摘要
Plant-derived carbon(C)inputs via foliar litter,root litter and root exudates are key drivers of soil organic C stocks.However,the responses of these three input pathways to climate warming have rarely been studied in alpine shrublands.By employing a 3-year warming experiment(increased by 1.3℃),we investigated the effects of warming on the relative C contributions from foliar litter,root litter and root exudates from Sibiraea angustata,a dominant shrub species in an alpine shrubland on the eastern Qinghai-Tibetan Plateau.The soil organic C inputs from foliar litter,root litter and root exudates were 77.45,90.58 and 26.94 g C m^(-2),respectively.Warming only slightly increased the soil organic C inputs from foliar litter and root litter by 8.04 and 11.13 g C m^(-2),but significantly increased the root exudate C input by 15.40 g C m^(-2).Warming significantly increased the relative C contributions of root exudates to total C inputs by 4.6%but slightly decreased those of foliar litter and root litter by 2.5%and 2.1%,respectively.Our results highlight that climate warming may stimulate plant-derived C inputs into soils mainly through root exudates rather than litter in alpine shrublands on the Qinghai-Tibetan Plateau.
植物通过凋落叶、根系凋落物和根系分泌物向土壤输入有机碳,显著影响土壤碳储量。然而,高寒灌丛生态系统这3种植物碳输入途径对气候变暖的响应仍不清楚。本文通过为期3年的野外增温实验,研究了青藏高原东部高寒灌丛优势种窄叶鲜卑花(Sibiraea angustata)凋落叶、根系凋落物和根系分泌物对土壤碳输入的相对贡献及其对增温的响应。研究结果表明,窄叶鲜卑花通过凋落叶、根系凋落物和根系分泌物向土壤输入有机碳的数量分别为77.45、90.58和26.94 g C m^(-2)。增温分别使凋落叶和根系凋落物有机碳输入轻微增加8.04和11.13 g C m^(-2),同时使根系分泌物有机碳输入显著增加15.40 g C m^(-2)。增温使根系分泌物有机碳输入途径相对贡献显著增加4.6%,分别使凋落叶和根系凋落物有机碳输入途径相对贡献轻微降低了2.5%和2.1%。这些结果表明,在青藏高原高寒灌丛生态系统中,气候变暖主要通过促进根系分泌物输入途径而不是凋落物输入途径来增加植物源土壤有机碳的输入。
基金
supported by the Open Project from the Ecological Security and Protection Key Laboratory of Sichuan Province(ESP1904,ESP2102)
the Doctoral Scientific Research Foundation of China West Normal University(18Q047)
the Scientific Research Innovation Team Project of China West Normal University(CXTD2020-4).
