The Relation between the Rate of Nutrient Uptake by Excised Barley Roots and their Content of Sucrose and Reducing Sugars

A re-examination of the results of previous experiments hasshown that the positive regression of the rate of nutrient uptakeby excised barley roots on sugar content is attributable tothe reducing sugar fraction. Partial regression coefficientsof the rates of uptake of potassium, nitrogen, and phosphoruson reducing sugar content were all positive; those on sucrosecontent were either not significant or negative. These results were confirmed for potassium by experiments inwhich the sugar content of the roots was varied by varying thenitrogen supply to the plants from which the roots were taken,by shading them or by supplying sucrose to the solution in whichthe excised roots were held.