Premium
Kinetic analyses of plant water relocation using deuterium as tracer – reduced water flux of Arabidopsis pip2 aquaporin knockout mutants
Author(s) -
Da Ines O.,
Graf W.,
Franck K. I.,
Albert A.,
Winkler J. B.,
Scherb H.,
Stichler W.,
Schäffner A. R.
Publication year - 2010
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/j.1438-8677.2010.00385.x
Subject(s) - arabidopsis , transpiration , biology , aquaporin , arabidopsis thaliana , flux (metallurgy) , water transport , botany , mutant , tracer , biophysics , microbiology and biotechnology , water flow , chemistry , biochemistry , gene , soil science , photosynthesis , environmental science , physics , organic chemistry , nuclear physics
Due to reduced evaporation and diffusion of water molecules containing heavier isotopes, leaf water possesses an elevated 18 O or 2 H steady‐state content. This enrichment has been exploited in plant physiology and ecology to assess transpiration and leaf water relations. In contrast to these studies, in this work the 2 H content of the medium of hydroponically grown Arabidopsis thaliana was artificially raised, and the kinetics of 2 H increase in the aerial parts recorded during a short phase of 6–8 h, until a new equilibrium at a higher level was reached. A basic version of the enrichment models was modified to establish an equation that could be fitted to measured leaf 2 H content during uptake kinetics. The fitting parameters allowed estimation of the relative water flux q leaf into the Arabidopsis rosette. This approach is quasi‐non‐invasive, since plants are not manipulated during the uptake process, and therefore, offers a new tool for integrated analysis of plant water relations. The deuterium tracer method was employed to assess water relocation in Arabidopsis pip2;1 and pip2;2 aquaporin knockout plants. In both cases, q leaf was significantly reduced by about 20%. The organ and cellular expression patterns of both genes imply that changes in root hydraulic conductivity, as previously demonstrated for pip2;2 mutants, and leaf water uptake and distribution contributed in an integrated fashion to this reduced flux in intact plants.