TY - JOUR
T1 - In vivo 23Na and 31P NMR measurement of a tonoplast Na+/H+ exchange process and its characteristics in two barley cultivars
AU - Fan, T. W.M.
AU - Higashi, R. M.
AU - Norlyn, J.
AU - Epstein, E.
PY - 1989
Y1 - 1989
N2 - A Na+ uptake-associated vacuolar alkalinization was observed in roots of two barley cultivars (Arivat and the more salt-tolerant California Mariout) by using 23Na and 31P in vivo NMR spectroscopy. A NaCl uptake-associated broadening was also noted for both vacuolar P(i) and intracellular Na NMR peaks, consistent with Na+ uptake into the same compartment as the vacuolar P(i). A close coupling of Na+ with H+ transport (presumably the Na+/H+ antiport) in vivo was evidenced by qualitative and quantitative correlations between Na+ accumulation and vacuolar alkalinization for both cultivars. Prolongation of the low NaCl pretreatment (30 mM) increased the activity of the putative antiport in Arivat but reduced it in California Mariout. This putative antiport also showed a dependence on NaCl concentration for California Mariout but not for Arivat. No cytoplasmic acidification accompanied the antiporter activity for either cultivar. The response of adenosine phosphates indicated that ATP utilization exceeded the capacity for ATP synthesis in Arivat, but the two processes seemed balanced in California Mariout. These comparisons provide clues to the role of the tonoplast Na+/H+ antiport and compensatory cytoplasmic adjustments including pH, osmolytes, and energy phosphates in governing the different salt tolerance of the two cultivars.
AB - A Na+ uptake-associated vacuolar alkalinization was observed in roots of two barley cultivars (Arivat and the more salt-tolerant California Mariout) by using 23Na and 31P in vivo NMR spectroscopy. A NaCl uptake-associated broadening was also noted for both vacuolar P(i) and intracellular Na NMR peaks, consistent with Na+ uptake into the same compartment as the vacuolar P(i). A close coupling of Na+ with H+ transport (presumably the Na+/H+ antiport) in vivo was evidenced by qualitative and quantitative correlations between Na+ accumulation and vacuolar alkalinization for both cultivars. Prolongation of the low NaCl pretreatment (30 mM) increased the activity of the putative antiport in Arivat but reduced it in California Mariout. This putative antiport also showed a dependence on NaCl concentration for California Mariout but not for Arivat. No cytoplasmic acidification accompanied the antiporter activity for either cultivar. The response of adenosine phosphates indicated that ATP utilization exceeded the capacity for ATP synthesis in Arivat, but the two processes seemed balanced in California Mariout. These comparisons provide clues to the role of the tonoplast Na+/H+ antiport and compensatory cytoplasmic adjustments including pH, osmolytes, and energy phosphates in governing the different salt tolerance of the two cultivars.
KW - Na/H antiport
KW - energy phosphates
KW - intracellular pH
KW - roots
KW - salt tolerance
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U2 - 10.1073/pnas.86.24.9856
DO - 10.1073/pnas.86.24.9856
M3 - Article
C2 - 2557632
AN - SCOPUS:0024854499
SN - 0027-8424
VL - 86
SP - 9856
EP - 9860
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 24
ER -