Foliar mineral nutrient uptake in carnivorous plants: what do we know and what should we know?

Abstract

Carnivorous plants (CPs) usually growin nutrient-poor, wet or aquatic environ-ments and possess foliar traps which cap-ture animal prey (Juniper et al., 1989).There are about 600 terrestrial and 50aquatic or amphibious species of CPswhich supplement the conventional min-eral nutrient uptake by roots or shootsfrom their environment by the absorp-tion of nutrients (mainly N, P, K, Mg)from prey carcasses captured by theirtraps (for the review, see Adamec, 1997,2002, 2011a). Among vascular plants, theyprobably have the greatest capacity offoliar mineral nutrient uptake which cancover 5–100% of their seasonal N and Pgain (consumption) but only 1–16% forK from captured prey (Adamec, 1997,2011a). The main ecophysiological strat-egy of terrestrial species as S-strategistsis slow growth and very effective min-eral nutrient economy. Due to new dis-coveries (e.g., Spomer, 1999; Andersonand Midgley, 2003; Pavloviˇc, 2012 ), theboundary between carnivory and non-carnivory remains slightly blurred. Inline with recent findings, the concept ofplant carnivory should be defined withan emphasis on the main benefit ofcarnivory—the uptake of mineral nutri-ents from prey(directly or indirectly) cap-tured bytraps.Moreover,asallplantswithglandularhairsarepotentially carnivorous(Spomer, 1999), a defining statement thatfoliar nutrient uptake from prey must be“ecologically significant” for CPs seemsreasonable (Plachno et al., 2009)whereascriteriasuchasproducingtheirowndiges-tive enzymes or prey attraction are onlymarginal.