نتایج جستجو برای: annual plants
تعداد نتایج: 304538 فیلتر نتایج به سال:
In the search for better herbicides a series of 1-alkyl-3-(alpha-hydroxy-(un)substituted benzylidene)pyrrolidine-2,4-diones were prepared and their structure-activity relationships studied. All their structures have been confirmed by (1)H-NMR and elemental analysis. The preliminary bioassay results indicated that some of them have high herbicidal activity against annual dicotyledonous and monoc...
Plant water use affects competition for nitrogen: why drought favors invasive species in California.
Abstract: Classic resource competition theory typically treats resource supply rates as independent; however, nutrient supplies can be affected by plants indirectly, with important consequences for model predictions. We demonstrate this general phenomenon by using a model in which competition for nitrogen is mediated by soil moisture, with competitive outcomes including coexistence and multiple...
In desert ecosystems, plant growth and nutrient uptake are restricted by availability of soil nitrogen (N) and phosphorus (P). The effects of both climate and soil nutrient conditions on N and P concentrations among desert plant life forms (annual, perennial and shrub) remain unclear. We assessed leaf N and P levels of 54 desert plants and measured the corresponding soil N and P in shallow (0-1...
The teosintes, the closest wild relatives of maize, are important resources for the study of maize genetics and evolution and for plant breeding. We genotyped 237 individual teosinte plants for 93 microsatellites. Phylogenetic relationships among species and subspecific taxa were largely consistent with prior analyses for other types of molecular markers. Plants of all species formed monophylet...
Feeding habits of yellowfin seabream, Acanthopagrus latus in the northern region of the Persian Gulf
Feeding habits of yellowfin seabream, Acanthopagrus latus was investigated in coastal waters of the Northern Persian Gulf. This investigation was conducted by monthly sampling of thirty fish from September 2011 through August 2012. Fish size ranged from 17.98 ± 2.07 to 32.31 ± 6.52 cm in total length and from 134.01 ± 45.62 to 720.46 ± 292.58 g in weight. The highest value of gastro-somatic ind...
The aim of this study was to describe the incidence distribution of colorectal cancer in Fortaleza, Ceará State, and Porto Alegre, Rio Grande do Sul State, Brazil, and the time trend in the disease from 1990 to 1999. Mean annual age-adjusted incidence rates and estimated annual percent change were calculated by gender, using population-based cancer registries. EAPC showed an increase in the rat...
Each Local Research Ethics Committee (LREC) is expected to produce an annual report for its establishing authority. Reports from 145 LRECs were examined with regard to (a) whether the committees were working within the terms of the most recent guidelines from the Department of Health and (b) observations on the role of LRECs with particular reference to accountability. Most LRECs had produced a...
On 28 January 2010 the European Centre for Disease Prevention and Control (ECDC) and the European Food Safety Authority (EFSA) launched their annual report on zoonoses and food-borne outbreaks for 2008. The report provides a comprehensive overview of zoonotic infections and disease outbreaks caused by consuming contaminated food. The number of reported human cases of the three most reported zoo...
Medusahead (Taeniatherum caput-medusae (L.) Nevski) is an exotic annual grass invading rangelands in the western United States. Medusahead is a serious management concern because it decreases biodiversity, reduces livestock forage production, and degrades the ecological function of rangelands. Despite the obvious importance of ranchers as partners in preventing and managing medusahead in rangel...
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