Laser-actuated holographic storage device

Device permits automatic selection of one out of thousands of pages in holographic memory system by using laser beam. In typical operation for 2 to 3 C temperature interval, using dc power supply with no power regulation, holograms were successfully written and erased over 2- by 2-cm area, using 80-mW argon laser beam

Impact of Root Herbivory on Grassland Community Structure: From Landscape to Microscale

Root herbivores are an important functional group in grassland ecosystems. Whilst there is a plethora of information on their impact as pests in productive grassland, few studies of their impact on biodiversity in upland grassland have been made. Root herbivores act in a number of ways, they reduce host plant biomass, alter root architecture, change root exudation patterns and increase water stress in the plant. Root herbivores may change above ground plant diversity, both through direct removal of plant species and through reduction in competitive ability of some species, through their feeding. In addition, we postulate that root herbivores affect soil microbial communities through changes in root exudation

Soil Biodiversity, Root Herbivory and Carbon and Nitrogen Cycling in Grassland Soils

This paper describes research on the relationships between grassland management practices and the diversity of biological communities in soil. Observations are being made in field trials with applications of nitrogen and lime and of insecticide to an original diverse sward and to a single species grass re-seed. The treatments are designed to produce different degrees of diversity in communities of soil animals and microbes. Assessments are being made over three years of the effects on the populations, activity and diversity of root-feeding animals, arbuscular mycorrhizal fungi, soil bacteria, fungi and micro fauna, including nonplant feeding nematodes. Associated laboratory experiments assess the effects of root herbivores with different feeding sites and mechanisms on the quality and quantity of rhizosphere deposition and it relationship to microbial communities. In this way, we shall develop an understanding of the relationships between root-herbivory and soil biodiversity and between of biodiversity and soil energy and nutrient transformations

Can arbuscular mycorrhizal fungi be used to control the undesirable grass Poa annua on golf courses

Summary 1. Poa annua (annual meadow-grass or annual bluegrass) is the most problematic weed of temperate zone golf putting greens. In the UK there are no chemicals approved for its control, although several herbicides and plant growth regulators are available in the USA. Reducing P. annua levels in ®ne turf would greatly reduce the heavy reliance on pesticides and water that currently exists. 2. This paper reports on an observational and a manipulative study in golf putting greens, aimed at determining whether arbuscular mycorrhizal (AM) fungi have any potential for the reduction of this weed in ®ne turf. 3. All 18 greens on three golf courses were sampled, and in two courses a negative relation between AM fungi and P. annua abundance was found, upholding previous results. In greens where AM fungi were relatively common (as measured by root colonization), P. annua was rare, and vice versa. Furthermore, when the fungi were common, abundance of the desirable turfgrass Agrostis stolonifera was greater. 4. Two explanations are suggested for these relations, a competitive one, in which AM fungi alter the balance of competition between the two grasses, and an antagonistic one, in which the fungi may directly reduce the growth of P. annua. 5. In a manipulative experiment, where mycorrhizal inoculum was added to a golf green, the colonization level of A. stolonifera roots was enhanced, as was the abundance of this grass. Furthermore, there was a suggestion that adding inoculum could decrease the abundance of P. annua. 6. AM fungi have the potential to be a much more environmentally sound method of P. annua control in sports turf than the currently used chemicals