TRANSPIRAÇÃO E CONDUTÂNCIA ESTOMÁTICA DE Eucalyptus sp EM RESPOSTA À RADIAÇÃO GLOBAL E DIFERENTES CONDIÇÕES HÍDRICAS
DOI:
https://doi.org/10.15809/irriga.2013v18n4p607Abstract
1 RESUMO
Este trabalho objetivou avaliar a transpiração e condutância estomática de dois clones comerciais de Eucalyptus sp associados à radiação global e em diferentes disponibilidades hídricas. Os indivíduos encontravam-se sob a mesma faixa de potencial hídrico foliar antemanhã (0 a -3,0 MPa). Os resultados apontam diferenças de comportamento entre os clones avaliados, sendo que o clone C041 possui um maior controle da transpiração. O clone P4295 apresentou um maior decréscimo da relação da transpiração e condutância estomática por unidade de radiação e os valores foram sistematicamente superiores ao do clone C041. Entretanto, estatisticamente, a relação Etotal/Rgtotal mostrou-se diferente somente em potenciais hídricos antemanhã < -1,0 Mpa. O conhecimento da transpiração permitirá a elaboração de modelos de transpiração para essa cultura e o conhecimento do funcionamento de um importante componente de saída de água da bacia hidrográfica.
Palavras-chaves: ecofisiologia vegetal, potencial hídrico foliar, trocas gasosas
TONELLO, K.C.; TEIXEIRA FILHO, J.
LEAF TRANSPIRATION AND STOMATAL CONDUCTANCE OF Eucalyptus sp IN RESPONSE TO GLOBAL RADIATION AND DIFFERENT SOIL WATER CONDITIONS
2 ABSTRACT
This study had as objective to evaluate transpiration and stomatal conductance of two commercial clones of Eucalyptus sp in periods between February and June of 2010. Leaf scale was associated with global radiation (RG) and different levels of water availability. Data on transpiration (E) and stomatal conductance (GS) of the clones were obtained by porometry and were associated with global radiation. The clones were under the same range of predawn leaf water potential (0 to -3,0 MPa). The results showed significant differences between clones, and the C041 clone had greater control of transpiration. The P4295 clone had a higher decrease of the relation transpiration and stomatal conductance per radiation unity, and the values were consistently higher than those of the C041 clone. However, statistically significant differences were found in the relation Etotal/Rgtotal only for predawn water potentials < -1.0 MPa. The understanding of how transpiration works, will enable the construction of transpiration models for this crop and the understanding of an important water leaving component of the watershed.
Keywords: vegetal ecophysiology, gas exchange, leaf scale, predawn leaf water potential, Eucalyptus hybrid
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