SOME PHYSIOLOGICAL STUDIES ON THE EFFECT OF THE GROWTH RETARDANT (PIX) ON Vicia faba PLANT

Abstract

In the present investigation, Viciafaba plants were sprayed with the growth retardant mepiquat chloride. The effect of mepiquat on the growth, endogenous growth regulating substances, photosynthetic pigments, carbohy­ drates, nucleic acids and nitrogenous constituents are presented. The results showed that the low concentration of the growth caused retardant significant increases in most of the growth parameters and the higher concentration resulted in a reduction in these parameters. Besides all concentrations of mepiquat induced slight decreases in auxins, gibberellins and cytokinins contents and slightly increased the inhibitors content. The same concentrations of mepiquat increased chlorophyll a, chlorophyll b, chlorophyll (a+ b) and carotenoid contents in Vicialeaves.

All concentrations of the growth retardant increased reducing sugars, sucrose, polysaccharides and total sugars. The concentrations of mepiquat induced highly significant decreases in DNA and RNA contents except the first concentration which induced highly significant increases. High significant increases were observed in the total-N, protein-N, total soluble-N and arnino-N contents, at lower concentration, while induced highly significant decreases in the same contents at the higher concentration.