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Leaf tissue water relations in tree species from contrasting habitats within the upper Rio Negro forests of the Amazon region

Published online by Cambridge University Press:  29 August 2012

M. A. Sobrado
M. A. Sobrado*
Affiliation:
Laboratorio de Biología Ambiental de Plantas, Departamento de Biología de Organismos, Universidad Simón Bolívar, Apartado 89.000, Caracas 1080 A, Venezuela
*
Email: msobrado@usb.ve
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Extract

The landscape of the upper Rio Negro basin (North Amazon) exhibits distinctive habitats that are associated with differential soil characteristics and topographical conditions as well as species composition (Herrera et al. 1978). The mixed forests thrive on well-structured oxisols on slightly more elevated areas. The valleys with sandy podzols are occupied by the ‘Amazon caatinga’ complex with three distinct zones: the bottom valley and the gentle slopes, both of which have closed forests, and the sandy domes with open forests (‘bana’ or sclerophyllous forest; Breimer 1985). From the mixed forest towards the caatinga valley-slope-dome habitats, the leaf δ15N signatures become increasingly negative, suggesting a trend in N limitation in the same direction (Sobrado 2010). Thus, negative leaf δ15N signatures depleted in 15N compared with the soil indicate a very tight N cycle in all of the habitats. Water availability follows a similar pattern from the top of the oxisol towards the flooded valley bottom of the caatinga, with extreme water-table fluctuations in the sandy domes (Klinge 1978). Thus, parallel variation in nutrient and water availabilities exist in this area that are associated with soil characteristics and topography. Under such contrasting habitats, species-specific responses would be linked to particular conditions of the habitat at a local scale (Comita & Engelbrecht 2009, Engelbrecht et al. 2007). A number of studies in these habitats have shown that this is the case for soil fertility (Coomes 1997, Medina et al. 1990, Sobrado 2010, Sobrado & Medina 1980). Similarly, the hydraulic characteristics and long-term water use are species specific and related to particular conditions of the habitat at the local scale (Sobrado 2010). In this report, it was hypothesized that the leaf tissue water relations of species thriving in different habitats may reflect the water availability at the particular sites as well. The leaf tissue water relations of species thriving in the extreme nutrient and water-supply conditions of the sandy domes from the caatinga complex have been previously studied in detail (Sobrado 2009a). However, these data are currently not available for the species that thrive in the surrounding area of the closed forests, and importantly, such information would allow for a comparison across habitats. Therefore, the present study assessed the minimum leaf water potential (midday) under field conditions as well as the leaf tissue water relations by using pressure-volume analysis of dominant tree species in the top canopy of these high-stature forests.

Keywords

Amazon caatingaCaryocar glabrumdrought toleranceEperua leucanthaMicranda spruceimixed forestOcotea aciphyllaosmotic potentialoxisolsclerophyllous leavestropical podzolturgor maintenanceVenezuelawater potential
Type
Short Communication
Information
Journal of Tropical Ecology , Volume 28 , Issue 5 , September 2012 , pp. 519 - 522
Copyright
Copyright © Cambridge University Press 2012

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References

LITERATURE CITED

BREIMER, R. F. 1985. Some observations on soils in relation to forest types in San Carlos de Rio Negro, Venezuela. Pp. 108–110 in Breimer, R. F., van Kekem, A. J. & van Reuler, H. (eds). Guidelines for soil survey in ecological research. MAB Technical Notes No 17. UNESCO, Paris.Google Scholar
COMITA, L. S. & ENGELBRECHT, B. M. J. 2009. Seasonal and spatial variation in water availability drive habitats associations in a tropical forest. Ecology 90:2755–2765.CrossRefGoogle Scholar
COOMES, D. A. 1997. Nutrient status of Amazonian caatinga forests in a seasonally dry area: nutrient fluxes in fine litter fall and analysis of soils. Canadian Journal of Forest Research 27:831–839.Google Scholar
ENGELBRECHT, B. M. J., COMITA, L. S., CONDIT, R., KURSAR, T. A., TYREE, M. T., TURNER, B. L. & HUBBELL, S. P. 2007. Drought sensitivity shapes species distribution patterns in tropical forests. Nature 447:80–82.CrossRefGoogle ScholarPubMed
HERRERA, R., JORDAN, C. F., KLINGE, H. & MEDINA, E. 1978. Amazon ecosystems. Their structure and functioning with particular emphasis on nutrients. Interciencia 3:223–232.Google Scholar
KLINGE, H. 1978. Studies on the ecology of Amazon caatinga forest in Southern Venezuela. Acta Cientifica Venezolana 29:258–262.Google Scholar
LENZ, T. I., WRIGHT, I. J. & WESTOBY, M. 2006. Interrelations among pressure-volume curve traits across species and water availability gradients. Physiologia Plantarum 127:423–433.CrossRefGoogle Scholar
MEDINA, E., GARCIA, V. & CUEVAS, E. 1990. Sclerophylly and oligotrophic environments: relationships between leaf structure and mineral nutrient content, and drought resistance in tropical rain forests in the upper Rio Negro region. Biotropica 22:51–54.CrossRefGoogle Scholar
READ, J., SANA, G. D., GARINE-WICHATITSKY, M. & JAFFRÉ, T. 2006. Sclerophylly in two contrasting tropical environments: low nutrient vs. low rainfall. American Journal of Botany 93:1601–1614.CrossRefGoogle ScholarPubMed
SALLEO, S., NARDINI, A. & LO GULLO, M. A. 1997. Is sclerophylly of Mediterranean evergreens an adaptation to drought? New Phytologist 135:603–612.CrossRefGoogle Scholar
SOBRADO, M. A. 2008. Leaf characteristics and diurnal variation of chlorophyll fluorescence in leaves of the ‘Bana’ vegetation of the Amazon region. Photosynthetica 46:202–207.CrossRefGoogle Scholar
SOBRADO, M. A. 2009a. Leaf tissue water relations and hydraulic properties of sclerophyllous vegetation on white sands of the upper Rio Negro in the Amazon region. Journal of Tropical Ecology 25:271–280.CrossRefGoogle Scholar
SOBRADO, M. A. 2009b. Cost–benefit relationships in sclerophyllous leaves of the ‘Bana’ vegetation in the Amazon region. Trees 23:429–437.CrossRefGoogle Scholar
SOBRADO, M. A. 2010. Leaf characteristics, wood anatomy and hydraulic properties in tree species from contrasting habitats within upper Rio Negro forests in the Amazon region. Journal of Tropical Ecology 26:215–226.CrossRefGoogle Scholar
SOBRADO, M. A. 2011. Leaf pigment composition and fluorescence signatures of top canopy leaves in species of the upper Rio Negro forests. Research Journal of Botany 6:141–149.CrossRefGoogle Scholar
SOBRADO, M. A. & MEDINA, E. 1980. General morphology, anatomical structure and nutrient content of sclerophyllous leaves of the ‘Bana’ vegetation. Oecologia 45:341–345.CrossRefGoogle ScholarPubMed
TURNER, I. M. 1994. A quantitative analysis of leaf form in woody plants from the world's major broad-leaved forest types. Journal of Biogeography 21:413–419.CrossRefGoogle Scholar
TYREE, M. T. & HAMMEL, M. 1982. The measurements of the turgor pressure and water relations of plants by the pressure-bomb technique. Journal of Experimental Botany 23:267–283.CrossRefGoogle Scholar