The Effect of Temperature Treatments on Growth and the Metabolism of Ribonucleic Acid in Relation to Cell Division and Cell Elongation of Pisum sativum Roots

We observed the effects of a range of temperatures on root elongation, cell production, total RNA in the root tip, and changes in various nucleic acid fractions in dividing and elongating areas of pea roots. High temperatures affected elongation of roots more adversely than cell production. In the tip section of the root, growth was positively associated with a decrease in the first soluble RNA peak that eluted from a MAK column, and with an increase in ribosomal RNA. There was no similar change in these RNA fractions in the elongating area of the pea root. In pulse type tests sRNA-1 labeled first and the isotype was depleted upon subsequent growth. The specific activity of sRNA-1 and the depletion of the radioactivity was not nearly so great in the elongating as in the dividing portion of the pea root.