Relations among water availability, fungicide treatment and corn seed germination

Objetivando estudar relações entre a disponibilidade de água e o comportamento das sementes de milho durante a germinação, o trabalho empregou potenciais hídricos variáveis entre 0 e -12 atm. Dois enfoques foram dados à pesquisa. No primeiro, a deficiência hídrica foi diretamente comparada à condição de plena disponibilidade de água; no segundo, os déficits eram admitidos como pré-condicionadores fisiológicos que, sucedidos por 5 dias com plena disponibilidade de água, foram comparados com uma testemunha que não passou por restrições hídricas. As sementes, tratadas ou não com o produto fungicida, tiveram o seu comportamento avaliado quanto à capacidade de absorção de água, à emissão das estruturas embrionárias, à qualificação das plântulas e ao seu crescimentoObjectifying to study, fundamentally, some relations between the availability of water and the performance for corn seeds during the germination, the present work was developed employing substrates with variable hydric potential between 0 and -12 atm, through the use of aqueous solutions of polyethylene glycol (PEG) during different periods of time. The adopted methodology provided two main objectives to the research. In the first of time, realized in two stages called Studies 1 and 2, the water deficit was directly compared to the condition of absolute availability of water, in identical periods of exposition; in the second objective (Study 3) the deficits were admitted as osmotic seed treatment; in such a way, the deficient periods were succeeded by fixed term of 5 days without hydric limitations and compared on a control that remained equally reservations as to the quantity of water during 5 days. The seeds, treated or didn't treat with fungicide product, had their performance evaluated as to the capacity of absorption of water, as to the emergence of embryonic structures, as to seedlings qualification and as to its growt