Abstract
The effects of La3+ on inward K+ channels at plasma membrane in vicia guard cells are investigated using the whole-cell patch-clamp recording mode. It is shown that La3+ on both sides of plasma membrane blocks inward K+ currents in a concentration-dependent manner, indicating that La3+ binding sites may exist on both sides of plasma membrane in guard cells in vicia. The dose response is fitted by the Michaelis-Menten relation characterized by an inhibitor constant K i of 2.56±0.25 μmol · L−1 (outside membrane) and (1.18±0.11)×10−15 mol · L−1 (inside membrane). Intracellular La3+ has much stronger inhibitory effect on inward K+ currents than extracellular La3+ does, suggesting there may exist stronger binding sites inside membrane than outside membrane. Since ion channel activities of guard cells directly affect plant stomatal movement and water status, our results imply that rare earth elements might have potential practical values in regulating plant water status and strengthening plant drought endurance.
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References
Ni Jiazuan, Bioinorganic Chemistry of Rare Earth Elements (in Chinese), 2nd ed., Beijing: Science Press, 2002, 5–26.
Nie Chengrong, Li Huashou, Li Mei et al., Influence of nitrate rare earth elements on the growth of peanut seedling under water stresss, Soil and Fertilizer (in Chinese), 2002(3): 11–14.
Hou Yuyun, Jing Lanhua, Zeng Fuli, The research of the effect of La3+ in the damage of wheat seedling leaves under drought stress, Acta Bot. Boreal-Occident Sin. (in Chinese), 2001, 21(6): 1134–1141.
Li Hesheng, Modern Plant Physiology (in Chinese), Beijing: Higher Education Press, 2002, 135–137.
Pei, Z. M., Kuchitsu, K., Ward, J. M. et al., Differential abscisic acid regulation of guard cell slow anion channels in arabidopsis wild type and abil and abi2 mutants, Plant Cell, 1997, 9: 409–423.
Schroeder, J. I., K+ transport properties of K+ channels in the plasma membrane of vicia faba guard cell, J. Gen. Physiol., 1988, 92: 667–683.
Schroeder, J. I., Fang, H. H., Inward-rectifying K+ channels in guard cell provide a mechanism for low-affinity K+ uptake, Proc. Natl.Acad. Sci.USA., 1991, 88: 11583–11587.
Hill, B., Ionic Channels of Excitable Membrane, Sundorland: Sinauner Associates Inc, 1984, 206–207.
Wei Chunying, Yang Pin, Quantitative study on La3+ influx mediated by the sodium-calcium exchange in human lymphocytes, Science in China, Ser. B, 2002, 45(6): 586–597.
Pineros, M., Tester, M., Characterization of a voltage-dependent Ca2+-selective channel from wheat roots, Planta, 1995, 195: 478–488.
Gelli, A., Blumwald, E., Hyperpolarization-activated Ca2+-permeable channels in the plasma membrane of tomato cells, J. Membrane Biol., 1997, 155: 35–45.
Dietrich, P., Dreyer, I., Wiesner, P. et al., Cation sensitivity and kinetics of guard cell potassium channels differ among species, Planta, 1998, 205: 277–287.
Grobov, A., Blatt, M. R., A steep dependence of inward-rectifying K+ channels on cytosolic free calcium concentration increase evoked by hyperpolarization in guard cells, Plant Physiol., 1999, 119:277–287.
Lewis, B. D., Spalding, E. P., Nonselective block by La3+ of arabidopsis ion channels involved in signal transduction, J. Membrane Biol., 1998,162: 81–90.
Xue Shaowu, Yang Pin, Du Huizhi, Determination of lanthanum effect on myocardiac potassium channels, Acta Chimica Sinica (in Chinese), 2002, 60(1): 169–170.
Duan, S. M., Cooke, I. M., Selective inhibition of transient K+ current by La3+in crab peptide secretory neurons, J. Neurophysiol., 1999, 81: 1848–1855.
Luan, S., Signaling drought in guard cell, Plant, Cell and Environ., 2002, 25: 229–237.
Schroeder, J. I., Allen, G. J., Hugouvieux, V. et al., Guard cell signal transduction, Annu. Rev. Plant Physiol. Plant Mol. Biol., 2001, 52: 627–658.
Xue Shaowu, Yang Pin, Pei Zhenming, The role of ion channel of plant guard cells in stomatal movements, Plant Physiol. Communications, 2004, 40(4), 489–494.
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Xue, S., Yang, P. Effects of La3+ on inward K+ channels at plasma membrane in guard cells. Sc. China Ser. B-Chem. 48, 143–147 (2005). https://doi.org/10.1360/04yb0031
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DOI: https://doi.org/10.1360/04yb0031