Seasonal patterns of nitrogen, phosphorus and potassium utilization by three Pinguicula species

Allocation of the nutrients N, P and K to reproductive tissue was investigated in three species of Pinguicula from the subarctic part of Scandinavia. These species have contrasting distribution: Pinguicula alpina L. grows on calcareous soils, Pinguicula villosa L. on nutrient-poor bogs and Pinguicula vulgaris L. is widely distributed. For flowering individuals, the relative allocation of nutrients to sexual reproduction was lowest for P. alpina (42-45%) and highest for P. villosa (56-68%). Expressed on a population basis, P. vulgaris had the largest relative reproductive allocation (9.3-12%) and P. villosa the smallest (7.4-8.6%). Pinguicula villosa allocated a larger proportion of dry matter than nutrients to reproduction while the other two species allocated similar proportions of all resources studied to reproduction. The proportion of the maximum nutrient pool lost through reproductive organs, leaves and roots ranged from 0% (P in non-flowering specimens of P. vulgaris) to 82% (K in flowering P. alpina). Flowering individuals lost a larger fraction of their nutrient pool than non-flowering (68% versus 42%, means for all species and nutrients).