Plant Biol (Stuttg) 2006; 8(6): 765-769
DOI: 10.1055/s-2006-924540
Research Paper

Georg Thieme Verlag Stuttgart KG · New York

Respiration and Photosynthesis of Bladders and Leaves of Aquatic Utricularia Species

L. Adamec1
  • 1Institute of Botany of the Academy of Sciences of the Czech Republic, Section of Plant Ecology, Dukelská 135, 379 82 Třeboň, Czech Republic
Further Information

Publication History

Received: September 28, 2005

Accepted: August 10, 2006

Publication Date:
03 January 2007 (online)

Preview

Abstract

In aquatic species of carnivorous Utricularia, about 10 - 50 % of the total biomass consists of bladders. Utricularia bladders are physiologically very active organs though their chlorophyll content may greatly be reduced. To specify energetic costs of carnivory, respiration (RD) and net photosynthetic rate (PN) were compared in bladders and leaves or shoot segments of six aquatic Utricularia species with differentiated (U. ochroleuca, U. intermedia, U. floridana) or non-differentiated shoots (U. vulgaris, U. australis, U. bremii) under optimum conditions (20 °C, [CO2] 0.20 mM, 400 µmol m-2 s-1 PAR). RD of bladders of six Utricularia species (5.1 - 8.6 mmol kg-1 FW h-1) was 75 - 200 % greater, than that in leaves in carnivorous or photosynthetic shoots (1.7 - 6.1 mmol kg-1 FW h-1). Within individual species, this difference was statistically significant at p < 0.002 - 0.01. However, PN in photosynthetic leaves/shoots (40 - 117 mmol kg-1 FW h-1) exceeded that in bladders (5.2 - 14.7 mmol kg-1 FW h-1) 7 - 10 times. RD of empty bladders of U. ochroleuca was exactly the same as that in bladders containing prey. Though Utricularia bladders are essential for uptake of growth limiting mineral nutrients N and P from prey as the main benefit of carnivory, the current results support previous work showing that bladder function requires greater metabolic (maintenance) cost and very low photosynthetic efficiency (great RD : PN ratio).

References

L. Adamec

Institute of Botany of the Academy of Sciences of the Czech Republic
Section of Plant Ecology

Dukelská 135

379 82 Třeboň

Czech Republic

Email: adamec@butbn.cas.cz

Guest Editor: S. Porembski