Effect of Nutrients on Growth Rate and Carbohydrate Storage in Oxytropis sericea: A Test of the Carbon Accumulation Hypothesis.

The pool of storage carbohydrates in plants may be formed in competition with allocation to growth ("true reserves") or, where growth is inhibited by external factors, with no cost to growth ("accumulated reserves"). The latter hypothesis was addressed using Oxytropis sericea, a perennial herb from the Rocky Mountains. To generate variation in growth rate, greenhouse-cultivated plants were assigned to low or high nutrient levels in 2 yr. Age of plants was also varied either by conducting consecutive harvests (1996) or using plants of different initial age (1997). In both years, plants from the high-nutrient group attained larger vegetative biomass than plants in the low-nutrient group and also displayed an overall lower carbon allocation to storage, consistent with the accumulation hypothesis.