| 1. |
- Ahlman, Linnéa, 1987, et al.
(författare)
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Stress Detection Using Proximal Sensing of Chlorophyll Fluorescence on the Canopy Level
- 2021
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Ingår i: AgriEngineering. - : MDPI AG. - 2624-7402. ; 3:3, s. 648-668
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Tidskriftsartikel (refereegranskat)abstract
- Chlorophyll fluorescence is interesting for phenotyping applications as it is rich in biological information and can be measured remotely and non-destructively. There are several techniques for measuring and analysing this signal. However, the standard methods use rather extreme conditions, e.g., saturating light and dark adaption, which are difficult to accommodate in the field or in a greenhouse and, hence, limit their use for high-throughput phenotyping. In this article, we use a different approach, extracting plant health information from the dynamics of the chlorophyll fluorescence induced by a weak light excitation and no dark adaption, to classify plants as healthy or unhealthy. To evaluate the method, we scanned over a number of species (lettuce, lemon balm, tomato, basil, and strawberries) exposed to either abiotic stress (drought and salt) or biotic stress factors (root infection using Pythium ultimum and leaf infection using Powdery mildew Podosphaera aphanis ). Our conclusions are that, for abiotic stress, the proposed method was very successful, while, for powdery mildew, a method with spatial resolution would be desirable due to the nature of the infection, i.e., point-wise spread. Pythium infection on the roots is not visually detectable in the same way as powdery mildew; however, it affects the whole plant, making the method an interesting option for Pythium detection. However, further research is necessary to determine the limit of infection needed to detect the stress with the proposed method.
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| 2. |
- Alsanius, Beatrix, et al.
(författare)
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Dining in Blue Light Impairs the Appetite of Some Leaf Epiphytes
- 2021
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: The phyllosphere is subjected to fluctuating abiotic conditions. This study examined the phenotypic plasticity (PP) of four selected non-phototrophic phyllosphere bacteria [control strain: Pseudomonas sp. DR 5-09; Pseudomonas agarici, Bacillus thuringiensis serovar israeliensis (Bti), and Streptomyces griseoviridis (SG)] regarding their respiration patterns and surfactant activity as affected by light spectrum and nutrient supply.Methods: The PP of the strains was examined under four light regimes [darkness (control); monochromatic light-emitting diodes (LED) at 460 nm (blue) and 660 nm (red); continuously polychromatic white LEDs], in the presence of 379 substrates and conditions.Results: Light treatment affected the studied bacterial strains regarding substrate utilization (Pseudomonas strains > SG > Bti). Blue LEDs provoked the most pronounced impact on the phenotypic reaction norms of the Pseudomonas strains and Bti. The two Gram-positive strains Bti and SG, respectively, revealed inconsistent biosurfactant formation in all cases. Biosurfactant formation by both Pseudomonas strains was supported by most substrates incubated in darkness, and blue LED exposure altered the surface activity profoundly. Blue and white LEDs enhanced biofilm formation in PA in highly utilized C-sources. Putative blue light receptor proteins were found in both Pseudomonas strains, showing 91% similarity with the sequence from NCBI accession number WP_064119393.Conclusion: Light quality–nutrient interactions affect biosurfactant activity and biofilm formation of some non-phototrophic phyllosphere bacteria and are, thus, crucial for dynamics of the phyllosphere microbiome.
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| 3. |
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| 4. |
- Alsanius, Beatrix, et al.
(författare)
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Light and Microbial Lifestyle: The Impact of Light Quality on Plant-Microbe Interactions in Horticultural Production Systems-A Review
- 2019
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Ingår i: Horticulturae. - : MDPI AG. - 2311-7524. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Horticultural greenhouse production in circumpolar regions (>60 degrees N latitude), but also at lower latitudes, is dependent on artificial assimilation lighting to improve plant performance and the profitability of ornamental crops, and to secure production of greenhouse vegetables and berries all year round. In order to reduce energy consumption and energy costs, alternative technologies for lighting have been introduced, including light-emitting diodes (LED). This technology is also well-established within urban farming, especially plant factories. Different light technologies influence biotic and abiotic conditions in the plant environment. This review focuses on the impact of light quality on plant-microbe interactions, especially non-phototrophic organisms. Bacterial and fungal pathogens, biocontrol agents, and the phyllobiome are considered. Relevant molecular mechanisms regulating light-quality-related processes in bacteria are described and knowledge gaps are discussed with reference to ecological theories.
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| 5. |
- Alsanius, Beatrix, et al.
(författare)
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New challenges for organic greenhouse horticulture in Sweden
- 2020
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; , s. 1079-1084
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Swedish consumers buy increasing amounts of organic food. Also, the Swedish Government aspires to increase food sovereignty and volume of organic food stuff in public meals from 36 (2017) to 60% in 2030. There is a substantial mismatch between demand and the production of organic vegetables. Today, 4.9% of the total greenhouse area in Sweden is used for organic production. The majority of organic production of greenhouse vegetables in Sweden is performed in containers and confined beds. The approval of the revised European regulation for organic farming in 2018 reinforces production in natural soil, leads to dramatic changes for organic greenhouse horticulture in Sweden. Confined beds need to be phased out. Cultivation methods that conserve or increase organic matter in the soil should be used. Thus, soil bound systems using crop rotations and soil fertility maintaining activities need to be implemented. This corroborates with increased burden of soil borne diseases and lower yields. Such systems, well established in southern Europe, cannot be translated to northern European conditions, due to constraints in climate and day length, as well as constraints due to greenhouse construction (permanent construction). This presentation displays the challenges and consequences to meet the changed legislation.
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| 6. |
- Alsanius, Beatrix, et al.
(författare)
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Rooftop aquaponics
- 2017
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Ingår i: Rooftop urban agriculture. - Cham : Springer International Publishing. - 9783319577197 ; , s. 103-112
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Bokkapitel (refereegranskat)
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| 7. |
- Alsanius, Beatrix, et al.
(författare)
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Sustainable Greenhouse Systems - the Potential of Microorganisms
- 2011
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; , s. 155-167
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Konferensbidrag (refereegranskat)abstract
- Due to the high input of means of production and productivity, environmental issues have been highlighted in horticulture for some years. They concern the impact of horticultural production systems on the environment in a narrow (i.e., occupational, crop) and broader (CO2 emission, nutrient leakage, chemical pollution) sense. In all production systems, multiple plant-microbial interactions occur. The resident microflora may be plant growth-enhancing, -neutral or -deleterious. Also microorganisms hazardous to the consumer may occur. To create sustainable horticultural cropping systems, irrespectively of the type of production management (organic or conventional/integrated production), microorganisms can enhance productivity by improved nutrient availability and crop health if their demands are optimized. Stimulatory growth responses encompass direct (i.e., production of plant hormones) or indirect (i.e., formation of compounds antagonizing plant pathogens, induced resistance) effects. Early reports indicate at the stimulatory effect of microorganisms on crop development (emergence, time of blossom) and yield. Their effect could be optimized when added as multiple strain treatments. In this context, organic carbon availability is an important factor. Organic compounds in sustainable greenhouse systems initially received negative attention as they were suspected as the causal agent for phytotoxic plant response. However, various recent studies could show the potential of microorganisms to degrade organic compounds in the nutrient solution of sustainable greenhouse cropping systems and consortia of efficient degraders of specific phenolic compounds were found to provoke higher biomass production in the presence of the phenolic compound. Other investigations indicate that the quality and quantity of organic compounds available is crucial for microbial metabolite production and thus level of growth promotion or antagonism. By habitat management, the preconditions for metabolite formation and crop response by introduced microorganisms or the indigenous microflora may be optimized. However, key mechanisms have to be identified in order to provoke the consistent formation of the appropriate metabolite at relevant sites within the growing system. Microbial markers may be used in order to predict the health status in closed cropping systems and to time microbial management in the cropping system.
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| 8. |
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| 9. |
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Caspersen, Siri, et al.
(författare)
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Blueberry-Soil interactions from an organic perspective
- 2016
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Ingår i: Scientia Horticulturae. - : Elsevier BV. - 0304-4238 .- 1879-1018. ; 208, s. 78-91
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Tidskriftsartikel (refereegranskat)abstract
- Demand for organic blueberries has risen in response to consumers' interest in healthy eating and greater awareness of the environment. Although organic production systems share many challenges with conventional systems, they have specific limitations and questions. Synchronisation of plant nutrient demand with the release of mineral nutrients from organic nutrient sources presents a particular challenge for the organic grower. In this paper we address belowground challenges in blueberry production from an organic perspective, such as soil properties and amendments as well as the choice of mulching material and organic fertilisers. We also address potential toxicity problems for blueberries associated with high concentrations of aluminium and manganese as well as salt stress. Symbiosis with ericoid mycorrhizal fungi is of potential interest in organic blueberry production as the fungi may improve plant access to nutrients from organic sources. The effects of management factors and limitations associated with the commercial utilisation of the symbiosis are also discussed.
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| 14. |
- Caspersen, Siri, et al.
(författare)
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Organic production systems in Northern highbush blueberries
- 2013
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Ingår i: NJF Report. - 1653-2015. ; 9, s. 141-142
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The production of highbush blueberries is increasing worldwide. Organic production of blueberries in Sweden is presently very limited but is expected to have a great potential to expand as the berries are popular and have a good shelf life. The fact that blueberries require acid soils raises several questions concerning suitable substrates in combination with mycorrhizal inoculation and fertilization in organic production systems. Field and pot experiments have been established during 2011 and 2012 with the aim of developing a sustainable production system for high quality organic blueberries. After the second experimental year, total fruit yields were similar for plants grown in a plastic tunnel and in the open field. Yields were not affected by the addition of 10% forest soil to the peat-based substrate. Inoculation with ericoid mycorrhizal fungi had little effect on shoot length in a greenhouse pot experiment. Blueberries may be particularly suitable for organic production as the need for fertilizers is low combined with a relatively low disease pressure on the blueberry crop in the Nordic countries. The Swedish blueberry production might be expected to expand in the near future. The development of a successful and resource-efficient growing system for organic blueberries may encourage new blueberry growers to chose organic production.
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| 15. |
- Chakraborty, Amrita, et al.
(författare)
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Yeast and fruit fly mutual niche construction and antagonism against mould
- 2022
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 36:7, s. 1639-1654
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Tidskriftsartikel (refereegranskat)abstract
- A goal in insect–microbe ecology is to understand the mechanisms regulating species associations and mutualistic interactions. The spotted wing drosophila Drosophila suzukii develops in ripening fruit, unlike other drosophilids that typically feed on overripe fruit, and is associated with the yeast Hanseniaspora uvarum. We hypothesized that D. suzukii and H. uvarum engage in niche construction leading to a mutualistic relation, facilitating the exploitation of fruit and berries as larval substrate. We show that H. uvarum proliferates on both ripe and on unripe raspberries, mediates attraction of D. suzukii larvae and adult flies, enhances egg-laying in mated females and is a sufficient food substrate to support larval development. Moreover, H. uvarum suppresses the antagonistic grey mould, Botrytis cinerea in collaboration with D. suzukii larvae, and produces less ethanol than baker's yeast. H. uvarum thus creates favourable conditions for D. suzukii larval development, which is susceptible to ethanol and grey mould. D. suzukii, on the other hand, vectors H. uvarum to suitable substrates such as raspberries, where larval feeding activity enhances growth of H. uvarum. Larval feeding also helps to suppress B. cinerea, which otherwise outcompetes H. uvarum on raspberry, in the absence of fly larvae. In conclusion, H. uvarum enhances D. suzukii larval development on unripe berries, and D. suzukii promotes H. uvarum dispersal and growth on berries. Yeast and fly modify their shared habitat in reciprocal niche construction and mutual interaction. Read the free Plain Language Summary for this article on the Journal blog.
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| 16. |
- Gharaie, Samareh, et al.
(författare)
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Light spectrum modifies the utilization pattern of energy sources in Pseudomonas sp. DR 5-09
- 2017
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Despite the overruling impact of light in the phyllosphere, little is known regarding the influence of light spectra on non-phototrophic bacteria colonizing the leaf surface. We developed an in vitro method to study phenotypic profile responses of bacterial pure cultures to different bands of the visible light spectrum using monochromatic (blue: 460 nm; red: 660 nm) and polychromatic (white: 350-990 nm) LEDs, by modification and optimization of a protocol for the Phenotype MicroArray (TM) technique (Biolog Inc., CA, USA). The new protocol revealed high reproducibility of substrate utilization under all conditions tested. Challenging the non-phototrophic bacterium Pseudomonas sp. DR 5-09 with white, blue, and red light demonstrated that all light treatments affected the respiratory profile differently, with blue LED having the most decisive impact on substrate utilization by impairing respiration of 140 substrates. The respiratory activity was decreased on 23 and 42 substrates under red and white LEDs, respectively, while utilization of one, 16, and 20 substrates increased in the presence of red, blue, and white LEDs, respectively. Interestingly, on four substrates contrasting utilization patterns were found when the bacterium was exposed to different light spectra. Although non-phototrophic bacteria do not rely directly on light as an energy source, Pseudomonas sp. DR 5-09 changed its respiratory activity on various substrates differently when exposed to different lights. Thus, ability to sense and distinguish between different wavelengths even within the visible light spectrum must exist, and leads to differential regulation of substrate usage. With these results, we hypothesize that different light spectra might be a hitherto neglected key stimulus for changes in microbial lifestyle and habits of substrate usage by non-phototrophic phyllospheric microbiota, and thus might essentially stratify leaf microbiota composition and diversity.
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| 17. |
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| 18. |
- Hultberg, Malin, et al.
(författare)
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Suppression of disease in tomato infected by Pythium ultimum with a biosurfactant produced by Pseudomonas koreensis
- 2010
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Ingår i: BioControl (Dordrecht). - : Springer Science and Business Media LLC. - 1386-6141 .- 1573-8248. ; 55:3, s. 435-444
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Tidskriftsartikel (refereegranskat)abstract
- The use of biosurfactants is a promising alternative in biological control of zoospore-producing oomycetes, which are a major plant pathogen world-wide in a wide variety of crops. Oomycetes are of particular concern in closed hydroponic cultivation systems. The present study investigated the efficacy of a biosurfactant produced by Pseudomonas koreensis and added as a crude extract against the oomycete Pythium ultimum in hydroponic tomato cultivation. A significant reduction in disease was observed. Biosurfactant addition did not affect the indigenous root microflora when evaluated as sole carbon source utilisation. Chemical analysis, using electrospray hybrid mass spectrometry (ESI-MSMS), of the biosurfactant indicated it to be lokisin, a cyclic lipopeptide. These results confirm that biosurfactants are important in developing sustainable biological control strategies for oomycetes.
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| 19. |
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| 20. |
- Khalil, Sammar, et al.
(författare)
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Biological control of root pathogens in strawberry cultivation in tunnel
- 2017
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1156, s. 811-815
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Konferensbidrag (refereegranskat)abstract
- Cultivation of strawberries in tunnels has been of interest in the last few years as a mean to expand the cultivation season and increase yield. The need to move the tunnels due to soil depletion is a disadvantage for production in tunnels. By shifting to a substrate cultivation, the tunnels could be stationary and open up for the possibility to expand the cultivation season and increase yield. However, a lot of factors must be optimized when cultivation of strawberries in substrate is considered. Among these factors is the spread of root pathogens belonging to fungal genera Phytophthora, Pythium, Fusarium and Verticillium that are the underlying cause for crow, rot and wilt diseases. In the current study a sustainable and secure strawberry production approach against root diseases using the biocontrol agent Binab T with Trichoderma isolates as active ingredients is evaluated. Investigations were carried out in tunnel on three different strawberry cultivars. The fungal pathogens Phytophthora cactorum and Verticillium dahlia were used as model pathogens and investigated with and without the presence of Binab T. The effect of Binab T on the investigated root pathogens varied depending on the plants cultivar and the type of pathogen present in the cultivation system. The best biocontrol against both pathogens was obtained with the strawberry cultivar 'Rumba'. Variations in this effect were observed when 'Honeoye' and 'Sonata' cultivars were used.
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| 21. |
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| 22. |
- Khalil, Sammar, et al.
(författare)
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Comparison of two commercial recirculated aquacultural systems and their microbial potential in plant disease suppression
- 2021
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Ingår i: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 21
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Tidskriftsartikel (refereegranskat)abstract
- Background Aquaponics are food production systems advocated for food security and health. Their sustainability from a nutritional and plant health perspective is, however, a significant challenge. Recirculated aquaculture systems (RAS) form a major part of aquaponic systems, but knowledge about their microbial potential to benefit plant growth and plant health is limited. The current study tested if the diversity and function of microbial communities in two commercial RAS were specific to the fish species used (Tilapia or Clarias) and sampling site (fish tanks and wastewaters), and whether they confer benefits to plants and have in vitro antagonistic potential towards plant pathogens. Results Microbial diversity and composition was found to be dependent on fish species and sample site. The Tilapia RAS hosted higher bacterial diversity than the Clarias RAS; but the later hosted higher fungal diversity. Both Tilapia and Clarias RAS hosted bacterial and fungal communities that promoted plant growth, inhibited plant pathogens and encouraged biodegradation. The production of extracellular enzymes, related to nutrient availability and pathogen control, by bacterial strains isolated from the Tilapia and Clarias systems, makes them a promising tool in aquaponics and in their system design. Conclusions This study explored the microbial diversity and potential of the commercial RAS with either Tilapia or Clarias as a tool to benefit the aquaponic system with respect to plant growth promotion and control of plant diseases.
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| 23. |
- Khalil, Sammar, et al.
(författare)
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Effect of growing medium water content on the biological control of root pathogens in a closed soilless system
- 2011
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Ingår i: Journal of Horticultural Science and Biotechnology. - : Informa UK Limited. - 1462-0316 .- 2380-4084. ; 86, s. 298-304
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Tidskriftsartikel (refereegranskat)abstract
- The water content of the growing medium and its interaction with a biocontrol agent was studied in a closed soilless culture system in order to identify factors that could increase the efficiency and decrease the variability of biocontrol agents. Pumice was chosen as the growing medium because of its high water-holding capacity and in view of the high water content required for the growth of the root pathogen. The commercial biocontrol agent Binab T (active strains Trichoderma polysporum and T harzianum) was evaluated at 50% and 70% water content. Studies were carried out in a controlled environment, in a climate chamber, using tomato as the model plant and Pythium ultimum as the model pathogen. Pathogen levels were affected by the water content of the medium and the biocontrol treatment, while the amount of biocontrol agent was not affected by the water content of the growing medium. The Trichoderma strains in Binab T were able to reduce the amount of pathogen and the incidence of disease at both water contents tested. The biocontrol activity of Binab T against P ultimum, as indicated by the level of glucanase production, was affected by variations in the water content of the growing medium. The pathogen, the biocontrol agent, and the water content of the growing medium, all had an impact on the microbial communities resident in the system.
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| 24. |
- Khalil, Sammar, et al.
(författare)
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Effects of growing medium on the interactions between biocontrol agents and tomato root pathogens in a closed hydroponic system
- 2009
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Ingår i: Journal of Horticultural Science and Biotechnology. - : Informa UK Limited. - 1462-0316 .- 2380-4084. ; 84, s. 489–494-
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Tidskriftsartikel (refereegranskat)abstract
- Three commercial biocontrol agents [Trichoderma polysporum plus T harzianum (Binab T), Gliocladium cantenitlatum (Gliomix), and Streptomyces griseoviridis (Mycostop)] were evaluated for their Ability to reduce root diseases caused by Pythium aphanidermatum, Phytophthora cryptogea, or Fusarium oxysporum f. sp. radicis-lycopersici in hydroponically-grown tomatoes. Studies were performed using two types of growing medium, peat or pumice, under controlled conditions in a closed irrigation system. The level of disease control varied depending on the biocontrol agent, growing medium, and pathogen. In pumice, amendment with Binab T, Gliomix, or Mycostop reduced the levels and disease incidence of all three pathogens. However, Mycostop had no significant effect on the level of any of the three pathogens in peat, although Binab T and Gliomix both achieved successful biocontrol. In both growth media, biocontrol of F oxysporum f. sp. radicis-lycopersici was poor compared with that of P aphanidermatum or P cryptogea. Overall, tomato plant growth increased after the introduction of any of the biocontrol agents, in the presence of any of the three pathogens, compared with the untreated controls.
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| 25. |
- Khalil, Sammar, et al.
(författare)
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Effekt av reningsutrustning på näringsfällning och mikroflora i bioreaktorbaserad in vitro-produktion av växtråvara
- 2015
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Ingår i: LTV-fakultetens faktablad.
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Annan publikation (populärvet., debatt m.m.)abstract
- Detta faktablad baseras på två projekt med det gemensamma syftet att utveckla en hållbar in vitro-baserad produktion av växtråvara. Syftet har även varit att utveckla ett system för recirkulering av näringslösning i storskalig bioreaktorbaserad odling. Två reningssystem testades – rening med ”Advanced Oxidation Technologies” (AOT) under 2013 och med kolfilter under 2014. Reningssystemen testades utifrån effektivitet att minska näringsfällningar och mikroflora. Resultaten från detta projekt visar att kolfiltrering är en effektiv metod att använda i bioreaktorsystem för att hämma fällningar av de flesta näringsämnen samt förekomsten av mikroorganismer. Annan reningsutrustning behöver dock testas för att uppnå en effektivare rening. Kiselackumulering är också ett problem som bör undersökas närmare.
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