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Sirvi Autor "Duma, M." järgi

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  • Pisipilt
    Kirje
    Assessment of common bean responses to light spectral composition and microbial inoculation using non-destructive methods
    (Estonian University of Life Sciences, 2026) Alsina, I.; Dubova, L.; Duma, M.
    Non-destructive methods are increasingly used to evaluate plant physiological status. This study assessed the applicability of spectrometry and chlorophyll fluorescence for monitoring common bean (Phaseolus vulgaris) responses to light quality and microbial seed inoculation. A two-factor growth chamber experiment was conducted using LED lighting of equal intensity but different red-to-blue ratios (1:1, red-dominated, blue-dominated) and seeds that were either uninoculated or inoculated with Rhizobium phaseoli strains or Proseed-Met. Non-destructive measurements were performed on the same leaves using a spectroradiometer RS-3500 and a FluorPen FP110 fluorometer. Vegetation indices were calculated to evaluate stress, pigment content, senescence, and water status, while fluorescence parameters described photosynthetic performance. Spectrometric indices more clearly reflected light treatment effects, showing higher pigment content under red light, greater senescence under balanced light, and increased stress under red-dominated spectra. Fluorescence parameters were mainly affected by microbial inoculation and were higher in inoculated plants. Limited correlations between the two methods indicated that they capture different aspects of plant physiology. Blue-dominated light increased pod number, whereas red light reduced pod and seed mass. Microbial inoculation alone did not significantly affect yield, but the highest seed yield was observed in Rhizobium-inoculated plants under blue light. The results highlight the importance of light spectral composition for bean productivity and support the combined use of spectrometric and fluorescence methods for comprehensive physiological assessment.
  • Pisipilt
    Kirje
    Comparison of lycopene and β-carotene content in tomatoes determined with chemical and non-destructive methods
    (2019) Alsina, I.; Dubova, L.; Duma, M.; Erdberga, I.; Avotiņš, A.; Rakutko, S.
    Tomatoes 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.
  • Pisipilt
    Kirje
    Evaluation of different lighting sources on the growth and chemical composition of lettuce
    (2018) Sergejeva, D.; Alsina, I.; Duma, M.; Dubova, L.; Augspole, I.; Erdberga, I.; Berzina, K.
    Experiment were carried out in Latvia University of Agriculture in plant growth room. Lettuce Lactuca sativa L. var foliosum cv. ‘Dubacek’ and L . sativa L. cv. ‘Michalina’ were grown under 4 types of lights (luminescence lamps, commercial light emitting diodes (LED) lamps (V - TAC premium series – for plant growing) and two different Lumigrow LED strips - dominant wavelength - blue or red with 14 h ph otoperiod and total photosynthetic active radiation (PAR) 100 μmol m - 2 s - 1 in all variants. Plant weight, length, amount of leaves were measured. Content of chlorophylls, carotenoids, phenols, flavonoids in lettuce was determined three times per vegetation period. In experiments were found that higher lettuce yield was under commercial LED (V - TAC premium series), but these plants contain less soluble sugars, pigments and phenols. Better plant quality was obtained with luminescence lamps. These lettuces have higher sugar, phenols and flavonoids content. Lettuce growth under blue dominate LED (LEDb) was delayed, but these plants contain higher chlorophylls content. The differences in plant growth, response to light and biochemical content b etween cultivars wer e detected.