编号
040034804
推送时间
20220620
研究领域
森林培育
年份
2022
类型
期刊
语种
英语
标题
Carbon allocation to root exudates is maintained in mature temperate tree species under drought
来源期刊 New Phytologist
期
第348期
发表时间
20220411
关键词
belowground carbon allocation;
carbon partitioning;
experimental drought;
Fagus sylvatica (European beech);
fine-root exudation;
Picea abies (Norway spruce);
rhizosphere;
temperate forest C budget.;
摘要
Carbon (C) exuded via roots is proposed to increase under drought and facilitate important ecosystem functions. However, it is unknown how exudate quantities relate to the total C budget of a drought-stressed tree, that is, how much of net-C assimilation is allocated to exudation at the tree level.
We calculated the proportion of daily C assimilation allocated to root exudation during early summer by collecting root exudates from mature Fagus sylvatica and Picea abies exposed to experimental drought, and combining above- and belowground C fluxes with leaf, stem and fine-root surface area.
Exudation from individual roots increased exponentially with decreasing soil moisture, with the highest increase at the wilting point. Despite c. 50% reduced C assimilation under drought, exudation from fine-root systems was maintained and trees exuded 1.0% (F. sylvatica) to 2.5% (P. abies) of net C into the rhizosphere, increasing the proportion of C allocation to exudates two- to three-fold. Water-limited P. abies released two-thirds of its exudate C into the surface soil, whereas in droughted F. sylvatica it was only one-third.
Across the entire root system, droughted trees maintained exudation similar to controls, suggesting drought-imposed belowground C investment, which could be beneficial for ecosystem resilience.
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孙小满
服务院士
尹伟伦
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