Trees

, Volume 14, Issue 5, pp 263–270

Leaf gas exchange in a clonal eucalypt plantation as related to soil moisture, leaf water potential and microclimate variables

  • M. S. Mielke
  • M. A. Oliva
  • N.F. de Barros
  • R. M. Penchel
  • C. A. Martinez
  • S. da Fonseca
  • A.C. de Almeida
Original Article

DOI: 10.1007/s004680050012

Cite this article as:
Mielke, M., Oliva, M., de Barros, N. et al. Trees (2000) 14: 263. doi:10.1007/s004680050012

Abstract 

In order to determine how environmental and physiological factors affect leaf gas exchange in a 9-year-old clonal eucalypt plantation (Eucalyptus grandis Hill ex. Maiden hybrids) in the State of Espirito Santo, Brazil, the diurnal patterns of predawn leaf water potential (Ψpd), and leaf gas exchange were monitored from November 1995 to August 1996. Soil water content (Θ) and microclimatic variables were also recorded. Most of the rainfall during the experimental period occurred from October to December 1995 and from March to April 1996, causing a significant variation in Θ and Ψpd. A high positive correlation (r2=0.92) was observed between Ψpd and Θ measured at 0.3 m depth from the soil surface. During conditions of high soil water availability, the maximum values of stomatal conductance for water vapor (gs) and net photosynthetic rate (A) were over 0.4 mol m–2 s–2 and l5 µmol m–2 s–1, respectively. The results showed that Ψpd and leaf gas exchange of the examined trees were susceptible to changes in the water content of the upper soil layers, where the major concentration of active roots occur. Multiple linear regression analysis indicated that photosynthetic active radiation (Q), vapor pressure deficit (VPD), atmospheric CO2 molar fraction (Ca), and Ψpd were the most important factors controlling gs whereas Q and VPD were the main microclimatic variables controlling A.

Key words  Eucalyptus grandis Leaf water potential Net photosynthetic rate Stomatal conductance Water supply 

Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • M. S. Mielke
    • 1
  • M. A. Oliva
    • 1
  • N.F. de Barros
    • 2
  • R. M. Penchel
    • 3
  • C. A. Martinez
    • 1
  • S. da Fonseca
    • 3
  • A.C. de Almeida
    • 4
  1. 1.Departamento de Biologia Vegetal Universidade Federal de Viçosa, 36571-000, Viçosa, MG, Brazil e-mail: moliva@mail.ufv.br Tel.: +55-31-8992050, Fax: +55-31-8992580BR
  2. 2.Departamento de Solos, Universidade Federal de Viçosa 36571-000, Viçosa, MG, BrazilBR
  3. 3.Centro de Pesquisa & Tecnologia, Aracruz Celulose S.A. Aracruz, ES, 29197-000, BrazilBR
  4. 4.Produçao e Suprimento de Madeira, Aracruz Celulose S.A. Aracruz, ES, 29197-000, BrazilBR

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