Effect of water deficit on wheat seedlings: osmotic adjustment and growth reduction

RA BARCIA; LB PENA; CE AZPILICUETA; MP BENAVIDES; SM GALLEGO

Potrero de los Funes, San Luis.

Congreso; XLVII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.; 2011

SAIB

Plants are often exposed to environmental stress challenges. In this sense, plant growth reduction is the main visible symptom of abiotic stress. The aim of the present study was to examine how water restriction modified the proliferation and expansion of root cells in wheat, a C3 species that usually grows in temperate climate regions, including drought prone-environment. Polyethylene glycol (PEG6000) was used to adjust the osmotic potential in the culture system. A decrease in the growth rate was observed with the increase in PEG concentrations, and from 38% PEG in the solution inhibited seed germination. After 3 days, coleoptile and root length were reduced by 53% and 35%, respectively, by 22% PEG, respect to controls. Seedlings treated with 22% PEG showed an osmotic adjustment, measured as an increase in tissue total conductance, osmolarity, proline and protein content. Evans blue staining, relative osmolarity and conductance showed a conserved integrity of the plasma membrane in treated seedlings, without evidence of cell death. Despite cell length in root apical meristem was similar in C and treated seedlings, a different transcript accumulation of genes involved in cell cycle (RDR, PCNA, MCM) and cell expansion (TaEXPB3, TaEXPB5) were observed. More results are necessary to understand the relationship between drought-induced osmotic adjustment and growth in wheat seedlings.