In plants, blue light with a short wavelength can promote light reaction in photosynthesis and increase dry mass. Photosynthesis plays an important role in supporting carbohydrates for primary and secondary metabolism processes. Flavonoids are phenolic compounds, a class of plant secondary metabolites, that can be obtained from many medicinal herbs. These phenolic compounds are involved in the reactive oxygen species scavenging system, inhibit lipid peroxidation by free-radical, chelate redox-active metals resulting in their antioxidant ability and cardioprotective effects. In this study, H. corymbosa (L.) Lam., one of the common medicinal herbs, was cultured for 4 weeks under conditions of 450 nm blue LED (light-emitting diode) lights at the different light intensity as treatments and fluorescent lamp light as a control to investigate the effects of blue light on photosynthesis and flavonoid accumulation in leaves. The results show that blue light at 450 nm promoted photosynthetic rate by enhancing stomatal opening, electron transport rate in light reaction. Blue light also enhanced photoprotection by decrease the quantum yield of non-photochemical losses, increase the quantum yield of non-photochemical quenching and gained 24% more in dry mass. The accumulation of flavonoid and total phenolic compounds in leaves was followed by a decrease in sucrose. These events proved that blue light enhances photosynthesis and increase carbohydrate and flavonoid accumulation in leaves.

Hedyotis corymbosa (L.) Lam is a wild herb that is used in traditional Indian, Chinese, and African medicine. Light-emitting diode (LED) technology is paving the way to enhance crop production and inducing targeted photomorphogenic, biochemical, or physiological responses in plants. This study examines the efficiency of H. corymbosa (L.) Lam production under blue 450 nm and red 660 nm LED lights for overall plant growth, photosynthetic characteristics, and the contents of metabolite compounds. Our research showed that blue LED lights provided a positive effect on enhancing plant growth and overall biomass. In addition, blue LED lights are more effective in controlling the production of sucrose, starch, total phenolic compounds, and total flavonoid compared to red LED lights. However, blue and red LED lights played essential but different roles in photosynthetic characteristics. Our results showed the potential of colored LED light applications in improving farming methods and increasing metabolite production in herbs.

In recent years, light-emitting diode (LED) technology has been applied to improve crop production and induce targeted biochemical or physiological responses in plants. This study investigated the effect of different ratios of blue 450 nm and red 660 nm LEDs on the overall plant growth, photosynthetic characteristics, and total triterpenoid production in the leaves of Hedyotis corymbosa in vitro plants. The results showed that a high proportion of blue LED lights had a positive effect on enhancing photosynthesis and the overall biomass. In addition, blue LED lights were shown to be more effective in controlling the production of the total triterpenoid content compared with the red LED lights. Moreover, it was also found that plants grown under a high proportion of red LEDs exhibited reduced photosynthetic properties and even induced damage to the photosynthetic apparatus, which indicated that the blue or red LED lights played contrary roles in Hedyotis corymbosa.

Hedyotis corymbosa (L.) Lam a native herbaceous species containing many phenolic compounds is used in traditional medicine and medicinal technology. Phenolic acid, as well as many other secondary metabolites are photosynthetic-derived products. In this research, red LEDs (660 nm) and white fluorescent light were used to investigate the effects of different light sources on the photosynthesis and leaf phenolic compound accumulation of in vitro and ex vitro plants. Red LED (50 umol/m2/sec) promoted the stem elongation without changing plant biomass of in vitro plants. Increasing red LED intensities (from 50 to 100 or 150 umol/m2/sec) decrease maximum photochemical quantum yield of PS II (Fv/Fm) and coefficient of photochemical fluorescence quenching (qP), but stabilized electron transfer (ETR) and coefficient of non-photochemical fluorescence quenching (qN) of in vitro leaves. Under 100 umol/m2/sec of red LED, ex vitro leaf area, carotenoid contents, isolated chloroplast. Hill reaction and total sugar content were significantly reduced in comparison to those parameters from control plants under white light. Ex vitro plants' total carbohydrate contents were not statistically different the total leaf phenolic content of ex vitro plants under red LED light exposure was much higher than that the of control.

Water hyacinth (Eichhornia crassipes [Mart.] Solms) is a fast-growing aquatic plant recognized as a highly invasive weed, posing substantial economic, ecological and social threats. This study evaluates the invasive spread rate of water hyacinth through the plant tissue culture method - culturing the apical and lateral buds separately at different stages to investigate the regenerative ability of Eichhornia crassipes. [Mart.] Solms shoots. Additionally, this study evaluated the potential for sexual reproduction from water hyacinth seeds at different stages. After four weeks of culture, a double-layered MS medium (solid agar base with a liquid overlay) under aerobic conditions, supplemented with 0.75 mg/L benzyladenine (BA) and 0.25 mg/L naphthalene acetic acid (NAA), was found to be optimal for in vitro growth of water hyacinth buds and seeds. The invasive spread rate of water hyacinth is based on both vegetative propagation from buds and sexual reproduction from seeds. The strongest regeneration from the apical buds and axillary buds with stolon and rootlets reached the highest rate of 60 %. The highest germination reached 40 % from water hyacinth fruit at stage 4 - the stage when the flower turns dark brown.