Ion fluxes across the pitcher walls of three Bornean Nepenthes pitcher plant species : flux rates and gland distribution patterns reflect nitrogen sequestration strategies
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Authors
Moran, Jonathan A.
Hawkins, Barbara J.
Gowen, Brent E.
Robbins, Samantha L.
Issue Date
2010
Type
Article
Language
en
Subject
Digestive Glands , H+ , Ion Flux , MIFE , Nepenthes , NH+4 , phytotelm , pitcher plant , scanning electron microscopy
Alternative Title
Abstract
Nepenthes pitcher plant species differ in their prey capture strategies, prey capture rates, and pitcher longevity. In
this study, it is investigated whether or not interspecific differences in nutrient sequestration strategy are reflected
in the physiology and microstructure of the pitchers themselves. Using a non-invasive technique (MIFE), ion fluxes in
pitchers of Nepenthes ampullaria Jack, Nepenthes bicalcarata Hook.f., and Nepenthes rafflesiana Jack were
measured. Scanning electron microscopy was also used to characterize the distribution of glandular and other
structures on the inner pitcher walls. The results demonstrate that nutrient sequestration strategy is indeed mirrored
in pitcher physiology and microstructure. Species producing long-lived pitchers with low prey capture rates (N.
ampullaria, N. bicalcarata) showed lower rates of NH4
+ uptake than N. rafflesiana, a species producing short-lived
pitchers with high capture rates. Crucially, species dependent upon aquatic commensals (N. ampullaria, N.
bicalcarata) actively manipulated H+ fluxes to maintain less acid pitcher fluid than found in ‘typical’ species; in
addition, these species lacked the lunate cells and epicuticular waxes characteristic of ‘typical’ insectivorous
congeners. An unexpected finding was that ion fluxes occurred in the wax-covered, non-glandular zones in N.
rafflesiana. The only candidates for active transport of aqueous ions in these zones appear to be the epidermal cells
lying beneath the lunate cells, as these are the only sites not visibly coated with epicuticular waxes.
Description
Citation
Moran, J. A., Hawkins, B. J., Gowen, B. E., & Robbins, S. L. (2010). Ion fluxes across the pitcher walls of three Bornean Nepenthes pitcher plant species: flux rates and gland distribution patterns reflect nitrogen sequestration strategies. Journal of Experimental Botany, 61:5, 1365-1374. doi: 10.1093/jxb/erq004
Publisher
Journal of Experimental Botany