XVI International Botanical Congess

Alpine plants are stress-tolerators, with conservative resource allocation patterns. Oxytropis sericea (Fabaceae) from the Colorado Rockies maintains a large carbohydrate storage pool, which allows its rapid leaf and inflorescence growth at the start of the season. We hypothesized that carbohydrate reserves are involved in mediating future costs of reproduction in this plant. Carbohydrate stores, however, were not depleted by reproduction. On the other hand, reproduction lowered nitrogen and phosphorus content in perennial organs. This finding, together with enhancement of growth by nutrient addition, indicates that mineral nutrients rather than carbon constitute a limiting resource and an appropriate trade-off currency. We also suggest a role for meristem availability in mediating future costs of reproduction.