# The unexpected contribution of bryophytes to the global COS budget

Teresa E. Gimeno

► To cite this version:

Teresa E. Gimeno. The unexpected contribution of bryophytes to the global COS budget. 14. MEDE-COS & 13. AEET meeting. Human driven scenarios for evolutionary and ecological changes, Jan 2017, Séville, Spain. 268 p. hal-02733474

HAL Id: hal-02733474

https://hal.inrae.fr/hal-02733474

Submitted on 2 Jun 2020

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XIV MEDECOS
&
XIII AEET meeting

Human driven scenarios for evolutionary and ecological changes

Abstract book

31st January - 4th February 2017

Seville, Spain

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XIV MEDECOS &
XIII AEET meeting

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A E E T

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ASOCIACIÓN ESPAÑOLA
DE ECOLOGÍA TERRESTRE

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Estación
Biológica
Doñana

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EXCELENCIA
SEVERO
OCHOA

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Abstract book of the XIV MEDECOS & XIII AEET meeting,
Seville, Spain, 31st January - 4th February 2017

Issued in Open Access, under the terms of Commons attribution Non Commercial License

Doi.: 10.7818/MEDECOSandAEETCongress.2017

Editorial deadline: 20th December, 2016.

Publisher: Asociación Española de Ecología Terrestre (AEET)

C/ Tulipán s/n, 28399, Móstoles, Madrid, Spain

Layout: Imprenta Sand, S.L. Seville. Spain.
S.06-19-Poster

Xylem anatomy along a rainfall gradient reflects common responses at multi-species level

García-Cervigón, A.I.¹, Fajardo, A.², von Arx, G.³, Olano, J.M.⁴

(1) Universidade de Lisboa. (2) Centro de Investigación en Ecosistemas de la Patagonia. (3) Swiss Federal Institute for Forest, Snow and Landscape Research WSL. (4) Universidad de Valladolid

Correspondence e-mail: [ana.gcervigon.morales@gmail.com](mailto:ana.gcervigon.morales@gmail.com)

Environment either filters particular phenotypes from a species or species from the regional pool. Thus, some tree species modify their hydraulic system to cope with varying spatio-temporal climatic constraints. Understanding how trees adapt along their distribution ranges is critical to develop vegetation models able to predict shifts on species distribution areas due to climate change. We explored variations in xylem anatomy, a critical component of the tree hydraulic system, along an abrupt rainfall gradient in the Chilean Patagonia (from 2500 mm to 600 mm of annual precipitation), in order to determine general trends in xylem adjustments. We selected three study areas and four sampling sites per area. Two generalist and two specialist species were sampled in each study area (eight species in total). We evaluated xylem anatomy in permanent histological preparations of branch sections to obtain information on vessel size and position that allowed estimating vessel density, grouping and hydraulic conductivity. A consistent regional trend associated to rainfall appeared: when rainfall decreased, mean vessel size decreased but vessel density and grouping increased. In contrast, neither percentage of conductive area, nor hydraulic conductivity per area varied along the gradient. These results suggest the existence of common responses to water availability beyond the generalist-specialist character of woody species; the environment selects similar traits at the within and across-species level. Apparently, increases in hydraulic safety of xylem anatomy were not linked to a decrease in conductivity, suggesting a poor trade-off between both components of hydraulic system functionality at this scale.

S.06-20-Oral

The unexpected contribution of bryophytes to the global COS budget

Gimeno, T.E.¹

(1) INRA

Correspondence e-mail: [teresa.gimeno@bordeaux.inra.fr](mailto:teresa.gimeno@bordeaux.inra.fr)

Carbonyl sulphide serves a tracer of gross primary productivity (photosynthesis) and nocturnal stomatal aperture, provided that COS flux is unidirectional and that carbonic anhydrase (CA, responsible for COS uptake) is light independent. These assumptions cannot be tested in plants where stomata close at night, but in astomatous bryophytes gas exchange is only limited by diffusion through capillary water or by hydration. In bryophytes, net COS fluxes in the light and in the dark should mimic those of CO2 in the light as (1) stomata cannot limit COS uptake, (2) CA is light independent and (3) COS flux into the vegetation is assumed unidirectional. We measured COS, H2O and CO2 fluxes in bryophytes in the light and in the dark, through complete desiccation and with decreasing [COS]. In the light, as capillary water evaporated, CO2 and COS uptake increased to a maximum and as dehydration continued CO2 uptake decreased towards 0, whereas net COS flux went from uptake to emission. In the dark, net COS uptake was greater than in the light and little or no net COS emission was observed near dehydration. COS uptake increased with [COS] at a similar rate in the light and in the dark, but COS emission at minimal [COS] (0±5 ppt) was greater in the light. We show that bryophytes have an expected contribution to COS cycling: they act as sinks at night and sources in the light. We suggest that GPP from COS uptake could be overestimated in areas where biological crusts dominate biogeocycles