Physiological Mechanisms of Drought Resistance in Four Native Ornamental Perennials

摘要: Understanding physiological drought resistance mechanisms in ornamentals may help growers and landscapers minimize plant water stress after wholesale production. We characterized the of four potted, native, ornamental perennials: purple coneflower (Echinacea purpurea (L.) Moench), orange (Rudbeckia fulgida var. Sullivantii (Beadle & Boynt.) Cronq.), beebalm (Monarda didyma L.), swamp sunflower (Helianthus angustifolius L.). measured a) stomatal conductance leaves drying plants, b) lethal potential relative content, c) leaf osmotic adjustment during period. Maintenance opening as dry, low status values, ability to osmotically adjust indicate tolerance, with reverse indicating avoidance. Echinacea had (ψ L ) content (RWC) at closure ψ RWC, results high dehydration other three species. Rudbeckia a similar displayed relatively large adjustment. Monarda highest RWC an intermediate , yet Helianthus became desiccated more rapidly than species, despite having closure; it very little adjustment, tolerance. Despite differences sensitivity, all perennials fall predominantly drought-avoidance category, tolerance previously reported for wide range