Resumo

QUIROZ-FLORES, Agustín; RAMIREZ-GARCIA, Pedro  e  LOT-HELGUERAS, Antonio. Seasonal changes of biomass of Nymphoides fallax ornduff (menyanthaceae) in the lagoon of Tecocomulco, Hidalgo, Mexico. Polibotánica [online]. 2014, n.37, pp.93-108. ISSN 1405-2768.

During an annual cycle was quantified the vertical stratification of the biomass of Nymphoides fallax and analyzed the physical and chemical variables of water and sediments in laguna Tecocomulco, Hidalgo. The annual net production of N. fallax was 3 070.1 g DW m². In June, biomass reached its maximum (958.4 g DW m²). The contribution of foliar biomass of N. fallax to total biomass ratio was 10% that of petioles reaches 40% and the contribution of belowground biomass, sometimes exceeded 50%. The level of phosphorus in sediments was above the amount needed to sustain crop production (≥ 0.04%). From the results obtained in this study, we concluded that in those coastal areas of the lagoon where farmers have built levees, these propitiated that during the rainy season the water column abruptly changes from 10 cm to 75 cm and raise the levels of phosphorus in waters and sediments, which in turn appear to induce stress on N. fallax stands. After extreme events of these types, this species can be temporarily substituted by other species best adapted to the new physical and chemical environmental conditions.

Palavras-chave : Nymphoides fallax; biomass; waters; sediments; phosphorus.

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