Abstract

The effects of butachlor (2-chloro-2', 6'-diethyl-N-(butoxy-methyl) acetanilide) on seed germination of barnyardgrass (Echinochloa crus-galli (L.) Beauv.) and subsequent seedling growth were investigated. Results showed butachlor treatment did not affect seed germination up to a concentration of 200 ppm, but it delayed the time of radicle emergence through the pericarp of seed for 12 hours. Futher seedling growth was severly inhibited. Emergence of both the primary leaf from the coleoptile and the root were inhibited by a 6 ppm concentration of butachlor. Time elapse studies of the effect of butachlor on the development of amylase and protease activities revealed that the inhibition these activities observed during the early period of seed germination prevented the degradation of reserve carbohydrates and proteins in the endosperm. However butachlor treatment did not affect the polyriboosome level in the initial 36 hours period of seed germination.