Parasitic plants

The product (4) is a synthetic germination stimulant for parasitic plants. Normally these plants germinate only when the host is growing. Premature germination induced by (4) increases yields of sorghum (an African food crop) planted later. 

The synthetic studies which have been described have resulted in significant improvements in the preparation of racemic strigol and have also provided access to several analogs which will subsequently be tested for seed germination activity in order to elucidate key structure-activity relationships. These results and further investigations will hopefully lead to effective synthetic compounds for the control of witchweed and related parasitic plants. 

Goff, L. J. H. and Coleman A. W. (1995), Fate of parasite and host organelle DNA during cellular transformation of red algae by their parasites , Plant Cell, 7, 1899-1911... 

Suicidal germination Parasitic plant control Runyon et al. (2009)... 

Sauerbom J, Linke KH, Saxena MC, Koch W (1989) Solarization a physical control method for weeds and parasitic plants (Orobanche spp.) in Mediterranean agriculture. Weed Res 29 391-397... 

Intercropping with trap or catch crop against parasitic plants is often practiced in resource-poor regions but as parasitic plants it has considerable success. This approach is more effective than use of pesticides, cheap and environmentally... 

Parasitic plants often use chemicals released by their host plant to stimulate seed germination, to locate the host, or for haustorial development. Many different compounds are involved, including strigolactones, quinones, coumarins, flavonoids, and other phenolics. Flavonoids contribute to signaling in some species but not others. Haustorial development in Triphysaria versicolor can be induced in vitro by the anthocyanidins petunidin, cyanidin, pelargonidin, delphinidin, as well as their glycosides obtained from the host plant.Anthocyanins are not usually found in root exudates, however, and thus the mechanism by which they affect natural signals for parasitic plants in the soil is not clear. 

Kim, D. et al., On becoming a parasite. Evaluating the role of wall oxidases in parasitic plant... 

Matvienko, M. et al., Quinone oxidoreductase message levels are differentially regulated in parasitic and non-parasitic plants exposed to allelopathic quinines. Plant J., 25, 375, 2001. 

R. Brown and coworkers observed that seeds of Striga, known as witchweed, a semi-parasitic plant of grasses and corn, germinated only in the presence of root exudates from the living host. They isolated the sirupy exudate, [VJ > + 20° (water), resembling a pentose, but did not specifically identify the active substance. A study of many carbohydrates, mostly pentoses, showed that only D-ihreo-pentulose, C 3) — 32° (water), had the required activity L-[Pg.416]

Benzoquinones, such as 2,6-dimethoxybenzoquinone (1.62), are present in root exudates of maize and stimulate parasitic plants to form haustoria (Matvienko et al., 2001). Ubiquinones, such as ubiquinonc(j) (1.63), where (3) indicates the number of isoprenoid sidechains, is also known as Coenzyme Q and has a role in electron transport in the mitochondria. 

Bouwmeester, H.J., Matusova, R., Zhongkui, S., Beale, M.H. Secondary metabolite signalling in host-parasitic plant interactions.Curr Opin Plant Biol 2003 6 358-364. 

Keyes, W.J., Taylor, J.V., Apkarian, R.P., Lynn, D.G Dancing together. Social controls in parasitic plant development. Plant Physiol 2001 127 1508-1512. 

Adding to the forest pest complex are a variety of diseases. This can include parasitic plants such as mistletoe, fungal diseases, and a variety of bacterial diseases (10). 

Though parasitic plants such as mistletoe, fungal disease, and bacterial diseases were indigenous to the forest, then as they are now, control in the standing timber was largely achieved by management practices. However, after cutting, chemical treatment, such as with pentachlorophenol, would be employed. 

Parasitic plants can be broadly divided into hemiparasites and holoparasites, according to the presence or absence of chlorophylls. The holoparasites depend on their hosts to get the nutrients and to complete their life cycle, as they are not able to fix carbon through photosynthesis. The hemiparasites take from their host just minerals and water, and their parasitism can be facultative. 

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