Leaf spectral reflectance is a crucial indicator of leaf physiology both in eco-physiology and remote sensing. To assess how alpine plants acclimate or adapt to altitudinal environments, we examined leaf optical properties at wavelengths from 280 to 1100 nm in 797 leaves of 38 broad-leaved herbaceous species along an altitudinal gradient from 3200 m to 4400 m on the northeastern Qinghai-Tibetan Plateau. The mean leaf reflectance of all observed species increased with altitude at a rate of 6.3 %, 3.1 %, and 2.3 % km^–1 in the ultraviolet (UV, 280–400 nm), photosynthetically active radiation (PAR, 400–700 nm), and near-infrared radiation (NIR, 700–1100 nm) regions, respectively. Increased leaf reflectance along the altitudes was found both within and among species. Within the UV region, a notable increase in spectral reflectance was observed at approximately 301 and 355 nm compared to other wavelengths. Within the PAR region, the peak wavelength of spectral reflectance shifted toward shorter wavelengths at a rate of 9.3 nm per km increase in altitude. The study suggests that alpine broad-leaved species can precisely adjust leaf reflectance. Therefore, it is essential to interpret plant physiology carefully by exploiting leaf spectral reflectance in diverse environments and plant species.

中文翻译：

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青藏高原阔叶树种叶片光谱反射率的海拔变化


叶片光谱反射率是生态生理学和遥感中叶片生理学的重要指标。为了评估高山植物如何适应或适应海拔环境，我们沿着青藏高原东北部3200 m至4400 m的海拔梯度，检测了38种阔叶草本植物的797片叶子在280至1100 nm波长下的叶片光学特性。高原。所有观察到的物种的平均叶片反射率随着海拔的升高而增加，在紫外线（UV，280-400 nm）、光合有效辐射（PAR，400-700 nm）中分别以 6.3 %、3.1 % 和 2.3 % km-1 的速度增加。和近红外辐射（NIR，700–1100 nm）区域。在物种内部和物种之间都发现沿海拔高度的叶子反射率增加。在 UV 区域内，与其他波长相比，在大约 301 和 355 nm 处观察到光谱反射率显着增加。在 PAR 区域内，光谱反射率的峰值波长以海拔每增加 9.3 nm 的速度向较短波长移动。研究表明，高山阔叶树种可以精确调节叶片反射率。因此，有必要通过利用不同环境和植物物种中的叶子光谱反射率来仔细解释植物生理学。