AJPS  Vol.6 No.13 , August 2015
Leaf Tissue Water Relations Are Associated with Drought-Induced Leaf Shedding in Tropical Montane Habitats
Abstract: In tropical montane areas, water limitation is a common occurrence, and both pioneer and forests species experience water stress during the dry season. Adjustments of leaf area during periods of drought allow for the maintenance of the water supply and physiological functions of the remaining leaves. Here, we compared leaf blade water relations between pioneer and forest tree species. Leaf pressure-volume (P-V) curves were determined from samples taken prior to the dry season, to assess how leaves of the different species were adapted to prepare for and endure water deficits. The following parameters were calculated: osmotic potential at full (Ψπ(100)) and zero (Ψπ(0)) turgor, relative water content at zero turgor (RWC0), volumetric elastic modulus (ε) as well as apoplasm (A) and symplasm (S) water content and their ratio (A/S). Although the pioneer and forest species occupied contrasting habitats, and both groups were clearly differentiated with respect to their water transport capability and water use efficiency, their leaf tissue water relations showed clear differences across species but not between the groups. Some species underwent leaf shedding and accumulated xylem embolisms during the dry season, and their leaves had high cell elasticity. Consequently, these species presented large cell volume changes with turgor loss. Conversely, species with rigid leaves were able to undergo lower leaf turgor with only small changes in cell volume during drought, which might aid to preserve leaf cell function, maintain water uptake, and consequently avoid accelerated leaf senescence and shedding during the dry season.
Cite this paper: Sobrado, M. (2015) Leaf Tissue Water Relations Are Associated with Drought-Induced Leaf Shedding in Tropical Montane Habitats. American Journal of Plant Sciences, 6, 2128-2135. doi: 10.4236/ajps.2015.613214.

[1]   Binelli, E.K., Gholz, H.K. and Duryea, M.L. (2001) Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem. Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Miami, 1-20.

[2]   Finegan, B. (1984) Forest Succession. Nature, 312, 109-114.

[3]   Nogueira, A., Martinez, C.A., Ferreira, L.L. and Prado, C.H.B.A. (2004) Photosynthesis and Water Use Efficiency in Twenty Tropical Tree Species of Differing Succession Status in a Brazilian Reforestation. Photosynthetica, 42, 351-356.

[4]   Tabarelli, M., Lopes, A.V. and. Peres, C.A. (2008) Edge-Effects Drive Tropical Forest Fragments towards an Early-Successional System. Biotropica, 40, 657-661.

[5]   Swanson, M.E., Franklin, J.F, Beschta, R.L., Crisafulli, C.M., Dellasala, D.A., Hutto, R.L., Lindenmayer, D.B. and Swanson, F.J. (2011) The Forgotten Stage of Forest Succession: Early-Successional Ecosystems on Forest Sites. Frontiers in Ecology and the Environment, 9, 117-125.

[6]   Davies, S.J. and Semui, H. (2006) Competitive Dominance in a Secondary Successional Rain-Forest Community in Borneo. Journal of Tropical Ecology, 22, 53-64

[7]   Bazzaz, F.A. (1979) The Physiological Ecology of Plant Succession. Annual Review of Plant Ecology and Systematic, 10, 351-371.

[8]   Bazzaz, F.A. and Carlton, R.W. (1982) Photosynthetic Acclimation to Variability in the Light Environment of Early and Late Successional Plants. Oecologia, 34, 313-316.

[9]   Zangerl, A.R. and Bazzaz, F.A. (1983) Responses of an Early and Late Successional Species of Polygonium to Variation in Resource Availability. Oecologia, 56, 397-808.

[10]   Dusenge, M.E., Wallin, G., Gårdesten, J., Niyonzima, F., Adolfsson, L., Nsabimana, D. and Uddling, J. (2015) Photosynthetic Capacity of Tropical Montane Tree Species in Relation to Leaf Nutrients, Successional Strategy and Growth Temperature. Oecologia, 177, 1183-1194.

[11]   Becker, P., Meinzer, F.C. and Tsuda, M. (1999) Hydraulic Conductance of Angiosperms versus Conifers: Similar Transport Sufficiency at the Whole-Plant Level. Tree Physiology, 19, 445-452.

[12]   Becker, P., Meinzer, F.C. and Wullschleger, S.W. (2000) Hydraulic Limitation of Tree Height: A Critique. Functional Ecology, 14, 4-11.

[13]   Tyree, M.T., Velez, V. and Dalling, J.L. (1998) Growth Dynamics of Root and Shoot Hydraulic Conductance in Seedling of Five Neotropical Tree Species: Scalling to Show Possible Adaptation to Differing Light Regimes. Oecologia, 114, 293-298.

[14]   Sobrado, M.A. (2003) Hydraulic Characteristics and Leaf Water Use Efficiency in Trees from Tropical Montane Habitats. Trees: Structure and Function, 17, 400-406.

[15]   Huc, R., Ferhi, A. and Guehl, J.M. (1994) 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, 297-305.

[16]   Abrams, M.D. (1988) Comparative Water Relations of Three Successional Hardwood Species in Central Wisconsin. Tree Physiology, 4, 263-273.

[17]   Sobrado, M.A. (2008) Leaf and Photosynthetic Characteristics of Pioneer and Forest Species in Tropical Montane Habitats. Photosynthetica, 46, 604-610.

[18]   Baruch, Z., Hernandez, A.B. and Montilla, M.G. (1989) Dinámica de Crecimiento, Fenología y Repartición de Biomasa en Gramíneas Nativas e Introducidas en una Sabana Neotropical. Ecotrópicos, 2, 1-13.

[19]   Tyree, M.T. and Hammel, H.T. (1972) The Measurement of the Turgor Pressure and the Water Relations of Plants by the Pressure-Bomb Technique. Journal of Experimental Botany, 23, 267-282.

[20]   Turner, N.C. (1981) Techniques and Experimental Approaches for the Measurement of Plant Water Status. Plant and Soil, 58, 339-366

[21]   Melkonian, J.J., Wolfe, J. and Stenponkus, P.L. (1982) Determination of the Volumetric Modulus of Elasticity of Wheat Leaves by Pressure-Volume Relations and the Effect of Drought Conditioning. Crop Science, 22, 116-123.

[22]   Maréchaux, I., Bartlett, M., Sack, L., Baraloto, C., Engel, J., Joetzjer, E. and Chave, J. (2015) Drought Tolerance as Predicted by Leaf Water Potential at Turgor Loss Point Varies Strongly Across Species Within an Amazonian Forest. Functional Ecology.

[23]   Abrams, M.D. (1988) Sources of Variation in Osmotic Potentials with Special Reference to North American Tree Species. Forest Science, 34, 1030-1046.

[24]   Cheung, Y.N.S., Tyree, M.T. and Dainty, J. (1975) Water Relations Parameters on Single Leaves Obtained in a Pressure Bomb and Some Ecological Interpretations. Canadian Journal of Botany, 53, 1342-1346.

[25]   Dainty, J. (1972) Plant Cell Water Relations: The Elasticity of the Cell Wall. Proceedings of the Royal Society of Edinburgh, Section A, Mathematical and Physical Sciences, 70, 89-93.

[26]   Saito, T. and Terashima, I. (2004) Reversible Decreases in the Bulk Elastic Modulus of Mature Leaves of Deciduous Quercus Species Subjected to Two Drought Treatments. Plant, Cell and Environment, 27, 863-873.

[27]   Bolaños, J.A. and Longstreth, D.J. (1984) Salinity Effects on Water Potential Components and Bulk Elastic Modulus of Alternanthera philoxeroides (Mart.) Griseb. Plant Physiology, 75, 281-284.

[28]   Clifford, S.C., Stefan, S.K., Corlett, J.E., Jossi, S., Sankhla, N., Popp, M. and Jones, H.G. (1998) The Role of Solute Accumulation, Osmotic Adjustment and Changes in Cell Wall Elasticity in Drought Tolerance in Ziziphus mauritiana (Lamk.). Journal of Experimental Botany, 49, 967-977.

[29]   Sobrado, M.A. (1986) Aspects of Tissue Water Relations and Seasonal Changes of Leaf Water Potential Components of Evergreen and Deciduous Species Coexisting in Tropical Dry Forests. Oecologia, 68, 413-416.

[30]   Xingdon, H.E., Peifang, C., Yubao, G., Jianguo, L., Haitao, W., Pingping, X. and Xu, Z. (2007) Drought Resistance of Four Grasses Using Pressure-Volume Curve. Frontiers in Biology China, 2, 425-430.