The purpose of our paper was to evaluate the influence of LED-s emitted light and sunlight treatments on the hemp (Cannabis sativa L.), sprouts. The sprouts were illuminated with three types of LED-s spectrum variants red (R), blue (B) and green (G), and the sunlight represented the reference. Our results showed that blue (B) light LED-s determined a high level of rate and fresh weight of hemp sprouts. The phytochemical compounds content (polyphenols, flavonoids), antioxidant activity (determined by DPPH assay), and protein concentration were evaluated in hemp (Cannabis sativa L.) sprouts. The content of polyphenols, flavonoids and protein was significantly higher after exposure to blue (B) light LED-s, while sunlight while green (G) light LED-s improved the antioxidant capacity.

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Our aim was to elaborate an efficient and reproducible protocol for medium-term culture of the threatened taxon Dianthus nardiformis. To reduce the growth, sucrose, mannitol, polyethylene glycol, Abscisic acid and Jasmonic acid were tested. For assessing the in vitro response, the growth and regeneration were registered after different time intervals. Mannitol is the most effective for medium-term preservation viable cultures which can be maintained unlimited time through transfer at every 3 months. In its presence, somatic embryogenesis was induced and in vitro growth in the minimal cultures was reduced between 9 and 12 times comparing to the control. Antioxidant enzymes assay revealed qualitative and quantitative differences among the experimental variants, and also between different concentrations of the same compound in correlation with the growth reduction and regeneration. POX was the most suitable to detect the efficiency of different treatments to induce medium-term cultures.

Light is an important environmental factor for plants. The quality of light and the wavelength stimulate enzyme activation, regulate enzyme synthesis pathways and promote bioactive compound accumulation. In this respect, the utilization of LED light under controlled conditions in agriculture and horticulture could be the most suitable choice for increasing the nutritional values of various crops. In recent decades, LED lighting has been increasingly used in horticulture and agriculture for commercial-scale breeding of many species of economic interest. Most studies on the influence of LED lighting on the accumulation of bioactive compounds in any type of plants (horticultural, agricultural species or sprouts) and also biomass production, were carried out in growth chambers under controlled conditions, without natural light. Illumination with LED could be a solution for obtaining an important crop with maximum efficiency, with a high nutritional value and minimum effort. To demonstrate the importance of LED lighting in agriculture and horticulture, we carried out a review based on a large number of results cited in the literature. The results were collected from 95 articles and were obtained using the keyword LED combined with plant growth; flavonoids; phenols; carotenoids; terpenes; glucosinolates; food preservation. We found the subject regarding the LED effect on plant growth and development in 11 of the articles analyzed. The treatment of LED on phenol content was registered in 19 articles, while information regarding flavonoid concentrations was revealed by 11 articles. Two articles we reviewed debate the accumulation of glucosinolates and four articles analyzed the synthesis of terpenes under LED illumination and 14 papers analyzed the variation in content of carotenoids. The effect of LED on food preservation was reported in 18 of the works analyzed. Some of the 95 papers contained references which included more keywords.

The present study presents the influence exercised by LED (light emitting diodes)-s emitted white (W), red (R), blue (B) light on sprouting of buckwheat seeds and evaluated the effects on content of phenolic compounds, antioxidant capacity and flavonoids.The fresh weight of hypocotyls, showed that the R light has generated the best influence for sprouts and W light has generated the most adverse influence. The content of flavonoids was stimulated by R LED for variant sprouts with testa (V3), while both B and R LED inhibited for variant without testa (V4, V6). The higher concentration of polyphenols was obtained for V5 variant illuminated with B LED and increased for V4 variant illuminated with R LED. The antioxidant capacity was higher for V3 variant illuminated with B light and stimulated by R LED in V4 variant.The results contribute to the establishment an efficient working protocol, for obtaining sprouts from buckwheat seeds, with a comprehensive content of bioactive components, various nutrients by applying the R LED treatment.

Cotinus coggygria Scop. (smoketree) and Fragaria × ananassa Duch. (strawberry) are two industrially important species due to their composition in bioactive compounds. In this study, we investigated the effects of acute low-dose gamma irradiation (15, 20, 25, 30, 35 and 40 Gy) on two red callus cultures established in smoketree and strawberry. The biomass production, dry weight, content of phenols, flavonoids, monomeric anthocyanins’, index of anthocyanins polymerization and antioxidant activity were evaluated. For the smoketree callus, a negative correlation between irradiation doses and callus biomass accumulation was observed. For the strawberry callus, irradiation did not significantly affect the accumulation of the biomass. An increased dry weight was observed in irradiated smoketree callus, while for treated strawberry callus, a decrease was recorded. Irradiation with 30 Gy was stimulative for polyphenols’ accumulation in both cultures; however, the increase was significant only in the strawberry callus. The flavonoids increased in the 30 Gy strawberry variants, while it significantly decreased in smoketree callus irradiated with 35 and 40 Gy. In irradiated strawberry callus, except for the 25 Gy variant (1.65 ± 0.4 mg C-3-GE/g DW), all treatments caused an increase in anthocyanins’ accumulation. In smoketree, except for the 15 Gy variant (2.14 ± 0.66 mg C-3-GE/g DW), the irradiation determined an increase in anthocyanins synthesis, with the highest value being seen in the 20 Gy variant (2.8 ± 0.94 mg C-3-GE/g DW). According to UPLC-HRMS investigations, an unidentified compound increased by 99% at the 30 Gy dose in strawberry callus, while in smoketree, maslinic acid increased by 51% after irradiation with 40 Gy. The results of this study showed, for the first time, the differential response of two performant callus cultures to low-dose gamma irradiation, a biotechnological method that can be used to stimulate the synthesis of important flavonoids and triterpenes.

In the current context of climate change and life on Earth, the purpose of this paper is to establish the effects of different light treatments (i.e., LEDs—white, blue, red, and sunlight) and two different substrates (i.e., gauze and biochar) on garden cress sprouts. In this respect, sprouts’ fresh weight and fresh length were statistically analyzed. In the case of the fresh weight, the results indicated that the most suitable substrate for better growth is biochar under all of the light treatments, with a 5.78% weight increase. On the other hand, the highest particular value regarding weight was obtained for gauze substrate under sunlight treatment, with a 4.08% weight increase compared to biochar substrate and sunlight treatment. Furthermore, red LED and biochar used as substrate improved the development of short radicles, with a decrease in length of 94.80% compared to gauze substrate and red LED treatment. The effect of LED irradiation was completed with biochemical analyses concerning polyphenols, flavonoid content, and antioxidant activity. Results suggest that blue LED is the most suitable source of artificial light to promote the accumulation of secondary metabolites, with a 9.88% higher concentration of flavonoids compared to the other light variants (2.22 ± 0.40 mg rutin equivalent/g fresh weight) and 37.98% higher concentration of polyphenols compared to the other light variants (2.76 ± 1.05 mg gallic acid equivalent/g fresh weight) in garden cress sprouts. The illumination with white LED produced the highest effect concerning antioxidant activity, with a 37.60% higher free radical scavenging activity.