A new benzoxazolinone, 5-chIoro-6-methoxy-2-benzoxazolinone (Cl-MBOA)
caused growth inhibition of roots and shoots of oat (Avena sativa), ti
mothy (Phleum pratense), crabgrass (Digitaria sanguinalis), ryegrass (
Lolium multiflorum), cockscomb (Amaranthus Caudatus), cress (Lepidium
sativum) and lettuce (Lactuca sativa); increasing the dose of Cl-MBOA
increased inhibition. The concentrations for 49% inhibition of root gr
owth were 0.12, 0.14, 0.17, 0.19, 0.46, 0.57 and 0.76 mM for timothy,
crabgrass, ryegrass, oat; cockscomb, cress and lettuce, respectively,
and the concentrations for 40% inhibition of shoot growth were 0.25, 0
.28, 0.36, 0.40, 7.9, 12.5 and 19.6 mM for timothy, crabgrass, ryegras
s, cockscomb, cress and lettuce, respectively. The contents of Cl-MBOA
. in shoots and roots of 14-day-old maize (Zea mays) seedlings were 37
.5 and 8.7 mu g g(-1) fr. wt. The presence of this compound in maize s
eedlings, coupled with its effect on growth, suggest that it may play
an important role in maize allelopathy. (C) 1998 Elsevier Science Ltd.
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