FOLIAR AREA, STOMATAL CARACTERISTICS AND WATER RELATIONS IN THE HALOPHYTE PROSOPIS STROMBULIFERA UNDER SALINITY

REGINATO , MARIANA ANDREA; LLANES, ANALÍA SUSANA; REINOSO, HERMINDA; MOSCHETI, ELSA; LUNA, MARÍA VIRGINIA

Córdoba

Congreso; First meeting of Argentine Biology Societies; 2009

Sociedad Latinoamericana de Microscopía Electrónica.; Centro Regional de Investigaciones Científicas y Tecnológicas (Mendoza, Argentina)

Plant leaves respond to stress modifying their foliar area, stomatal density and water relations. In this study foliar area, stomatal density (SD), epidermal cell density (ECD), stomatal index (SI), stomatal area, and water relations (Ψw, Ψo, relative water content (RWC) and transpiration) modifications were analyzed in seedlings grown hydroponically in Hoagland solutions with addition of 50 mmol/l NaCl for NaCl treatment, 38 mmol/l Na2SO4 for Na2SO4 treatment and the isoosmotic mixture of salts for bisaline treatment every 48 h until final Ψo = -1, -1,88, and -2,6 MPa were reached. Control plants were grown in Hoagland 25%. Leaves of P. strombulifera NaCl treated plants showed a RWC higher than control plants with a decrease in SD (lower number of bigger stomata). These characteristics maybe a mechanism of alleviation of the injury caused by excessive accumulation of Na+ in tissues, diminishing the transpiration rate and favoring higher water use efficiency. In the other hand, leaves of Na2SO4 treated plants showed high values of Ψw and Ψo and the higher transpiration rate, witch cause water disturbance and correlates with the decrease in total and specific foliar area and the increase in SD (highest number of smaller stomata) in these plants. Therefore, all these settings in the epidermal morphology are closely related to water use efficiency and photosynthesis in this species.