Influência da disponibilidade de oxigênio sobre a germinação, crescimento e atividade das enzimas álcool desidrogenase e lactato desidrogenase em açaí (Euterpe oleracea Mart.)

Abstract

The effect of oxigen availability on some metabolic events associated to the germination of seeds, survival of seedlings and formation of aerenchyma in roots of "açaí" seedlings (Euterpe oleracea Mart.) was intended to be studied. Therefore, the activity of the enzymes Alcohol dehydrogenase (ADH) and Lactate dehydrogenase (LDH), at several times of application of the aerated and anoxical treatments in seeds and seedlings was assessed. In addition to the percentage of seed germination. In spite of not finding differences in the percentage of seed germination between the treatments, after return to the aerated conditions, it was observed that aerobic conditions delayed germination. During the experimental period the activity curves of the enzymes Alcohol dehydrogenase and Lactate dehydrogenase in seeds and seedlings showed a similar behaviour between treatments. The seeds presented a less active aerobic metabolism than the one observed in seedlings. in seedlings it was noticed that the activity of the two enzymes (ADH and LDH), has aiways been greater in shoots than in roots and that the activity of the enzyme Lactate dehydrogenase wassuperior to the activity of Alcohol dehydrogenase, not mínding either the tissue or the period evaluated. It was also noticed that the seedlings subjected to the anoxical treatment did not developped, but resumed their development when re-exposed to aerated condition. These results demonstrate that both 'açaí" seeds and seedlings showed a high degree of tolerance to oxigen deficience, metabolically adjusting in different Levels.