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Continuous light (CL) or a predominant nitrogen supply as ammonium (NH4 +) can induce leaf chlorosis and inhibit plant growth. The similarity in injuries caused by CL and NH4 + suggests involvement of overlapping mechanisms in plant responses to these conditions; however, these mechanisms are poorly understood. We addressed this topic by conducting full factorial experiments with tomato plants to investigate the effects of NO3 − or NH4 + supply under diurnal light (DL) or CL. We used plants at ages of 26 and 15 days after sowing to initiate the treatments, and we modulated the intensity of the stress induced by CL and an exclusive NH4 + supply from mild to strong. Under DL, we also studied the effect of nitrogen (N) deficiency and mixed application of NO3 − and NH4 +. Under strong stress, CL and exclusive NH4 + supply synergistically inhibited plant growth and reduced chlorophyll content. Under mild stress, when no synergetic effect between CL and NH4 + was apparent on plant growth and chlorophyll content, we found a synergetic effect of CL and NH4 + on the accumulation of several plant stress hormones, with an especially strong effect for jasmonic acid (JA) and 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of ethylene, in xylem sap. This modulation of the hormonal composition suggests a potential role for these plant hormones in plant growth responses to the combined application of CL and NH4 +. No synergetic effect was observed between CL and NH4 + for the accumulation of soluble carbohydrates or of mineral ions, indicating that these plant traits are less sensitive than the modulation of hormonal composition in xylem sap to the combined CL and NH4 + application. Under diurnal light, NH4 + did not affect the hormonal composition of xylem sap; however, N deficiency strongly increased the concentrations of phaseic acid (PA), JA, and salicylic acid (SA), indicating that decreased N concentration rather than the presence of NO3 − or NH4 + in the nutrient solution drives the hormone composition of the xylem sap. In conclusion, N deficiency or a combined application of CL and NH4 + induced the accumulation of JA in xylem sap. This accumulation, in combination with other plant hormones, defines the specific plant response to stress conditions.
Martina Paponov; Aleksandr Arakelyan; Petre Dobrev; Michel Verheul; Ivan Paponov. Nitrogen Deficiency and Synergism between Continuous Light and Root Ammonium Supply Modulate Distinct but Overlapping Patterns of Phytohormone Composition in Xylem Sap of Tomato Plants. Plants 2021, 10, 573 .
AMA StyleMartina Paponov, Aleksandr Arakelyan, Petre Dobrev, Michel Verheul, Ivan Paponov. Nitrogen Deficiency and Synergism between Continuous Light and Root Ammonium Supply Modulate Distinct but Overlapping Patterns of Phytohormone Composition in Xylem Sap of Tomato Plants. Plants. 2021; 10 (3):573.
Chicago/Turabian StyleMartina Paponov; Aleksandr Arakelyan; Petre Dobrev; Michel Verheul; Ivan Paponov. 2021. "Nitrogen Deficiency and Synergism between Continuous Light and Root Ammonium Supply Modulate Distinct but Overlapping Patterns of Phytohormone Composition in Xylem Sap of Tomato Plants." Plants 10, no. 3: 573.
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.
Jiangsan Zhao; Dmitry Kechasov; Boris Rewald; Gernot Bodner; Michel Verheul; Nicholas Clarke; Jihong Clarke. Deep Learning in Hyperspectral Image Reconstruction from Single RGB images—A Case Study on Tomato Quality Parameters. Remote Sensing 2020, 12, 3258 .
AMA StyleJiangsan Zhao, Dmitry Kechasov, Boris Rewald, Gernot Bodner, Michel Verheul, Nicholas Clarke, Jihong Clarke. Deep Learning in Hyperspectral Image Reconstruction from Single RGB images—A Case Study on Tomato Quality Parameters. Remote Sensing. 2020; 12 (19):3258.
Chicago/Turabian StyleJiangsan Zhao; Dmitry Kechasov; Boris Rewald; Gernot Bodner; Michel Verheul; Nicholas Clarke; Jihong Clarke. 2020. "Deep Learning in Hyperspectral Image Reconstruction from Single RGB images—A Case Study on Tomato Quality Parameters." Remote Sensing 12, no. 19: 3258.
A greenhouse climate-crop yield model was adapted to include additional climate modification techniques suitable for enabling sustainable greenhouse management at high latitudes. Additions to the model were supplementary lighting, secondary heating and heat harvesting technologies. The model: 1) included the impact of different light sources on greenhouse air temperature and tomato production 2) included a secondary heating system 3) calculated the amount of harvested heat whilst lighting was used. The crop yield model was not modified but it was validated for growing tomato in a semi-closed greenhouse equipped with HPS lamps (top-lights) and LED (inter-lights) in Norway. The combined climate-yield model was validated with data from a commercial greenhouse in Norway. The results showed that the model was able to predict the air temperature with sufficient accuracy during the validation periods with Relative Root Mean Square Error <10%. Tomato yield was accurately simulated in the cases under investigation, yielding a final production difference between 0.7% and 4.3%. Lack of suitable data prevented validation of the heat harvest sub-model, but a scenario is presented calculating the maximum harvestable heat in an illuminated greenhouse. Given the cumulative energy used for heating, the total amount of heating pipe energy which could be fulfilled with the heat harvestable from the greenhouse air was around 50%. Given the overall results, the greenhouse climate(-crop yield) model modified and presented in this study is considered accurate enough to support decisions about investments at farm level and/or evaluate beforehand the possible consequences of environmental policies.
Isabella Righini; Bram Vanthoor; Michèl J. Verheul; Muhammad Naseer; Henk Maessen; Tomas Persson; Cecilia Stanghellini. A greenhouse climate-yield model focussing on additional light, heat harvesting and its validation. Biosystems Engineering 2020, 194, 1 -15.
AMA StyleIsabella Righini, Bram Vanthoor, Michèl J. Verheul, Muhammad Naseer, Henk Maessen, Tomas Persson, Cecilia Stanghellini. A greenhouse climate-yield model focussing on additional light, heat harvesting and its validation. Biosystems Engineering. 2020; 194 ():1-15.
Chicago/Turabian StyleIsabella Righini; Bram Vanthoor; Michèl J. Verheul; Muhammad Naseer; Henk Maessen; Tomas Persson; Cecilia Stanghellini. 2020. "A greenhouse climate-yield model focussing on additional light, heat harvesting and its validation." Biosystems Engineering 194, no. : 1-15.
There is a large potential in Europe for valorization in the vegetable food supply chain. For example, there is occasionally overproduction of tomatoes for fresh consumption, and a fraction of the production is unsuited for fresh consumption sale (unacceptable color, shape, maturity, lesions, etc.). In countries where the facilities and infrastructure for tomato processing is lacking, these tomatoes are normally destroyed, used as landfilling or animal feed, and represent an economic loss for producers and negative environmental impact. Likewise, there is also a potential in the tomato processing industry to valorize side streams and reduce waste. The present paper provides an overview of tomato production in Europe and the strategies employed for processing and valorization of tomato side streams and waste fractions. Special emphasis is put on the four tomato-producing countries Norway, Belgium, Poland, and Turkey. These countries are very different regards for example their climatic preconditions for tomato production and volumes produced, and represent the extremes among European tomato producing countries. Postharvest treatments and applications for optimized harvest time and improved storage for premium raw material quality are discussed, as well as novel, sustainable processing technologies for minimum waste and side stream valorization. Preservation and enrichment of lycopene, the primary health promoting agent and sales argument, is reviewed in detail. The European volume of tomato postharvest wastage is estimated at >3 million metric tons per year. Together, the optimization of harvesting time and preprocessing storage conditions and sustainable food processing technologies, coupled with stabilization and valorization of processing by-products and side streams, can significantly contribute to the valorization of this underutilized biomass.
Trond Løvdal; Bart Van Droogenbroeck; Evren Caglar Eroglu; Stanislaw Kaniszewski; Giovanni Agati; Michel Verheul; Dagbjørn Skipnes. Valorization of Tomato Surplus and Waste Fractions: A Case Study Using Norway, Belgium, Poland, and Turkey as Examples. Foods 2019, 8, 229 .
AMA StyleTrond Løvdal, Bart Van Droogenbroeck, Evren Caglar Eroglu, Stanislaw Kaniszewski, Giovanni Agati, Michel Verheul, Dagbjørn Skipnes. Valorization of Tomato Surplus and Waste Fractions: A Case Study Using Norway, Belgium, Poland, and Turkey as Examples. Foods. 2019; 8 (7):229.
Chicago/Turabian StyleTrond Løvdal; Bart Van Droogenbroeck; Evren Caglar Eroglu; Stanislaw Kaniszewski; Giovanni Agati; Michel Verheul; Dagbjørn Skipnes. 2019. "Valorization of Tomato Surplus and Waste Fractions: A Case Study Using Norway, Belgium, Poland, and Turkey as Examples." Foods 8, no. 7: 229.
Non-destructive tools for evaluating the lycopene content in tomatoes is of great interest to the entire fruit chain because of an increasing demand for beneficial health products. With the aim of developing compact low-cost reflectance sensors for lycopene determination, we compared Partial Least Squares (PLS) prediction models by using either directional or total reflectance in the 500–750 nm range. Directional reflectance at 45° with respect to the LED lighting direction was acquired by means of a compact spectrometer sensor. Total reflectance was acquired through a 50-mm integrating sphere connected to a spectrometer. The analysis was conducted on two hydroponic greenhouse cultivated red tomato varieties, namely the large round ‘Dometica’ (average diameter: 57 mm) and the small cherry ‘Juanita’ (average diameter: 26 mm). For both varieties, the spectral variance of directional reflectance was well correlated to that of total reflectance. The performances of the PLS prediction models were also similar, with R2 of cross-validation between 0.73 and 0.81. The prediction error, relative to the mean lycopene content of full ripe tomatoes, was similar: i.e. around 16–17% for both varieties and sensors. Our results showed that directional reflectance measured by means of portable, low-cost and compact LED-based sensors can be used with an adequate precision for the non-destructive assessment of lycopene in tomatoes.
Leonardo Ciaccheri; Lorenza Tuccio; Andrea A. Mencaglia; Anna G. Mignani; Ewelina Hallmann; Kalina Sikorska-Zimny; Stanislaw Kaniszewski; Michè̀l J. Verheul; Giovanni Agati. Directional versus total reflectance spectroscopy for the in situ determination of lycopene in tomato fruits. Journal of Food Composition and Analysis 2018, 71, 65 -71.
AMA StyleLeonardo Ciaccheri, Lorenza Tuccio, Andrea A. Mencaglia, Anna G. Mignani, Ewelina Hallmann, Kalina Sikorska-Zimny, Stanislaw Kaniszewski, Michè̀l J. Verheul, Giovanni Agati. Directional versus total reflectance spectroscopy for the in situ determination of lycopene in tomato fruits. Journal of Food Composition and Analysis. 2018; 71 ():65-71.
Chicago/Turabian StyleLeonardo Ciaccheri; Lorenza Tuccio; Andrea A. Mencaglia; Anna G. Mignani; Ewelina Hallmann; Kalina Sikorska-Zimny; Stanislaw Kaniszewski; Michè̀l J. Verheul; Giovanni Agati. 2018. "Directional versus total reflectance spectroscopy for the in situ determination of lycopene in tomato fruits." Journal of Food Composition and Analysis 71, no. : 65-71.