Premium
Living on borrowed time – Amazonian trees use decade‐old storage carbon to survive for months after complete stem girdling
Author(s) -
Muhr Jan,
Trumbore Susan,
Higuchi Niro,
Kunert Norbert
Publication year - 2018
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15302
Subject(s) - girdling , carbon fibers , botany , amazon rainforest , biology , horticulture , zoology , chemistry , ecology , mathematics , algorithm , composite number
Summary Nonstructural carbon ( NSC ) reserves act as buffers to sustain tree activity during periods when carbon (C) assimilation does not meet C demand, but little is known about their age and accessibility; we designed a controlled girdling experiment in the Amazon to study tree survival on NSC reserves. We used bomb‐radiocarbon ( 14 C) to monitor the time elapsed between C fixation and release (‘age’ of substrates). We simultaneously monitored how the mobilization of reserve C affected δ 13 CO 2 . Six ungirdled control trees relied almost exclusively on recent assimilates throughout the 17 months of measurement. The Δ 14 C of CO 2 emitted from the six girdled stems increased significantly over time after girdling, indicating substantial remobilization of storage NSC fixed up to 13–14 yr previously. This remobilization was not accompanied by a consistent change in observed δ 13 CO 2 . These trees have access to storage pools integrating C accumulated over more than a decade. Remobilization follows a very clear reverse chronological mobilization with younger reserve pools being mobilized first. The lack of a shift in the δ 13 CO 2 might indicate a constant contribution of starch hydrolysis to the soluble sugar pool even outside pronounced stress periods (regular mixing).