Sprayed ABA improves stomatal conductance by inducing half-opening of the pores in wheat plants

TRAVAGLIA C; CASTILLO C; COHEN A; BALBOA R; BOTTINI R; REINOSO H

Uspallata, Mendoza

Jornada; XXIII Reunión Científica Anual Sociedad de Biología de Cuyo. III Reunión Anual Sociedad Argentina de Microscopía; 2005

Soc. de biología de Cuyo, Soc. Argentina de Microscopía

Sprayed ABA improves stomatal conductance by inducing half-opening of the pores in wheat plants Travaglia C, Castillo C, Cohen A, Balboa R, Bottini R, Reinoso H. Universidad Nacional de Río Cuarto, X5804ZAB Río Cuarto. ctravaglia@exa.unrc.edu.ar The plant hormone abscisic acid (ABA) controls stomatal closing, and it has also been reported as regulating transport of assimilates to developing seeds or fruits. The purpose of this study was to evaluate the effect of ABA on physiological parameters and production in wheat plants grown under field conditions, especially in anthesis and at the mid and late grain filling stages. The experiment (from July to November 2004) included a completely randomized block design, with 6 replicates of the treatments: Control (foliar spray of water + 1% alcohol) and ABA 300 mg l-1 (foliar spray of cis ± trans-ABA, 99 % purity, Sigma-Aldrich). At different phenological stages biomass production, stomatal conductance on flag leaf at midday (LI?1600 portable porometer, LiCor, USA), aperture by microscope observation (Zeiss Axiophot), water-soluble carbohydrate content (phenol-sulfuric-acid method) and yield components were assessed. Exogenous ABA enhanced stomatal conductance and promoted a high % of half-opened stomata, thus making more effective the balance between the loss of water by transpirations and the CO2 uptake for photosynthesis. It also enhanced re-mobilization of shoot-stored carbon reserves towards the grains, thereby enhancing the grain yield.