Abstract

Transfer of excised maize root from wet sawdust to water caused a considerable reduction in the exudation rate of the root. After 1-day aging in water, the exudation rate increased about 8-fold and the exudation continued for 3 days. Osmotic pressure of the exudate from the root decreased with time after excision reaching almost zero in 2 days in spite of a high exudation rate. Concentrations of sugars, acids, Ca2+ and Mg2+ in the exudate decreased with the decrease of osmotic pressure, while the decrease in K+ concentration delayed and P1 concentration increased.

The gas content of the root, especially of O2, increased during aging in water. The accumulated O2 gas may promote water uptake, because degasification of the root by evacuation induced a decrease of water uptake. Also, the longitudinal gradient of the O2 content in the root coincides with the gradient of water uptake intensity.

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