Hydraulic lift in a neotropical savannah

MOREIRA M.Z., SCHOLZ F.G., BUCCI S.J., STERNBERG L.S., GOLDSTEIN G., MEINZER F.C., AND FRANCO A.C

FUNCTIONAL ECOLOGY

British Society

Año: 2003 vol. 17 p. 573 - 581

0269-8463

1. We report here our findings on hydraulic lift in the savanna vegetation of central Brazil (Cerrado). We used both a heat pulse and isotopic labeling techniques to determine whether hydraulic lift occurred in two common species, and whether neighboring small shrubs and trees were utilizing this water. 2. Both techniques showed uptake of water by tap roots and reverse flow of water in lateral roots.  3. Roots transferred hydraulically lifted water to the soil and small shrubs and trees neighboring the labeled individuals were labeled by deuterated water. 4. Isotopic mass balance equations and sap flow measurements, however, showed that water taken up by the central tap root in each individual measured here constitutes only a small percentage of total flux of water through the treated plants. Mass balance equations also indicate that small shrubs and trees neighboring the treated plant only utilized a few thousands of a percent of the label. 5. Hydraulic lift through the taproot of the studied species, therefore, seems to be of little consequence to water relations of neighboring small shrubs and trees.