Original paper
Mineral nutrition in aquatic carnivorous plants: effect of carnivory, nutrient reutilization and K+ uptake
Adamec, Lubomír
Fundamental and Applied Limnology Volume 188 Nr. 1 (2016), p. 41 - 49
published: May 1, 2016
ArtNo. ESP141018801003, Price: 29.00 €
Abstract
Processes of mineral nutrition were studied in the shoots of 5 rootless species of aquatic carnivorous plants. Aldrovanda vesiculosa and Utricularia australis shoots pre-cultivated with or without prey exhibited zero or very low NO3 –uptake (for 4 h) in both prey variants, while NH4 +uptake in both species was around 1 mmol kg–1 FWh–1and was slightly higher in the –Prey variants. Thus, both species preferred NH4 +uptake over NO3 –. Phosphate uptake ranged between 26–91 μmol kg–1 FW h–1 and was significantly higher in the +Prey variant only in A. vesiculosa. K+ uptake by shoots at 15 μM NH4 +was very low or rather distinctly negative due to an uptake interference with NH4 +. K +uptake in light from a NH4 +-free medium was always greatest in the apical (or photosynthetic in U. stygia) shoot segments, and ranged from 0.07–0.61 mmol kg–1FW h–1 in 5 aquatic carnivorous species, while it was always the lowest or even negative (in U. vulgaris and U. stygia) in basal or carnivorous shoot segments. A. vesiculosa and U. australis shoots grown at high (83 μM) and very low K+ concentration (2–4 μM) showed no growth decrease at the low K+ concentration. Relatively efficient N and P reutilization (28–62 %) but very low or negative K reutilization (5.3 to –8.5%) was found in senescent shoot segments in both species. The results confirmed that prey capture in aquatic carnivorous plants has significant effects on the uptake of mineral N and P from the ambient water. It is not clear whether or not these changes are due to alterations in the shoot N and P content. However, it is apparent that the physiological responses of aquatic species to prey capture are highly species-specific.
Keywords
aldrovanda vesiculosa • feeding on prey • utricularia spp • k+ uptake • shoot nutrient content • shoot polarity • mineral nutrient uptake • p and k reutilization • n