Pioneer and late stage tropical rainforest tree species (French Guiana) growing under common conditions differ in leaf gas exchange regulation, carbon isotope discrimination and leaf water potential.
Oecologia
; 99(3-4): 297-305, 1994 Sep.
Article
em En
| MEDLINE
| ID: mdl-28313884
Leaf gas exchange rates, predawn Ψwp and daily minimum Ψwm leaf water potentials were measured during a wet-to-dry season transition in pioneer (Jacaranda copaia, Goupia glabra andCarapa guianensis) and late stage rainforest tree species (Dicorynia guianensis andEperua falcata) growing in common conditions in artificial stands in French Guiana. Carbon isotope discrimination (Δ) was assessed by measuring the stable carbon isotope composition of the cellulose fraction of wood cores. The Δ values were 2.7 higher in the pioneer species than in the late stage species. The calculated time integratedC i values derived from the Δ values averaged 281 µmol mol-1 in the pioneers and 240 µmol mol-1 in the late stage species. The corresponding time-integrated values of intrinsinc water-use efficiency [ratio CO2 assimilation rate (A)/leaf conductance (g)] ranged from 37 to 47 mmol mol-1 in the pioneers and the values were 64 and 74 mmol mol-1 for the two late stage species. The high Δ values were associated-at least inJ. copaia-with high maximumg values and with high plant intrinsinc specific hydraulic conductance [Câg/(Ψwm-Ψwp], which could reflect a high competitive ability for water and nutrient uptake in the absence of soil drought in the pioneers. A further clear discriminating trait of the pioneer species was the very sensitive stomatal response to drought in the soil, which might be associated with a high vulnerability to cavitation in these species. From a methodological point of view, the results show the relevance of Δ for distinguishing ecophysiological functional types among rainforest trees.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Prognostic_studies
País/Região como assunto:
America do sul
/
Caribe ingles
/
Guyana
Idioma:
En
Revista:
Oecologia
Ano de publicação:
1994
Tipo de documento:
Article
País de afiliação:
França
País de publicação:
Alemanha