title: Steady-state chlorophyll fluorescence (Fs) measurements as a tool to follow variations of net CO2 assimilation and stomatal conductance during water-stress in C3 plants.
abstract: Water stress experiments were performed with grapevines (Vitis vinifera L.) and other C3 plants in the field, in potted plants in the laboratory, and with detached leaves. It was found that, in all cases, the ratio of steady state chlorophyll fluorescence (Fs) normalized to dark-adapted intrinsic fluorescence (Fo) inversely correlated with non-photochemical quenching (NPQ). Also, at high irradiance, the ratio Fs/Fo was positively correlated with CO2 assimilation in air, with electron transport rate calculated from fluorescence, and with stomatal conductance, but no clear correlation was observed with qP. The significance of these relationships is discussed. The ratio Fs/Fo, measured with a portable instrument (PAM-2000) or with a remote sensing FIPAM system, provides a good method for the early detection of water stress, and may become a useful guide to irrigation requirements.
authors.affiliation: Laboratori de Fisiologia Vegetal, Departament de Biologia, Universitat de les Illes Balears-Institut Mediterrani d'Estudis Avançats (UIB-CSIC). Carretera de Valldemossa Km. 7.5, E-07071 Palma de Mallorca. Balears, Spain Laboratoire pour l'Utilization du Rayonnement Electromagnétique (LURE), Centre Universitaire Paris-Sud, B.P. 34; F-91898 Orsay Cedex, France Research School of Biological Sciences, Institute of Advanced Studies, Australian National University, Box 475, Canberra, ACT 2601, Australia.
authors.forename: Jaume
authors.initials: J
authors.lastname: Flexas
authors.forename: José Mariano
authors.initials: JM
authors.lastname: Escalona
authors.forename: Sebastian
authors.initials: S
authors.lastname: Evain
authors.forename: Javier
authors.initials: J
authors.lastname: Gulías
authors.forename: Ismaël
authors.initials: I
authors.lastname: Moya
authors.forename: Charles Barry
authors.initials: CB
authors.lastname: Osmond
authors.forename: Hipólito
authors.initials: H
authors.lastname: Medrano