出版社：Fundación Científica y Tecnológica de la Asociación Chilena
摘要：A comparison was made of the seasonal production of biomass of Egeria densa (rooted and submerged Hydrophyte) and of Limnobium laevigatum (hydrophyte floating free on the surface ), in the lower basin of Cayumapu river, a tributary of Cruces river, in Valdivia, Chile. During the study , both species competed in the swamplands close to Cayumapu river; however, after completion of the on-site sampling there was a sharp reduction of their populations. The biomass of the two species was collected on a monthly basis, which, after being washed, was separated in the different organs making up the cormus of each (roots, stolons, stalks, submerged, natant and aerial leaves). Both species showed a high seasonal variation of biomasss and an increase of necromass in spring, suggesting a factor that destroys the biomass formed during that favourable time. Biomass of Limnobium laevigatum roots is higher than that of the Egeria densa, which correlates with each one functions. Biomass/necromass relationship was different in both species, indicating a different seasonability in their growths. Both species showed high contents of ash and protein, common to all macrophytes. Limnobium laevigatum populations complete their life cycle, developing male and female flowers , which form fruits and seeds. On the contrary, those of Egeria densa are vegetative lines formed exclusively by male individuals. Caloric value turned out to be higher in Egeria densa, which gives it a higher ecological efficiency as compared with Limnobium laevigatum. For the latter, however a higher aggressiveness was established, determined apparently by the form of floating life that inhibits the development of submerged plants by shadowing.
