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Lecture – Effects of post-harvest storage conditions on flavor-related volatiles and fruit taste quality of five greenhouse tomato varieties produced during wintertime
Emilie Haugvaldstad, Henk Maessen, Dmitry Kechasov
Academic – Artificial top-light is more efficient for tomato production than inter-light
Michel Verheul, Henk Maessen, Martina Paponov, ...
AuthorsMichel Verheul Henk Maessen Martina Paponov Anush Panosyan Dmitry Kechasov Muhammad Naseer Ivan Paponov
Studies of whole-plant responses of tomato to light environments are limited and cannot be extrapolated from observations of seedlings or short-term crops in growth chambers. Effects of artificial light sources like high pressure sodium (HPS) and light emitting diodes (LED) are mainly studied as supplement to sunlight in greenhouses. Since natural sunlight is almost neglectable in Norway during wintertime, we could study effects of different types of artificial light on crop growth and production in tomato. The goal of this experiment was to quantify the effects of artificial HPS top-light, installed at the top of the canopy, and LED inter-light, installed between plant rows, on fresh and dry matter production and fruit quality of greenhouse tomatoes under controlled and documented conditions. Our aim was to optimize yield under different light conditions, while avoiding an unfavourable source-sink balance. Tomato plants were grown under HPS top light with an installed capacity of 161, 242 and 272 W m−2 combined with LED inter-light with an installed capacity of 0, 60 or 120 W m−2. We used stem diameter as a trait to regulate air temperature in different light treatments in order to retain plant vigour. Results show that both HPS top light and LED inter-light increased tomato yield. However, the positive effect of supplemental LED inter-light decreased at higher amounts of HPS top light. Under the conditions in this experiment, with neglectable incoming solar radiation, an installed amount of 242 Watt m-2 HPS top light and a daily light integral (DLI) of 30 mol m-2 day-1 resulted in best light use efficiency (in gram fresh tomato per mol). Addition of LED inter-light to HPS top light reduced light use efficiency. Results show that winter production using artificial light in Norway is more energy efficient compared to production under sunlight in southern countries. Results can be used for modelling purposes.
Lecture – Organic waste as fertilizer for sustainable cultivation of tomato in modern greenhouses
Academic – Organic Waste-Based Fertilizer in Hydroponics Increases Tomato Fruit Size but Reduces Fruit Quality
Dmitry Kechasov, Michel Verheul, Martina Paponov, ...
AuthorsDmitry Kechasov Michel Verheul Martina Paponov Anush Panosyan Ivan Paponov
In regions with intensive agricultural production, large amounts of organic waste are produced by livestock animals. Liquid digestate from manure-based biogas production could potentially serve as fertilizer if integrated with closed horticultural irrigation systems. The aim of this experiment was to investigate how fertilizer based on liquid biogas by-products of pig manure digestion can affect the growth and production of tomato plants. Integration of a nitrification bioreactor presumes a significantly lower concentration of nutrient solutions and a higher level of oxygenation than classical mineral cultivation. Therefore, additional controls were included. We compared plant growth and fruit quality traits of tomato plants grown in a hydroponic solution with organic fertilizer with two levels of mineral fertilizer. The tomatoes grown with organic waste-based liquid fertilizer showed reduced growth rates but increased mean fruit size, resulting in no significant change in total yield compared with high-mineral cultivation. The growth rate was similarly reduced in plants cultivated with low-mineral fertilizer. Plants cultivated with organic waste-based fertilizer had high Cl− concentration in xylem sap, leaves, and, ultimately, fruits. The leaves of plants cultivated with organic waste-based fertilizer contained higher concentrations of starch and soluble carbohydrate and low concentrations of phosphorous (P) and sulfur (S). The plants grown with organic waste-based or low-mineral medium showed significantly poorer fruit quality than the plants cultivated with the high-mineral solution. The low-mineral treatment increased xylem sap contribution to fruit weight because of higher root power. The organic waste-based fertilization did not change the root power but increased fruit size. In conclusion, organic waste-based cultivation is a possible solution for sustainable plant production in greenhouses. However, additional adjustment of nutrient supply is required to improve fruit quality.
Academic – Deep Learning in Hyperspectral Image Reconstruction from Single RGB images—A Case Study on Tomato Quality Parameters
Jiangsan Zhao, Dmitry Kechasov, Boris Rewald, ...
AuthorsJiangsan Zhao Dmitry Kechasov Boris Rewald Gernot Bodner Michel Verheul Nicholas Clarke Jihong Liu Clarke
Hyperspectral imaging has many applications. However, the high device costs and low hyperspectral image resolution are major obstacles limiting its wider application in agriculture and other fields. Hyperspectral image reconstruction from a single RGB image fully addresses these two problems. The robust HSCNN-R model with mean relative absolute error loss function and evaluated by the Mean Relative Absolute Error metric was selected through permutation tests from models with combinations of loss functions and evaluation metrics, using tomato as a case study. Hyperspectral images were subsequently reconstructed from single tomato RGB images taken by a smartphone camera. The reconstructed images were used to predict tomato quality properties such as the ratio of soluble solid content to total titratable acidity and normalized anthocyanin index. Both predicted parameters showed very good agreement with corresponding “ground truth” values and high significance in an F test. This study showed the suitability of hyperspectral image reconstruction from single RGB images for fruit quality control purposes, underpinning the potential of the technology—recovering hyperspectral properties in high resolution—for real-world, real time monitoring applications in agriculture any beyond.
Poster – EFFECT OF ORGANIC FERTILISER ON METABOLIC PROFILE OF HYDROPONICALLY CULTIVATED TOMATO
Dmitry Kechasov, Roald Kommedal, Michel Verheul, ...
AuthorsDmitry Kechasov Roald Kommedal Michel Verheul Ivan Paponov
No abstract has been registered
Lecture – Effect of organic fertiliser on productivity and quality of hydroponically cultivated tomato
Dmitry Kechasov, Michel Verheul, Paponov Ivan
AuthorsDmitry Kechasov Michel Verheul Paponov Ivan
Recycling of waste fractions from farms and greenhouses might reduce environmental pollution. However, recycling of nutrient solution in greenhouse is risky due to danger of disease spread. Nitrification bacteria can be used for aerobic conversion of ammonia to nitrate in organic waste and may function as stable microbial community protecting against pathogen attacks by enhancing induced systemic resistance of plants. We developed a hydroponic cultivation system “Organoponics” allowing growth of tomato plant on organic fertilizer with recirculation of nutrient solution. Liquid by-product of biogas production has been used as organic fertilizer. A moving-bed bioreactor was integrated in the system for aerobic nitrification of ammonia. Influence of fertilizer composition (organic, mineral matching organic, standard mineral) and addition of plant growth promoting bacteria on biomass distribution, tomato fruit quality were investigated. Plants grown on organic fertilizer were more generative with largest root index. They also produced fruits with significantly larger average size along whole cluster. Addition of the bacteria to root rhizosphere improved yield and quality parameters of plants received organic fertilization and negatively affected the same parameters in plants received mineral fertilization.
Academic – Evolutionary Maintenance of the PTS2 Protein Import Pathway in the Stramenopile Alga Nannochloropsis
Dmitry Kechasov, Imke de Grahl, Pierre Endries, ...
AuthorsDmitry Kechasov Imke de Grahl Pierre Endries Sigrun Reumann
The stramenopile alga Nannochloropsis evolved by secondary endosymbiosis of a red alga by a heterotrophic host cell and emerged as a promising organism for biotechnological applications, such as the production of polyunsaturated fatty acids and biodiesel. Peroxisomes play major roles in fatty acid metabolism but experimental analyses of peroxisome biogenesis and metabolism in Nannochloropsis are not reported yet. In fungi, animals, and land plants, soluble proteins of peroxisomes are targeted to the matrix by one of two peroxisome targeting signals (type 1, PTS1, or type 2, PTS2), which are generally conserved across kingdoms and allow the prediction of peroxisomal matrix proteins from nuclear genome sequences. Because diatoms lost the PTS2 pathway secondarily, we investigated its presence in the stramenopile sister group of diatoms, the Eustigmatophyceae, represented by Nannochloropsis. We detected a full-length gene of a putative PEX7 ortholog coding for the cytosolic receptor of PTS2 proteins and demonstrated its expression in Nannochloropsis gaditana. The search for predicted PTS2 cargo proteins in N. gaditana yielded several candidates. In vivo subcellular targeting analyses of representative fusion proteins in different plant expression systems demonstrated that two predicted PTS2 domains were indeed functional and sufficient to direct a reporter protein to peroxisomes. Peroxisome targeting of the predicted PTS2 cargo proteins was further confirmed in Nannochloropsis oceanica by confocal and transmission electron microscopy. Taken together, the results demonstrate for the first time that one group of stramenopile algae maintained the import pathway for PTS2 cargo proteins. To comprehensively map and model the metabolic capabilities of Nannochloropsis peroxisomes, in silico predictions needs to encompass both the PTS1 and the PTS2 matrix proteome.
Academic – Supplemental Light-Emitting Diode Inter-Lighting Increases Tomato Fruit Growth Through Enhanced Photosynthetic Light Use Efficiency and Modulated Root Activity
Martina Paponov, Dmitry Kechasov, Jozef Lacek, ...
AuthorsMartina Paponov Dmitry Kechasov Jozef Lacek Michel Verheul Ivan Paponov
We investigated the effect of supplemental LED inter-lighting (80% red, 20% blue; 70 W m−2; light period 04:00–22:00) on the productivity and physiological traits of tomato plants (Flavance F1) grown in an industrial greenhouse with high pressure sodium (HPS) lamps (235 W m−2, 420 µmol m−2 s−1 at canopy). Physiological trait measurements included diurnal photosynthesis and fruit relative growth rates, fruit weight at specific positions in the truss, root pressure, xylem sap hormone and ion compositions, and fruit quality. In the control treatment with HPS lamps alone, the ratio of far-red to red light (FR:R) was 1.2 at the top of the canopy and increased to 5.4 at the bottom. The supplemental LED inter-lighting decreased the FR:R ratio at the middle and low positions in the canopy and was associated with greener leaves and higher photosynthetic light use efficiency (PLUE) in the leaves in the lower canopy. The use of LED inter-lighting increased the biomass and yield by increasing the fruit weight and enhancing plant growth. The PLUE of plants receiving supplemental LED light decreased at the end of the light period, indicating that photosynthesis of the supplemented plants at the end of the day might be limited by sink capacity. The supplemental LED lighting increased the size of fruits in the middle and distal positions of the truss, resulting in a more even size for each fruit in the truss. Diurnal analysis of fruit growth showed that fruits grew more quickly during the night on the plants receiving LED light than on unsupplemented control plants. This faster fruit growth during the night was related to an increased root pressure. The LED treatment also increased the xylem levels of the phytohormone jasmonate. Supplemental LED inter-lighting increased tomato fruit weight without affecting the total soluble solid contents in fruits by increasing the total assimilates available for fruit growth and by enhancing root activity through an increase in root pressure and water supply to support fruit growth during the night.