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Light and Electron Microscope Studies on Synergistic Interaction between Gibberellic Acid and 4-Ethoxy-1-(p-tolyl)-s-triazine-2,6 (1H, 3H)-dione in Growth of Rice Leaf Sheaths
MASAMI OGAWA, HIROSHI MIYAKE and EIZO MAEDA
Journal of Experimental Botany
Vol. 31, No. 121 (April 1980), pp. 533-544
Published by: Oxford University Press
Stable URL: http://www.jstor.org/stable/23689791
Page Count: 12
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4-Ethoxy-1-(p-tolyl)-s-triazine-2,6(1H,3H)-dione (TA) dramatically and synergistically promoted gibberellic acid-induced elongation of rice second leaf sheaths. The elongation from 84 to 132 h after sowing occurred only at the region 0—2 mm from the base in control samples, at the 0—4 mm region in TA- or GA-treated samples, and at the 0—12 mm region in TA plus GA-treated samples. The increase in elongation rate induced by TA and/or GA was greatest in the 0—2 mm region and decreased gradually toward the ligule. The longitudinal growth induced by TA and/or GA was due to the increase in cell numbers by cell division, as well as to increase in length of cells. Electron microscopic examinations revealed that TA and/or GA suppressed the development of plastids which caused the leaf colour to be pale. Irrespective of TA and/or GA treatment(s), microtubules were observed to be exclusively oriented perpendicular to the longitudinal axis of the cell in actively elongating zones, and in fully elongated zones they were randomly oriented.
Journal of Experimental Botany © 1980 Oxford University Press