Dodder is a parasitic weed that is troublesome to the growth of many plants. Our study shows that this invasive species contains strong allelopathic potential, exerting strong inhibition against the growth of indicator plants and noxious paddy weeds in bioassay and pot trials. In a greenhouse, incorporation of 0.5 t ha−1 of dried dodder plants to paddy soil reduced spontaneous growth of paddy weeds by about 50%, whereas the 1.5 to 2 t ha−1 dose suppressed biomass of paddy weeds by more than 75% and completely controlled emergence of barnyardgrass and monochoria. By the use of a separation resin, 22 compounds were separated from dodder and identified by gas chromatography–mass spectrometry as belonging to terpenes, long-chain fatty acids, phenols, phenolic acids, and lactone. Among these compounds, 15 substances were quantified and tested for their herbicidal activity. Quantity of cinnamic acid was the highest (37.3 mg g−1), followed by dihydro-5,6-dehydrokavain (DDK; 6.0 mg g−1), myristic acid (3.2 mg g−1), and methyl cinnamate (2.1 mg g−1), whereas the amounts of other compounds were between 0.01 and 0.1 mg g−1. It is suggested that the content of the terpenes within dodder, which was rather high in amount (0.41–2.1 mg g−1), correlated to its strength of chemical cues to find host plants. Cinnamic acid, DDK, methyl cinnamate, and vanillin exerted the most potent herbicidal activities against radish growth. Findings of this study propose that cinnamic acid, DDK, and methyl cinnamate are responsible for its strong phytotoxic action of dodder plants. However, whether these plant growth inhibitors and other compounds detected from the dodder can suppress emergence of their hosts as well as contributing to its strong invasiveness needs further elucidation.
Abstract:In recent years, Non-Point Source Pollution has been rising as a significant environmental issue. The sediment-laden water problem is causing serious impacts on river ecosystems not only in South Korea but also in most countries. The vegetative filter strip (VFS) has been thought to be one of the most effective methods to reduce the transport of sediment to down-gradient area. However, the effective width of the VFS first needs to be determined before VFS installation in the field. To provide an easy-to-use interface with a scientific VFS modeling engine, the Web GIS-based VFSMOD system was developed in this study. The Web GIS-based VFSMOD uses the UH and VFSM executable programs from the VFSMOD-w model as core engines to simulate rainfall-runoff and sediment trapping. To provide soil information for a point of interest,
OPEN ACCESSWater 2013, 5 1195 the Google Map interface to the MapServer soil database system was developed using the Google Map API, Javascript, Perl/CGI, and Oracle DB programming. Three modules of the Web GIS-based VFSMOD system were developed for various VFS designs under single storm, multiple storm, and long-term period scenarios. These modules in the Web GIS-based VFSMOD system were applied to the study watershed in South Korea and these were proven as efficient tools for the VFS design for various purposes.
We performed bias correction in future climate change scenarios to provide better accuracy of models through adaptation to future climate change. The proposed combination of the change factor (CF) and quantile mapping (QM) methods combines the individual advantages of both methods for adjusting the bias in global circulation models (GCMs) and regional circulation models (RCMs). We selected a study site in Songwol-dong, Seoul, Republic of Korea, to test and assess our proposed method. Our results show that the combined CF + QM method delivers better performance in terms of correcting the bias in GCMs/RCMs than when both methods are applied individually. In particular, our proposed method considerably improved the bias-corrected precipitation by capturing both the high peaks and amounts of precipitation as compared to that from the CF-only and QM-only methods. Thus, our proposed method can provide high-accuracy bias-corrected precipitation data, which could prove to be highly useful in interdisciplinary studies across the world.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.