Cation-Exchange Capacity of Plant Roots

Competitive adaptation by plants to nutrient shortage through modification of root growth and surface charge

“…Higher root CEC increased P uptake when rock phosphate was the sole source of P, presumably through the enhanced solubilisation of rock phosphate as a result of Ca binding in the root (Asher & Ozanne 1961). Negative correlations between CEC and the uptake of potassium (Drake et al 1951) and nitrate and phosphate (Butler et al 1962) have been reported, and the magnitude of the root CEC has been ·considered to be an ecological adaptation by plants (Wacquant 1978).…”

“…The other nutrients were supplied to 19 pots in a linear scale from 1.0 to 0.25 of the standard concentration after the second week of the 7-week growth period. At harvest, the roots were washed free from sand and the root CEC determined by the electro-dialysis method of Drake et al (1951). The shoots were analysed for N by the micro-Kjeldahl method.…”

The Effect of Calcium on Potassium Accumulation in Corn and Soybean Roots

“…This is particularly striking in the case of mono-and divalent cation absorption by grasses and legumes (5,8); the former tend to accumulate much more potassium and less calcium than the latter.…”

Pasture establishment on a podzolised soil in Northland

“…) postulate that the distribution of a number of ions, including H 2 P04 I, between cation exchangers of differing exchange capacity is such that the exchanger having the lowest capacity will possess the greatest activity of the ion in its micellar solution and that this effect will be greater as the relative overall ion activity increases. In the present case the soil had a low cation exchange capacity (7-9 me./l00 g), while clovers have a high root exchange capacity (Drake et al 1951). The" salt effect" could have operated, since for about six weeks after planting there was little rain.…”