Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Alectrol and orobanchol, germination stimulants for Orobanche minor, from its host red clover.

Abstract

Three seed germination stimulants of the parasitic weed, clover broomrape (Orobanche minor), were isolated from the root exudate of its host, red clover (Trifolium pratense) using a XAD-4 column and HPLC. Germination stimulation activity of root exudate and root tissue from red clover was confirmed using an O. minor seed germination assay. The structure of 2 of the stimulants was determined. One was identified as alectrol and the other was a novel strigol-related compound, which was named orobanchol. Orobanchol is tentatively proposed to be a strigol isomer based on its MS and NMR spectral data. GC-MS techniques to analyse strigolactones are described.