Estimation of Optimal MesophyH Structure Parameter of Rice Leaves
水稻叶片最优叶肉结构参数估算

Leaves are a basic component of plant canopy and their optical properties have great influence on canopy reflectance spectra that can be obtained by remote sensors.In principle,the reflectance spectra are determined by the biochemical constituents and biophysical structure of the leaves.The accurate estimation of leaf structure may help to separate its contribution to leaf spectra and improve the inversion of leaf biochemical information that is widely used in many fields.In this paper,leaf biophysical structure is described as an assumed dimensionless variable-leaf mesophyll structure parameter noted as N.It is one of four input variables of the PROSPECT model,a well-known within-leaf radiative tranfer model.Model simulated spectra show that it has great effect on leaf reflectance and transmittance spectra ranging from visible to shortwave infrared radiation.Three methods,including two empirical methods and one model inversion method,are examined and compared.Results show that the calculated N by model inversion method can provide least RMSE between measured spectra and model simulated spectra if leaf biochemical variables are given.Its value is generally less than Ns calculated by empirical methods based on its relation with specific leaf area(SLA).Furthermore,four bands,550nm,816nm,1210nm and 1722nm,are selected to be sensitive for N estimation using stepwise multiple linear regression(SMLR).