title: Foliole movement and canopy architecture of Larrea tridentata (DC.) Cov. in Mexican deserts.
abstract: The creosote bush (Larrea tridentata) is a common desert perennial with bifoliate, amphistomatic, divaricate leaves. The leaves can vertically close their folioles and vary their profile with respect to direct solar radiation. Field data from different Mexican deserts showed a significant correlation between foliole aperture and mean foliole inclination: in plants in which folioles were more open, the foliole surfaces were less vertical. In a series of field experiments in the Chihuahuan Desert, foliole aperture varied significantly with the water-status of the plant and the hour of the day. In moist plants, folioles opened in the early morning and closed in the afternoon. Water-stressed plants showed significantly lower foliole apertures. A simulation of the light interception patterns of the plants showed that foliole closure in water-stressed individuals reduces direct radiation interception by around 24%. Most (64%) of the reduction in interception was due to the vertical inclination of the photosynthetic surfaces induced by foliole closure in the water-stressed plants. The rest (36%) of the reduction in interception was due to differential self-shading between foliole pairs, which was higher in the closed folioles of the water-stressed plants, but operated more towards the early hours of the day.
authors.affiliation: Centro de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, 04510, México, D.F., México.
authors.forename: Exequiel
authors.initials: E
authors.lastname: Ezcurra
authors.affiliation: Centro de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, 04510, México, D.F., México.
authors.forename: Santiago
authors.initials: S
authors.lastname: Arizaga
authors.affiliation: Departmento de Biología, División CBS, Universidad Autónoma Metropolitana-Iztapalapa, Apartado Postal 55-535, 09340, México, D.F., México.
authors.forename: Pedro Luis
authors.initials: PL
authors.lastname: Valverde
authors.affiliation: Centro de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, 04510, México, D.F., México.
authors.forename: Cristina
authors.initials: C
authors.lastname: Mourelle
authors.affiliation: Centro de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, 04510, México, D.F., México.
authors.forename: Arturo
authors.initials: A
authors.lastname: Flores-Martínez
keywords: Canopy architecture; Deserts; Foliole movement; Larrea tridentata; Mexico