ABSTRACT
The aim of this study was to estimate the influence of biotic and abiotic factors on Suaeda maritima reproduction on a salt marsh. Individuals of Suaeda maritima were submitted in natural conditions to four series of densities (100, 1,000, 4,000 and 8,000 plants/m2). When density increases, individuals tend to be less or non-branched, while individual biomass decreases. Consequently, individual seed production decreases as density increases. Despite morphological modifications, Suaeda maritima present density-dependent mortality. For a unit area, total biomass and seed production are higher at intermediate density (1,000 plants/m2). Environmental factors could interfere with self-thinning. They seem to limit the effect of competition on mortality and to have an influence on individual and total seed production. This experiment stressed the importance of a biotic factor such as intra-specific competition, which occurs at the same time as abiotic factors, in Suaeda maritima dynamics in the field.
Subject(s)
Plant Development , Plants/anatomy & histology , Biomass , Ecology , Environment , Seasons , Seeds/physiologyABSTRACT
The glycine betaine content of higher plants can be determined by rapid and simple isocratic high-performance liquid chromatography on a C(18) column. The method described is particularly suitable for a large number of samples. Starting from a complex dry plant, it consists of a single aqueous extraction followed by a purification over a sole cationic ion-exchange resin (AG1, OH(-)) before simple HPLC quantification. The single-step purification was allowed because the AG1, OH(-) resin removed 80% of the total amino acids contained in the extracts. Proline, which interferes with GB HPLC quantification, was completely retained by this column. The optimized method for GB quantification was then validated by comparaison with an (1)H NMR method.
