Ecofisiologia da germinação de sementes e de plantas de Styracaceae em diferentes fisionomias de cerrado
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Data
2013-02-28
Autores
Kissmann, Camila [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As espécies Styrax ferrugineus Ness & Mart., S. camporum Pohl. e S. pohlii A. DC. apresentam distintos padrões de ocorrência. S. ferrugineus é comumente encontrada no Cerrado sensu strictu (s. str.), enquanto S. camporum apresenta ampla distribuição no Cerrado sensu latu (s.l.), especialmente nas bordas dos fragmentos e S. pohlii é abundante nas florestas ripárias e de galeria. As performances germinativas das sementes e ecofisiológicas das plantas destas três espécies foram avaliadas através de experimentos de enterrio das sementes e plantio recíprocos em fragmentos de Cerrado s.str, Cerradão (clareira e sub-bosque) e mata ripária, os quais diferem em disponibilidade hídrica no solo e na atmosfera e luminosidade. Simultaneamente, o crescimento e desempenho fotossintético de S. pohlii em resposta ao alagamento do solo foram estudados em casa de vegetação. As sementes das três espécies germinaram em todos os locais experimentais onde foram enterradas. Porém, as plantas jovens de S. ferrugineus e S. camporum não sobreviveram às condições de baixa irradiância e alta disponibilidade de água no solo, encontradas na floresta ripária. A sobrevivência e o sucesso de S. pohlii neste ambiente parece estar relacionado ao rápido crescimento inicial da parte aérea, para obtenção de luz, e à adaptação que ela apresenta em resposta ao alagamento do solo. S. pohlii foi capaz de sobreviver a alagamentos sazonais e mostrou rápida recuperação fisiológica após inundação artificial. S. camporum apresentou maior eficiência fotossintética, crescimento e biomassa quando as plantas foram cultivadas sob altas irradiâncias, em comparação a ambiente sombreados, o que explica o maior número de indíviduos nas bordas em comparação ao interior dos fragmentos de Cerrado. Os dados de trocas gasosas, fluorescência e crescimento de...
The species Styrax ferrugineus Ness & Mart., S. camporum Pohl. and S. pohlii A. DC. show distinct geographical distribution patterns. S. ferrugineus is commonly found in the Cerrado sensu stricto (s. str.), whereas S. camporum is widely distributed in the Cerrado sensu lato (s. l), especially at the edge of vegetation fragments, and S. pohlii is abundant in riparian and gallery forests. Seed germination performances and ecophysiological performances of plants of these three species were assessed through reciprocal burial and planting experiments in a Cerrado s. str. fragment, a Cerradão fragment (gap and understory conditions) and in a riparian forest remnant, where water and light resources are differently availabe. Concurently, growth and photosynthetic parameters of S. pohlii potted plants in response to soil flooding was assessed in a greenhouse experiment. Seeds from each of the tree species were able to germinate in every experimental condition where the seeds were buried. Nevertheless, young plants of S. ferrugineus and S. camporum did not survive the low irradiance and high soil water availability found in the riparian forest. The survival and the success of S. pohlii in such environment seems to be related to a faster shoot initial length in order to capture sunlight, and to the adjustment that this species exhibits in reponse to different levels of soil flooding, enabling this species to fast recover from flooding periods. S. camporum showed higher photosynthetic performance, growth and biomass production when it was cultivated under high irradiances in comparison to shaded environments. These results explain the higher number of individuals of this species observed at the edge in comparison to the interior of Cerrado fragments. Gas exchange, fluorescence and growth parameters measured on S. pohlii and S. ferrugineus... (Complete abstract click electronic access below)
The species Styrax ferrugineus Ness & Mart., S. camporum Pohl. and S. pohlii A. DC. show distinct geographical distribution patterns. S. ferrugineus is commonly found in the Cerrado sensu stricto (s. str.), whereas S. camporum is widely distributed in the Cerrado sensu lato (s. l), especially at the edge of vegetation fragments, and S. pohlii is abundant in riparian and gallery forests. Seed germination performances and ecophysiological performances of plants of these three species were assessed through reciprocal burial and planting experiments in a Cerrado s. str. fragment, a Cerradão fragment (gap and understory conditions) and in a riparian forest remnant, where water and light resources are differently availabe. Concurently, growth and photosynthetic parameters of S. pohlii potted plants in response to soil flooding was assessed in a greenhouse experiment. Seeds from each of the tree species were able to germinate in every experimental condition where the seeds were buried. Nevertheless, young plants of S. ferrugineus and S. camporum did not survive the low irradiance and high soil water availability found in the riparian forest. The survival and the success of S. pohlii in such environment seems to be related to a faster shoot initial length in order to capture sunlight, and to the adjustment that this species exhibits in reponse to different levels of soil flooding, enabling this species to fast recover from flooding periods. S. camporum showed higher photosynthetic performance, growth and biomass production when it was cultivated under high irradiances in comparison to shaded environments. These results explain the higher number of individuals of this species observed at the edge in comparison to the interior of Cerrado fragments. Gas exchange, fluorescence and growth parameters measured on S. pohlii and S. ferrugineus... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Plant ecology, Ecologia vegetal, Fotossintese, Biomassa, Ecofisiologia, Germinação, Estiracacea, Cerrados
Como citar
KISSMANN, Camila. Ecofisiologia da germinação de sementes e de plantas de Styracaceae em diferentes fisionomias de cerrado. 2013. 126 p. Tese - (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Rio Claro, 2013.