Triticeae plants preferentially responded to S-1-α-methylbenzyl-3-p-tolylurea in root growth and tetrazolium reduction assays

• Published in: Weed biology and management Vol. 5; no. 2; pp. 62 - 68
• Main Authors: Tanaka, C, Itagaki, M, Arai, S, Omokawa, H
• Format: Journal Article
• Language: English
• Published: Melbourne, Australia Blackwell Science Pty 01.06.2005
• Subjects: barley; chiral response; cross-intergenus response; dose response; growth retardation; herbicides; Hordeum vulgare; mechanism of action; phytotoxicity; Poaceae; Pooideae; root growth; rye; Secale cereale; tetrazolium; Triticeae plants; Triticum aestivum; weed control; wheat
• ISSN: 1444-6162; 1445-6664
• DOI: 10.1111/j.1445-6664.2005.00161.x

Optically active 1‐α‐methylbenzyl‐3‐p‐tolylurea (MBTU) shows diverse plant physiological properties. Gramineae plants exhibit enantioselective root growth inhibition by R/S‐MBTU. In the present paper, the dose–growth response (DGR) towards the optically active MBTUs was examined in the tribe Triticeae plants, including Hordeum vulgare L., Secale cereale L., Triticum aestivum L. and Aegilops cylindrica Host., and compared with those of the genus Bromus (B. inermis Leyss), which is classified into the tribe Bromeae, and the genus Oryza. In spite of their phylogenetic difference, the Triticeae plants responded homogeneously in their chiral recognition. Of particular interest, is the result of the dichotomic enantioselective response of tested Gramineae plants. Only the genus Oryza responds to R‐MBTU, and the tribes Triticeae (Triticum, Aegilops, Secale and Hordeum) and Bromeae (Bromus) preferentially respond to the S‐enantiomer. The tetrazolium–phenazine methosulfate–formazan (TPF) assay was demonstrated to measure redox activity of root tips of the MBTU‐treated Oryza sativa and T. aestivum, which are the typical dichotomic, enantioselective‐responsive plants. In Oryza and Triticum root tips, enantioselective responses of reduction activity in TPF assays were strongly related to those of root growth inhibition in DGR assays, suggesting aggressive participation of the MBTU in the generation of the reducing mechanism in mitochondria.