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Issoufou H. B. A., Delzon S., Laurent J. P., Saadou M., Mahamane A., Cappelaere Bernard, Demarty Jérome, Oi Monique, Rambal S., Seghieri Josiane. (2013). Change in water loss regulation after canopy clearcut of a dominant shrub in Sahelian agrosystems, Guiera senegalensis J. F. Gmel. Trees-Structure and Function, 27 (4), p. 1011-1022. ISSN 0931-1890.

Titre du document
Change in water loss regulation after canopy clearcut of a dominant shrub in Sahelian agrosystems, Guiera senegalensis J. F. Gmel
Année de publication
2013
Type de document
Article référencé dans le Web of Science WOS:000321913500015
Auteurs
Issoufou H. B. A., Delzon S., Laurent J. P., Saadou M., Mahamane A., Cappelaere Bernard, Demarty Jérome, Oi Monique, Rambal S., Seghieri Josiane
Source
Trees-Structure and Function, 2013, 27 (4), p. 1011-1022 ISSN 0931-1890
This paper analyzes the effect of the canopy age of Guiera senegalensis J.F. Gmel on water regulation processes and adaptative strategy to drought over a period of 2 years. The species is widespread in the agricultural Sahel. Before sowing, farmers cut back the shrubs to limit competition with crops. The stumps resprout after the millet harvest. Leaf water potential and stomatal conductance were measured in two fallows and in the two adjacent cultivated fields. Leaf transpiration rate and soil-to-leaf hydraulic conductance were deduced. The decrease in both stomatal and plant hydraulic conductance caused by seasonal drought was greater in mature shrubs than in current year resprouts. The decrease in predawn and midday leaf water potentials in response to seasonal drought was isohydrodynamic, and it was greater in mature shrubs, suggesting that current year resprouts are under less stress. In resprouts, the leaf transpiration rate stopped increasing beyond a hydraulic conductance threshold of 0.05 mol. m(-2) s(-1) MPa-1. Vulnerability to cavitation was determined on segments of stems in the laboratory. The leaf water potential value at which stomatal closure occurred was -2.99 +/- A 0.68 MPa, which corresponded to a 30 % loss in xylem conductivity. Thanks to its positive safety margin of 0.6 MPa, G. senegalensis can survive above this value. The observed strategy places G. senegalensis among the non-extreme xeric plants, leading us to suppose that this species will be vulnerable to the expected increase in regional drought.
Plan de classement
Bioclimatologie [072] ; Sciences du monde végétal [076] ; Etudes, transformation, conservation du milieu naturel [082]
Description Géographique
ZONE SAHELIENNE ; NIGER
Localisation
Fonds IRD [F B010060543]
Identifiant IRD
fdi:010060543
Contact