Allelochemicals in wheat (Triticum aestivum L.): Cultivar difference in the exudation of phenolic acids

Analysis by GC-MS/MS showed that a worldwide collection of 58 wheat accessi ons differed significantly in the amounts of 7 known phenolic acids exuded by the living roots of 17-day-old wheat seedlings. The quantities of exuded allelochemicals varied with the specific compound and ranged from 2.3 to 1 8.6, from 0.6 to 17.5, from 0.1 to 4.9, from 0.0 to 52.7, from 0.33 to 12.7 , from 1.5 to 20.5, and from 1.6 to 23.4 mug/L of water/agar for p-hydroxyb enzoic, vanillic, cis-p-coumaric, syringic, cis-ferulic, trans-p-coumaric, and trans-ferulic acids, respectively. The concentrations of p-hydroxybenzo ic and vanillic acids exuded by wheat seedlings were normally distributed i n the 58 accessions. The level of each phenolic acid in root exudates did n ot correlate well to that previously observed in wheat. In comparison with weakly allelopathic accessions, strongly allelopathic accessions exuded lar ger quantities of allelochemicals into the growth medium. The chemical basi s for wheat seedling allelopathy is an area for further investigation.