Seasonal and spatial rhythm of seed production in savannas of "La Iguana" experimental station, Guárico state, Venezuela ; Ritmo estacional y espacial de producción de semillas en las sabanas de la estación experimental "La Iguana" estado Guárico, Venezuela
We determined fruiting species and seed number produced by the herbaceous vegetation in savannas, at five dates, three soil types, and two topographic levels. A total of 90 1m 2 -quadrats were randomly selected by sampling date, and all fruits were counted by plant species separately. Seeds contained in ten fruits of every fruiting species found in the quadrats were counted, and the mean seed number by fruit was used to calculate the seed number m -2 by plant species and sampling date. It was found that seed density and fruiting species number drop to the lowest values during drought and onset... Mehr ...
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Dokumenttyp: | Artikel |
Erscheinungsdatum: | 2018 |
Verlag/Hrsg.: |
Sociedad Venezolana de Ecología
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Schlagwörter: | Seeds / Fruit production / Seasonal variability / Spatial heterogeneity / Savannas / Venezuela / Semillas / Fructificación / Variabilidad estacional / Heterogeneidad espacial / Sabana |
Sprache: | Spanish |
Permalink: | https://search.fid-benelux.de/Record/base-27261723 |
Datenquelle: | BASE; Originalkatalog |
Powered By: | BASE |
Link(s) : | http://erevistas.saber.ula.ve/index.php/ecotropicos/article/view/10255 |
We determined fruiting species and seed number produced by the herbaceous vegetation in savannas, at five dates, three soil types, and two topographic levels. A total of 90 1m 2 -quadrats were randomly selected by sampling date, and all fruits were counted by plant species separately. Seeds contained in ten fruits of every fruiting species found in the quadrats were counted, and the mean seed number by fruit was used to calculate the seed number m -2 by plant species and sampling date. It was found that seed density and fruiting species number drop to the lowest values during drought and onset of rains, and reach maxima in the middle and end of the rainy season. Grasses constitute 49.7% of the total seeds carried by the vegetation, legumes 20.6%, and sedges 8.9%. Most grasses and sedges fruit during the first half of the rainy season, whereas most legumes and many others plant families produced seeds toward the end of the wet season. Late fruiting species have larger seeds than precocious or early fruiting species. Significant differences in seed production were detected between soil types but not between topographic levels. ; Se determinaron las especies en fructificación y el número de semillas que porta la vegetación herbácea en sabanas, en cinco fechas, tres tipos de suelo, y dos niveles del relieve. Se seleccionaron aleatoriamente 90 cuadratas de 1m 2 por fecha, y en ellas se contaron los frutos por especie. Se contaron las semillas de diez frutos, y con el promedio se calculó el número de semillas m -2 por especie y fecha. Se evidenció que la densidad de semillas y el número de especies en fructificación son mínimos al final de la sequía y al inicio de lluvias, y alcanzan valores máximos a mediados y final de la estación lluviosa. Las gramíneas producen 49,7% del total de semillas, las leguminosas el 20,6%, y las ciperáceas el 8,9%. La mayoría de las gramíneas y las ciperáceas fructifican en la primera mitad de la estación lluviosa, mientras que las leguminosas y la mayoría de las familias restantes ...