BIOLOGICALLY-ACTIVE SECONDARY METABOLITES OF BARLEY .1. DEVELOPING TECHNIQUES AND ASSESSING ALLELOPATHY IN BARLEY

Allelopathic effects of barley (Hordeum vulgare L.) on white mustard ( Sinapis alba L.) were assessed using modified bioassays that reduced o ther environmental influences. In a Petri dish bioassay, germination o f white mustard was delayed and the radicle lengths were significantly inhibited at a density of 0.5 barley seed/cm(2). In a 'siphoning' bio assay apparatus, when the two species were sown together, radicle elon gation of white mustard was not inhibited one day after sowing but bec ame increasingly inhibited as bioassay time increased. Barley alleloch emicals were released from the roots in a hydroponic system for at lea st 70 days after commencement of barley germination. Solutions removed from the hydroponic system of growing barley delayed germination and inhibited growth of white mustard. The allelopathic activity of barley was further confirmed at a density of 0.3 barley seed/cm(2) in a modi fied stairstep apparatus.