Abstract
Leaf-sheath pulvini of excised segments from oat (Avena sativa L.) were induced to grow by treatment with 10 μM indole-3-acetic acid (IAA), gravistimulation, or both, and the effects of calcium, EGTA, and calcium channel blockers on growth were evaluated. Unilaterally applied calcium (10 mM CaCl2) significantly inhibited IAA-induced growth in upright pulvini but had no effect on growth induced by either gravity or gravity plus IAA. Calcium alone had no effect on upright pulvini. The calcium chelator EGTA alone (10 mM) stimulated growth in upright pulvini. However, EGTA had no effect on either IAA-or gravity-induced growth but slightly diminished growth in IAA-treated gravistimulated pulvini. The calcium channel blockers lanthanum chloride (25 mM), verapamil (2.5 mM), and nifedipine (2.5 mM) greatly inhibited growth as induced by IAA (⩾50% inhibition) or IAA plus gravity (20% inhibition) but had no effect on gravistimulated pulvini. Combinations of channel blockers were similar in effect on IAA action as individual blockers. Since neither calcium ions nor EGTA significantly affected the graviresponse of pulvini, we conclude that apoplastic calcium is unimportant in leaf-sheath pulvinus gravitropism. The observation that calcium ions and calcium channel blockers inhibit IAA-induced growth, but have no effect on gravistimulated pulvini, further supports previous observations that gravistimulation alters the responsiveness of pulvini to IAA.
Similar content being viewed by others
References
Arslan-Cerim N (1966) The redistribution of radioactivity in geotropically stimulated hypocotyls of Helianthus annuus pretreated with radioactive calcium. J Exp Bot 17:236–240
Biro RL, Hale CC, Wiegand OF, Roux SJ (1982) Effects of chlorpromazine on gravitropism in Avena coleoptiles. Ann Bot 50:737–745
Brock TG, Kapen EH, Ghosheh NS, Kaufman PB (1991) Dynamics of auxin movement in the gravistimulated leafsheath pulvinus of oat (Avena saliva). J Plant Physiol 138:57–62
Brock TG, Kaufman PB (1988a) Altered growth response to exogenous auxin and gibberellic acid by gravistimulation in pulvini of Avena sativa. Plant Physiol 87:130–133
Brock TG, Kaufman PB (1988b) Competency for graviresponse in the leaf-sheath pulvinus of Avena sativa: Onset to loss. Amer J Bot 75:1672–1677
Brock TG, Kaufman PB (1988c) Effect of dark pretreatment on the kinetics of response of barley pulvini to gravistimulation and hormones. Plant Physiol 88:10–12
Brock TG, Kaufman PB (1990) Movement in grass shoots. In: Satter RL, Gorton HL, Vogelmann TC (eds) The pulvinus: Motor organ for leaf movement. Academic Press, New York, pp 59–71
Brock TG, Lu CR, Ghosheh NS, Kaufman PB (1989) Localization and pattern of graviresponse across the pulvinus of barley (Hordeum vulgare). Plant Physiol 91:744–748
Cholodny N (1926) Beitrage zur Analyse der geotropischen Reaktion. Jahrb Wiss Bot 65:447–459
Dayanandan P, Hebard FV, Baldwin VD, Kaufman PB (1977) Structure of gravity-sensitive sheath and internodal pulvini in grass shoots. Amer J Bot 64:1189–1199
De Guzman CC, Dela Fuente RK (1984) Polar calcium flux in sunflower hypocotyl segments. I. The effect of auxin. Plant Physiol 76:347–352
Dela Fuente RK (1984) Role of calcium in the polar secretion of indoleacetic acid. Plant Physiol 76:342–346
Evans ML, Moore R, Hasenstein K-H (1986) How roots respond to gravity. Sci Amer 254:112–118
Goswami KKA, Audus LJ (1976) Distribution of calcium, potassium and phosphorous in Helianthus annuus hypocotyls and Zea mays coleoptiles in relation to tropic stimuli and curvatures. Ann Bot 40:49–64
Kaufman PB, Brock TG, Song I, Rho YB, Ghosheh NS (1987) How cereal grass shoots perceive and respond to gravity. Amer J Bot 74:1446–1457
Kaufman PB, Song I (1987) Hormones and the orientation of growth. In: Davies PJ (ed) Plant hormones and their role in plant growth and development. Martinus Nijhoff Publishers, Dordrecht, pp 375–392
Lee JS, Evans ML (1985) Polar transport of auxin across gravistimulated roots and maize and its enhancement by calcium. Plant Physiol 77:824–827
Lee JS, Mulkey TJ, Evans ML (1983a) Gravity-induced polar transport of calcium across root tips of maize. Plant Physiol 73:874–876
Lee JS, Mulkey TJ, Evans ML (1983b) Reversible loss of gravitropic sensitivity in maize roots after tip application of calcium chelators. Science 220:1375–1376
Lee JS, Mulkey TJ, Evans ML (1984) Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors. Planta 160:536–543
Maeda I (1958) The effects of growth regulators on the geotropism of the leaf sheath basal region in wheat. J Exp Bot 9:343–349
Moore R, Evans ML (1986) How roots perceive and respond to gravity. Amer J Bot 73:574–587
Osborne DJ, Wright M (1977) Gravity-induced cell elongation. Proc Royal Soc London Ser B 199:551–564
Pickard B (1985) Role of hormones, protons and calcium in geotropism. In: Pharis RP, Reid DM (eds) Encyclopedia of plant physiology (new series), vol 11. Springer-Verlag, Berlin, pp 179–261
Slocum RD, Roux SJ (1983) Cellular and subcellular localization of calcium in gravistimulated oat coleoptiles and its possible significance in the establishment of tropic curvature. Planta 157:481–492
Song I, Lu CR, Brock TG, Kaufman PB (1988) Do starch statoliths act as the gravisensors in cereal grass pulvini? Plant Physiol 86:1155–1162
Stinemetz CL, Evans ML (1986) The effect of calmodulin antagonists on the asymmetric redistribution of Ca+ and IAA following gravistimulation. Proc Amer Soc Grav and Space Biol, 2nd Annual Symposium of the NASA Space Biology Program, Charlottesville, VA, p 9
Went FW, Thimann KV (1926) Phytohormones. Macmillan, New York
Wright M, Mousdale DMA, Osborne DJ (1978) Evidence for a gravity regulated level of endogenous auxin controlling cell elongation and ethylene production during geotropic bending in grass nodes. Biochem Physiol Pflanzen 172:581–596
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Brock, T.G., Burg, J., Ghosheh, N.S. et al. The role of calcium in growth induced by indole-3-acetic acid and gravity in the leaf-sheath pulvinus of oat (Avena sativa). J Plant Growth Regul 11, 99–103 (1992). https://doi.org/10.1007/BF00198021
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00198021