Effect of some Chemical Mutagens on the Growth, Phytochemical Composition and Induction of Mutations in Khaya senegalensis

Abstract

Induced mutation using chemical mutagen is a method to create genetic variation resulting in new varieties with better characteristics. However, their effects in forest trees have received relatively little attention, particularly in Khaya senegalensis. Here, I study the effect of sodium azide and dimethyl sulphate on the growth and phytochemical composition of Khaya senegalensis, in addition to produce genetic variation on the vegetative growth. Seeds of Khaya senegalensis were soaked in dimethyl sulphate solutions (0, 1000, 2000, 3000, 4000 and 5000 ppm) and sodium azide solutions (200, 400, 600, 800 and 1000 ppm) for 15 h. Number of branches and leaves increased significantly on plants treated with 2000 ppm dimethyl sulphate in both seasons. The concentration of 3000 ppm dimethyl sulphate (DMS) increased significantly plant height in the first season but did not differ significantly in the second season. Plants treated with all concentrations of sodium azide increased alkaloid contents in the leaves and bark in both seasons. In addition, they enhanced the accumulation of saponins. The treatments of 4000 ppm dimethyl sulphate in the second season produced dwarfed plant with reddish stem. While, the treatment of 3000 ppm dimethyl sulphate produced plant having reddish pedicel leaflets. In addition, plant with biggest and fast growth was found using 300 ppm dimethyl sulphate in the second season, this last mutant was more genetically distinct to control as found by peroxidase isozyme patterns.