HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (23) Citing Articles via Google Scholar Google Scholar Articles by Petersen, J. Articles by Hurle, K. Search for Related Content PubMed Articles by Petersen, J. Articles by Hurle, K. Agricola Articles by Petersen, J. Articles by Hurle, K. Related Collections Other Soil Management Tillage Weed Management Allelopathy Other Tubers

ALLELOPATHY SYMPOSIUM

Weed Suppression by Release of Isothiocyanates from Turnip-Rape Mulch

^a Inst of Sugar Beet Research, Holtenser Landstr. 77, 37079 Goettingen, Germany
^b Inst. of Phytomedicine, Weed Science Dep., Hohenheim Univ., 70593 Stuttgart, Germany

Corresponding author (petersen{at}ifz-goettingen.de)

The allelopathic potential of isothiocyanates (ITC) released by turnip–rape mulch [Brassica rapa (Rapifera Group)–Brassica napus L.] was evaluated. Six different ITCs were identified from chopped turnip–rape by HPLC-DAD/HPLC-MS. All plant parts contained 2-phenylethyl-ITC. In the shoot n-butyl and 3-butenyl-ITC dominated. Younger leaves, flowers, and buds also contained small amounts of benzyl and allyl-ITC. Furthermore, marginal amounts of 4-pentenyl-ITC were detected. In the soil, where turnip–rape mulch was incorporated, only low amounts of ITCs were detected. It was shown that the DT₅₀ of ITCs in soil are very short. Germination tests with weed seeds in aqueous ITC solutions showed, that aryl-ITCs were the most suppressive compounds. Within the alkyl-ITCs, the activity decreased with increasing molecular mass. The susceptibility of different weed species to ITCs mainly depended on seed size. Smaller seeds tended to be more sensitive. Further studies demonstrated a high biological activity of ITCs in the vapor phase. n-Butyl-ITC was more suppressive in the vapor phase than in aqueous solution, while 2-phenylethyl-ITC showed the opposite effect. Results demonstrated that weed suppression observed in the field was probably due to the high amounts of ITCs identified in turnip–rape mulch. Isothiocyanates were strong suppressants of germination on tested species—spiny sowthistle [Sonchus asper (L.) Hill], scentless mayweed (Matricaria inodora L.), smooth pigweed (Amaranthus hybridus L.), barnyardgrass [Echinochloa crusgalli (L.) Beauv.], blackgrass (Alopecurus myosuroides Huds.), and wheat (Triticum aestivum L.)—and probably interact with weed seeds in the soil solution and as vapor in soil pores.

Abbreviations: DT, disappearance time • ED, effective dosage • HPLC, high-performance liquid chromatography • ITC, isothiocyanate • MS, mass spectrometry • PAD, photodiode array detector • TSM, thousand seed mass

This article has been cited by other articles:

				C. M. Cherr, J. M. S. Scholberg, and R. McSorley Green Manure Approaches to Crop Production: A Synthesis Agron. J., February 7, 2006; 98(2): 302 - 319. [Abstract] [Full Text] [PDF]