title: Water relations of the tos1 tomato mutant at contrasting evaporative demand.
abstract: The tos1 (tomato osmotically sensitive) mutant, isolated from an in vitro screen of root growth during osmotic stress, was less sensitive to exogenous ABA, but accumulated more ABA under osmotic stress than WT plants. We assessed growth and water relations characteristics of hydroponically grown tos1 seedlings (in the absence of osmotic stress) at low and high evaporative demands. Growth of tos1 was severely inhibited at both high and low evaporative demands. Twenty DAS, WT and tos1 genotypes had a similar leaf water and turgor potential, but mature tos1 plants (45 day old) showed a significant diurnal loss of leaf turgor, with recovery overnight. Increased evaporative demand increased turgor loss of tos1 plants. High evaporative demand at the beginning of the day decreased stomatal conductance of tos1, without diurnal recovery, thus whole plant transpiration was decreased. De-topped tos1 seedlings showed decreased root hydraulic conductance and had a 1.4-fold increase in root ABA concentration. Impaired root function of tos1 plants failed to meet transpirational water demand and resulted in shoot turgor loss, stomatal closure and growth inhibition.
authors: Departamento de Mejora Vegetal, Estación Experimental La Mayora, Consejo Superior de Investigaciones Cientí ficas, 29750 Algarrobo-Costa, Málaga, Spain.
authors: Oliva
authors: O
authors: Jurado
authors: Alfonso
authors: A
authors: Albacete
authors: M Carmen
authors: MC
authors: Martínez-Ballesta
authors: Micaela
authors: M
authors: Carvajal
authors: Francisco
authors: F
authors: Pérez-Alfocea
authors: Ian C
authors: IC
authors: Dodd
authors: M Remedios
authors: MR
authors: Romero-Aranda
mesh_terms: D001272:Atmosphere / Q000737:chemistry; D018533:Biomass; D017343:Genes, Plant / Q000235:genetics*; D018551:Solanum lycopersicum / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D009154:Mutation / Q000235:genetics*; D009995:Osmosis; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000502:physiology; D054046:Plant Stomata / Q000502:physiology; D018526:Plant Transpiration / Q000502:physiology*; D055548:Vapor Pressure; D014835:Volatilization; D014867:Water / Q000502:physiology*; D014885:Waxes / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D014885:Waxes; D014867:Water