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LOCALIZATION AND MECHANISM OF CALCIUM STIMULATION OF RUBIDIUM ABSORPTION IN THE MUNG BEAN ROOT
Author(s) -
Tanada T.
Publication year - 1962
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1962.tb15048.x
Subject(s) - rubidium , phaseolus , absorption (acoustics) , calcium , stimulation , biophysics , biology , botany , biochemistry , potassium , chemistry , endocrinology , materials science , organic chemistry , composite material
T anada , T. (Mineral Nutrition Lab., ARS, Beltsville, Md.) Localization and mechanism of calcium stimulation of rubidium absorption in the mung bean root. Amer. Jour. Bot. 49(10): 1068–1072. Illus. 1962.—Rates of Rb absorption were determined for various regions along the axis of the mung bean root (Phaseolus aureus). The rate was found to be highest in the apical 2.5–5.0‐mm zone. This region also had the largest Ca activation of Rb uptake, while the mature sections showed less Ca stimulation of Rb absorption. The effect of Ca was relatively greater at low Rb concentrations than at higher. Kinetic analysis suggests that Ca increases Rb uptake by increasing the affinity of binding sites for Rb ions. Time studies indicated that Ca has to penetrate the cellular membrane before its activating effect becomes manifest. Roots grown under Ca deficiency generally absorbed Rb at a faster rate than normal roots. In the presence of Ca, Rb absorption in the younger region of these Ca‐deficient roots showed relatively less or no increase, and in the mature sections it decreased markedly.