Plasticity in sunflower leaf and cell growth under high salinity

ORTEGA, LEANDRO; BUSTOS, DOLORES; CÉCCOLI, GABRIEL; SENN, MARÍA EUGENIA; VEGETTI, ABELARDO CARLOS; TALEISNIK, EDITH

Mar del Plata- Buenos Aires- Argentina

Congreso; XV Congreso Latinoamericano- XXX Reunión Argentina de Fisiología Vegetal; 2014

Sociedad Argentina de Fisiología Vegetal

Four sunflower lines displaying a range of leaf Na+ concentration under high salinity were used to explore whether the responses to osmotic and ionic components of salinity can be distinguished in leaf expansion kinetics analysis. It was expected that at the onset of the treatment, the osmotic component was predominant on kinetics changes, followed by ion inclusion effects, later on. Changes in cell division and expansion rates, associated to differential leaf Na+ accumulation, were also expected. Plants were grown with or without 130 mM NaCl solution. Kinetics curves were compared in leaves formed before, during and after the salt treatment onset. Leaf areas were smaller in salinized plants, but the curves did not reveal differences that could be attributed to differential Na+ accumulation: similar changes in expansion kinetics were observed in lines with different magnitudes of salt accumulation. Nevertheless, in a Na+-including line, cell divisions were affected earlier, resulting in leaves with fewer cells than in a Na+-excluding line. A salinity induced change in shape of the leaf epidermal cells is reported for the first time. Mature pavement cells in control plants leaves, showed typical jigsaw-puzzle shape, while in treated ones; they tended to be closer-to-circular and with fewer lobes.