Effect of calcium on enzymes of antioxidant system in maize (Zea mays L.) âSaracuraâ â BRS-4154 plantlets submitted to how oxygen availability / Efeito do cÃlcio em enzimas do sistema antioxidante em plÃntulas do milho (Zea Mays L.) âSaracuraâ â BRS-4154 submetidas à baixa disponibilidade de oxigÃnio

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The present work aimed to verify the influence of calcium in the ADH and antioxidant system enzymes, like SOD, CAT, APX and GR, in maize seedlings "Saracura" during the period of low availability of oxygen and the onset of pos-stress recovery. In this research there were used maize plantlets, âSaracuraâ (BRS-4154), cycle 17. The germination was made in germination paper wet in water or CaCl2 (0,75% w/v) and kept in germination chamber at 272ÂC in dark, during four days. After this period it was made the flooding by submerging the plantlets in PVC tubes containing buffer with and without CaCl2, bubbling the gaseous nitrogen for three minutes. The tubes were sealed and kept in dark for 3, 6, 12, 24, 48 and 72 hours. For the controls (without flooded) the rolls were kept in germination chamber. After each period, the roots were collected to enzymatic analysis and the re-aeration was made, where the plantlets were removed from the rolls and distributed in germination paper in direct contact with air during 30 minutes, and after this time the roots were collected. The flooding survival was made based in the greening and plantlet vigour after seven days cultivation in box with vermiculite in growth chamber. The enzymatic activities were made for ADH, SOD, CAT, APX and GR and the activity gels were obtained for ADH, SOD and CAT. The ADH showed lower activity in the calcium presence, suggesting a lower energetic demand during the flooding period. It was verified an increase in SOD activity in the period of re-aeration and the high activities of CAT in this period and during the flooding, suggesting that in the absence of calcium can be formed higher amount of EROs. In this plantlets, the elimination of these radicals could been made mainly by CAT. In the presence of calcium, lower activities of ADH and CAT, jointly with APX induction in the periods of flooding and re-aeration and of the GR during the stress, suggest the elimination of EROs, in this case, could be made by the ascorbate/glutathione patway. In this way, the more effective patway enzyme activity could be related with the increase of tolerance from maize âSaracuraâ plantlets caused by calcium presence.

ASSUNTO(S)

milho cÃlcio alagamento antioxidant system calcium sistema antioxidante flooding maize fisiologia vegetal

ACESSO AO ARTIGO

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