Seed germination and post-seminal development of Victoria amazonica (Poepp.) J. C. Sowerby (Nymphaeaceae) in Central Amazon

Resumen

The Amazon floodplains are specific ecosystems with high biodiversity and endemism, divided in varzeas, white fertile waters, and Igapos with poor and acid waters, black or clear, and mixed waters between the two typologies. The main purpose of this investigation was to characterize the seed germination and post-seminal development of Victoria amazonica (Poepp.) J.C. Sowerby, one of the few hydrophytes occurring in varzea and mixed waters in the region. In addition, it was evaluated the influence of environmental characteristics on the growth of the plants. Germination was monitored in seeds with and without scarification, in control and treatments with water low oxygen and in the dark. The plant development was monitored in field and laboratory; material from juvenile and adult plants was collected at six sampling sites near Manaus. Germination is favored in the dark, in hypoxic conditions, in water and seed coat shaved. The seedling has two cotyledons, one inside the seed and the other with an acicular shape, eophyll deltoid-hastate, abortive primary root and adventitious roots. New eophylls and the first metaphyll appear in twenty-day-old plants. The stem is rhizomatous. The mixed water environment was not very different from the varzea which is reflected in a similar chemical composition of the plants of both systems. The rhizomes of the varzea environment have caloric value three times higher than that of mixed water. This condition and the presence of larger leaves suggest the varzea floodplain to be more favorable environment for growth of Victoria amazonica.