Dual Mechanisms of Ion Uptake in Relation to Vacuolation in Corn Roots

摘要: Absorption isotherms for chloride and rubidium ions have been determined through a wide concentration range nonvacuolate root tips, vacuolate subapical sections of corn root. In the 0 to 0.5 mm, absorption is hyperbolic with in both tips proximal sections. At high concentrations, 1 50 second multiple-hyperbolic isotherm noted tissue, while rises exponentially. A linear exponentially rising taken signify diffusive permeation. The same distinction between tip tissue characterizes Rb absorption. uptake indifferent nature counterion at all concentrations tip, exerts predictable influence on tissue. effect poorly absorbable anion greater range. Evidence presented metabolic ion transport into tips. Verification offered that mediated by dual mechanisms, thesis developed high-affinity (low K s ) system mediates passage plasma membrane low-affinity (high implements tonoplast.