Comparison of Lactuca sativa growth performance in conventional and RAS-based hydroponic systems

A recent study related to aquaponics has shown that hydroponic lettuce grown in aquaculture-derived supplemented water grew significantly better than lettuce grown in a conventional hydroponic system. The principal objective of this study was to verify this finding in a larger setup. Even though the aquaculture water that was added to the aquaculture-based hydroponic system contained relatively high amounts of sodium, we were still able to observe an enhanced growth performance of the lettuce in that system compared to the lettuce grown in the conventional hydroponic nutrient solution. The lettuce final fresh weight was 7.9%, and its final dry weight even 33.2% higher than the one of the hydroponic control.</p

Slateelt op water in plastic tunnels en onder glas met LED-licht : teelt de Grond uit, onderzoek 2014-2017

A shift occurs in leaf crops from field cultivation to cultivation in plastic tunnels and glass greenhouses. As part of the research program ‘Teelt de Grond uit’, funded by Dutch Topsector Horticulture, WUR Greenhouse Horticulture conducted research into the optimization of lettuce cultivation on water in a plastic ‘cabrio’ tunnel greenhouse with LED lighting. High-quality lettuce could be grown, but especially in the case of iceberg lettuce, the growing season was too long in the winter season. The growth of lettuce was stimulated by a higher light intensity of the LEDs, higher room and water temperatures and the addition of a bio-stimulant. A higher plant density gave smaller heads, but more kilos per unit area. In follow-up research in a glass greenhouse, very fast cultivation was realized by applying a lot of LED grow light, high temperatures, humidification and a high CO2 content. The average cultivation time from sowing to harvesting in the dark months of the year was about 40 days. With this cultivation method, 3 times more lettuce heads could be harvested than in a cultivation of heavy lettuce without lighting. A problem was the regular occurrence of tipburn. There were clear differences between lettuce types and cultivars. A very high RH in the night largely prevented the occurrence of tipburn in the final phase of cultivation. The cost price of this cultivation method approaches that of the cultivation of heavy lettuce in the soil

Overzichtsdocument: 7 jaar Chrysant op water

Over a period of seven years (2009-2016) hydroponic chyrsanthemum cultivation has been developed andtested in practice. Where the system delivered up to 25% higher yields at smaller scale, the larger systems of250-300 m2 turned out very sensitive to root infection. Research then focussed to understanding the key factorsthat caused the plants to become sensitive. However, where the larger system showed much disease incidenceevery summer for three years in a row, at smaller scale the symptoms could not be induced despite applicationof extreme cultivation measures.The studies were the first to apply next generation sequencing to microbial populations in cultivation systems.The results gave evidence for shifting population dynamics due to inoculation and water temperature. Also theinoculation with beneficial microbes was found to have a positive effect on recovery of the roots upon infection.This effect, however, was only found in the research-facility. At larger scale potential beneficial effect could notprevent significant yield loss

Gene expression profiling in pachyonychia congenita skin

BACKGROUND: Pachyonychia congenita (PC) is a skin disorder resulting from mutations in keratin (K) proteins including K6a, K6b, K16, and K17. One of the major symptoms is painful plantar keratoderma. The pathogenic sequelae resulting from the keratin mutations remain unclear. OBJECTIVE: To better understand PC pathogenesis. METHODS: RNA profiling was performed on biopsies taken from PC-involved and uninvolved plantar skin of seven genotyped PC patients (two K6a, one K6b, three K16, and one K17) as well as from control volunteers. Protein profiling was generated from tape-stripping samples. RESULTS: A comparison of PC-involved skin biopsies to adjacent uninvolved plantar skin identified 112 differentially-expressed mRNAs common to patient groups harboring K6 (i.e., both K6a and K6b) and K16 mutations. Among these mRNAs, 25 encode structural proteins including keratins, small proline-rich and late cornified envelope proteins, 20 are related to metabolism and 16 encode proteases, peptidases, and their inhibitors including kallikrein-related peptidases (KLKs), and serine protease inhibitors (SERPINs). mRNAs were also identified to be differentially expressed only in K6 (81) or K16 (141) patient samples. Furthermore, 13 mRNAs were identified that may be involved in pain including nociception and neuropathy. Protein profiling, comparing three K6a plantar tape-stripping samples to non-PC controls, showed changes in the PC corneocytes similar, but not identical, to the mRNA analysis. CONCLUSION: Many differentially-expressed genes identified in PC-involved skin encode components critical for skin barrier homeostasis including keratinocyte proliferation, differentiation, cornification, and desquamation. The profiling data provide a foundation for unraveling the pathogenesis of PC and identifying targets for developing effective PC therapeutics

Towards commercial aquaponics: a review of systems, designs, scales and nomenclature

Aquaponics is rapidly developing as the need for sustainable food production increases and freshwater and phosphorous reserves shrink. Starting from small-scale operations, aquaponics is at the brink of commercialization, attracting investment. Arising from integrated freshwater aquaculture, a variety of methods and system designs has developed that focus either on fish or plant production. Public interest in aquaponics has increased dramatically in recent years, in line with the trend towards more integrated value chains, greater productivity and less harmful environmental impact compared to other production systems. New business models are opening up, with new customers and markets, and with this expansion comes the potential for confusion, misunderstanding and deception. New stakeholders require guidelines and detail concerning the different system designs and their potentials. We provide a definitive definition of aquaponics, where the majority (> 50%) of nutrients sustaining the optimal plant growth derives from waste originating from feeding aquatic organisms, classify the available integrated aquaculture and aquaponics (open, domestic, demonstration, commercial) systems and designs, distinguish four different scales of production (≤ 50, > 50–≤ 100 m2, > 100–≤ 500 m2, > 500 m2) and present a definite nomenclature for aquaponics and aquaponic farming allowing distinctions between the technologies that are in use. This enables authorities, customers, producers and all other stakeholders to distinguish between the various systems, to better understand their potentials and constraints and to set priorities for business and regulations in order to transition RAS or already integrated aquaculture into commercial aquaponic systems