Chiral response of Oryzeae and Paniceae plants in α‐methylbenzyl‐3‐ p ‐tolyl urea agar medium

The results presented here support the hypothesis that plants of the tribe Oryzeae respond enantioselectively and homogeneously to optically active 1‐α‐methylbenzyl‐3‐ p ‐tolylurea (MBTU) in root growth inhibition, in contrast to Echinochloa species. The Oryzeae plants tested in this study belong to different genera ( Oryza, Leersia, Chikusichloa and Zizania ), to different species ( O sativa, O glaberrima, O alta, O coarctata, O latifolia, O minuta, O rufipogon ), to various ecospecies of Oryza (japonica, indica, japonica × indica, javanica) and to different levels of evolution [cultivated rice ( O sativa and O glaberrima ) and ancestral wild rice species]. In spite of their different phylogenic status and diverse sensitivity, the root growth of all members of the genus Oryza was inhibited more by R ‐MBTU than by S ‐MBTU. Zizania palustris, Z latifolia, Leersia oryzoides and Chikusichloa aquatica belonging to the tribe Oryzeae exhibited similar chiral recognition to the Oryza plants, suggesting that Oryzeae have a common chiral recognition mechanism in their response to optically active MBTUs. In contrast, Echinochloa plants ( E crus‐galli (L) Beauv var crus‐galli and E colonum (L) Link), belonging into subfamily Panicoideae tribe Paniceae , responded in a different way, where their root growth was more sensitive to S ‐MBTU than to the antipodal R ‐MBTU. A reverse chiral response between the tribe Oryzeae and the genus Echinochloa was clearly indicated in this study. This diverse response may be relevant to Gramineae classification. Copyright © 2003 Society of Chemical Industry