淹水胁迫下棉花叶片高光谱特征及叶绿素含量估算模型

为即时监测淹水胁迫下棉花功能叶叶绿素含量,确立叶绿素含量与单叶光谱特征参数的定量关系,本文以遮雨棚内蕾期淹水胁迫下的盆栽棉花为研究对象,淹水后每 3 d对棉花叶片进行测定、取样,综合分析叶绿素含量与高光谱特征参数的相关性,并构建和验证叶绿素含量的估算模型.结果表明: 随着淹水胁迫程度的加重,叶片叶绿素含量下降;叶片原始光谱反射率、一阶微分光谱反射率分别在580、697 nm波段附近与叶绿素含量呈显著负相关;利用差值指数和归一化指数建立的估算模型优于单波段线性模型,其中以植被指数(DR₆₉₇-DR₇₃₈)/(DR₆₉₇+DR₇₃₈)为自变量建立的模型棉花单叶叶绿素含量估算值与实测值拟合度最好,拟合系数为0.814,可用于淹水胁迫下棉花单叶叶绿素含量的估测.

Hyper-spectral characteristics and estimation model of leaf chlorophyll content in cotton under waterlogging stress

In order to rapidly monitor chlorophyll content in cotton functional leaf, and establish the quantitative relationship between chlorophyll content and spectral characteristic parameter of single cotton leaf, cotton was pot cultivated in a rain-shelter and subjected to waterlogging at squaring stage. Cotton leaf samples were taken and measured every 3 days after waterlogging. The correlation between chlorophyll content and spectral characteristic parameter was synthetically analyzed, and then the estimation model of chlorophyll content was established and verified. The results showed that the chlorophyll content decreased with increasing waterlogging stress. The original spectral reflectance and first-order differential spectral reflectance was negatively correlated with the chlorophyll content in the band near 580 and 697 nm. The estimation model established by difference vegetation index and normalized difference vegetation index performed better than that established by linear model of single band. Furthermore, the estimation model with (DR₆₉₇-DR₇₃₈)/(DR₆₉₇+DR₇₃₈) as the independent variable fitted the best with the correlation coefficient of 0.814, which could be utilized to estimate chlorophyll content of single leaf under waterlogging stress.