Abstract
The changes in spectral reflectance of plant leaves due to overlapping, leaf thickness, content of chlorophyll and content of water in leaf were investigated using spectrophotometer with integrating sphere. As experimental plants, we selected soybean (c.v. Fukuyutaka), sweet potato (c.v. Benikomachi) and mulberry (c.v. Tokiyutaka), which were main upland cultivar in Japan.
1) Spectral reflectance of leaf surface in near infrared range increased in ASLW (accumulated of specific leaf weight, g/cm2). In visible range, even if ASLW increased, spectral reflectance of leaf surface not increased.
2) In near infrared range, spectral reflectance of leaf surface linearly increased with increasing SLW (specific leaf weight, g/cm2) in the range of 0-0.05 g/cm2, which showed leaf thickness. For soybean leaves, the equation was "Reflectance in near infrared range (800-1100 nm, %)=2010× SLW+47.2", where correlation coefficient (r) was 0.905. The correlation coefficient value was 0.514 for sweet potato and 0.806 for mulberry respectively.
3) Spectral reflectance of leaf surface from visible range to near infrared range increased with decreasing the leaf water content.
