New assessment tool for artificial plant lighting: case of tomato (Lycopersicon Esculentum Mill.)

Growing crops under artificial conditions need a very favourable environment, especially the spectral composition of radiation influencing the plant biometry greatly. The study objective was to find how to assess the closeness of real growing conditions to the optimal ones using a single coefficient, which would reflect several time dependencies of individual growth indicators. The plant growth friendliness factor (KG)was proposed for this purpose. Tomato transplants (Lycopersicon Esculentum Mill., ‘Polonaise F1’) were grown in a peat substrate under two lighting systems with different light quality.One system consisted of eight fluorescent lamps OSRAM L58W / 840 LUMILUX Cool White and eight lamps L58W / 77 FLUORA mounted on the standardframe, alternating the lamp types (Type I spectrum).In theother lighting system, the PCB Star LEDs with wavelengths of red 630 nm and far-red 735 nm were added(Type II spectrum). The irradiance level was maintained at 140 μmol m-2 s -1 , the photoperiod was 16 h. The ratio of long-wave flux to the total flux KL was calculated for these lighting systems (0.37 rel.units for Type I spectrum and 0.50 rel.units for Type II spectrum) and KG factor was determined by the proposed formula. The value ofKG was found to be twice as small for Type I spectrumthan for Type II spectrum. The significant difference in biometric parameters of tomato transplants grown under Type I and Type II spectrawas revealed. The plants grown in the environment characterized by higher KG, were higher; they had more significantwet mass and stem neck diameter

Radiation use efficiency by tomato transplants grown under extended photoperiod

The study focused on the effect of an extended photoperiod on the radiation use efficiency (RUE) by the tomato transplants (Solanum lycopersicum L.) in the pre–reproductive period. In two consecutive series of experiments, the photoperiod was 16 and 22 hours. The photon irradiance at the plant tops was maintained at low, medium and high levels: 100, 170 and 240 μmol m–2 s –1 , respectively. The plants were grown under two lighting systems with different light quality. The difference was7% higher blue flux share in Spectrum II. The use of an extended photoperiod, especially in combination with high irradiance level, resulted in the plant leaf chlorosis. When varying the radiation dose components, the deviation from the reciprocity law was recorded. By the analysis results, the chlorophyll degradation was a response to the extended photoperiod rather than the radiation dose. Without additional blue flux, under a regular photoperiod, RUE reduced by 8% at the high irradiance level. Under extended photoperiod, the shift from the low to high irradiance level reduced RUE by 20–37%, with bigger reduction values being observed at higher irradiance levels. Seven percent addition of blue flux made it possible to increase RUE by 5–8% at the same and lower irradiance levels and under the regular photoperiod. With the extended photoperiod under these conditions, RUE decreased by 8–21%. The study results verify a great influence of an extended photoperiod on RUE, while the degree of influence depends on other parameters of light environment – light quality and irradiance level

Possibilities of cucumber powdery mildew detection by visible and near-infrared spectroscopy

Received: July 16th, 2021 ; Accepted: November 6th, 2021 ; Published: February 1st, 2022 ; Correspondence: [email protected] are one of the most demanded and widely grown greenhouse vegetables. Important factors that influence quality and quantity of yield are diseases. Powdery mildew (caused by Podosphaera xanthii and/or Golovinomyces cichoracearum), is one of the most harmful cucumber diseases. Early detection of mildew via non-destructive methods can optimize schemes of fungicide application. The study aimed to find regularities in the reflected light spectra, indices described in the literature, and severity of mildew. Plants were grown in the polycarbonate greenhouse under artificial lighting in a 16 h photoperiod with PAR at the tips of plants 200 ± 30 µmol m-2 s-1. Leaf reflection spectra were obtained using spectroradiometer RS-3500 (Ltd. Spectral Evolution). Spectral range 350–2,500 nm, bandwidth 1 nm. The severity of cucumber mildew was evaluated using 10 point scale (0- no symptoms, … 9 - the plant is dead). The vegetation indices found in the literature have been calculated. The obtained results show that the calculated indices have different sensitivities. The strongest correlation between the degree of cucumbers infection with powdery mildew and the light reflectance spectrum was found in the green range of visible light around 550 nm. Disease-Water Stress Index-2 (DSWI-2), Structure Intensive Pigment Index (SIPI), and Normalized Difference Vegetation Index (NDVI) are the most suitable indices for determining powdery mildew in cucumbers. New indices for detection of powdery mildew have been created. None of the studied indices allows determining the powdery mildew at the early stages of disease development when powdery mildew severity is below 10%

Determination of tomato quality with hyperspectral imaging

Received: February 1st, 2023 ; Accepted: July 14th, 2023 ; Published: October 13th, 2023 ; Correspondence: [email protected] (Solanum lycopersicum L.) are a widely used vegetable in the human diet throughout the year, both fresh and in various processed products. Tomatoes contain compounds important to human health and are an important source of vitamins, antioxidants, and mineral elements. Performing biochemical analyses is an expensive, environmentally unfriendly and time-consuming process; therefore, a way to determine the biochemical composition of tomatoes using non-destructive methods is being sought. The study includes 45 varieties of tomatoes with different colors - red, pink, orange, brown, yellow, and bicolor tomato fruits. The content of dry matter, soluble dry matter, titratable acidity, lycopene, β-carotene, total phenol, and flavonoids was determined by standard biochemical procedure. Reflectance spectrums of tomato fruits were obtained with Remote Sensing Portable Spectroradiometer RS-3500 (Ltd. Spectral Evolution, Haverhill, MA, USA) at the wavelength 350–2,500 nm with a 1 nm interval. In order to determine the content of various biochemical parameters in tomatoes, the vegetation indices found in the literature were used, and new ones were developed. The research demonstrated that the developed vegetative indices allow to detect lycopene and β-carotene content non-destructively. For the determination of the dry matter, soluble solids and phenolic content, indices designed for detecting water content can be used, but their correlation coefficients with chemical methods are moderately high - 0.65, 0.56 and 0.57, respectively. It was found that the best correlation between biochemically detected parameters and vegetation indices is for lycopene > β-carotene > dry matter> total phenols = titratable acidity ≥ soluble solids > taste index > flavonoids

Comparison of lycopene and β-carotene content in tomatoes determined with chemical and non-destructive methods

ArticleTomatoes are one of the most popular vegetables due of their wide use as food. Tomatoes are not only tasty fruit, but one of its benefits - high carotenoids content is well-known. Non-destructive analyses methods are used more and more in different industries. It is cheaper, faster and environmentally friendly way of analyse than traditional chemical methods. But these methods need references to the traditional ones. The aim of this study was to find the correlation between lycopene and β-carotene content in tomatoes determined with reflectance spectrometer and extraction of pigments. Content of two carotenoids (lycopene and β-carotene) was determined in 27 varieties of tomatoes. Red, pink, orange, yellow and brown fruits were included in experiment. Reflectance spectrums of tomatoes fruits were obtained with remote sensing portable spectroradiometer RS-3500 (Ltd.Spectral Evolution). Tetrahydrofuran was used for extraction of pigments. Absorption spectra of extract were obtained by spectrophotometer UV-Vis -1800 (Ltd. Shimadzu). Linear regression analyses were performed to correlate spectral data with lycopene and β-carotene concentrations measured by pigment extraction. The best reflectance region for lycopene spectral detection was 570 ± 5 nm, but for β-carotene 487 ± 5 nm. Reflectance indexes for both pigments were worked out. High linear correlation (R2 > 0.9) between spectral parameters and lycopene concentration was detected. Correlation between results obtained with methods used for β-carotene determination was lower and depended of colour of tomatoes fruits

Lighting source as cause of changes in cucumbers’ physiology and morphology

The demand of fresh fruits and vegetables is growing. Therefore cultivation of them is essential all year round. The growth in the dark period of a year is not imaginable without artificial lighting sources. Therefore the experiments were carried out to investigate the effects of three different lighting sources on the growth of cucumbers at the early stages of development. Plants were grown in the polycarbonate greenhouse under three different lighting sources: Led cob Helle top LED 280, induction lamp and high pressure sodium lamp Helle magna. Cucumbers were grown in 16h photoperiod with PAR at the tips of plants 200 ± 20 µmol m-2 s -1 . Plant growth parameters, specific leaf area, pigments, phenols and flavonoids content in leaves, leaf light reflection parameters were determined. Results showed that cucumber plants grown under Led cob Helle top LED 280 in average were smaller, with less chlorophyll, carotenoids and phenols, but leaves have higher chlorophyll a and b ratio and specific leaf area in comparison with traditionally used in greenhouses High Presure Sodium Lamps (HPSL). Cucumber plants grown under Induction lamp in average were shorter, but with larger leaf area, with higher chlorophyll and carotenoids content, but decreased phenols content in comparison with HPSL. Lichtenthaler index 1 (LIC1) and NDVI are useful for assessing the physiological state of cucumber plants. Despite the fact that the plants grow well and develop normally under all lamps, the results show that sodium lamps are the most suitable for cucumbers. Further research is needed to adjust LED lighting for cucumber cultivation

Energy Saving Technologies

Th is book is an overview of existing Th eoretical background, Legal bases and best practice examples on existing Energy Saving Technologies. Chapter 1: Energy Saving Technologies in Generation, Conversion of Electrical Energy Th e overview of Energy Saving Technologies, and its application of practice examples promoted by European strategies in power supply. - cogeneration, traditional, DER - effi cient control systems - smart metering concept Chapter 2: Energy Saving Technologies in Transmission, Distribution of Electrical Energy Th e technological overview for energy transmission, distribution, such as: fl exible AC transmission systems, DC transmission systems, effi cient control and metering system. Chapter 3: Energy Saving Technologies: in Industry Th e overview of Electric drives as Energy Saving Technologies are given in particular: optimal selection of electric motor power and application of frequencyregulated electric drives are described as well as SCADA system application; monitoring of unauthorised connections. Chapter 4: Energy Saving Technologies: in Public and Private Sector Th e technological overview of effi cient lighting, energy consumption by transport, street lighting system as a practical example of energy saving technologies. Chapter 5: Legal Bases on Existing Energy Saving Technologies Th e overview of EU Directives on Energy Effi ciency, on Promotion of the use of energy Energy Eff ective Lighting, and Energy Performance of Buildings Directive are described; the main concept and application areas as well as benefi ts from using those concepts are described in the chapter