Fourteen-day-old Phaseolus vulgaris L. cv. Top Crop (bush bean) plants were sprayed with the plant growth stimulant, potassium naphthenate (20 mM). Seven days after treatment the contents of glutamic acid dehydrogenase, glutamic-oxaloacetic transaminase, nitrate reductase, glutamine synthetase, and cytochrome oxidase in the trifoliate leaf blades of treated plants were significantly larger, and the specific activity of the last four was significantly greater. Potassium nephthenate (1 AM) in the assay solutions did not significantly alter the activity of these enzymes in the cell-free extracts of untreated plants. Leaf Naphthenic acid is the name applied to the complex mixture of acids extracted from petroleum. The diesel oil fraction (180-400 C) may contain 0.03% naphthenic acid. The structure of the individual higher molecular-weight acids in the mixture has yet to be determined, but it is known that others are carboxylic derivatives of cyclopentane, cyclohexane, and cyclo- heptane. The carboxyl group of most of the acids is separated from the saturated ring by an aliphatic side chain containing one or more methylene groups. In our laboratory, gas-liquid chromatography of naphthenates derived from the diesel fraction of a Venezuelan crude oil yielded a tracing in which most of the components appeared to be in the C. to C17 range.Within this range there were 25 major peaks.The acid mixture and some of its individual members have been shown to stimulate the vegetative and reproductive growth of a large variety of plants. Severson (16) has tabulated their effects on growth, yield, and composition of over 50 species.The stimulated growth of the green bush bean, Phaseolus vulgaris L. cv. Top Crop, following naphthenate application, has been shown to be accompanied by increased rates of photosynthesis and respiration, and greater specific activity of phosphorylase, phosphoglycerate kinase, nitrate reductase, and glutamic-pyruvic transaminase (5). The activity of catalase in grape (9) and of peroxidase and ascorbic acid oxidase in cotton (1) has also been found to be stimulated as a result of naphthenate application.It has been suggested (5) that the stimulation of plant growth by naphthenates rests to a large extent on an increased flow of metabolic intermediates and a greater supply of energy as ATP, coupled with an enhanced activity of anabolic enzymes.The investigation described below uses Phaseolus vulgaris cv. Top Crop in a study of the effect of KNap' on the amount and activity of four enzymes of nitrogen metabolism and of cytochrome oxidase; the contents of DNA and RNA, amino acids, and protein; and the incorporation of '4C-leucine into protein.MATERIALS AND METHODS Growth of Plants. Five seeds of the bush bean Phaseolus vulgaris L. cv. Top Crop were sown in 15-cm pots of composted soil. Seven days later the seedlings were thinned to two per pot, and 5 days after this one plant was allowed to remain. As a result, the population was very uniform.The plants were grown in a growth room fitted with coo...

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A 0.5% solution of potassium naphthenates (KNap) was applied to the foliage of hydroponically grown 14‐ day‐old bush bean (Phaseolus vuigaris L., cultivar ‘Top Crop’) plants to determine the effect of this chemical mixture on the uptake and distribution of root‐fed 32P among leaf blade, stem, and root tissues. The plants were grown in eiither a phosphate‐free (−P plants) or a complete nutrient solution. The uptake of 32P was not changed by KNap treatment. The percentage distribution of 32P among the various plant organs, however, was markedly affected by the presence or absence of phosphate in the nutrient solution and by treatment. The enhanced translocation of 32P observed, especially in −P plants, may be associated in a casual way with the characteristic stimulation of metabolic processes in the aerial portions of naphthenate‐treated plants.

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