Establishment growth and bud-bank formation in Epilobium angustifolium: the effects of nutrient availability, plant injury, and environmental heterogeneity

Abstract

Plant establishment is a risky phase of the plant life cycle because juvenile individuals cannot produce seeds and their vegetative regeneration is constrained by a lack of reserve meristems and carbon storage. On the other hand, conditions in the period following establishment, during establishment growth, affect the vegetative regeneration and clonal growth of the plant in the future. Bud-bank formation was studied in a root-sprouting clonal herb Epilobium angustifolium L. (= Chamaenerion angustifolium (L.) Scop.), a plant with root buds differing in size and number of leaf primordia, during establishment growth. We tested two hypotheses: (i) large and small buds differ in their response to stress and disturbance, and (ii) a heterogeneous soil environment does not affect bud-bank formation. We rejected both hypotheses because (i) the proportion of small buds was about 80% and was not affected by nutrient availability and substrate heterogeneity, and (ii) plants produced more buds per root biomass under conditions of nutrient shortage in both homogeneous and heterogeneous substrates, but the effect was masked by lower root biomass. Thus, bud production for the whole plant was not affected by either nutrient availability or soil heterogeneity and reached 20 to 100 buds per plant.