Effect of waterlogging on qualitative and quantitative changes of indole compounds and levels of related enzymes in seed and leachates of groundnut

The qualitative and quantitative changes in indole compounds and activity of some enzymes like polyphenol oxidase, peroxidase and IAA-oxidase were analyzed in seed and leachates of groundnut (Arachis hypogaea L.) cultivar TCG 1704 at 24, 48, 72 and 96 h of waterlogging. The 24 h seed waterlogging period was treated as control for the comparison of indole compounds and enzymes at 48, 72 and 96 h of waterlogging. In both seed and leachates, four indole derivatives identical to indole-3-acetic acid (IAA), indole-3-acetaldehyde (IAAld), indole-3-aldehyde (IAid) were identified chromatographically. The identity of IAA was confirmed by spectral analysis. Peak amounts of indole compounds were recorded quantitatively in the control seed and leachates which decreased gradually at 96 h. On the other hand, polyphenol oxidase, peroxidase and IAA oxidase enzyme levels were increased at 96 h in both seed and leachates. However, the level of polyphenol oxidase and IAA-oxidase were highest in the leachates than the seed. In contrast, peroxidase has highest activity in the seed than the leachates. It is inferred that during waterlogging conditions, fresh synthesis of indole compounds is inhibited and the release of indole compounds in leachate was probably to protect the seed from unfavorable conditions of anoxia.