Fruit and seed biometry and germination of Victoria amazonica (Poepp.) J.C. Sowerby (Nymphaeaceae) from the Pantanal floodplain

摘要

Numerous plant species are ea sily established in the wide flood plains of the Pantanal wetlands due to the environmental heterogeneity. Th e aquatic macrophytes excel in permanently flooded areas, particularly Nymphaeaceae species. Victoria amazonica , popularly known as th e vitória-régia, is hallmarked for its beauty. However, the biology and conditions necessary for the seed germination of this flowering plant remain unknown. In the present study, the fruit and seed morphology and biometry were described and the seed germination was evaluated under different abiotic conditions. To this end, mature fruits of V. amazonica were collected from the bays near Paraguay River in the south Pantanal floodplain. The fruits and seeds were described and measured usin g digital caliper. Intact and mechanically scarified seeds were germinated under different temperature, light and substratum conditions, and the initial development was described. The fruits measured 67.5 x 119.7 mm in size and contained 100-700 seeds. The average seed measured 10.6 mm in length and 9.8 mm in width. The highest germination occurred at 25 o C, independent of the light condition. The seeds we re considered neutral photoblastic. The seedlings showed heterophylly, and the main root was degene rated, forming adventitious roots. Morphological differences were observed in seedlings developed under different light conditions.