Some physiological studies on the effect of the growth retardant [Pix] on vicia faba plant: morphological characteristics and metabolic activities during growth and development

ABSTRACT

The effect of MC on growth, photosynthetic pigments, carbohydrates, nitrogenous constituents, nucleic acids and the activity of certain enzymes of Vicia faba plants were studied. The results showed that the relatively low concentration [250 ppm] of the Pix caused significant increases in most of the growth parameters. Meanwhile the relatively higher concentration [1500 ppm] resulted in a reduction in these parameters. All used concentrations of mepiquat increased chlorophyll a, chlorophyll b, chlorophyll [a+b] and carotenoid contents in Vicia leaves. All concentrations of Pix also increased reducing sugars, sucrose, polysaccharides and total sugars. On the contrary, highly significant decreases in DNA and RNA contents were detected. On the other hand, high significant increases were observed in the total-N, protein-N, total soluble-N and amino-N contents at lower concentration, while induced highly significant decreases in the same contents with the higher concentrations were induced. Concerning alpha-amylase, Beta-amylase, protease and RN-ase activities the growth retardant [MC] induced high significant decreases. Contrary IAA-oxidase activity showed high significant increases