Ridge crest versus swale: contrasting plant–water relations and performance indexes in two understory plant species in a coastal maritime forest

[摘要] Coastal-ridge plains are progradational landforms composed of elevated ridges and low-lying swales. The transitions between ridges and swales are steep, promoting dynamic shifts between xeric and mesic systems. Two understory plants that co-occur in ridge plains of North American mid-Atlantic maritime forests are Sabal minor and Ilex vomitoria . As coastal-ridge plains foster varying amounts of surface and sub-surface water driven largely by topography, the purpose of this study was to evaluate plant–water relations and chlorophyll a fluorescence in these two species. Ridge plants had lower leaf- and xylem-water potentials, lower osmotic potential ( I. vomitoria ), and lower symplastic water content ( S. minor ). Although there were no differences in potential- and effective-quantum yields, there were decreases in fluorescence performance index for ridge I. vomitoria and swale S. minor . While the data support potential water-stress conditions in ridge plants of both species, the data also suggest that I. vomitoria and S. minor use different physiological processes to tolerate hydrologically dynamic ridge–swale maritime forests.

[学科分类] 纳米科学和纳米技术

[关键词] elastic modulus;fluorescence;Ilex vomitoria;osmotic potential;Sabal minor;water potential