EFFECTS OF SOIL WATERLOGGING ON THE ENERGY STATUS AND DISTRIBUTION OF SALIX NIGRA AND S. EXIGUA (SALICACEAE) IN THE ATCHAFALAYA RIVER BASIN OF LOUISIANA

Abstract

The influence of soil waterlogging on the distribution and energy status of Salix nigra and S. exigua were studied in the field and laboratory. Differential flooding in natural stands of Salix spp. and under controlled conditions in the greenhouse demonstrated that S. nigra was more tolerant of waterlogged soil conditions than was S. exigua. Salix nigra exhibited a significantly higher leaf energy status and greater ability to oxidize waterlogged soil when flooded than did S. exigua. However, S. exigua appeared to be more tolerant of moisture stress than S . nigra as indicated by the significantly higher leaf resistances to water vapor exchange and higher leaf water potentials of S. exigua. These data support the theory that the reason S. nigra inhabits lower elevation sites than S . exigua in the Atchafalaya River Basin may be the differential tolerance of these two species to soil waterlogging on one extreme and moisture deficiencies on the other.