Induction of water deficit tolerance by cold shock and salicylic acid during germination in the common bean/Inducao da tolerancia ao estresse hidrico por choque frio e acido salicilico durante a germinacao em feijoeiro

The application of short-term stresses or elicitors in seedlings or embryos with high metabolic activity might increase multi-adversity tolerance. Beans seeds cv. IAC-Carioca were exposed to cold shock temperatures (S-7°C [24h.sup.-1]) and salicylic acid (SA-0.01 mM [48h.sup.-1]) during imbibition to study physiological responses to osmotic stress physiological responses. The seeds were soaked in paper towel imbibed in water or salicylic acid at 25°C for 24h. The seed were subsequently submitted to temperatures of 7°C and 25°C for another 24h in water or salicylic acid. Following each treatment, the seeds were transferred to mannitol solutions (0, -0.3, -0.6, and -1.2 MPa) and evaluated after seven days for germination, vigour, shoot and root length, dry mass, proline accumulation and protein electrophoretic profile. Treatments with salicylic acid and cold shock did not affect germination, but germination was reduced through the mannitol-induced progression of water deficit. However, both salicylic acid and cold shock treatments affected seed vigour. The application of salicylic acid increased root and total seedling length and dry weight, especially at intermediate water stress levels. Both salicylic acid and cold shock treatments changed the protein pattern of the treated seeds, but only SA showed promise as a technology for seed treatment. Keywords: Phaseolus vulgaris, thermic shock, elicitor, vigour, protein. Estresses curtos ou aplicacao de elicitores em mudas ou embrioes com atividade metabolica pode aumentar a resistencia a adversidade. Aplicacoes de choque termico (S-7°C [24h.sup.-1]) e acido salicilico (SA-0,01mM [48h.sup.-1]) durante a embebicao foram avaliados em sementes de feijao para estudar as respostas ao estresse hidrico. As sementes foram embebidas em papel toalha com agua ou acido salicilico a 25°C durante 24h, e submetidas por outras 24h a 7 ou 25°C em agua ou acido salicilico. As sementes foram transferidas para solucoes de manitol (0; -0,3; -0,6; -1,2 MPa) e apos sete dias foram avaliadas a germinacao, vigor, comprimento e massa seca de parte aerea e raizes, acumulo de prolina e perfil proteico. A germinacao nao foi afetada pelo tratamento com acido salicilico e choque frio, mas diminuiu com a progressao do deficit hidrico induzido por manitol. O vigor foi afetado por ambos, acido salicilico e choque frio. O acido salicilico incrementou o comprimento e peso total seco de raiz e total de plantula, especialmente em niveis de estresse in