Studies on the uptake and translocation of ¹⁴C-amino acids in cotton

Abstract

The uptake and translocation of 7 ¹⁴C-amino acids were studied, in part, in 2 ages of intact cotton plants. Application of the radioactive amino acids was to roots, petioles and leaf blades of these plants. The 7 amino acids tested were DL-arginine, DL-histidine, DL-aspartic acid, DL-glutamic acid, DL-serine, DL-valine and DL-leucine. The results obtained from these experiments, the first in which radioactive amino acids and intact cotton plants were utilized, are summarized as follows: 1. The uptake of the 7 amino acids by roots of 16-day-old cotton plants was greater when the molecules possessed no net charge. 2. The uptake of these 7 amino acids is an energy requiring process as they were not leached from treated roots. Their uptake was inhibited by 2 respiratory inhibitors, DNP and NaCN. 3. Roots of 30-day-old cotton plants have the capacity to take up and hold these amino acids in large quantities. 4. Upward movement of these amino acids from the roots was through the xylem as upward movement was not restricted by girdling a section of the hypocotyl. ...