Effects of Vigna radiate Seeds Treatment by Aminoptrine and Trimethoprim in the Activity of Dihydrofolate Reductase Enzyme and its Seedlings, Calli Growth


The results of Vigna radiate seeds treatment before planting with aminoptrine and trimethoprim at 10-1, 10-2,10-3,10-4 and 10-5 molar to decrease in the rate of germination, average length of roots and growth of seedlings and calli derived from Vigna radiate seedling segments that grown on Murashige and Skoog (MS) medium supplement with 2.0 mg/l benzyladenine (BA) and 0.5mg/l naphthalene acidic acid (NAA).The sensitivity of DHFR, isolated from Vigna radiate callus, to aminoptrine or trimethoprim varied depending on the type and concentrations of inhibitor used. Aminoptrine caused 53% inhibition of DHFR at 10-4 M, however the inhibitory effect of trimethoprim on DHFR was less than that of aminoptrine.Also addition of inhibitors to the media greatly affected the fresh weight and other cell constituents. There was a 51% decrease in the total folate content in the presence of 10-4M aminoptrine or 10-3M trimethoprim. Addition of aminoptrine at 10-1M caused a 100% inhibition in the folate, proteins, nucleic acids content and callus death after 30 days of growth.The pattern of changes in cell constituents of callus grown on media with inhibitors was similar to that of DHFR activity and fresh weight of callus