Pea plants were grown in complete culture solution and in deficiencies of phosphorus, nitrogen, or potassium for a period of about 5 weeks. Excised roots of these plants were treated with a complete, aerated culture solution for varying periods of time and the changes in respiration rate, phosphorus, nitrogen, potassium, sugar, and starch contents measured.There were changes in fresh weight and dry weight of the excised roots during treatment. The dry weight decreased with time but the water content changes were variable. Uptake of water was correlated with uptake of potassium and sucrose content in some instances.There was no evidence of a ‘salt respiration’ in those cases where active accumulation occurred.The rates of gain or loss of phosphorus, nitrogen, or potassium at 0 hours, 8 hours, and 16 hours were calculated and it was found that the rate depended both on content of element in the root and the sugar cotent. There was very little evidence that one element affected the rate of uptake of another. Simultaneous loss of one element and gain of another occurred in some instances.The observations appear to be best explained on the assumption that the absorbed ions are fixed in the cells in the form of loosely bound compounds and that these compounds are formed from sugars.