Physiological, morphological and growth responses to rhizosphere hypoxia by seedlings of North American bottomland oaks

Abstract

Bottomland oak species of the S United States are distributed along topographical gradients in floodplains. Becuuse differences in soil aeration are associated with these gradients, the authors tested the hypothesis that oak species will exhibit diverging resistances to rhizosphere hypoxia. Four species which occupy different sites in floodplains, Quercus lyrata, Q. laurifolia, Q. phellos, and Q. nigra, were used in two experiments designed to examine seedling resonses during establishment and late in the first growing season. Evidence of oaks differing in resistance to rhizosphere hypoxia is presented, and results are discussed in relation to species distribution in floodplains.