Root turnover and productivity of coniferous forests

Fine roots and mycorrhizae have recently been shown to produce a major portion of the organic matter entering decomposition. Roots and mycorrhizae constitute 63 to 70% of total net primary production in Douglas-fir and Pacific silver fir stands. The importance of roots in primary production makes the method of root extraction from the soil important. Wet-sieving with small mesh screens is more effective than hand-sorting for fine roots and mycorrhizae. Screen size, the efficiency of recovery, the physiological status of the roots and coversion factors to derive biomass from the numbers of root tips should be stated. Published data is enhanced if the phenological status of the stand, its age, tree density, and soil texture are quoted.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43475/1/11104_2005_Article_BF02182643.pd

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

The effect of drainage on nutrient release from fen peat and its implications for water quality:a laboratory simulation

The effect of peat moisture status on N, S, Ca, and Mg release to drainage waters was examined using a constant temperature laboratory incubation. Peat samples originating from drained and undrained sites in West Sedgemoor, Somerset Levels, SW England were compared. Three treatments: long term waterlogging, aeration, and fluctuating aeration and waterlogging were imposed on all peat samples. These treatments resulted in different rates and total amounts of N, S, Ca, and Mg release, with waterlogging resulting in highest solute release. The total amounts and rates of release of S, Ca, and Mg from peat that was undrained prior to incubation always exceeded that from drained site peat samples regardless of peat moisture status. Although the degree of waterlogging or aeration affected the rate and total amount of watersoluble N released during incubation, there was no difference between peat that was drained, and peat that was undrained, prior to incubation. Drainage of currently undrained and waterlogged peat in West Sedgemoor will result in the transfer of high concentrations of S, Ca, and Mg from the peat to the drainage ditch