Carbon distribution within the plant and rhizosphere for Lolium perenne subjected to anaerobic soil conditions

Perennial ryegrass was subjected to a range of anaerobic treatments. The distribution of C within the plant was determined by pulse labelling the shoots with ¹⁴C-CO₂. A 5 h anaerobic period before pulse labelling reduced by 2.5-10 times the ¹⁴C remaining in the plants and released into the soil. The distribution of the ¹⁴C within the plant was also affected by anaerobiosis. Short periods of anaerobiosis (5 or 10 h) led to increased root-soil ¹⁴C respiration (monitored for 7 days). A longer period of anaerobiosis (48 h) initially inhibited root-soil ¹⁴C respiration, but when aerobiosis was restored. 57% of the total ¹⁴C fixed by the plant was respired by the roots-soil during the following 7 days compared to 19% for the aerobic control. There was a two-thirds reduction in the percentage C retained by the plants stressed for the 48 h compared to the aerobic control. At harvest, all anaerobic treatments were associated with more ¹⁴C remaining in the soil as a proportion of the total ¹⁴C fixed by the plant compared to the aerobic control. © 1990.

Distribution of assimilated carbon within the plant and rhizosphere of Lolium perenne:Influence of temperature

Perennial rye-grass plants were pulse labelled with [¹⁴C]-CO₂ over a range of temperatures (5-25°C). The fate of the label was determined within the plant and soil. The temperature at which plants were pulse labelled had a marked effect on the distribution of the label within the plant and soil system. Root-soil respiration increased from 5.7 to 24.15% when expressed as a percentage of net assimilated label. The percentage of label remaining in the plant root and in the soil was greater at 5 and 25°C, with a minimum for both these components at 15°C. At 15°C the percentage of net assimilated label that remained in the shoots was greater than at other temperatures, with this percentage decreasing at the lower and higher temperatures. © 1989.

Biosecurity and Emerging Plant Health Problems in Turf Production and Maintenance

Recent research has supported the view that the distributions of many pests and diseases have extended towards higher latitudes over the last 50 years. Probably driven by a combination of climate change and trade, this extension to the ranges of hundreds of plant pathogens may have serious implications not only for agriculture, horticulture and forestry, but also for turf production &maintenance. Here we review our data relating to the current status of three emerging pest and disease problems across North West Europe (rapid blight, Labyrinthula sp. , the root knot nematode, Meloidogyne minor and the pacific stem gall nematode, Anguina pacificae ) and discuss the factors which may be involved in their spread and increasing impact on the turf industry. With turf production and maintenance becoming an increasingly international business, we ask if biosecurity and the promotion of plant health in turf production fields and associated sport facilities should be a greater priority for the industry. We also examine if a lack of effective biosecurity measures in the materials supply chain has led to increased plant health problems.

Chp8, a diguanylate cyclase from Pseudomonas syringae pv tomato DC3000 suppresses the PAMP flagellin, increases EPS and promotes plant immune evasion.

The bacterial plant pathogen Pseudomonas syringae causes disease in a wide range of plants. The associated decrease in crop yields results in economic losses and threatens global food security. Competition exists between the plant immune system and the pathogen, the basic principles of which can be applied to animal infection pathways. P. syringae uses a type III secretion system (T3SS) to deliver virulence factors into the plant that promote survival of the bacterium. The P. syringae T3SS is a product of the hypersensitive response and pathogenicity (hrp) and hypersensitive response and conserved (hrc) gene cluster, which is strictly controlled by the codependent enhancer-binding proteins HrpR and HrpS. Through a combination of bacterial gene regulation and phenotypic studies, plant infection assays, and plant hormone quantifications, we now report that Chp8 (i) is embedded in the Hrp regulon and expressed in response to plant signals and HrpRS, (ii) is a functional diguanylate cyclase, (iii) decreases the expression of the major pathogen-associated molecular pattern (PAMP) flagellin and increases extracellular polysaccharides (EPS), and (iv) impacts the salicylic acid/jasmonic acid hormonal immune response and disease progression. We propose that Chp8 expression dampens PAMP-triggered immunity during early plant infection.

Method for rapid extraction of pectic substances from plant materials

A method is described for the rapid extraction of pectic substances from alcohol insoluble solids (AIS) from material of plant origin, especially fruit. Samples of AIS can be prepared for galacturonic acid assay within 60 min using extraction with 0·5m HCl in a Fibertec-1 system (Tecator) for 30 min. The extraction conditions are carefully standardised and operator error is reduced by the elimination of transfer steps, particularly during filtration. The results obtained for plant-derived alcohol insoluble solids containing from 10% to 33% pectic substances were in close agreement with those obtained by enzymic hydrolysis using a commercially available enzyme preparation (Ultrazyme). The method will have application in the rapid, routine estimation of pectic substances in plant materials. © 1987.

Species composition of coastal dune vegetation in Scotland has proved resistant to climate change over a third of a century

Climate change is expected to have an impact on plant communities as increased temperatures are expected to drive individual species' distributions polewards. The results of a revisitation study after c. 34years of 89 coastal sites in Scotland, UK, were examined to assess the degree of shifts in species composition that could be accounted for by climate change. There was little evidence for either species retreat northwards or for plots to become more dominated by species with a more southern distribution. At a few sites where significant change occurred, the changes were accounted for by the invasion, or in one instance the removal, of woody species. Also, the vegetation types that showed the most sensitivity to change were all early successional types and changes were primarily the result of succession rather than climate-driven changes. Dune vegetation appears resistant to climate change impacts on the vegetation, either as the vegetation is inherently resistant to change, management prevents increased dominance of more southerly species or because of dispersal limitation to geographically isolated sites.

An optimized process design for oxymethylene ether production from woody-biomass-derived syngas

The conversion of biomass for the production of liquid fuels can help reduce the greenhouse gas (GHG) emissions that are predominantly generated by the combustion of fossil fuels. Oxymethylene ethers (OMEs) are a series of liquid fuel additives that can be obtained from syngas, which is produced from the gasification of biomass. The blending of OMEs in conventional diesel fuel can reduce soot formation during combustion in a diesel engine. In this research, a process for the production of OMEs from woody biomass has been simulated. The process consists of several unit operations including biomass gasifi- cation, syngas cleanup, methanol production, and conversion of methanol to OMEs. The methodology involved the development of process models, the identification of the key process parameters affecting OME production based on the process model, and the development of an optimal process design for high OME yields. It was found that up to 9.02 tonnes day1 of OME3, OME4, and OME5 (which are suitable as diesel additives) can be produced from 277.3 tonnes day1 of wet woody biomass. Furthermore, an optimal combination of the parameters, which was generated from the developed model, can greatly enhance OME production and thermodynamic efficiency. This model can further be used in a techno- economic assessment of the whole biomass conversion chain to produce OMEs. The results of this study can be helpful for petroleum-based fuel producers and policy makers in determining the most attractive pathways of converting bio-resources into liquid fuels.

Exogenous RNA interference exposes contrasting roles for sugar exudation in host-finding by plant pathogens

Plant parasitic nematodes (PPN) locate host plants by following concentration gradients of root exudate chemicals in the soil. We present a simple method for RNA interference (RNAi)-induced knockdown of genes in tomato seedling roots, facilitating the study of root exudate composition, and PPN responses. Knockdown of sugar transporter genes, STP1 and STP2, in tomato seedlings triggered corresponding reductions of glucose and fructose, but not xylose, in collected root exudate. This corresponded directly with reduced infectivity and stylet thrusting of the promiscuous PPN Meloidogyne incognita, however we observed no impact on the infectivity or stylet thrusting of the selective Solanaceae PPN Globodera pallida. This approach can underpin future efforts to understand the early stages of plant-pathogen interactions in tomato and potentially other crop plants.

A rising e-channel tide lifts all boats? the impact of manufacturer multi-channel encroachment on traditional selling and leasing

Organizing and managing channels of distribution is an important marketing task. Due to the emergence of electronic commerce on the Internet, e-channel distribution systems have been adopted by many manufacturers. However, academic and anecdotal evidence both point to the pressures arising from this new e-channel manufacturing environment. Questions marks therefore remain on how the addition of this e-channel affects the traditional marketing strategies of leasing and selling. We set up several two-period dual-channel models in which a manufacturer sells a durable product through both a manufacturer-owned e-channel and an independent reseller (leaser) who adopts selling (leasing) to consumers. Our main results indicate that, direct selling cost aside, product durability plays an important role in shaping the strategies of all members. With either marketing strategy, the additional expansion of an e-channel territory may secure Pareto gains, in which all members benefit.

Implementation of a cogeneration plant for a food processing facility. A case study

The present work presents an investigation regarding the feasibility analysis of a cogeneration plant for a food processing facility with the aim to decrease the cost of energy supply. The monthly electricity and heat consumption profiles are analyzed, in order to understand the consumption profiles, as well as the costs of the current furniture of electricity and gas. Then, a detailed thermodynamic model of the cogeneration cycle is implemented and the investment costs are linked to the thermodynamic variables by means of cost functions. The optimal electricity power of the co-generator is determined with reference to various investment indexes. The analysis highlights that the optimal dimension varies according to the chosen indicator, therefore it is not possible to establish it univocally, but it depends on the financial/economic strategy of the company through the considered investment index.