAD值敏感,EVI2对灌浆期的SPAD值敏感。

In order to explore the variation regularity and response characteristics between chlorophyll relative content(SPAD value)in rice leaves and spectra at different growth stages,the measured hyperspectral and SPAD value of rice leaves at the key stages of rice development were collected,and the change of spectral characteristics of rice leaves and its response to the change of SPAD values with the progress of growth stage were studied,and the sensitive bands of SPAD value and rice vegetation index of difference vegetation index(DVI),ratio vegetation index(RVI)and enhanced vegetation index(EVI2)at four growth stages were analyzed and compared.The results showed that the SPAD value decreased gradually with the development of growth period,and the spectral reflectance of visible light showed a consistent trend of gradual increase.Near infrared band was sensitive to SPAD value at booting stage,visible light(red light)band was sensitive to SPAD value at heading stage,filling stage and maturity stage.Different vegetation indices were significantly correlated with SPAD value,DVI was sensitive to SPAD value at booting stage and ripening stage,RVI was sensitive to SPAD value at heading stage and EVI2 was sensitive to SPAD value at filling stage.