Calcium chloride penetrates plant cuticles via aqueous pores

Abstract

Penetration of calcium chloride across astomatous cuticular membranes (CMs) isolated from leaves of Pyrus communis L. has been studied. Penetration was a first-order process when calcium chloride concentrations ranged from 2 gl(-1) to 10 gl(-1). Rate constants were increased 10-fold by adding wetting agents but they did not depend on temperature. The accelerators tributyl phosphate and diethyl sebacate had no effect on rates of penetration. Increasing humidity over the salt residue on the CMs from 50 to 90% increased rate constants by about 2-fold. Extracting cuticular waxes from pear leaf CMs increased rate constants by factors of 2 to 3, depending on humidity. Leaf CMs from Malus domestica Borkh., Populus aelha L., Stephanotis floribunda Brongn. and Schefflera actinophylla (Endl.) Harms were also permeable to CaCl2. Highest rate constants were observed with poplar CMs while Schefflera CMs exhibited the lowest permeability. By comparing these results with the well established transport properties of the lipophilic pathway it is concluded that calcium chloride hexahydrate penetrated cuticular membranes via aqueous pores.

Influence of Formulation on the Cuticular Penetration and on Spray Deposit Properties of Manganese and Zinc Foliar Fertilizers

“…As experimental field trials often provide inconsistent results depending on the specific climatic conditions of single seasons, the study of the foliar penetration efficacy of foliar nutrients has long been extended to model systems based on the use of isolated astomatous cuticles [3,[5][6][7]. Any study of the mechanism and efficacy of foliar absorption must consider ion penetration of the cuticle.…”

“…The mechanisms of cuticular penetration of polar and hydrophilic compounds, as usually contained in foliar fertilizers, are currently not fully understood [9]. The cuticle is a lipid semipermeable membrane where the existence of aqueous pores [5,6] has been suggested as a pathway of penetration of ionic or hydrophilic compounds, such as nutrient ions. Although these aqueous pores in the cuticle cannot be evidenced by electron microscope or other optical techniques, sophisticated ion permeability studies provide strong evidence of their existence [3].…”

“…Although these aqueous pores in the cuticle cannot be evidenced by electron microscope or other optical techniques, sophisticated ion permeability studies provide strong evidence of their existence [3]. Any penetration of compounds through these aqueous pores implicates that such compounds or nutrients must be dissolved in water [3,5,6]. Water solubility is a key factor for foliar uptake, since absorption will occur only when the applied compound is dissolved in a liquid phase-usually water-and will subsequently diffuse into the plant organs [3,6].…”

Improving the performance of calcium-containing spray formulations to limit the incidence of bitter pit in apple (Malus x domestica Borkh.)

“…The effectiveness of Ca sprays is largely influenced by the prevailing environmental conditions, particularly relative air humidity (Schönherr, 2000(Schönherr, , 2001. In this regard, Schönherr (2001) pointed out the relevance of the point of deliquescence (POD) of Ca compounds in relation to the rate of diffusion through the cuticle.…”

Effect of the interaction between fungicide application time and rainfall simulation interval on Asian Soybean Rust control effectiveness

“…Temperature is related to the permeability of substances through the cuticular waxes associated with the cutin, wherein permeability increases rapidly with increasing temperature SCHÖNHERR, 1995). Relative humidity influences absorption, since it affects cuticle moisture and solute absorption mechanisms (FERNÁNDEZ et al, 2008), such as the evaporation rate of applied solutions (SCHÖNHERR, 2000). In addition to these two factors, light and dew also seem to affect the performance of fungicides in disease control.…”