摘要:
通过对长白山不同海拔下岳桦叶片反射光谱的研究, 探讨岳桦叶片对高山环境的适应机制。结果表明：不同海拔间岳桦叶片光谱反射率及光谱指数有较大差异。在1 750～2 000 m海拔梯度内, 叶绿素归一化指数（chlNDI）显示:岳桦叶片叶绿素相对含量先升高再降低；光化学反射指数（PRI）显示岳桦叶片光合有效辐射利用效率在2 000 m处最小。类胡萝卜素指标（CAI）显示,岳桦叶片类胡萝卜素相对含量在1 750、1 900、2 000 m之间无显著差异。此外, 林线外岳桦叶片叶绿素相对含量及光合有效辐射利用效率均比2 000 m处高, 而叶片类胡萝卜素相对含量比2 000 m处低。分析表明：随海拔升高, 岳桦叶片的生理状况发生了变化, 所受胁迫的强度也发生了变化；1 900 m是岳桦的最适生长区, 林线外环境不利于岳桦生长, 限制了岳桦分布。
Abstract:
The leaf spectral reflectance of the Betula ermanii along an altitudinal gradient in the Changbai mountains was measured in an attempt to reveal underlying physiological mechanisms of environmental adaptation of Betula ermanii. The results showed significant differences in the spectral reflectance at different elevations, and the spectral indices also varied significantly. From 1 750 m to 2 000 m, the chlorophyll normalized difference index (chlNDI) indicated that chlorophyll concentrations increased at first and then decreased. Photochemical reflectance index (PRI) indicated lower PAR use efficiency at 2 000 m than lower elevations. Carotenoid index (CAI) indicated that the carotenoid concentrations at 1 750, 1 900 and 2 000 m had no significant difference. In addition, both chlorophyll concentrations and PAR use efficiency in the timberline were higher than those at 2 000 m, while the carotenoid concentration was lower than that at 2 000 m. Hence, we conclud that physiological conditions and stress are different at different elevations, and near 1 900 m is the best region for the growth of B. ermanii; the surroundings above the timberline is unsuitable for the growth and development, thus, higher elevation limits its distribution.
百度学术
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