Reduction in leaf size at higher altitudes across 39 broad-leaved herbaceous species on the Northeastern Qinghai-Tibetan Plateau
Reduction in leaf size at higher altitudes across 39 broad-leaved herbaceous species on the Northeastern Qinghai-Tibetan Plateau
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青藏高原东北部39种阔叶草本植物在高海拔地区叶片尺寸减小
DOI：
10.1093/jpe/rtac051
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发表时间：
2022-04
影响因子：
2.7
通讯作者：
Yanhong Tang
中科院分区：
文献类型：
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作者：
Xinran Ke;Huixing Kang;Yanhong Tang
摘要。在不同环境下，物种内部和物种之间的叶片大小存在显著差异。然而，目前尚不清楚叶片大小如何随海拔变化，是否存在一种普遍的海拔模式，以及是什么决定了叶片大小的海拔变异。因此，我们旨在通过关注青藏高原东北部高海拔地区的阔叶草本植物来解决这些问题。我们测量了青藏高原东北部冷龙岭和达坂山两个山坡上从3200米到4400米的开阔区域内39种阔叶草本植物的叶片大小、叶长、叶宽和单位面积叶质量。我们分析了与叶片倾斜度和叶表面特征相关的叶片大小的海拔模式，并应用叶片能量平衡模型来探讨潜在机制。叶片大小在较高海拔处显著减小。海拔降低主要归因于叶长的减小，并且在不同物种以及具有不同倾斜度和叶表面特征的叶片中有所不同。一个结合当地环境测量的叶片能量平衡模型表明，小叶片的叶温比大叶片更紧密地跟随气温，并且在较高纬度地区叶片大小的影响更为显著。基于观测结果，我们提出阔叶草本植物在青藏高原的分布上限约为5400米海拔。
Abstract. Leaf size varies conspicuously within and among species under different environments. However, it is unclear how leaf size would change with elevation, whether there is a general elevational pattern, and what determines the altitudinal variation of leaf size. We thus aimed to address these questions by focusing on the broad-leaved herbaceous species at high altitudes on the northeastern Qinghai-Tibetan Plateau. We measured the leaf size, leaf length, leaf width and leaf mass per area for 39 broad-leaved herbaceous species inhabited in the open areas along two mountain slopes from 3 200 m to 4 400 m at the Lenglongling and the Daban Mountain, the northeastern Qinghai-Tibetan Plateau. We analyzed the altitudinal patterns in leaf size in relation to leaf inclination and leaf surface features, and applied a leaf energy balance model to discuss the underlying mechanisms. Leaf size decreased significantly at higher altitudes. The altitudinal reduction was mainly attributed to the reduction of leaf length, and differed in different species, and in leaves with different inclination and leaf surface features. A leaf energy balance model with local environmental measurements demonstrated that leaf temperature tracks air temperature more closely in small than in large leaves, and the leaf-size impact is even stronger at higher latitudes. Based on the observational findings, we proposed that the distribution limit for broad-leaved herbaceous species would be at an elevation of about 5 400 m on the Qinghai-Tibetan Plateau.