Effects of Two Diphenylether Herbicides on Common Purslane(Portulaca oleracea)

Abstract

Nitrofen (2,4-dichlorophenyl-p-nitrophenyl ether) and oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl) benzene] are 2 diphenylether herbicides which are phytoactive on common purslane(Portulaca oleraceaL.). The stomata of common purslane are normally open during the day and closed at night. Nitrofen and oxyfluorfen applications to common purslane leaves cause the stomata to close which is a result of increased membrane permeability. A slight increase (0.6 C) in leaf temperature and a decrease (2 bars) in the apparent water potential was evident after 6 h. Membrane degradation caused some cells to collapse and caused the leaves to appear pitted. Ethylene synthesis was stimulated (0.9 ppmv) causing a loss of plastids from the bundle sheath cells and finally leaf abscission, 8 to 24 h after treatment.