Strategies to improve quality and safety and reduce cost of production in organic and low-input crop production systems. QLIF subproject 3: Crop production methods

Organic crop production seeks to produce high quality foods while reducing the inputs in order to promote environmental quality and conserve resources. This necessitates optimal production systems in terms of soil fertility and plant health. Studies in QLIF subproject 3 have shown that soils may gain an improved potential to release N from added amendments through adaptation of management practices. Likewise, long-term management strategies may influence suppressiveness of soils to economically important diseases. Application of manures and other organic soil fertility inputs do not pose any additional safety risk in ready-to-eat vegetables, such as head lettuce, if good farming practice is applied. Even under experimental worst-case conditions, pathogen transfer from soil treated with farmyard manure to vegetables was not substantial. Pest and disease control was studied both at seed and field levels, and it was shown, e.g., that ß-amino-butyric acid was efficient in controlling downy mildew in lettuce under field conditions. Finally, for organic wheat production systems, an integrated assessment indicated that yields and protein contents can be increased by improved cultivar choice and fertility management regimes promoting biological N fixation in the soil

Evaluation and registration of plant protection inputs for organic farming

Organic farmers may only use those plant protection products which are listed in Annex II B of the ‘Organic Regulation’ 2092/91 and also registered for use at national level. At present, new compounds may only be listed in Reg. 2092/91, if they do not come into direct contact with the crop (although in perennial crops, contact outside the growing season of the edible parts is possible), which is a major obstacle for progress. The EU-funded ORGANIC INPUTS EVALUATION project aims at making Reg. 2092/91 more flexible with regard to new products, while safeguarding the principles of organic farming. Registra-tion under the ‘Pesticide Directive’ 91/414 represents a considerable financial hurdle. The REBECA project will propose registration requirements which are better adapted for biological control agents, plant extracts and other low-risk products. The aim is to accelerate registration and make it more cost-effective, without compromises to the level of safety

Preliminary Results on Contents of Resveratrol in Wine of Organic and Conventional Vineyards

Phytoalexins are compounds synthesised by plants in response to various stresses. In grapevines, these compounds belong to the stilbene family. Several studies have shown that resveratrol is usually triggered by infection of berries by Botrytis cinerea. In organic viticulture, grapevines are usually more stressed by attempted or successful infections of various pathogens than in conventionally grown grapevines. Furthermore, crop protection agents such as acidified clays or copper may trigger defence reactions of the plants. The aim of this study was to verify if differences between organically and conventionally produced wines exist. The preliminary results will be used as a starting point for further research of quality aspects of organic grape-vine production

Development of strategies to improve quality and safety and reduce cost of production in organic and ‘low input‘ crop production systems

The overall aims of organic and low input crop production include the economically viable and environmentally sound production of high quality food and feed. Technological bottlenecks in such systems include insufficient and instable yields and in some instances unsatisfactory processing, sensory and/or nutritional quality of the final product. Recently, concerns have also been raised that the intensive use of manures may lead to increased risk for contamination of food by enteropathogenic micro-organisms. Crop production in low input systems is based on key pillars, i.e. (i) a fertile soil which provides sufficient capacity to allow for plant growth while preventing soil-borne diseases, (ii) high quality, disease-free seeds and plant material, (iii) a crop-specific soil fertility management to provide sufficient nutrients for optimum plant growth, and (iv) adequate crop protection techniques to prevent damage due to noxious organisms. In the QLIF project we develop improved component strategies to overcome technological bottlenecks in annual (wheat, lettuce, tomato) and perennial (apple) crop production systems. In this paper we report the progress achieved so far

Lamplighter model of a random copolymer adsorption on a line

We present a model of an AB-diblock random copolymer sequential self-packaging with local quenched interactions on a one-dimensional infinite sticky substrate. It is assumed that the A-A and B-B contacts are favorable, while A-B are not. The position of a newly added monomer is selected in view of the local contact energy minimization. The model demonstrates a self-organization behavior with the nontrivial dependence of the total energy, $E$ (the number of unfavorable contacts), on the number of chain monomers, $N$: $E\sim N^{3/4}$ for quenched random equally probable distribution of A- and B-monomers along the chain. The model is treated by mapping it onto the "lamplighter" random walk and the diffusion-controlled chemical reaction of $X+X\to 0$ type with the subdiffusive motion of reagents.Comment: 8 pages, 5 figure

Functional consequences of the asymmetric architecture of the ctenophore statocyst

Author Posting. © Marine Biological Laboratory, 2015. This article is posted here by permission of Marine Biological Laboratory for personal use, not for redistribution. The definitive version was published in Biological Bulletin 229 (2015): 173-184.Ctenophores, or comb jellies, are geotactic with a statocyst that controls the activity of the eight ciliary comb rows. If a ctenophore is tilted or displaced from a position of vertical balance, it rights itself by asymmetric frequencies of beating on the uppermost and lowermost comb rows, turning to swim up or down depending on its mood. I recently discovered that the statocyst of ctenophores has an asymmetric architecture related to the sagittal and tentacular planes along the oral-aboral axis. The four groups of pacemaker balancer cilia are arranged in a rectangle along the tentacular plane, and support a superellipsoidal statolith elongated in the tentacular plane. By controlled tilting of immobilized ctenophores in either body plane with video recording of activated comb rows, I found that higher beat frequencies occurred in the sagittal than in the tentacular plane at orthogonal orientations. Similar tilting experiments on isolated statocyst slices showed that statolith displacement due to gravity and the resulting deflection of the mechanoresponsive balancers are greater in the sagittal plane. Finally, tilting experiments on a mechanical model gave results similar to those of real statocysts, indicating that the geometric asymmetries of statolith design are sufficient to account for my findings. The asymmetric architecture of the ctenophore statocyst thus has functional consequences, but a possible adaptive value is not known

Formation of the statolith in the ctenophore Mnemiopsis leidyi

Author Posting. © Marine Biological Laboratory, 2014. This article is posted here by permission of Marine Biological Laboratory for personal use, not for redistribution. The definitive version was published in Biological Bulletin 227 (2014): 7-18.The aboral sensory organ (apical organ) of ctenophores contains a statocyst with a single large statolith. The statolith comprises living cells (lithocytes), each containing a large membrane-bound concretion. The statolith is supported on the distal ends of four compound motile mechanoresponsive cilia (balancers) which control the beat frequencies of the eight locomotory comb rows, and thereby the orientation of animals to gravity. In Mnemiopsis leidyi and Pleurobrachia pileus, lithocytes arise in the thickened epithelial floor of the apical organ on opposite sides along the tentacular plane. Lithocytes progressively differentiate and migrate toward the apical surface where they bud off next to the bases of the balancers. New lithocytes are transported up the balancers by ciliary surface motility to form the statolith (Noda, 2013). The statolith has a superellipsoidal shape due to the rectangular arrangement of the four balancers and the addition of new lithocytes to its ends via the balancers. The size of the statolith increases with animal size, starting at the highest rate of growth in younger stages and gradually decreasing in larger animals. The total number of developing lithocytes in the epithelial floor increases rapidly in smaller animals and reaches a plateau range in larger animals. Lithocytes are therefore produced continually throughout life for enlargement of the statolith and possibly for turnover and replacement of existing lithocytes. The dome cilia enclosing the statocyst were observed to propagate slow, low-ampitude waves distally. The dome cilia may act as an undulating screen to prevent foreign objects in the seawater from being transported non-specifically up the balancers to make a defective statolith