[Typical plant spectral characteristics analysis in wild duck lake along water environment gradient]

Typical submerged plants, floating plants, emerged plants, hygrophyte plants, and mesophyte plants were chosen, and derivative method and continuum removal method were used to analyze the spectral characteristics and changing trend of plants along water environment gradient. Emerged plants and hygrophyte plants have the highest reflectance value; floating plants have lower value, while submerged plants take the lowest reflectance value due to the effect of water surface. Derivative method could emphasize the changed trends of original spectral curve, thus more characteristic bands could take on. Spectral curves reached the fastest increasing points around 520 and 710 nm, which could be considered as characteristics bands to distinguish submerged plants and others. Emerged plants and hygrophyte plants have the peak green value. According to water environment gradient from high to low, the red edges of submerged plants, floating plants and emerged plants increase, while hygrophyte plants and mesophyte plants have lower red edge value. Original spectral curves were translated to absorption curves by continuum removal, the absorption depth changes from low to high as follows: submerged plants < floating plants < merged plants < hygrophyte plants, while that is lower for mesophyte plants compared to hygrophyte plants. Absorption area increased along water environment gradient from high to low except mesophyte plants.