DOI: 10.5061/dryad.5tb2rbpfh
title: Drought decreases carbon flux but not transport speed of newly fixed carbon from leaves to sinks in a giant bamboo forest

description: Carbon (C) allocation among different plant tissues is crucial for
 maintaining the C balance in forest ecosystems, especially under changing
 climate conditions. The partitioning of newly assimilated C among plant
 tissues, interconnected ramets, and soil in forests dominated by giant
 clonal plants, such as moso bamboo (Phyllostachys edulis), and the
 influence of drought on this partitioning remains poorly
 understood. In August 2019, we performed in situ
 labeling of the entire crown of R0 (ramets that emerged in 2019) of moso
 bamboo with 13CO2 in plots subjected to a 5–year drought or left untreated
 (ambient control) in subtropical China. We then traced the 13C signatures
 in the leaves, twigs, and fine roots of R0, R1 (ramets that emerged in
 2018 and are connected with R0), and R2 (ramets that emerged in 2017 and
 are connected with R1), as well as in soil organic C (SOC) and soil
 respiration over the course of one year post–labeling. Drought
 reduced leaf 13C assimilation and its allocation to sink tissues
 but did not alter the velocity of C transport from source to sink compared
 to controls. The peak 13C signal was observed on day 15 for SOC and on day
 5 for respired CO2 in both drought and ambient control forests. Labeled
 13C was detected in R1 ramets on day 3 and in R2 on day 7 post–labeling.
 This study reveals that new assimilates produced by the
 'younger' R0 ramets are preferentially retained within their own
 tissues to meet their own demands rather than being allocated to
 interconnected neighboring R1 and R2 ramets. In forests dominated
 by large clonal plants, such as giant moso bamboo, drought can alter the
 allocation of newly assimilated C within the tissues of source ramets but
 may not affect its allocation among interconnected ramets or within
 plant–soil systems. Our findings highlight the complexity of newly
 assimilated C partitioning in these forests and suggest that clonal
 integration may mitigate drought–induced dieback in older ramets through
 resource sharing under climate change.
description: <strong>Experimental design and
 sampling</strong> In July 2014, three bamboo
 forests with similar slopes and altitudes were selected (Table S1). In
 each forest, two 12 m × 12 m plots were established, separated by a
 10–m–wide buffer zone (Fig. S2). One plot out of them was randomly
 selected to be subjected to drought (i.e., throughfall exclusion), while
 the other served as a control (natural rainfall) (hereafter referred to as
 ‘drought’ and ‘control’, respectively). For the drought treatment, we set
 up transparent PVC waterproof boards suspended at about 1.5 m above the
 ground surface to exclude 70–80% of precipitation. A trench measuring 12 m
 in length, 40 cm in width, and 60 cm in depth (with roots concentrated in
 the 20–40 cm soil depth) was dug to prevent water from flowing into the
 drought treatment area from the surrounding soil and to restrict root
 access to areas outside the throughfall exclusion treatment area. PVC
 waterproof boards were inserted into the trench before the soil was
 refilled. The throughfall exclusion (drought) treatment started in
 November 2014, and soil moisture was monitored using an EM 50 data logger
 (Meter, America) with 5TE sensors (Fig. S3). The outer 1 m of each plot’s
 four sides was excluded from sampling to avoid edge effects, resulting in
 an effective subplot area of 10 m × 10 m. The biomass of the bamboo stands
 was estimated both before (2014) and after the treatments (2019) using the
 field–based method of Ouyang et al. (2022) (Figs. S4, S5).
description: # Drought Decreases Carbon Flux but Not Transport Speed of Newly Fixed
 Carbon from Leaves to Sinks in a Giant Bamboo Forest Dataset DOI:
 [10.5061/dryad.5tb2rbpfh](10.5061/dryad.5tb2rbpfh) ## Description of the
 data and file structure In 2019, we conducted an experiment in China using
 stable carbon isotopes to track their movement in young bamboo plants and
 among their older, interconnected neighbors. The experiment was carried
 out under both long-term dry conditions (a five-year drought) and normal
 conditions. We monitored the labeled carbon signals for a year, examining
 leaves, branches, roots, soil, and the carbon released from the soil. ###
 Files and variables File:
 Data_Dryad_Drought_Decreases_Carbon_Flux_but_Not_Transport_Speed_of_Newly_Fixed_Carbon_from_Leaves_to_Sinks_in_a_Giant_Bamboo_Forest.xlsx Description: The unit and full name of the abbreviations in the headline are: Ramets includes: R0 (ramets that emerged in 2019); R1 (ramets that emerged in 2018 and are connected with R0); R2 (ramets that emerged in 2017 and are connected with R1) Sample time: (days) the time after the labelling experiment Treatment: no experimental treatment, including control (CK) and drought (D); Leaves (L), Branches (B), Root (R). d13C/12C: ‰ 13C abundance in different organs or soil. Amt%: % C concentration in different organs or soil. ## Sharing/Access information None. ## Code/software excel ## Version changes **8-July-2025:** Upload the original raw data from the laboratory according to the reader's suggestion.