No abstract

Cyanamide is an allelochemical produced by hairy vetch (Vicia villosa Roth.). Its phyotoxic effect on plant growth was examined on roots of onion (Allium cepa L.) bulbs. Water solution of cyanamide (2–10 mM) restricted growth of onion roots in a dose-dependent manner. Treatment of onion roots with cyanamide resulted in a decrease in root growth rate accompanied by a decrease in accumulation of fresh and dry weight. The inhibitory effect of cyanamide was reversed by its removal from the environment, but full recovery was observed only for tissue treated with this chemical at low concentration (2–6 mM). Cytological observations of root tip cells suggest that disturbances in cell division may explain the strong cyanamide allelopathic activity. Moreover, in cyanamide-treated onion the following changes were detected: reduction of mitotic cells, inhibition of proliferation of meristematic cells and cell cycle, and modifications of cytoskeleton arrangement.

Cyanamide (CA) has been reported as a natural compound produced by hairy vetch (Vicia villosa Roth.) and it was shown also to be an allelochemical, responsible for strong allelopathic potential in this species. CA phytotoxicity has been demonstrated on various plant species, but to date little is known about its mode of action at cellular level. Treatment of tomato (Solanum lycopersicum L.) roots with CA (1.2 mM) resulted in inhibition of growth accompanied by alterations in cell division, and imbalance of plant hormone (ethylene and auxin) homeostasis. Moreover, the phytotoxic effect of CA was also manifested by modifications in expansin gene expression, especially in expansins responsible for cell wall remodeling after the cytokinesis (LeEXPA9, LeEXPA18). Based on these results the phytotoxic activity of CA on growth of roots of tomato seedlings is likely due to alterations associated with cell division.Electronic supplementary materialThe online version of this article (doi:10.1007/s00425-012-1722-y) contains supplementary material, which is available to authorized users.

No abstract

No abstract

We examined the response of plants of various crop and weed species to cyanamide in order to evaluate allelochemical-mediated interactions between the species. We studied germination and seedling growth in the common weeds Galium aparine L. and Amaranthus retroflexus L., and the crops Zea mays L., Triticum aestivum L., Lactuca sativa L., Solanum lycopersicum L. and Sinapis alba L. as acceptor plants. Concentration-dependent phytotoxic effects of cyanamide were noted during seed germination and in the root and shoot growth of the tested plants. The monocotyledonous plants generally were less sensitive to cyanamide treatment. Seed germination and seedling growth of the dicotyledonous plants were strongly inhibited by the allelochemical at both tested concentrations (1.2 mM, 3 mM). We conclude that cyanamide has potential for use as a natural herbicide only in specific field systems of cyanamide-tolerant monocotyledonous crops accompanied by cyanamide-sensitive dicotyledonous weeds.K Ke ey y w wo or rd ds s:

Allelopathic interactions have mainly negative character on targeting plants. Inhibition and/or delay of seed germination or seedling growth of acceptor plants is an effect of mostly diversified mode of action of allelochemicals.1 It means that inhibition of activity of one enzyme or slowdown of the process triggers cascade of events leading to initialization of signal transduction and/or switching on cell's defense mechanisms. However, nature of allelopathic interactions is time and dose dependent and differs in various plant species and depends on other environmental factors. Most studies on allelopathy are conducted under laboratory conditions due to elimination of non-direct effects coming from environment. In this way, the phenomenon of interaction of allelochemical on acceptor plants is called phytotoxicity.Cyanamide (CA) is one of the newly discovered allelochemical, found in hairy vetch (Vicia villosa subs. cracca Roth.) and crucial for its allelopathic potential.2 Research on phytotoxic action of CA confirmed its abilities in inhibition of seed germination and seedling growth of various plant species. 3Mode of action of CA on root growth was partially examined in onion bulbs. 4 Our former studies, conducted on tomato seedlings, indicated disturbances in root tip cells division leading to reduction of length of root tip zone, as the main reason of CA-induced root growth inhibition. 5 This, in consequence, reorganized every other root zones. Moreover, disorder in mitosis was correlated with altered expression of expansin genes (LeEXPA9 and LeEXPA18) involved in reconstitution of cell wall after Mode of action of allelochemicals in target plants is currently widely studied. Cyanamide is one of the newly discovered allelochemical, biosynthesized in hairy vetch. recently, it has been recognized that cyanamide is plant growth inhibitor, which affects mitosis in root tip cells and causes, e.g., disorder in phytohormonal balance. We also demonstrated that Ca may act as oxidative stress agent but it strictly depends on plant species, exposure time and doses. roots of tomato seedling treated with water solution of 1.2 mM cyanamide did not exhibit elevated reactive oxygen species concentration during the whole culture period.