POTENCIAL HÍDRICO XILEMÁTICO EN CUATRO ESPECIES ARBUSTIVAS NATIVAS DEL NORESTE DE MÉXICO

Abstract

Since water stress is the most limiting factor in this region, the aim of the current study was to establish how the xylem water potential (Ψ) in native shrubs such as Celtis pallida (Ulmaceae), Acacia amentacea (Leguminosae) Forestiera angustifolia (Oleaceae), and Parkinsonia texana (Leguminosae) is influenced by soil water content, air temperature, relative humidity, and rainfall. The study was carried out in an area located the municipality of China, state of Nuevo Leon. Using a Scholander pressure bomb the Ψ were estimated at 15 days intervals between January 15 and September 28, 2009 in five different plants per species at 06:00 h (predawn) and 14:00 h (midday). At the wettest period, Ψ oscillated from -0.30 (C. pallida) to -0.90 MPa (P. texana) at predawn, in contrast, at the driest period, Ψ oscillated from -2.18 (P. texana) to -3.94 MPa (F. angustifolia) at predawn. At midday, P. texana and F. angustifolia achieved the highest (-1.14 MPa) and lowest (-3.38 MPa) Ψ values, respectively. Average soil water content at depth profile 0-50cm showed between 82 and 33 % of the variation of Ψ at predawn. Soil water content at different soil depths, and relative humidity were significantly and positively correlated with Ψ at predawn; whereas air temperature and vapor pressure deficit was negatively correlated. A. amentacea and P. texana maintainedhigh values in Ψ at predawn and midday under water stress conditions, so these species may be considered as drought tolerant species.