WATER RELATIONS OF SALVIA-SPLENDENS BONFIRE AS INFLUENCED BY POTASSIUM NUTRITION AND MOISTURE STRESS CONDITIONING

The influence of K nutrition (25, 75, 150, 300, 450, and 600 mg K/liter) and moisture stress conditioning (MSC) (exposing plants to four sublethal dry-down cycles) on leaf water relations, evapotranspiration, growth, and nutrient content was determined for salvia (Salvia splendens F. Sellow 'Bonfire'). Potassium concentration and MSC had an interactive influence on osmotic potential at full (pi-100) and zero (pi-0) turgor. Differences in osmotic potential between MSC and non-MSC plants for pi-100 and pi-0 increased with increasing K concentration. Increasing K concentration and MSC resulted in active osmotic adjustment and, consequently, increased cellular turgor potentials. Foliar K content increased with increasing K concentration and MSC. High K concentrations and MSC both reduced plant evapotranspiration on a per-plant and per-unit-leaf-area basis. Greatest shoot dry weight occurred for plants grown with 300 mg K/liter and non-MSC. Total leaf area increased with increasing K concentration, but MSC had little effect.