THE ACTION OF GROWTH INHIBITORS ON CARBOHYDRATE METABOLISM IN THE PEA

Abstract

A study was made of the carbohydrates of isolated pea stem sections that had been grown in H2O, H2O plus auxin and in various inhibitors. The reducing sugar content of the sections averaged 1.12% of the fresh wt. This value fell to 0.86% after 24 hrs,'' growth in auxin. In the presence of an amt. of inhibitor that brought about 50% growth inhibition, the reducing sugar content was further decreased to the following values: growth in 6 X 10-4 [image] iodoacetate, 0.64%, 10-4 [image] arsenite, 0.71% and in 5 X 10-3 [image] fluoride 0.48%. This further decrease of the reducing sugar in the presence of auxin plus an inhibitor could not be accounted for in other combinations such as sucrose, starch and dextrose. Further, there was no significant increase in phosphorylated compounds after inhibition. A study of the respiration of such sections showed that the inhibitors did not promote destruction of the sugars. There was no increase in the rate of respiration with iodoacetate and arsenite. With fluoride the final respiration rate was slightly higher than that of the controls. It has been shown that with pea stem sections there is a slight increase in respiration rate (15%) in the presence of auxin (indoleacetic acid, 1 mg./l.). The inhibitors, therefore, cause conversion of sugar to non-carbohydrate materials.