High-affinity sodium uptake in land plants

High-affinity sodium uptake in land plants.

High-affinity Na(+) uptake in plants and its mediation by HKT transporters have been studied in very few species. This study expands the knowledge of high-affinity Na(+) uptake in land plants for both uptake characteristics and involvement of HKT transporters. In non-flowering plants, we analyzed the Na(+) content of wild mosses, carried out experiments on K(+) and Na(+) uptake in the micromola...

High-affinity potassium uptake in plants.

oocyte]. Oocytes were incubated for 24 to 48 hours, treated with coelenterazine [10 ,uM coelenterazine (Molecular Probes, Eugene, OR) and 30 p.M reduced glutathione in OR-2 media (no calcium)] for 2 to 3 hours with gentle orbital shaking in the dark at 18°C, and retumed to ND-86 medium with calcium (maintained in the dark with shaking) until measurements were initiated. For luminometer measurem...

High-affinity potassium and sodium transport systems in plants.

All living cells have an absolute requirement for K+, which must be taken up from the external medium. In contrast to marine organisms, which live in a medium with an inexhaustible supply of K+, terrestrial life evolved in oligotrophic environments where the low supply of K+ limited the growth of colonizing plants. In these limiting conditions Na+ could substitute for K+ in some cellular functi...

High-Affinity Potassium Uptake Transporter from Higher Plants

Novel p-type ATPases mediate high-affinity potassium or sodium uptake in fungi.

Fungi have an absolute requirement for K+, but K+ may be partially replaced by Na+. Na+ uptake in Ustilago maydis and Pichia sorbitophila was found to exhibit a fast rate, low Km, and apparent independence of the membrane potential. Searches of sequences with similarity to P-type ATPases in databases allowed us to identify three genes in these species, Umacu1, Umacu2, and PsACU1, that could enc...