Delayed senescence in leaves treated with the protein synthesis inhibitor MDMP

Abstract

Changes in cell constituents and enzyme activity were determined in senescing leaf segments of meadow fescue (Festuca pratensis) treated with the protein synthesis inhibitor 2-(4-methyl-2,6-dinitroanilino)-N-methylpropionamide (MDMP). At an optimal concentration of 10-5 M the d-isomer of MDMP reduced incorporation of [14C]leucine into protein by leaf segments to about 5% of control, but l-MDMP at the same concentration was ineffective. d-MDMP prevented loss of chlorophyll and activation of ribonuclease and greatly reduced the rate of decline of fraction 1 protein and phosphoglycerokinase (PGK) during senescence. On the other hand, changes occurring in leaf sections treated with l-MDMP were practically identical with those occurring in control tissue. These results are discussed in relation to the role of protein synthesis in foliar senescence. © 1976.