湿地植物在生态水分、 物质能量循环中起到重要作用， 能够综合反映湿地的生境特征。 分别选取典型沉水植物、 浮水植物、 挺水植物、 湿生植物和中生植物， 采用导数法和包络线去除法， 分析不同水分环境梯度下植物的光谱特征和变化趋势。 挺水植物、 湿生植物和中生的反射率值最高， 其次为浮水植物类型， 沉水植物受到水体的强烈影响， 反射率值最低。 导数法能够将原始光谱曲线的变化趋势放大， 呈现出更多的特征波段。 光谱曲线在520和710 nm附近达到增长最快点， 并可作为区别沉水植物与其他植物类型的特征波段。 挺水植物香蒲和湿生植物三叶鬼针草的绿峰值最高。 依照水分环境由高到低变化， 沉水植物、 浮水植物和挺水植物的红边值逐渐上升， 湿生植物和中生植物的红边值略低。 包络线去除法将原始的光谱曲线转化成吸收曲线， 吸收深度变化表现为沉水植物<浮水植物<挺水植物<湿生植物， 而中生植物值要略低于湿生植物。 除中生植物外， 植物在500和675 nm附近的吸收面积随着水分环境梯度的降低而升高。

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