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Seasonal characterization of antioxidant responses in plants of Ipomoea nil cv. Scarlet O'Hara.
Braz J Biol. 2012 Nov;72(4):831-7
Authors: Ferreira ML, Domingos M
Abstract Reactive oxygen species can be produced in leaf cells during normal aerobic metabolism or in a variety of exogenous factors, which may cause oxidative damage to plants, unless they have an efficient antioxidant defense system, consisting of enzymatic and non-enzymatic substances. This work raised the hypothesis that plants of Ipomoea nil cv. Scarlet O'Hara, a native species and ornamental vine of the tropics, might tolerate oxidative stress factors imposed by natural fluctuations in weather conditions through changes in the antioxidant profile.The objective of this study was to determine the variations in three leaf antioxidants in plants growing inside a greenhouse without air pollutants and exposed to varying meteorological conditions throughout the four seasons of the year and to observe if such variations are related to the oscillations in meteorological factors. Four experimental campaigns were carried out, one in each season of 2006. Each campaign lasted 28 days and started with 45 plants. Ascorbic acid (AA) concentrations and superoxide dismutase (SOD) and peroxidase (POD) activities were determined in leaves of five plants in nine sampling days of each campaign. The antioxidant responses oscillated throughout the year. The highest values were found during the spring. This seasonal antioxidant profile was associated to variations in temperature, relative humidity and global radiation. Plants of this cultivar may then tolerate oxidative stress naturally imposed by meteorological conditions.
PMID: 23295511 [PubMed - indexed for MEDLINE]
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A tiny plant that bows down to bury its seeds was recently discovered in rural northeastern Bahia, Brazil, one of the world's most biologically diverse areas.
For the first time in the history of medicinal plant research, Ethnopharmacology of Medicinal Plants: Asia and the Pacific sheds light on the pharmacological potentials of one of the most exiting and enormously rich sources of potential drugs: the medicinal plants of the Pacific Rim. Encompassing more than 6000 species of plant that are virtually unexplored for pharmacology, this volume ...
For local readers, a quick note: Linda Jennings, collections manager of the UBC Herbarium, is giving a talk on "Women Botanists of Western North America" this Thursday evening (see announcement on the Native Plant Society of BC web site). I'm not sure if it's a coincidence that it occurs so near to International Women's Day (March 8).
Also, the next BPotD series coming up is our annual focus on UBC plant research for UBC's Celebrate Research Week. That one will be followed later in the month by our March educational theme, "Biodiversity and the North".
Today's photograph is courtesy of Jordan, aka jrdnz@Flickr (original image | Creative Commons License). Many thanks.
Lindsay Bourque is responsible for today's write-up:
Throughout this series on sports and biodiversity, Botany Photo of the Day has featured plants that have contributed to the development of sports. However, the increase in sport recreation has also taken it toll on the environment. A 1994 study by the United States Forest Service concluded that habitat destruction was the leading cause of species endangerment, threatening 80 percent or more of federally listed species. In a separate study, recreation was found to affect 23-26 percent of threatened or endangered species with the most detrimental affect coming from the improper use of off-road vehicles. These vehicles can also cause acceleration of soil compaction and erosion, pollution of water and air, destruction of vegetation, and spread of invasive plant species.
There has been an ongoing battle between environmental protection groups and off-roading advocacy groups in Imperial County in southeast California regarding the use of the Imperial Sand Dunes Recreation Area (sometimes called the "Glamis Dunes"). On a peak weekend, upwards of 100 000 riders recreate in the dunes. Within the 720 km2 Recreation Area, the 105 km2 Algodones Dunes Wilderness Area (PDF map) forms a unique ecosystem fostering a number of endemic species. Some of these species are now endangered, primarily due to habitat loss previously caused by off-road vehicles. One species listed as threatened under the US Endangered Species Act is Astragalus magdalenae var. peirsonii, a desert ephemeral found only in the Algodones Dunes. Commonly known as Peirson's milkvetch, this attractive silvery plant germinates only during years of sufficient rainfall. Peirson's milkvetch produces the largest seeds of any milkvetch, providing an exceptional reservoir of stored carbohydrate for the next generation of plants to tap when germinating deep in the sand. In 2000, 200 km2 of the Algodones Dunes (including the Wilderness Area and buffer zones) were closed to off-road vehicles. Later studies showed the population rebounding. The Bureau of Land Management (BLM) is now reviewing the closure decision and may re-open portions of the dunes to off-road vehicles.
Again, I can't find any suitably-licensed photographs, so today's BPotD features more illustrations from the public domain work, Köhler's Medizinal Pflanzen (via Wikimedia Commons, image 1 | image 2). For photographs of Strychnos nux-vomica, please visit the Wikimedia Commons page: Strychnos nux-vomica.
Continuing with the "biodiversity and sports" series:
Most modern performance-enhancing drugs used in sports are either derived from animals or manufactured synthetically. However, some of the first performance-enhancing drugs were derived from plants, including an alkaloid present in large quantities in the two species featured today. Both Strychnos nux-vomica and Strychnos ignatii contain high quantities of strychnine (or, "rat poison").
Strychnos nux-vomica, or the strychnine tree, and Strychnos ignatii, or Ignatius-bean, are both native to tropical Asia, though the latter species also extends into warm temperate China. Individual trees of Strychnos nux-vomica grow to 25m (to 82ft.); Strychnos ignatii, on the other hand, is a liana, or woody vine. It climbs surrounding trees, reaching a maximum height of around 20m (65 ft.). Both species, though, were (are?) used in the production of traditional medicines.
Strychnine was first isolated as a chemical compound from the fruit of Strychnos ignatii in the early 19th century, though it wasn't until the mid-20th century that its chemical structure was determined. Strychnos nux-vomica is the most common source of this alkaloid. It is a stimulant; in lethal doses, it kills through muscular convulsions leading to either asphyxiation or exhaustion. Smaller doses of this muscle stimulant, however, can enhance athletic ability, and it is one of the first performance-enhancing drugs used in the modern Olympic games. In the 1904 Olympics, US marathon runner Thomas J. Hicks was injected with ~1mg of strychnine in solution--twice--and given brandy in order to complete the race and receive a gold medal. Read more: