| Summary: | Bean plants were grown in a phosphate-free nutrient solution to the early trifoliate stage. At this time, they were transferred to a minus phosphate nutrient solution containing 100 p.p.m. 3-amino-1,2,4-triazole for 48 hours, and then placed into a labelled phosphate nutrient solution for another hour. The plants were then returned to a phosphate-free nutrient solution and harvested one, 24, 48, and 96 hours after the period of initial phosphate uptake.
AT-treatment did not affect uptake of P³² but did decrease loss of P³² to the phosphate-free nutrient solutions after it had been absorbed by the plants. The proportion of absorbed phosphate found in the stems and leaves of AT-treated plants was higher than in these organs in the control plants. This phosphate represented an increase in both acid-soluble activity and acid-insoluble activity. The accumulation of acid-soluble activity in the shoots of AT-treated plants was an accumulation of inorganic phosphates, sugar phosphates, and nucleotides. AT appeared to inhibit downward translocation of acid-soluble and acid-insoluble activity.
The incorporation of P³² into esterified compounds (i.e., nucleotides and sugar phosphates) was unaffected by AT indicating that AT does not interfere with oxidative phosphorylation nor with glycolysis. However, AT did inhibit transfer of P³² from the acid-soluble fraction to the acid-insoluble fraction. Therefore, the principal effect of AT is to inhibit the incorporation of phosphate into one or more of the nucleic acid, phospholipid, or phosphoprotein fractions. === Science, Faculty of === Botany, Department of === Graduate
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