Effects of Selected Herbicides on Plant Protoplasts

Abstract

AbstractPlant protoplasts were released from immature tomato fruits by incubation with a 20% solution of polygalacturonase (Pectinol R‐10, Rhom & Haas) dissolved in 0.1 M KCl + 0.1 M MgCl2. In this salt solution the protoplasts remained stabilized for up to 8 h and were used as a source of exposed plasma membrane. Gross responses of protoplasts to selected chemicals and herbicides were recorded photomicroscopically.Paraquat (1,1′‐dimethyl‐4,4′‐bipyridinium ion) treatments resulted in a characteristic response which was different from that of general denaturants (trichloroacetic acid, ethanol, and detergents) and of osmotic shock. Initial phases of the paraquat response were characterized by a segregation of the cytoplasm into isolated areas on the inner membrane surface. The final phase was a rupture of the plasma membrane and collapse of the cell.The herbicides, 2,4′‐dinitro‐4‐trifluoromethyl‐diphenylether (preforan); 1,1‐dimethyl‐3‐(α,α,α‐trifluoro‐m‐tolyl)urea (fluometuron); 3‐(3‐chloro‐4‐bromophenyl)‐1‐methoxy‐1‐methylurea (chlorbromuron); and α,α,α‐trifluoro‐2,6‐dinitro‐N‐N‐dipropyl‐p‐toluidine (trifluralin) produced no apparent structural effect on the protoplasts.