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A light-emitting diode (LED) system covering plant-receptive wavebands from ultraviolet to far-red radiation (360 to 760 nm, "white" light spectrum) was investigated for greenhouse productions of Thymus vulgaris L. Biomass yields and amounts of terpenoids were examined, and the lights' productivity and electrical efficiency were determined. All results were compared to two conventionally used light fixture types (high-pressure sodium lamps (HPS) and fluorescent lights (FL)) under naturally low irradiation conditions during fall and winter in Berlin, Germany. Under LED, development of Thymus vulgaris L. was highly accelerated resulting in distinct fresh yield increases per square meter by 43% and 82.4% compared to HPS and FL, respectively. Dry yields per square meter also increased by 43.1% and 88.6% under LED compared to the HPS and FL lighting systems. While composition of terpenoids remained unaffected, their quantity per gram of leaf dry matter significantly increased under LED and HPS as compared to FL. Further, the power consumption calculations revealed energy savings of 31.3% and 20.1% for LED and FL, respectively, compared to HPS. In conclusion, the implementation of a broad-spectrum LED system has tremendous potential for increasing quantity and quality of Thymus vulgaris L. during naturally insufficient light conditions while significantly reducing energy consumption. [ABSTRACT FROM AUTHOR]

Light emitting diodes (LEDs) have recently been considered an efficient artificial light source in plant factories for enhancing plant growth and nutritional quality. Accordingly, this study aimed to review blue, red, and white LED light sources for efficiency and length of the growing period to produce seedlings of Scutellaria baicalensis with high nutritional value. The roots, stems, and leaves of S. baicalensis seedlings were grown under different LED lights and harvested after two and four weeks, and analyzed using high-performance liquid chromatography and gas chromatography time-of-flight mass spectrometry to identify and quantify primary and secondary metabolites. Roots, particularly in the seedlings treated with white LEDs were determined to contain the greatest concentrations of the representative compounds present in S. baicalensis: baicalin, baicalein, and wogonin, which show highly strong biological properties compared to the other plant organs. A total of 50 metabolites (amino acids, sugars, sugar alcohols, organic acids, phenolic acids, and amines) were detected in the roots, stems, and leaves of S. baicalensis seedlings, and the concentrations of primary and secondary metabolites were generally decreased with the increasing duration of LED illumination. Therefore, this study suggests that white LED light and a 2-week growing period are the most efficient conditions for the production of baicalin, baicalein, and wogonin. [ABSTRACT FROM AUTHOR]

It has been shown that monochromatic red and blue light influence photosynthesis and morphology in cucumber. It is less clear how green light impacts photosynthetic performance or morphology, either alone or in concert with other wavelengths. In this study, cucumber (Cucumis sativus) was grown under monochromatic blue, green, and red light, dichromatic blue–green, red–blue, and red–green light, as well as light containing red, green, and blue wavelengths, with or without supplemental far-red light. Photosynthetic data collected under treatment spectra at light-limiting conditions showed that both red and green light enhance photosynthesis. However, photosynthetic data collected with a 90% red, 10% blue, 1000 µmol photons m−2 s−1, saturating light show significantly lower photosynthesis in the green, red, and red–green treatments, indicating a blue light enhancement due to photosystem stoichiometric differences. The red–green and green light treatments show improved photosynthetic capacity relative to red light, indicating partial remediation by green light. Despite a lower quantum efficiency and the lowest ambient photosynthesis levels, the monochromatic blue treatment produced among the tallest, most massive plants with the greatest leaf area and thickest stems. [ABSTRACT FROM AUTHOR]

The aim of the presented studies was to evaluate the magnetic field (MF) effect on changes in some enzymes and phytohormones that takes place in the process of seed germination and growth of seedlings. Studies were led in the climatic chambers HERAEUS, on Petri dishes during six consecutive days. Pea seeds were divided into three groups from which one was the control (without stimulation) and two were treated with different doses of magnetic field (30 and 85 mT, respectively). Contents of amylolytic enzymes (AE) and phytohormones were determined at seven terms (0; 24; 48; 72; 96; 120 and 144 h) after placing them on the dishes. A favorable effect of seed stimulation with MF was found on the biochemical processes in the germinating seeds and pea seedlings. The size of changes in enzyme concentration was dependent mainly on the advancement of germination process (i.e., on length of time in which the seeds were on the dishes) and the MF treatment. The use of MF also had an effect on the increase in hormone content in the seeds and organs of seedlings, but values from objects treated with different doses did not differ significantly. [ABSTRACT FROM AUTHOR]

Manipulation of the LED illumination spectrum can enhance plant growth rate and development in grow tents. We report on the identification of the illumination spectrum required to significantly enhance the growth rate of sweet basil (Ocimum basilicum L.) plants in grow tent environments by controlling the LED wavebands illuminating the plants. Since the optimal illumination spectrum depends on the plant type, this work focuses on identifying the illumination spectrum that achieves significant basil biomass improvement compared to improvements reported in prior studies. To be able to optimize the illumination spectrum, several steps must be achieved, namely, understanding plant biology, conducting several trial-and-error experiments, iteratively refining experimental conditions, and undertaking accurate statistical analyses. In this study, basil plants are grown in three grow tents with three LED illumination treatments, namely, only white LED illumination (denoted W*), the combination of red (R) and blue (B) LED illumination (denoted BR*) (relative red (R) and blue (B) intensities are 84% and 16%, respectively) and a combination of red (R), blue (B) and far-red (F) LED illumination (denoted BRF*) (relative red (R), blue (B) and far-red (F) intensities are 79%, 11%, and 10%, respectively). The photosynthetic photon flux density (PPFD) was set at 155 µmol m−2 s−1 for all illumination treatments, and the photoperiod was 20 h per day. Experimental results show that a combination of blue (B), red (R), and far-red (F) LED illumination leads to a one-fold increase in the yield of a sweet basil plant in comparison with only white LED illumination (W*). On the other hand, the use of blue (B) and red (R) LED illumination results in a half-fold increase in plant yield. Understanding the effects of LED illumination spectrum on the growth of plant sweet basil plants through basic horticulture research enables farmers to significantly improve their production yield, thus food security and profitability. [ABSTRACT FROM AUTHOR]

Nasturtium is a popular herbal plant, widely cultivated as culinary and medicinal plants all over the world. However, the seed propagation of nasturtium is inefficient, and in-vitro propagation is sophisticated and high-cost. In this study, the cutting propagation method was employed to produce nasturtium seedlings. We aimed to determine the optimal conditions for cutting propagation of nasturtium seedlings by investigating the effects of node position and electric conductivity (EC) of nutrient solution on the root formation of the cuttings. Cuttings from five node positions (apical bud, 2nd node, 3rd node, 4th node, and 5th node) were subjected to water and five EC (1.0, 2.0, 3.0, 4.0, and 5.0 dS m−1) treatments with a hydroponic cultivation system in a plant factory. Results showed that all cuttings rooted successfully within two weeks. The cuttings from the apical bud position rooted earliest and produced the most roots regardless of EC level. Cuttings from other node positions produced longer roots and heavier root fresh and dry weights than those from the apical bud position. The cuttings under EC of 1.0 dS m−1 had the greatest root number, the longest root length, and the heaviest root fresh and dry weights regardless of node positions. The EC of 1.0 dS m−1 is considered the best condition for nasturtium cuttings for the range of EC tested in this study, and the cuttings from all the five node positions can be used as seedling materials. [ABSTRACT FROM AUTHOR]

Since the development of the "cholinergic hypothesis" as an important therapeutic approach in the treatment of Alzheimer's disease (AD), the scientific community has made a remarkable effort to discover new and effective molecules with the ability to inhibit the enzyme acetylcholinesterase (AChE). The natural function of this enzyme is to catalyze the hydrolysis of the neurotransmitter acetylcholine in the brain. Thus, its inhibition increases the levels of this neurochemical and improves the cholinergic functions in patients with AD alleviating the symptoms of this neurological disorder. In recent years, attention has also been focused on the role of another enzyme, butyrylcholinesterase (BChE), mainly in the advanced stages of AD, transforming this enzyme into another target of interest in the search for new anticholinesterase agents. Over the past decades, Nature has proven to be a rich source of bioactive compounds relevant to the discovery of new molecules with potential applications in AD therapy. Bioprospecting of new cholinesterase inhibitors among natural products has led to the discovery of an important number of new AChE and BChE inhibitors that became potential lead compounds for the development of anti-AD drugs. This review summarizes a total of 260 active compounds from 142 studies which correspond to the most relevant (IC 50 ≤ 15 μM) research work published during 2012-2022 on plant-derived anticholinesterase compounds, as well as several potent inhibitors obtained from other sources like fungi, algae, and animals., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)