Claim · model-written summary
At 1 mM external malate, carrot tissue uptake was linear over time.
- Taxon
- carrot
Daucus carotat0 - Treatment
- 1 mM external malatee0
- Outcome
- total uptake is linear with timee0
Not reportedMaterialGeneCompoundOrgan / stageInteractorInteractor roleSecond interactorSecond interactor roleComparatorSettingDirectionValueQualifier
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At 1 mM external malate total uptake is linear with time”
t0“Carrot”
Title
The Kinetics of Bicarbonate and Malate Exchange in Carrot and Barley Root Cells
W. J. CRAM; G. G. LATIES Journal of Experimental Botany 1974. doi:10.1093/jxb/25.1.11
Other claims from this paper (14)
- Observation Two-exponential fits to the two radiocarbon-loss plots gave inconsistent half times and were judged invalid.
- Observation A three-component model fit both radiocarbon-loss plots with equal rate constants and theoretically related intercepts.
- Observation The first fitted rate constant was about 7 h−1 and was attributed to cellular bicarbonate and carbon dioxide.
- Observation The second fitted rate constant was 1.5 h−1 and was attributed to cytoplasmic malate.
- Observation The third fitted rate constant was below 0.1 h−1 and was attributed to vacuolar malate.
- Observation The radiocarbon-loss data permit calculation of bicarbonate and carbon dioxide influx across the plasmalemma.
- Observation The data permit calculation of malate influx across the tonoplast during accumulation of endogenous malate.
- Observation At 1 mM external malate, uptake appeared limited by and equal to plasmalemma influx.
- Association At higher external malate concentrations, carbon dioxide evolution saturated.
- Association At higher external malate concentrations, tissue accumulation continued to rise.
- Observation Tonoplast malate influx did not saturate at high external malate concentrations.
- Observation Net malate efflux was very small but measurable.
- Observation External malate, chloride, nitrate, and sulfate did not stimulate efflux of radiolabeled malate.
- Observation The authors infer an absence of plasmalemma systems exchanging internal malate for the tested anions.