Biophysical and life-history determinants of hydraulic lift in Neotropical savanna trees
| Authors: | F.G. Scholz, S.J. Bucci, G. Goldstein, M.Z. Moreira, Frederick Meinzer, J.-C. Domec, R. Villalobos-Vega, A.C. Franco, F. Miralles-Wilhelm |
| Year: | 2008 |
| Type: | Scientific Journal |
| Station: | Pacific Northwest Research Station |
| DOI: | https://doi.org/10.1111/j.1365-2435.2008.01452.x |
| Source: | Functional Ecology DOI: 10.1 111/j.1365-2435.2008.01452.x |
Abstract
Measurements of sap flow in tap roots, lateral roots and stems, as well as stable isotope labeling techniques were used to determine the occurrence and relative magnitude of hydraulic lift in several individuals of nine co-occurring Brazilian savanna (Cerrado) tree species differing in life-history traits, and to assess physical and biological determinants of this process at the tree and ecosystem level. The occurrence of reverse sap flow observed in deciduous and brevideciduous species during the dry season was consistent with hydraulic lift. The evergreen species did not exhibit reverse flow. Consistent with their ability to carry out hydraulic lift, the brevideciduous and deciduous species had both shallow and tap roots (dimorphic root systems), whereas the evergreen species had mostly deep roots (monomorphic root systems). There was an inverse relationship between rates of reverse sap flow and seasonal loss of hydraulic conductivity in lateral roots, suggesting that hydraulic lift in Cerrado woody plants may help maintain the functionality of the lateral roots in exploring dry and nutrient-rich superficial soil layers without directly enhancing the amount of water uptake.