Atributos de proteção às gemas laterais em espécies lenhosas distribuídas no gradiente latitudinal do Cerrado
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Data
2018-02-27
Autores
Campos, Bruna Helena de
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Universidade Estadual Paulista (Unesp)
Resumo
A variação em atributos de proteção, principalmente os foliares, pode ter importante papel no desempenho das espécies ao longo de um gradiente de condições ambientais ou em hábitats heterogêneos. O domínio Cerrado está inserido em um gradiente climático e suas formações savânicas estão submetidas a queimadas recorrentes. Neste trabalho nós caracterizamos atributos de proteção às gemas em três espécies lenhosas, coocorrentes em fitofisionomias savânicas ao longo do gradiente latitudinal N-S do Cerrado e investigamos a ocorrência de fogo em uma escala espácio-temporal. Caracterizamos a posição das gemas nas plantas, morfologia e anatomia e indicadores de flamabilidade das mesmas. De modo geral, as plantas de diferentes localidades apresentaram diferenças quanto a altura das gemas na planta em relação ao nível do solo, sendo que plantas mais altas foram observadas nas latitudes menores e as mais baixas nas latitudes maiores, provavelmente devido a maior produtividade associada à proximidade da linha do Equador. Primórdios com maior área ocupada por idioblastos fenólicos foram observados nas duas localidades mais próximas à linha do Equador, possivelmente devido a alta intensidade de radiação. Além disso, registramos distintos regimes de queimada nas cinco localidades nos últimos 15 anos. Considerando a ampla distribuição geográfica das três espécies deste estudo, podemos concluir que suas gemas axilares toleram certa variação nos fatores climáticos como a amplitude de temperatura, radiação solar e pluviosidade. Além disso, essas espécies são capazes de persistir em ambientes com distintas frequências de fogo, sendo que a altura das gemas em relação ao nível do solo parece ser a característica mais determinante na manutenção dos rametas nessas localidades. A utilização de abordagens complementares, incluindo a caracterização do clima, frequência de fogo, características morfológicas e anatômicas das plantas, permitiu um conhecimento mais profundo sobre fatores abióticos potencialmente associados aos atributos de proteção às gemas e permitiu-nos inferir sobre as respostas interativas entre clima-planta-fogo em ecossistemas savânicos.
The variation in protection traits, especially the foliar ones, can play an important role in species performance along a gradient of environmental conditions or in heterogeneous habitats. The Cerrado domain is inserted in a climatic gradient and its savannah formations are under recurrent burning. In this study, we characterized bud protection traits of three woody species that co-ocurr in savannah phytophysiognomys along the Cerrado latitudinal gradient and we investigated fire occurrence in a spatio-temporal scale. We characterized bud position in each plant species, its morphology, anatomy and flammability indicators. In general, plants of different locations showed differences in bud height in relation to soil level. Taller plants were observed at lower latitudes and the smallest ones at higher latitudes, probably due to the higher productivity associated to the proximity to Equator line. Primordia with a larger area occupied by phenolic idioblasts were observed in the two locations nearest to the Equator line, possibly due to high radiation intensity. Besides that, we registered different fire regimes at the five locations in the last 15 years. Considering the wide distribution of the three species of this study, we can conclude that their axillary buds tolerate some variation in climatic factors like temperature, solar radiation and pluviosity amplitude. Besides that, this species are capable of persisting in environments under different fire frequency. Additionally, bud height in relation to the soil level seems to be the most determinant factor related to ramet maintenance in these locations. The use of complementary approaches, including climate and fire frequency, plants morphologic and anatomic characteristics, provided us with a deeper knowledge about potencially abiotic factor associated to bud protection traits and allowed us to infer about the interactive climate-plants-fire responses in savannah ecosystems.
The variation in protection traits, especially the foliar ones, can play an important role in species performance along a gradient of environmental conditions or in heterogeneous habitats. The Cerrado domain is inserted in a climatic gradient and its savannah formations are under recurrent burning. In this study, we characterized bud protection traits of three woody species that co-ocurr in savannah phytophysiognomys along the Cerrado latitudinal gradient and we investigated fire occurrence in a spatio-temporal scale. We characterized bud position in each plant species, its morphology, anatomy and flammability indicators. In general, plants of different locations showed differences in bud height in relation to soil level. Taller plants were observed at lower latitudes and the smallest ones at higher latitudes, probably due to the higher productivity associated to the proximity to Equator line. Primordia with a larger area occupied by phenolic idioblasts were observed in the two locations nearest to the Equator line, possibly due to high radiation intensity. Besides that, we registered different fire regimes at the five locations in the last 15 years. Considering the wide distribution of the three species of this study, we can conclude that their axillary buds tolerate some variation in climatic factors like temperature, solar radiation and pluviosity amplitude. Besides that, this species are capable of persisting in environments under different fire frequency. Additionally, bud height in relation to the soil level seems to be the most determinant factor related to ramet maintenance in these locations. The use of complementary approaches, including climate and fire frequency, plants morphologic and anatomic characteristics, provided us with a deeper knowledge about potencially abiotic factor associated to bud protection traits and allowed us to infer about the interactive climate-plants-fire responses in savannah ecosystems.
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gemas, cerrado, gradiente latitudinal, buds, Cerrado, latitudinal gradient