Structural and functional leaf traits of two Gochnatia species from distinct growth forms in a sclerophyll forest site in Southeastern Brazil
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Data
2012-12-01
Autores
Rossatto, Davi Rodrigo [UNESP]
Kolb, Rosana Marta [UNESP]
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Editor
Sociedade Botânica do Brasil
Resumo
O gênero Gochnatia é comumente encontrado em diferentes fitofisionomias do Cerrado do Estado de São Paulo, crescendo desde ambientes mais abertos até áreas florestais mais fechadas. Aqui foram comparadas a anatomia foliar e alguns parâmetros ecofisiológicos de duas espécies do gênero Gochnatia, uma arbustiva (Gochnatia barrosii Cabrera) e a outra arbórea (Gochnatia polymorpha (Less.) Cabrera), ambas ocorrendo em área de cerradão na Estação Ecológica de Assis, SP. Encontraram-se diferenças estruturais qualitativas entre as espécies, com G. barrosii apresentando folhas anfiestomáticas, com epiderme unisseriada e G. polymorpha apresentando folhas hipoestomáticas, com epiderme múltipla ou hipoderme, na face adaxial. Além disso, as folhas de G. barrosii apresentaram menores valores para a espessura dos tecidos (com exceção da epiderme na face abaxial) e da folha em relação a G. polymorpha. Foram observadas diferenças na assimilação de CO2 tanto em base de área quanto de massa seca foliar, além de diferenças na área foliar específica, sendo esta maior em G. barrosii. Apesar das folhas de G. barrosii possuírem estrutura bem menos escleromorfa do que as folhas de G. polymorpha, não foram encontradas diferenças na eficiência do uso de água. Os resultados sugerem que espécies de formas distintas de crescimento de um mesmo gênero possuem características foliares diferenciadas para lidar com as variações ambientais a que são submetidas.
Gochnatia is very common in different phytophysiognomies in the Cerrado of São Paulo State, occupying open and closed areas. In this study, we compared the leaf anatomy and some ecophysiological traits of two species of Gochnatia, one a shrub (Gochnatia barrosii Cabrera) and the other a tree (Gochnatia polymorpha (Less.) Cabrera), which both occur in an area of cerradão at the Estação Ecológica de Assis, SP. We found qualitative structural differences between the species, with G. barrosii presenting amphistomatic leaves with a uniseriate epidermis and G. polymorpha showing hypostomatic leaves and a multiple epidermis or hypodermis on the adaxial surface. Moreover, the G. barrosii leaves had lower values in tissue thickness (with the exception of the epidermis on the abaxial surface) and leaf thickness in relation to G. polymorpha. There were differences in CO2 assimilation both in area and leaf dry mass basis, and differences in specific leaf area, which was higher in G. barrosii. Although the G. barrosii leaves were much less sclerophyllous than the G. polymorpha leaves, we found no differences in the efficiency of water use. The results suggest that plants from the same genus, but with distinct growth forms, differ in their leaf traits to deal with the environmental variations that they grow in.
Gochnatia is very common in different phytophysiognomies in the Cerrado of São Paulo State, occupying open and closed areas. In this study, we compared the leaf anatomy and some ecophysiological traits of two species of Gochnatia, one a shrub (Gochnatia barrosii Cabrera) and the other a tree (Gochnatia polymorpha (Less.) Cabrera), which both occur in an area of cerradão at the Estação Ecológica de Assis, SP. We found qualitative structural differences between the species, with G. barrosii presenting amphistomatic leaves with a uniseriate epidermis and G. polymorpha showing hypostomatic leaves and a multiple epidermis or hypodermis on the adaxial surface. Moreover, the G. barrosii leaves had lower values in tissue thickness (with the exception of the epidermis on the abaxial surface) and leaf thickness in relation to G. polymorpha. There were differences in CO2 assimilation both in area and leaf dry mass basis, and differences in specific leaf area, which was higher in G. barrosii. Although the G. barrosii leaves were much less sclerophyllous than the G. polymorpha leaves, we found no differences in the efficiency of water use. The results suggest that plants from the same genus, but with distinct growth forms, differ in their leaf traits to deal with the environmental variations that they grow in.
Descrição
Palavras-chave
anatomia foliar, Cerrado, estômatos, trocas gasosas, Cerrado, gas exchange, leaf anatomy, stomata
Como citar
Acta Botanica Brasilica. Sociedade Botânica do Brasil, v. 26, n. 4, p. 849-856, 2012.