Acta Scientiarum Polonorum Hortorum Cultus

Assessment of the microbial quality of ready-to-eat vegetable salads and berry fruit available on Polish market

2024-07-01T11:03:11+02:00

The consumption and sale of ready-to-eat products, i.e., fresh-cut vegetable salads and fruit, have been growing tremendously in the present time. Therefore, the microbial safety of such products is of great concern. In the current study, a survey of general microbiological contamination (mesophilic bacteria, yeasts, molds, Enterobacteriaceae, coli bacteria, Enterococcus, Lactobacillus, and Escherichia coli) of fresh-cut vegetable salads and berry-packed fruits available in Polish supermarket was undertaken.
In ready-to-eat salads, the high number of mesophilic bacteria ranged from 6.43 to 8.56 log₁₀ cfu g^–1, and also Enterobacteriaceae with mean value from 3.45 to 4.08 log₁₀ cfu g^–1 was detected. Mesophilic bacteria, yeast, and Enterobacteriaceae were detected in all salad samples. The molds were detected in 45% of salad samples, and their mean number ranged from 0.63 log₁₀ cfu g^–1 in salads with carrot or beetroot to 1.80 log₁₀ cfu g^–1 in salads with rocket.
Berry fruit was also heavily microbiologically contaminated. In particular, the means of mesophilic bacteria, molds, and yeasts were high. The number of molds detected in fruit samples, especially in raspberry samples, could be alarming. Enterobacteriaceae, Enterococcus, and coli bacteria were detected in a few samples of berry fruit. None of the ready-to-eat salads and fruit samples were contaminated by Escherichia coli.
Based on the tests that were conducted, it was found that the microbiological quality was not satisfactory. The findings suggest that following hygienic measures during processing and handling, the microbiological quality of vegetable salads and berry fruit available in Polish markets should be improved.

Effects of Azotobacter spp., mycorrhizal fungi and shade treatments on plant growth and chlorophyll content in boxwoods plants

2024-07-01T11:03:20+02:00

In this study, two important commercial species, Buxus microphilla and B. herlandii, were evaluated. People do not want polluting and toxic fertilizers used to cultivate the plants they use for nutrition, and they do not want the plants they use as ornamental plants. The study investigated the effects of mycorrhizal and bacterial applications on plant growth and chlorophyll content. As a result of the study, it was concluded that bacterial applications on the development of boxwoods are more effective than mycorrhizal applications. Shading further increased the effect of the applications. In B. microphilla, in a 70% shade, plant height increased by 18.5% with mycorrhizal application, and plant width increased by 29.7% with bacterial application. In B. herlandii, bacterial application increased plant height by 13.3% and plant width by 20.4%. In shadowless application, the amount of chlorophyll in B. herlandii leaves was found to increase by 47.20% with bacteria and in B. microphilla, it increased by 65.86. In shadow application in B. herlandii, leaves were found to increase by 76.70% with bacteria; in B. microphilla, it increased by 94.93%. It was concluded that the bacteria application is more effective than others because Azotobacters fix the free nitrogen in the air to the boxwood soil, which needs continuous nitrogen for growth and development. For this reason, N-fixing bacteria applications to the soil can be used as an alternative to chemical fertilizer applications in boxwood cultivation or hedge formation.

Determination of biological activity of ethanol extracts of date-plum (Diospyros lotus) fruits and seeds growing in Turkey

2024-07-01T11:03:17+02:00

This study was carried out to evaluate quality criteria such as chemical composition and antioxidant and antibacterial activity values in 80% ethanol extracts of date-plum (Diospyros lotus) fruits and seeds. In addition, the macro and microelement concentrations of fruits and seeds were also investigated. According to the data obtained, when fruit and seed were compared, it was determined that the seed (81.72%) contained more components than the fruit (79.4%), and the antioxidant activity of the seed was also higher. While the main component of the seed was “Methyl hydrogen disulfide” with 43.21%, the main component of the fruit was “5-Hydroxymethylfurfural” with 24.2%. As a result of antimicrobial activity tests, neither seeds nor fruits have antimicrobial activity. At the same time, the nutritional content values of the seeds and fruits of this plant were analyzed and evaluated. When the data obtained are evaluated in terms of both macro and micronutrients, it has been observed that the nutritional content values of the fruit (K (3.63%), P (0.68 %), Cu (24.31%), Zn (10.49 mg kg–1) and Mn (25.29 mg kg–1) for fruits) are higher than the seeds. In conclusion, the findings from the evaluation of Diospyros lotus fruit and seeds in this study highlight the richness in chemical composition and high antioxidant activity of the seeds, as well as the nutritional superiority of the fruit. Therefore, further research to better understand and harness the potential health benefits of this plant could contribute to a deeper understanding of this field.

Determining appropriate methods for estimating pollen viability and germination rates in lisianthus

2024-07-01T11:03:04+02:00

Crossbreeding is a multi-stage process with inherent challenges and risks in developing new varieties. Success hinges on selecting highly fertile parents. In species like lisianthus, uncertainty persists regarding the optimal methods for assessing pollen quality, which is crucial for evaluating pollen parent fertility. This study seeks to identify the most reliable techniques for this purpose. Fresh and dead pollen from four lisianthus (Eustoma grandiflorum) varieties was used. The dead pollen was obtained by thermal inactivation. Five chemical staining methods (iodine-potassium iodide, 2,3,5-triphenyltetrazolium chloride – TTC, lactophenol cotton blue, safranin, acetocarmine) were employed to assess pollen viability, and two biological methods (Petri dishes, hanging drops) were used to determine the germination rate. Four solid medium cultures were employed in Petri dishes, while the hanging drop utilised four liquid medium cultures. Thirteen tests were conducted for each variety, evaluating fresh and dead pollen. The study found significant variations in pollen quality among lisianthus varieties and methods. Fresh pollen showed viability rates ranging from 56.87% to 99.41% and germination rates from 0.20% to 45.11%. TTC exhibited the lowest viability rate across all varieties, while the highest germination rate was observed in the liquid culture medium with only boric acid and PEG1500. Notably, TTC was the sole viability method that did not stain dead pollen, and no germination occurred in any method for dead pollen. TTC is the most reliable staining method, and a liquid culture medium with boric acid and PEG1500 effectively determines lisianthus pollen quality. Varying boric acid and PEG1500 concentrations are advisable.

The effect of zinc oxide nanoparticles on the growth and development of Stevia plants cultured in vitro

2024-07-01T11:03:08+02:00

Stevia (Stevia rebaudiana Bertoni) is an essential herbal plant used as a sweetener. The demand for stevia is growing due to its low caloric and medicinal value, hence the need for a more thorough investigation of its nutritional and biological properties. Nanoparticles of metal oxides have been found to have broad applications in agriculture for the stimulation of plant growth and development. The study aimed to assess the effect of various zinc oxide nanoparticles (ZnONPs) concentrations on stevia plants’ quantitative and qualitative traits obtained in in vitro cultures. Micropropagation of two stevia varieties, Candy and Morita, was carried out using explants of shoot tips placed on MS medium supplemented with 1.0 mg dm^–3 BA and 0.1 mg dm^–3 IBA and with ZnONPs at concentrations of 0 (control), 10, 20, 30 and 40 mg dm^–3. The obtained results indicated that high concentrations of ZnONPs stimulated the propagation of shoots. On the other hand, they negatively influenced shoot length, root number and length, and the fresh weight of the plantlets. The presence of zinc oxide nanoparticles in the medium increased the potassium, calcium, magnesium, and zinc content while decreasing the sodium and iron content in the regenerated stevia plantlets. The total phenolic content in the Candy variety was higher in the treatments with ZnONPs than in the control plants, while it was varied in the Morita variety. In both varieties, total antioxidant content measured by the ABTS method showed significantly higher in the treatments with 20–30 mg dm^–3 ZnONPs than in the control. The content of chlorophyll a, chlorophyll b and chlorophyll a + b in the Morita variety was higher in the treatments with 10 and 20 mg dm^–3 ZnONPs than in the control. On the other hand, high concentrations of ZnONPs negatively affected the content of carotenoids in both varieties. The study showed that stevia plants obtained in in vitro cultures on control media and media containing ZnONPs had a high content of valuable minerals, phytocompounds with antioxidant properties, and photosynthetic pigments.

Effect of drying temperature on the bioactive compounds content of rose hips (Rosa canina L.)

2024-07-01T11:03:14+02:00

Dog rose (Rosa canina L.) is a beautiful ornamental plant that provides fruit with high biological value. To be available throughout the year, rose hips need to be conserved, such as dried and canned. For this reason, a study was undertaken to investigate the effects of drying as the most common method for preservation. Therefore, the influence of variation drying temperature (20, 35 and 68 °C) on the content of flavonoids, total polyphenols, ascorbic acid, carotenoids and antioxidant activity - determined using the free radical source DPPH (2,2-diphenyl-1-picrylhydrazyl) and a test measuring the measuring of compounds to reduce ferric ions Fe³⁺ (FRAP) - of rose hips was the main topic in this study. Drying decreased total polyphenols (from 38.06 mg g^–1 by fresh fruits to 9.41 mg g^–1 drying to 20 °C), ascorbic acid (from 2000.5 mg 100 g^–1 by fresh fruits to 1308.2 mg 100 g^–1 drying to 68 °C) and flavonoids, the latter only in those dried at 35 °C (0.54 mg g^–1), but did not affect the antioxidant activity of DPPH (84.21–85.73%) and FRAP (2.99–3.41 mgTr g^–1). The study also showed that the extraction time influenced the antioxidant activity level of fruit infusions for the first time. The antioxidant potential FRAP value increased systematically with extraction time, but the DPPH values of extracts obtained from dried rose hips were not affected by the extraction time. These results indicate that changes in the antioxidant activity of extracts may not be linear and that the choice of the time of evaluation of this activity may determine the results.

A G6P1E isomerase of sugar metabolism is involved in the flower colors of Dianthus chinensis

2024-07-01T11:03:23+02:00

Dianthus chinensis L. is indigenous to northern China, Korea, Mongolia, Kazakhstan, and southeastern Russia. It is widely cultivated in urban landscapes. Its flower has a great variety of colors and color schemes. Sugars control and induce anthocyanin synthesis and accumulation in plants. In sugar metabolism, many enzymes are specific for their substrate’s α or β anomer. Gaining and characterizing genes involved in sugar metabolism and flower color will be beneficial in clarifying the role of sugar in the flower colors of D. chinensis. Glucose-6-phosphate-1-epimerase (G6P1E, EC 5.1.3.15) catalyzes the α or β change of glucose-6-phosphate at the branch point of glucose metabolism. DchG6P1E1 (MZ292712) was isolated in D. chinensis and characterized using the tobacco rattle virus (TRV)-based virus-induced gene silencing (VIGS) system. Its cDNA full length is 1401 bp, including an open reading frame of 918 bp. In the DchG6P1E1-silenced flowers, the reducing purple was observed, as well as the anthocyanin content, reducing sugar content, G6P1E activity, and DchG6P1E1 expression were significantly decreased. During the development of floral buds and among the three flower colors, the anthocyanin content, reduced sugar content, G6P1E activity, and DchG6P1E1 expression rose dramatically, with pigments increasing in the petals. Among the organs, the flowers had the highest anthocyanin contents and reducing sugar. The highest levels of G6P1E activity and DchG6P1E1 expression were in the roots. The anthocyanin content was positively related to the reducing sugar content at 0.05 levels by correlation analysis. In conclusion, DchG6P1E1 is a root-enriched gene associated with flower colors in D. chinensis.

Comparative response of three tropical groundcovers to salt stress

2024-07-01T11:03:27+02:00

The increasing interest in cultivating groundcover plants in warm and semiarid areas requires a better understanding of the salinity effects on landscape plants. This work aimed to study the response of three groundcovers (Alternanthera dentate, Sphagneticola trilobata, and Alternanthera amoena) to high sodium chloride concentrations. The trial was conducted in the natural greenhouse environment. Plants were raised in pots filling clay-loamy soil. Hewitt’s nutrient solution containing 0, 25, 50, 75, and 100 mM NaCl irrigated the plants. Plant growth, antioxidative enzyme activity, and the relative water content (RWC), proline, sodium, potassium, and chloride were determined. The study indicated that increasing NaCl concentration in the nutrient solution led to: a) significant differences in the fresh weight of shoots among salinity treatments and among species; b) increased root growth with increasing salinity stress up to the mild stress level of 25 mM NaCl, however at different rates with three species; c) reduced RWC of the leaves of three species grown under salinity-induced stress; d) the increased proline content of the leaves, and more pronounced increases with A. dentate and A. amoena from 0 to 50 mM NaCl, and with S. trilobata from 0 to 100 mM NaCl; e) significant changes in the activities of antioxidative enzymes including superoxide dismutase, peroxidase, and catalase; f) significant decrease of the K⁺/Na⁺ ratio along with increase of salinity stress; g) increased ratio of leaf/ root content of Cl^– in A. dentate and in particular, A. amoena; h) a significant reduction in visual qualities of all examined plants. Therefore, because of its ability to maintain leaf characteristics, visual quality, and salt-tolerance mechanisms even under high salinity, S. trilobata can be considered for urban landscaping projects in semiarid and saline areas where low-quality water is used for irrigation.