Dynamics of initial carbon allocation after drought release in mature Norway spruce—Increased belowground allocation of current photoassimilates covers only half of the carbon used for fine‐root growth. (30th August 2022)

• Record Type: Journal Article
• Authors: Hikino, Kyohsuke; Danzberger, Jasmin; Riedel, Vincent P.; Hesse, Benjamin D.; Hafner, Benjamin D.; Gebhardt, Timo; Rehschuh, Romy; Ruehr, Nadine K.; Brunn, Melanie; Bauerle, Taryn L.; Landhäusser, Simon M.; Lehmann, Marco M.; Rötzer, Thomas; Pretzsch, Hans; Buegger, Franz; Weikl, Fabian; Pritsch, Karin; Grams, Thorsten E. E.
• Is Part Of: Global change biology. Volume 28:Number 23(2022)
• Page Start: 6889
• Page End: 6905
• Publication Date: 2022-08-30
• Subjects: 13C labeling -- belowground carbon allocation -- carbon partitioning -- climate change -- drought recovery -- forest ecosystems -- Picea abies -- watering; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.16388
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: After drought events, tree recovery depends on sufficient carbon (C) allocation to the sink organs. The present study aimed to elucidate dynamics of tree‐level C sink activity and allocation of recent photoassimilates (Cnew ) and stored C in c. 70‐year‐old Norway spruce ( Picea abies ) trees during a 4‐week period after drought release. We conducted a continuous, whole‐tree 13 C labeling in parallel with controlled watering after 5 years of experimental summer drought. The fate of Cnew to growth and CO2 efflux was tracked along branches, stems, coarse‐ and fine roots, ectomycorrhizae and root exudates to soil CO2 efflux after drought release. Compared with control trees, drought recovering trees showed an overall 6% lower C sink activity and 19% less allocation of Cnew to aboveground sinks, indicating a low priority for aboveground sinks during recovery. In contrast, fine‐root growth in recovering trees was seven times greater than that of controls. However, only half of the C used for new fine‐root growth was comprised of Cnew while the other half was supplied by stored C. For drought recovery of mature spruce trees, in addition to Cnew, stored C appears to be critical for the regeneration of the fine‐root system and the associated water uptake capacity. Abstract : Our continuous, whole‐tree 13 C labeling experiment in parallel with watering after 5 years of recurrent summer drought revealed that c. 70‐year‐old Norway spruce trees ( Picea abies [L.] Karst.) enhanced their fine‐root growth after drought release, which was supported by preferential allocation of newly assimilated carbon (Cnew ). However, only half of the C used for fine‐root growth was comprised of Cnew while the other half was supplied by stored C. For drought recovery of mature spruce trees, in addition to Cnew, stored C appears to be critical for the regeneration of the fine‐root system and the associated water uptake capacity.