Allelopathy in maize II. Allelopathic potential of a new benzoxazolinone, 5-chloro-6-methoxy-2-benzoxazolinone and its analogues

Abstract

To characterize the allelopathic activity of a new benzoxazolinone, 5-chloro-6-methoxy-2-benzoxazolinone (Cl-MBOA), seeds or seedling of monocotyledonous and dicotyledonous plants were exposed to Cl-MBOA for two or three days in a Petri dish, and effects of Cl-MBOA on the seed germination and the plant growth were determined and compared to those of its analogues, 6-methoxy-2-benzoxazolinone (MBOA) and benzoxazolinone (BOA). Cl-MBOA, MBOA and BOA dose-dependently inhibited the seed germination and growth of roots and shoots of cockscomb (Amaranthus caudatus L.), cress (Lepidium sativum L.), lettuce (Lactuca sativa L.), crabgrass (Digitaria sanguinalis L.), timothy (Phleum pratense L.) and ryegrass (Lolium multiflorum Lam.). A new benzoxazolinone, Cl-MBOA was the most active in all bioassays followed in order by MBOA and BOA. The results that the attachment of Cl at C-5 position on MBOA leads to an increase in the activity.