Response of wheat treated with ABA and Azospirillum to water and salt stress

TRAVAGLIA C., WOLTERS E., REINOSO H.

Mendoza, Argentina

Congreso; XXVI Reunión Científica Anual Sociedad de Biología de Cuyo; 2008

The plant hormone abscisic acid (ABA) controls stomatal closure, reducing water stress. Plant growth-promoting bacteria of the genus Azospirillum enhance general plant growth and confer resistance to salt and water stress. The purpose of this study was to evaluate the growth of wheat plants treated with A. brasilense CD (Az), ABA, and their combination under water stress and salt stress under natural photoperiod. The emerged seedlings were inoculated with Az on roots before sowing in pots and sprayed with ABA at the beginning of shoot enlargement and at anthesis. Water and salt stress were imposed from ten days after sowing by reducing irrigation to 20% of the evapotranspiration of the previous day and by weekly irrigation with ClNa solution (from 0.085 to 0.2 M), respectively. Seventy days after sowing, total biomass, content of photosynthetic pigments, cellular membrane stability, and stomatal behaviour were evaluated at 1.00 p.m. Although the effect depended on the type of stress imposed, results indicate that both ABA and Az enhanced the growth of wheat plants. Under water stress, in most of the variables analyzed, the combination of treatments did not modify their individual beneficial effect, whereas under salt stress the combination improved the effect of the individual treatments.