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The paper describes a study of the effect of salts of natural naphthenic acids on the rooting of young sunflower cuttings and latteral branching of interspecies sunflower hybrids. Naphthenic acids were obtained by alkaline extraction from atmospheric gas oil fraction of Vojvodina crude oil "Velebit" and purified by column chromatography on alumina. Their sodium salts in concentrations of 1×10-7 mol/dm 3 stimulated the formation of adventitious roots in sunflower cuttings even by a factor of 40 compared with control, the effect being also observed in lateral branches of interspecies sunflower hybrids. The obtained results suggest the possibility of using naphthenic acids as a means for rooting of plant cuttings.

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Contents and distribution of N, K, Mg, Cu, Mn and Zn in pea plants treated with Cd at different age was investigated. Plants were treated with 10-7 or 10-5 M Cd for 48h 25th or 63rd days after seed germination. Results showed that more Cd was accumulated in plants treated with Cd at latter stages of growth and development. Treatments with both concentration of Cd caused accumulation of Cd in roots. Contents and distribution of the investigated macro- and micronutrients depended on Cd concentration and plant age

Yields of small grains have been significantly increased in recent decades primarily by breeding. No corresponding progress has been made regarding protein content in the grain. That was mostly due to a negative correlation existing between yield level and protein content. Protein synthesis requires a much larger amount of energy that that required for carbohydrate synthesis. A hypothesis explains this negative correlation by competition for energy between nitrogen metabolism and carbohydrate synthesis. The proponents of this hypothesis surmise that nitrate reduction unfolds mostly at the expense of the energy released upon oxidation of carbohydrates and organic acids (heterotrophic), and not at the expense of light energy (autotrophic). In small grains, nitrate reduction takes place mostly in leaves, i. e., it is autotrophic. Under conditions of optimum nitrogen supply, protein content and yield per unit area increase but grain yield does not decrease although it could be expected if there existed a competition for energy between nitrogen metabolism and carbohydrate synthesis. Protein content reduction in consequence to yield increase could be explained by the dilution effect, as evidenced by similar reductions of other substances in the grain, for example mineral elements. When considering the competition for energy between nitrogen metabolism and carbohydrate synthesis, it should not be overlooked that nitrogen stimulates the energy transport in plants indirectly, by stimulating the photosynthetic activity and thus the utilization of light energy by plants