Differential responses of two Stellaria longipes ecotypes to ultraviolet-B radiation and drought stress

Enhanced ultra violet-B (UVB) radiation and water deficit affect plant growth and development. We determined the effects of UVB and drought stress oil growth parameters and chemical attributes of two ecotypes (alpine and prairie) of Stellaria longipes under controlled-environment conditions. Clonal ramets of these ecotypes were growth under three UVB levels (0, 5, and 10 kJ m(-2) d(-1)) and exposed to two watering regimes (well watered and drought stressed) for 21 days. Compared to the alpine, the prairie ecotype was taller, had higher number of nodes, and greater leaf area and specific leaf weight (leaf dry weight: leaf area), which resulted in increased dry matter in this ecotype. Overall, 'prairie' was higher in total chlorophyll (Chl), but lower in Chla:b ratio, flavonoids, and ethylene, than 'alpine'. In both ecotypes, UVB and drought stress reduced growth and dry matter, whereas UVB increased carotenoids and flavonoids. Drought stress decreased ethylene evolution. These characteristics were also determined in plants growing in the field In the field-growing plants, 'prairie' had higher growth and dry matter, but lower Chla b ratio and flavonoids, than 'alpine'. The two ecotypes responded differentially to UVB and watering regime, as 'prairie' appeared to be more sensitive to UVB and drought Stress than 'alpine' (C) 2009 Elsevier GmbH. All rights reserved.