This study examines the effects of different LED light spectra and intensities on the growth, photosynthetic performance, and biochemical composition of the ‘Daruma’ cultivar of wasabi (Eutrema japonicum). The primary objective is to enhance the efficiency of indoor cultivation techniques for this economically significant crop. Wasabi seedlings were cultivated under LED lighting with four light intensities (35, 60, 90, and 140 µmol m⁻² s⁻¹) and three spectral combinations: red and white (1:1); red, white, and blue (1:1:1); and white. Growth parameters, including plant height, petiole length, leaf number, and yield metrics such as fresh weight and leaf area, were measured alongside photosynthetic activity and chemical analysis of glucosinolate levels. The results indicate that higher light intensities (particularly 140 µmol m⁻² s⁻¹) greatly enhance overall plant biomass, with red-dominant spectra promoting more significant growth and glucosinolate accumulation, a key secondary metabolite in wasabi. Lower intensities increased chlorophyll content and produced darker green foliage but decreased growth performance. Additionally, the interaction of red and blue light spectra with increased light intensity suggests that specific red light conditions are optimal for maximizing wasabi biomass and biochemical yield. These findings contribute valuable insights for optimizing light regimes for wasabi and similar shade-adapted crops in controlled indoor farming systems, potentially improving yield and quality in plant factories and supporting the future of indoor farming.

Vanda is an economically important orchid that is widely produced in Thailand. Usually, growers apply large amounts of fertilizer throughout the plant, covering the leaves and roots to ensure good quality products. Nitrogen fertilizer, in terms of ammonium (NH₄⁺) and nitrate (NO₃⁻), is generally used as an N source. In addition, nitrogen organic fertilizer (glutamine) is increasingly being used to promote rapid growth in some plants. However, the absorption efficiency of organic N compared with the inorganic form (NH₄⁺ and NO₃⁻) via the roots or leaves of Vanda has not been evaluated. Therefore, this research aimed to compare the fate of organic N (in glutamine form) and inorganic N in Vanda using a ¹⁵N tracer. Vanda ‘Patchara Delight’ was grown in a plastic greenhouse under a 50% shading net at an average temperature of 25 °C and 80% relative humidity (RH). The plants were sprayed weekly via roots or leaves with 100 mL of ¹⁵N solution, 2.5 mM ¹⁵NO₃⁻ + 2.5 mM NH₄⁺ (N1), 2.5 mM NO₃⁻ + 2.5 mM ¹⁵NH₄⁺ (N2), and 2.5 mM glutamine (¹⁵N₂)(N3) for 4 weeks. The plants were then sampled and separated into leaves and roots, and ¹⁵N abundance was analyzed using an elemental analyzer coupled with an isotope-ratio mass spectrometer or IRMS. The plants that received only glutamine via roots showed the highest ¹⁵N use efficiency (¹⁵NUE) of about 28.19% at 30 days after the first feeding (DAF), whereas ¹⁵NH₄⁺ resulted in the lowest ¹⁵NUE among ¹⁵N sources. Regardless of the application site, plants supplied with ¹⁵NH₄⁺ showed a lower labeled N concentration and labeled N content in stems and leaves than those fed with a combination of ¹⁵NO₃⁻ or a sole application of ¹⁵N-glutamine. The largest labeled N concentrations in stems, leaves and roots were found in plants supplied with sole glutamine via roots. At 30 DAF, ¹⁵N solution either combined with ¹⁵NO₃⁻ or solitary ¹⁵N-glutamine did not affect the labeled N concentration in leaves. Therefore, supplying organic N in glutamine form to Vanda can provide a 4–7% higher NUE than inorganic N, especially when supplying the solution to the roots.

Cut tulip flower production, typically cultivated using hydroponic systems, often faces the challenge of stem toppling due to calcium (Ca) deficiency in the nutrient solution. Growers generally grow various tulip cultivars to meet market demands. In hydroponic production, plants require precise nutrient concentrations to promote growth and development, as the food reserves in the mother bulb are insufficient and vary depending on the plant cultivar. This study aimed to assess the impact of different tulip cultivars and Ca deficiency on tulip growth, flowering, and physiological changes. Two cultivars of tulip, namely, ‘Strong Gold’ and ‘Orange Juice’, were subjected to three distinct nutrient solution treatments, namely (1) deionized water (DI) only (without any plant nutrition added), (2) complete solution (Hoagland’s complete nutrient solution), and (3) Ca deficiency solution. The results indicate that the ‘Orange Juice’ tulip was particularly susceptible to Ca deficiency, exhibiting stem toppling and flower abortion similar to those grown in DI. Ca deficiency led to a reduction in root length and leaf area but did not affect the plant height. Additionally, it had a negative impact on bulb qualities, resulting in a decreased bulb fresh weight and bulb circumference in both tulip cultivars. Furthermore, Ca deficiency and DI reduced the photosynthetic rates, and Ca deficiency increased the transpiration rate in the tulip. The leaf concentrations of nitrogen (N), phosphorus (P), and Ca were decreased under Ca deficiency and DI, while magnesium (Mg) levels increased under Ca deficiency treatment compared to the complete nutrient solution treatment.

The application of cold plasma technology in agriculture includes its use as a nitrate fertilizer, offering an alternative to traditional chemical fertilizers. This study investigated the effects of using plasma-activated water (PAW) as a nitrate source on the growth and flowering of Vanda orchids through two integrated experiments. Plants were treated with different nitrate concentrations (0, 100, 200, 300, and 400 mg/L) and fertilizing frequencies (weekly vs. biweekly), in combination with varying plant ages (1-, 2-, and 3-year-old plants). The analysis focused on several variables, including plant height, the number of leaves, fresh and dry biomass, and flowering traits, such as time to bloom, inflorescence length, floret number, floret diameter, and vase life. The leaf nitrate, total nitrogen, and gas exchange parameters were also recorded. The results demonstrate that the plants receiving 100 mg/L PAW-NO₃⁻ exhibited significantly greater plant height, fresh weight, and dry weight than the control (0 mg/L), with a trend toward a higher leaf number. Flowering occurred earlier in the 100 mg/L treatment group, with the first, second, and third inflorescences emerging at 208, 284, and 304 days after treatment, respectively. Additionally, this concentration produced the highest floret number per inflorescence and the longest vase life (12.63 days). Weekly fertilization resulted in more pronounced vegetative growth than biweekly application, particularly in 3-year-old plants—the only group to flower. Fertilizing frequency, however, had no effect on flower quality regarding the inflorescence length, floret number, or floret size. These findings suggest that 100 mg/L nitrate from plasma-activated water, applied weekly, optimally enhances growth and flowering performance in Vanda orchids.

Vanda orchids are a commercially significant genus in the global floriculture industry, yet their cultivation often depends on substantial chemical fertilizer inputs, which raise both economic and environmental concerns. Endophytic bacteria offer a promising, sustainable alternative by promoting plant growth and enhancing nutrient acquisition. This study aimed to characterize native endophytic bacteria and assess their potential to improve nitrogen uptake and growth in Vanda orchids. Three potent nitrogen-fixing bacterial isolates (2R13, 3S19, and 3R14) were selected for this research. Through 16S rRNA sequencing, they were identified as Curtobacteriumcitreum, Stenotrophomonas panacihumi, and Bacillus subtilis, respectively. The efficacy of these isolates was evaluated in both controlled in vitro and practical greenhouse conditions using various dilution ratios. Scanning electron microscopy confirmed the successful colonization of isolate 3S19 within the root tissue of inoculated Vanda plantlets. The results revealed a significant interaction between the bacterial treatments and the growing environment. In vitro, isolate 3S19 applied at a 1:25 ratio yielded the highest total nitrogen content (12.46 mg g⁻¹ DW). Conversely, in the greenhouse experiment, isolates 2R13 and 3S19 were most effective at a 1:50 ratio, achieving nitrogen contents of 11.18 and 10.83 mg g⁻¹ DW. Furthermore, bacterial inoculation in the greenhouse generally led to significant improvements in plant growth parameters, including height, leaf count, and root development, compared to non-inoculated controls. These findings highlight the potential of these endophytic bacteria as effective biofertilizers for Vanda orchid cultivation. The contrasting outcomes between the two experimental settings underscore the critical importance of optimizing application rates based on specific environmental conditions to maximize benefits in commercial production.