Geographic pattern and effects of climate and taxonomy on nonstructural carbohydrates of Artemisia species and their close relatives across northern China

Xuejun Yang, et al.


在中国北方蒿属植物非结构碳的地理格局及气候与物种效应
非结构碳是光合作用的主要产物,对研究当前环境条件和气候变化背景下生态系统的碳平衡具有重要意义。然而,目前在区域和全球尺度上对于气候与物种对非结构碳的影响还不清楚。我们研究了中国北方蒿属植物非结构碳的地理格局及气候与物种的效应。我们发现,随着海拔的增加植物可溶性糖含量降低,不同物种的非结构碳对海拔梯度的响应不同。非结构碳含量不受年气候条件的影响,但受到最暖月气候的显著影响。在非结构碳库内,物种解释的变异在可溶性糖中高于淀粉。这些结果表明,在区域尺度上非结构碳格局与地区尺度上不同;作为一种碳的暂时贮存状态,非结构碳在生长季可能更多的体现为光合作用过程的直接产物,而不是作为抵抗环境胁迫的物质。在区域尺度上,即使是亲缘关系近的物种在通过非结构碳的生理调节来适应环境条件也存在较大差异。


Abstract
Nonstructural carbohydrates (NSCs) are the primary products of photosynthesis and have implications for determining the carbon (C) limitation under current environmental conditions and the impact of climate change on the C balance in ecosystems. Yet, heretofore little was known about how climate and taxonomy affect NSC at the regional or global scale. We explored geographic patterns and effects of climate and taxonomy on the NSC in the aboveground organs of Artemisia species and their close relatives from 65 sites across northern China. Hierarchical linear models (HLMs) showed that sugar concentration decreased with increasing altitude and that the response of NSC to the altitudinal gradient differed among species. NSC concentration was affected by climate of the warmest quarter rather than annual climate. Sugar and starch concentrations differed significantly among species. Within the NSC C pool, species identity explained more of the total variance of sugar C than that of starch C. Our results show that the NSC pattern at a large geographical scale differs from that at the local scale. As a temporary storage of C, NSCs appear to be a direct product of the photosynthetic process rather than to function as protectants against environmental stresses during the growing season at the regional scale. Therefore, different species, even among closely related taxa, may vary in their adaptation to environmental gradients via the physiological adjustment of NSCs at the regional scale.