Allelopathic effects of volatile monoterpenoids produced by Salvia leucophylla: inhibition of cell proliferation and DNA synthesis in the root apical meristem of Brassica campestris seedlings

• Published in: Journal of chemical ecology 2005-05, Vol.31 (5), p.1187-1203
• Main Authors: Nishida, N, Tamotsu, S, Nagata, N, Saito, C, Sakai, A
• Format: Article
• Language: English
• Subjects: allelopathy; Animal and plant ecology; Animal, plant and microbial ecology; Autoecology; Biological and medical sciences; Brassica - growth & development; Brassica campestris; cell proliferation; Cell Proliferation - drug effects; Cells; Deoxyribonucleic acid; DNA; DNA - biosynthesis; Ecology; Fundamental and applied biological sciences. Psychology; General aspects; inhibitors; Monoterpenes - isolation & purification; Monoterpenes - pharmacology; monoterpenoids; Plant growth; plant growth substances; Plant Roots - physiology; Population Dynamics; Proteins; root meristems; Salvia - chemistry; Salvia leucophylla; seedling growth; Seedlings; Seedlings - growth & development; volatile compounds; Volatilization
• ISSN: 0098-0331; 1573-1561
• DOI: 10.1007/s10886-005-4256-y

Salvia leucophylla, a shrub observed in coastal south California, produces several volatile monoterpenoids (camphor, 1,8-cineole, beta-pinene, alpha-pinene, and camphene) that potentially act as allelochemicals. The effects of these were examined using Brassica campestris as the test plant. Camphor, 1,8-cineole, and beta-pinene inhibited germination of B. campestris seeds at high concentrations, whereas alpha-pinene and camphene did not. Root growth was inhibited by all five monoterpenoids in a dose-dependent manner, but hypocotyl growth was largely unaffected. The monoterpenoids did not alter the sizes of matured cells in either hypocotyls or roots, indicating that cell expansion is relatively insensitive to these compounds. They did not decrease the mitotic index in the shoot apical region, but specifically lowered mitotic index in the root apical meristem. Moreover, morphological and biochemical analyses on the incorporation of 5-bromo-2'-deoxyuridine into DNA demonstrated that the monoterpenoids inhibit both cell-nuclear and organelle DNA synthesis in the root apical meristem. These results suggest that the monoterpenoids produced by S. leucophylla could interfere with the growth of other plants in its vicinity through inhibition of cell proliferation in the root apical meristem.