Drought resistance and resilience of rhizosphere communities in forest soils from the cellular to ecosystem scale – insights from ¹³C pulse labeling
Abstract
The link between above- and belowground communities is a key uncertainty in drought and rewetting effects on forest carbon (C) cycle.
In young beech model ecosystems and mature naturally dry pine forest exposed to 15-yr-long irrigation, we performed ¹³C pulse labeling experiments, one during drought and one 2 wk after rewetting, tracing tree assimilates into rhizosphere communities.
The ¹³C pulses applied in tree crowns reached soil microbial communities of the young and mature forests one and 4 d later, respectively. Drought decreased the transfer of labeled assimilates relative to the irrigation treatment. The ¹³C label in phospholipid fatty acids (PLFAs) indicated greater drought reduction of assimilate incorporation by fungi (−85%) than by gram-positive (−43%) and gram-negative bacteria (−58%).
¹³C label incorporation was more strongly reduced for PLFAs (cell membrane) than for microbial cytoplasm extracted by chloroform. This suggests that fresh rhizodeposits are predominantly used for osmoregulation or storage under drought, at the expense of new cell formation. Two weeks after rewetting, ¹³C enrichment in PLFAs was greater in previously dry than in continuously moist soils. Drought and rewetting effects were greater in beech systems than in pine forest.
Belowground C allocation and rhizosphere communities are highly resilient to drought. Show more
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https://doi.org/10.3929/ethz-b-000663446Publication status
publishedExternal links
Journal / series
New PhytologistPublisher
WileySubject
Carbon allocation; Drought forest; Isotope tracing; Microbial community; PLFA; rhizosphereOrganisational unit
03648 - Buchmann, Nina / Buchmann, Nina
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Is supplemented by: https://doi.org/10.16904/envidat.477
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