Search Results (19)

Conventional micropropagation of cannabis struggles with excessive callus hyperhydration, slow growth, low rooting efficiency, and high contamination risk, all of which greatly restrict its feasibility for large-scale propagation. In contrast, photoautotrophic micropropagation (PAM) has emerged as an efficient and cost-effective propagation strategy that can significantly enhance plantlet growth and improve seedling quality by optimizing the LED lighting environment. This study investigated the effects of four light intensities (50, 100, 150, and 200 µmol m⁻² s⁻¹) and three photoperiods (16, 20, and 24 h d⁻¹) on the growth and rooting of two medicinal cannabis cultivars (the short-day cultivar ‘Charlotte’ and the day-neutral cultivar ‘Auto Charlotte’). Cluster analysis revealed that plantlets grown under the photoperiod of 20 h d⁻¹ and light intensity of 100–150 µmol m⁻² s⁻¹ exhibited optimal growth performance in terms of plant height, root length, leaf number, leaf area, biomass, and root activity. Moreover, increasing the light intensity from 50 to 100–150 µmol m⁻² s⁻¹ significantly enhanced net CO₂ exchange rates by 41.5% and 204.9% for Charlotte and Auto Charlotte, respectively, along with corresponding increases in dry matter accumulation of 44.3% and 27.9%. However, the plantlets exhibited photooxidative damage under continuous lighting and light intensity of 200 µmol m⁻² s⁻¹, as evidenced by reduced photosynthetic pigment content and suppressed antioxidant enzyme activity. Therefore, PAM of medicinal cannabis is recommended under the LED lighting environment with light intensity of 100–150 µmol m⁻² s⁻¹ and photoperiod of 20 h d⁻¹ to achieve optimal growth and rooting. These findings provide essential technical support for the large-scale propagation of vigorous, disease-free female plantlets with well-developed root systems and high genetic uniformity, thereby meeting the stringent quality standards for planting materials in the commercial cultivation of cannabis for medical and pharmaceutical use. Full article

The relationship between the gut microbiota and photoperiod has received widespread attention, and it is necessary to explore the probable common mechanisms involved. We tested whether the gut microbiota of animals with similar light-regulated life history traits would also exhibit consistent responses to the photoperiod. Here, two species of long-day breeders, striped hamsters (Cricetulus barabensis) and Djungarian hamsters (Phodopus sungorus), were raised under different photoperiods (long daylight, LD; short daylight, SD), and their cecal contents were collected to assess the gut microbiota. There was no difference in the gut microbial diversity between the groups of striped hamsters; however, in the Djungarian hamsters, lower Chao and Shannon indices were observed in the LD group than in the SD group. The bacterial community variation in the striped hamsters was reflected mainly in the enrichment of the genera Enterorhabdus and Jeotgalicoccus in the LD group; meanwhile, more taxa with significant changes in relative abundance under different photoperiods were found in the Djungarian hamsters, such as the enrichment of the genera Lactobacillus and Faecalibaculum in the LD group and the enrichment of the genera Ruminococcus and Colidextribacter in the SD group. The LD conditions substantially reduced the complexity of the gut microbial network in the Djungarian hamsters and increased the R² value of the striped hamster gut microbiota under fitting with a neutral community model. Moreover, the potential gut microbial functions in the striped hamsters were relatively stable, but variations were observed in multiple pathways between the groups of Djungarian hamsters. These results contribute to the understanding of host species specificity in the response of the gut microbiota to external changes. Full article

Currently, solid waste storage systems generate secondary pollutants such as leachates, derived from rainwater infiltration or produced during their storage, which affect water quality, human health, and the environment. This study evaluated a bioremediation system for leachates from the “Rancho Triste” landfill using Spirulina sp. as a microalgal strain. Its rapid adaptation to the leachate was identified through respirometry based on CO₂ measurement, allowing the modeling of microalgal adaptation using a Log-Normal Peak Shifted with Offset function. Tests conducted in a 0.5 L reactor determined an optimal treatment time of 10 days, achieving removals of 87.17% for iron, 28.96% for magnesium, and 90.74% for manganese. Subsequently, a 2³ factorial design was implemented to optimize the reduction of chemical oxygen demand (COD), evaluating agitation, lighting, and nitrogen supplementation, achieving a COD removal efficiency exceeding 50% under optimal conditions. The fed-batch technique enabled an enrichment of microbiological populations, which, together with bio-stimulation, bioventilation, and photoperiods, demonstrated the scalability of the bioprocess and the significant reduction of metallic and recalcitrant contaminants present in the leachate. This approach proposes an ecological alternative with potential application in water treatment industries aiming for carbon neutrality and optimal transformation of high-effluent volumes. Full article

This study addressed the following questions: How does continuous lighting (CL) impact plant physiology, and photosynthetic and stress responses? Does the impact of CL depend on the source of the light and other environmental factors (natural vs. artificial)? Do responses to CL differ for native and non-native plant species in the subarctic region and, if differences exist, what physiological reasons might they be associated with them? Experiments were conducted with three plants native to the subarctic region (Geranium sylvaticum L., Geum rivale L., Potentilla erecta (L.) Raeusch.) and three non-native plant species (Geranium himalayense Klotzsch, Geum coccineum Sibth. and Sm., Potentilla atrosanguinea Loddiges ex D. Don) introduced in the Polar-Alpine Botanic Garden (KPABG, 67°38′ N). The experimental groups included three species pairs exposed to (1) a natural 16 h photoperiod, (2) natural CL, (3) an artificial 16 h photoperiod and (4) artificial CL. In the natural environment, measurements of physiological and biochemical parameters were carried out at the peak of the polar day (at the end of June), when the plants were illuminated continuously, and in the second week of August, when the day length was about 16 h. Th experiments with artificial lighting were conducted in climate chambers where plants were exposed to 16 h or 24 h photoperiods for two weeks. Other parameters (light intensity, spectrum composition, temperature and air humidity) were held constant. The obtained results have shown that plants lack specific mechanisms of tolerance to CL. The protective responses are non-specific and induced by developing photo-oxidative stress. In climate chambers, under constant environmental conditions artificial CL causes leaf injuries due to oxidative stress, the main cause of which is circadian asynchrony. In nature, plants are not photodamaged during the polar day, as endogenous rhythms are maintained due to daily fluctuations of several environmental factors (light intensity, spectral distribution, temperature and air humidity). The obtained data show that among possible non-specific protective mechanisms, plants use flavonoids to neutralize the excess ROS generated under CL. In local subarctic plants, their photoprotective role is significantly higher than in non-native introduced plant species. Full article

Circadian disruption increases the development of cardiovascular disease and diabetes. We found that circadian disruption causes glucose intolerance, cardiac fibrosis and adipocyte tissue dysfunction in male sand rats, Psammomys obesus. Whether these effects occur in female P. obesus is unknown. Male and female P. obesus were fed a high energy diet and exposed to a neutral (12 light:12 dark, control) or short (5 light:19 dark, circadian disruption) photoperiod for 20 weeks. Circadian disruption impaired glucose tolerance in males but not females. It also increased cardiac perivascular fibrosis and cardiac expression of inflammatory marker Ccl2 in males, with no effect in females. Females had reduced proapoptotic Bax mRNA and cardiac Myh7:Myh6 hypertrophy ratio. Cardiac protection in females occurred despite reductions in the clock gene Per2. Circadian disruption increased adipocyte hypertrophy in both males and females. This was concomitant with a reduction in adipocyte differentiation markers Pparg and Cebpa in males and females, respectively. Circadian disruption increased visceral adipose expression of inflammatory mediators Ccl2, Tgfb1 and Cd68 and reduced browning marker Ucp1 in males. However, these changes were not observed in females. Collectively, our study show that sex differentially influences the effects of circadian disruption on glucose tolerance, cardiac function and adipose tissue dysfunction. Full article

Previous studies have shown that light quality and quantity affect methane emissions from plants. However, the role of photoperiod in plant-derived methane has not been addressed. We studied the effects of two photoperiods—long-day (16 h light/8 h dark), and short-day (8 h light/16 h dark)—on growth and methane emissions of lettuce (a long-day plant), mung bean (a short-day plant), and tomato (a day-neutral plant) under a temperature regime of 22/18 °C. All species were grown under both light durations. First, seeds were germinated in Petri dishes for one week, then plants were transferred to pots and randomly assigned to one of the two experimental conditions. Under each condition, twelve plants were grown for 21 days; at that time, plant growth and physiological traits, including plant dry mass, growth index, photosynthesis, chlorophyll fluorescence, total chlorophyll, nitrogen balance index, flavonoids, and anthocyanin, were measured. Lettuce plants under the short-day photoperiod had the highest methane emissions. Long-day plants that were exposed to short-day conditions and short-day plants that were exposed to long-day conditions were stressed; day-neutral plants were also stressed under short days (p < 0.05). All three species had decreased total dry mass under short-day conditions, most likely because of decreased photosynthesis and increased transpiration and stomatal conductance. Methane emission was positively correlated with shoot/root mass ratio, nonphotochemical quenching and anthocyanin; but was negatively correlated with stem height, dry mass, photosynthesis, water-use efficiency, total chlorophyll, and flavonoids (p < 0.05). This study revealed that, besides light intensity and quality, light duration can also affect methane emissions from plants. Full article

The photoperiodic sensitivity of soybean (Glycine max L.) is one of the limiting factors affecting plant growth and yield. At higher latitudes, early flowering and maturity with neutral reaction to photoperiods are required for adaptation of soybean plants to long-day conditions. Currently, the production and distribution of new varieties of soybeans adapted to widespread agricultural regions in northern Kazakhstan is in strong demand. Eleven soybean hybrid populations were obtained from crosses between 17 parents with four maturity groups, MG 000, 00, 0, and I. Marker-assisted selection (MAS) was assessed for suitable SSR markers and successfully applied for genes E1, E3, E4, and E7, targeting homozygous genotypes with recessive alleles. The identified and selected genotypes were propagated and tested in the conditions of 53° N latitude in the Kostanay region of northern Kazakhstan. Finally, 20 early maturing F₄ breeding lines were identified and developed with genotypes e1 e3 E4 e7, e1 E3 E4 e7, and e1 E3 e4 e7, all completing their growth period within 92–102 days. These breeding lines were developed by MAS and should provide very prospective superior varieties of soybean for northern Kazakhstan through a strategy that may be very helpful to other countries with high latitudes. Full article

Heavy metal contamination of agricultural soils is potentially concerning when growing crops for human consumption. Industrial hemp (Cannabis sativa L.) has been reported to tolerate the presence of heavy metals such as cadmium (Cd) in the soil. Therefore, the objectives of this study were to evaluate Cd uptake and translocation in two day-length sensitive (DLS) and two day-neutral (DN) hemp varieties grown for the medicinal market and to determine the impact of Cd exposure on cannabinoid concentrations in flowers. A hydroponic experiment was conducted by exposing plants to 0 mg·L⁻¹ Cd and 2.5 mg·L⁻¹ Cd in the nutrient solution. Cadmium concentrations ranged from 16.1 to 2274.2 mg·kg⁻¹ in roots, though all four varieties accumulated significant concentrations of Cd in aboveground tissues, with translocation factors ranging from 6.5 to 193. Whole-plant bioconcentration factors ranged from 20 to 1051 mg·kg⁻¹. Cannabinoid concentrations were negatively impacted by Cd exposure in DN varieties but were unaffected in DLS varieties. Biomass was reduced by Cd exposure demonstrating that these varieties might not be suitable for growth on contaminated soil or for phytoremediation. There is potential for Cd accumulation in flowers, showing the need for heavy metal testing of C. sativa consumer products. Full article

Strawberries are grown worldwide, and the fruit is known for its flavor, pleasant aroma, and the presence of important nutraceutical compounds. Under temperate conditions, the species is octaploid and presents a complex inheritance. Exploring polyploidy in varietal crosses is the main alternative to developing genotypes of high-temperature regions; thus, breeding programs must evaluate the interaction based on parameters, such as the heritability, stability, easy propagation, and adaptability to different soil and climate variations. To estimate the stability and temporal adaptability of pre-selected triple hybrids of day-neutral strawberries, thirty-six experimental genotypes, three commercial genotypes (‘Albion,’ ‘Monterey,’ and ‘Dover’), and four single hybrids (‘RVFS07,’ ‘RVFS06,’ ‘RVDA11,’ and ‘RVCA16’) were evaluated in a protected cultivation from August to February under tropical climate conditions (southern hemisphere) using the mixed linear model (MLM). The genotypes RVFS07M-34, RVFS07M-24, RCDA11M-04, RVFS07M-154, RVFS07M-36, RVFS07M-33, RVFS07M-80, RVFS07M-10, RVDA11M-21, RVDA11M-13, and RVFS06AL-132 had the highest values of total fruit mass, adaptability, and stability. The mean predicted genotypic values of the selected genotypes was 138% higher than the mean of the controls. Therefore, these genotypes have the potential to be released as cultivars. Full article

This study examines how the day neutral plant (DNP) Pelargonium × hortorum L.H. Bailey ‘Ringo 2000 Violet’ is impacted by LED night-interruption light (NIL) quality shifting in terms of flowering, morphogenesis, and transcription of photoreceptor genes. A closed-type plant factory with white (W) LEDs providing 180 μmol·m⁻²·s⁻¹ PPFD light for long day (LD, 16 h light, 8 h dark), short day (SD, 10 h light, 14 h dark), or SD with 4 h night interruption (NI) with 10 μmol·m⁻²·s⁻¹ PPFD LEDs was used to grow the plants. Two NIL qualities were employed, where after the first two hours, the NIL quality was switched from one to another among white (W), far-red (Fr), red (R), and blue (B). A total of 12 SD treatments with NIL quality shifting were used, with the LD and SD serving as the control: NI-BR (from B to R), NI-RB (from R to B), NI-RFr (from R to Fr), NI-FrR (from Fr to R), NI-BFr (from B to Fr), NI-FrB (from Fr to B), NI-WB (from W to B), NI-BW (from B to W), NI-FrW (from Fr to W), NI-WFr (from W to Fr), NI-RW (from R to W), and NI-WR (from W to R). LD refers to a 16 h long-day treatment. Geranium plants were taller in NI treatments that included Fr light than those in other NI treatments and were the shortest in the NI-WB treatment. Flowering was seen in all treatments and was notably encouraged by NI with Fr light, regardless of the sequence of light quality applied. In NI-FrR and NI-RFr, high expressions of phyA, phyB, and cry1 were observed. Flower formation and plant morphogenesis were both impacted by the photoperiod. Both morphogenesis and flowering were strongly impacted by the second NIL, but the first NIL had no effects on either. These findings indicate that NI-RFr and NI-FrR improve flowering, which may be used for commercial DNP production. Full article

The accumulation of carotenoids in plants is a key nutritional quality in many horticultural crops. Although the structural genes encoding the biosynthetic enzymes are well-characterized, little is known regarding photoperiod-mediated carotenoid accumulation in the fruits of some horticultural crops. Herein, we performed physiological and transcriptomic analyses using two cucumber genotypes, SWCC8 (XIS-orange-fleshed and photoperiod-sensitive) and CC3 (white-fleshed and photoperiod-non-sensitive), established under two photoperiod conditions (8L/16D vs. 12L/12D) at four fruit developmental stages. Day-neutral treatments significantly increased fruit β-carotene content by 42.1% compared to short day (SD) treatments in SWCC8 at 40 DAP with no significant changes in CC3. Day-neutral condition elevated sugar levels of fruits compared to short-day treatments. According to GO and KEGG analyses, the predominantly expressed genes were related to photosynthesis, carotenoid biosynthesis, plant hormone signaling, circadian rhythms, and carbohydrates. Consistent with β-carotene accumulation in SWCC8, the day-neutral condition elevated the expression of key carotenoid biosynthesis genes such as PSY1, PDS, ZDS1, LYCB, and CHYB1 during later stages between 30 to 40 days of fruit development. Compared to SWCC8, CC3 showed an expression of DEGs related to carotenoid cleavage and oxidative stresses, signifying reduced β-carotene levels in CC3 cucumber. Further, a WGCNA analysis revealed co-expression between carbohydrate-related genes (pentose-phosphatase synthase, β-glucosidase, and trehalose-6-phosphatase), photoperiod-signaling genes (LHY, APRR7/5, FKF1, PIF3, COP1, GIGANTEA, and CK2) and carotenoid-biosynthetic genes, thus suggesting that a cross-talk mechanism between carbohydrates and light-related genes induces β-carotene accumulation. The results highlighted herein provide a framework for future gene functional analyses and molecular breeding towards enhanced carotenoid accumulation in edible plant organs. Full article

Japanese cultivated gentians are perennial plants that flower in early summer to late autumn in Japan, depending on the cultivar. Several flowering-related genes, including GtFT1 and GtTFL1, are known to be involved in regulating flowering time, but many such genes remain unidentified. In this study, we obtained transcriptome profiling data using the Gentiana triflora cultivar ‘Maciry’, which typically flowers in late July. We conducted deep RNA sequencing analysis using gentian plants grown under natural field conditions for three months before flowering. To investigate diurnal changes, the plants were sampled at 4 h intervals over 24 h. Using these transcriptome data, we determined the expression profiles of leaves based on homology searches against the Flowering-Interactive Database of Arabidopsis. In particular, we focused on transcription factor genes, belonging to the BBX and MADS-box families, and analyzed their developmental and diurnal variation. The expression levels of representative BBX genes were also analyzed under long- and short-day conditions using in-vitro-grown seedlings, and the expression patterns of some BBX genes differed. Clustering analysis revealed that the transcription factor genes were coexpressed with GtFT1. Overall, these expression profiles will facilitate further analysis of the molecular mechanisms underlying the control of flowering time in gentians. Full article

Stevia rebaudiana cultivated in non-native tropical conditions tends to flower early, halting vegetative growth, resulting in lower biomass and yields of its valued steviol glycoside metabolites. While indoor cultivation allows manipulation of artificial lighting to mimic optimal conditions, it introduces an additional energy cost. The study objectives were to assess photoperiod manipulation as a lighting strategy to increase overall biomass and metabolite yields as well as to improve the efficacy of the electrical energy used for indoor cultivation of Stevia rebaudiana in non-native environmental conditions. Stevia was grown under artificial lighting with red, green, and blue wavelengths with photoperiods of 8 h, 12 h, 16 h, and intermittent light amounting to 16/24 h, each with a constant Daily Light Integral (DLI) of 7.2 mol m⁻² day⁻¹. Yield was measured as leaf dry weight biomass in combination with Liquid chromatography–mass spectrometry (LCMS) analysis of Stevioside and Rebaudioside A content. The photon flux density of the artificial and natural light as measured by a spectroradiometer, and the energy use data collected with a three-phase power quality logger, were compared for each treatment tested and to that from plants grown under natural light irradiation in a greenhouse. Yield and energy data were used to determine the efficacies of the lighting systems tested. Stevia plants under a continuous 16-h photoperiod (16H) had the highest productivity, resulting in the highest biomass accumulation and metabolite concentrations. The Stevioside and Rebaudioside A yields per plant were 975% higher than those obtained under natural daylight and day-neutral tropical photoperiod. Overall energy use and photon conversion efficacies were also highest under 16H at 65.10 g kWh⁻¹ for biomass accumulation, 12.40 g kWh⁻¹ for metabolite yields and 7.5 mg mol⁻¹ for photon conversion. These findings support the application of photoperiod manipulation as a viable approach to increase productivity and improve energy use efficacies for indoor cultivation of Stevia rebaudiana plants under artificial lighting in non-native environments with the 16-h photoperiod under red and blue artificial light supplemented with green spectrum as the best option. Full article

Carrots require a certain number of cold hours to become vernalized and proceed to the reproductive stage, and this phenomenon is genotype-dependent. Annual carrots require less cold than biennials to flower; however, quantitative variation within annuals and biennials also exists, defining a gradient for vernalization requirement (VR). The flowering response of carrots to day length, after vernalization has occurred, is controversial. This vegetable has been described both as a long-day and a neutral-day species. The objective of this study was to evaluate flowering time and frequency in response to different cold treatments and photoperiod regimes in various carrot genotypes. To this end, three annual genotypes from India, Brazil, and Pakistan, and a biennial carrot from Japan, were exposed to 7.5 °C during 30, 60, 90, or 120 days, and then transferred to either long day (LD) or short day (SD) conditions. Significant variation (p < 0.05) among the carrot genotypes and among cold treatments were found, with increased flowering rates and earlier onset of flowering being associated with longer cold exposures. No significant differences in response to photoperiod were found, suggesting that post-vernalization day length does not influence carrot flowering. These findings will likely impact carrot breeding and production of both root and seed, helping in the selection of adequate genotypes and sowing dates to manage cold exposure and day-length for different production purposes. Full article

There is increasing evidence for the induction of programmed cell death (PCD) in vascular plants by the cyanobacterial toxin microcystin-LR (MC-LR). Our aim was to detect the occurrence of PCD-related DNA strand breaks and their possible connections to specific nuclease and protease activities. DNA breaks were studied by the deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) method in the photoperiodically grown dicot model of white mustard (Sinapis alba). In-gel nuclease and protease activity assays showed changes in the activities of specific isoenzymes during treatments with MC-LR. Strand breaks occurred both in the developing root epidermis and cortex. Several isoenzyme activities were related to these breaks, for example: an increase in the activity of neutral 80–75 kDa, acidic high MW (100–120 kDa) and, most importantly, an increase in the activity of neutral 26–20 kDa nucleases, all of them having single-stranded DNA cleaving (SSP nuclease) activities. Increases in the activities of alkaline proteases in the 61–41 kDa range were also detected and proved to be in relation with MC-LR-induced PCD. This is one of the first pieces of evidence on the correlation of PCD-related DNA strand breaks with specific hydrolase activities in a model dicot treated with a cyanobacterial toxin known to have environmental importance. Full article