Low power continuous wave-laser seed irradiation effect on Moringa oleifera germination, seedling growth and biochemical attributes

Seed laser priming enhances defensive responses in milk thistle under Pb toxicity

Heavy metal stress negatively affects the growth of medicinal plants. While the effects of Helium-Neon (He-Ne) laser on seed germination and stress tolerance in plants has garnered significant attention, little is known concerning the impacts of He-Ne laser irradiation on heavy metal tolerance in plants. Therefore, the current study was conducted to appraise the effect of different durations (0, 20, and 40 min) of seed priming with He-Ne laser (10 mW mm-2) on the antioxidant system of Silybum marianum L. plants under various Pb concentrations (0, 250, and 500 ppm). Lead phytotoxicity was evident by significant reductions in fresh and dry weights of shoots and roots, total chlorophyll (TChl) content and relative water content (RWC), as well as increases in H2O2 and malondialdehyde contents in roots and leaves. Seed irradiation with He-Ne laser for 20 min significantly improved these parameters, enhancing Pb tolerance. Conversely, the prolonged laser priming (40 min) resulted in less favorable outcomes, including reduced growth, TChl content, and RWC, while also exacerbating oxidative damage to membranes even under non-stressful conditions. The 20-min laser priming systemically mitigated Pb-induced lipid peroxidation and H2O2 accumulation by boosting the activities of superoxide dismutase and catalase and increasing proline content in leaves and roots of milk thistle plants. These findings and multivariate analysis suggest that optimal dose of laser initiates a "stress memory" in seeds which is activated upon subsequent exposure to Pb stress, boosting the plant defensive mechanisms and enabling the plant to better cope with oxidative damage. This study underscore the promising potential of He-Ne laser priming as a novel strategy for increasing heavy metal tolerance in medicinal plants like milk thistle, offering an eco-friendly technique for maintaining their productivity under heavy metal stress.

The elicitation effects of diode and He-Ne laser irradiations on the alleviation of nutrient-deficiency induced damage in anthocyanin-producing red-fleshed apple cell suspension

PURPOSE

We explored the elicitation role of the laser irradiations on the alleviation of nutrient-deficiency induced damage in anthocyanin-producing red-fleshed apple cell suspension in continuous production of anthocyanin.

METHODS

Anthocyanin-producing red-fleshed apple cells were irradiated by 4 intensity levels of red He-Ne (RHNL) and blue diode (BDL) lasers for 20 min.

RESULTS

Nutrient deficiency indicated negative effect on total soluble proteins (TSP), superoxidase dismutase (SOD) activity, and total phenolics content (TPC) while it displayed a positive effect on malondialdehyde (MDA), total flavonoids content (TFC), O2-, H2O2-, and lipoxygenase (LOX) and polyphenol oxidase (PPO) activities in light controls, illustrating oxidative stress. The laser irradiations on suspension cells indicated variable effects on measured parameters and were time of growth-, levels of intensity-, and laser type-dependent. Likewise, the elicitation effects of lasers relied on a critical threshold among ROS generation and antioxidative system which determines the fate of cells against oxidative stress. The same trend was displayed by RHNL at 6.46 mWcm-2 intensity and BDL at 13.73 mWcm-2. These intensities resulted in a significant increase in SOD, APX, POD, and CAT activities and TSP, TPC, TFC, proline, and glycine betaine accumulation, while induced decrease in LOX, and PPO activities and MDA, and ROS generation, alleviating cellular injury from prolonged nutrient deficiency by diminishing lipid peroxidation and oxidative damages of cell membrane.

CONCLUSION

Results suggested that lasers application on mitigating nutrient deficiency stress relied on establishing a suitable balance between ROS generation and antioxidative system, which enables the nutrient-starved anthocyanin-producing cells to continuously produce anthocyanin.

Bio-Stimulant for Improving Simmondsia chinensis Secondary Metabolite Production, as Well as Antimicrobial Activity and Wound Healing Abilities

Simmondsia chinensis is a dioecious, long-lived perennial shrub. Its leaves contain several antioxidant flavonoids that have numerous pharmacological effects. Various strategies have been explored to propagate jojoba with enhanced pharmacological values. This research evaluates the bio-stimulatory impacts of He-Ne laser seed irradiation on seed germination, plantlet growth, and alteration of the composition and bioactivities of phytochemicals in jojoba plants. Jojoba seeds were irradiated for 5, 10, and 15 min before in vitro germination. Germination, growth, and multiplication parameters were recorded during germination, multiple-shoot induction, and rooting stages. The wound healing and antimicrobial activities of methanolic extracts from plant lines obtained from the non-irradiated (control) and 10 min irradiated seeds were compared by excision wound model in Wistar male rats and zone of inhibition assay. Our study revealed that laser irradiation increased seed germination, with the highest percentage observed in seeds irradiated for 10 min. Plant lines from the 10 min irradiated seeds produced more explants with higher explant heights and numbers of leaves, more roots, and higher photosynthetic pigment contents than those of control and other laser testings. By comparing plant extracts from the control and 10 min treatments, we observed that extracts from the 10 min treatment exhibited higher percentages of wound contraction and shorter epithelialization periods. In addition, these extracts also resulted in higher levels of angiogenesis elements (VEGF, TGF-β1, and HIF-1α) and reduced the inflammation regulators (IL-1β, IL-6, TNF-α, and NFκB) in the experimental rats. In concordance, extracts from the 10 min treatment also explained raised antibacterial activities towards Staphylococcus aureus and Escherichia coli. Our findings show that pre-sowing seed treatment with a He-Ne laser (632.8 nm) could be a good technique for stimulating S. chinensis plant growth and increasing the impact compound levels and biological activities.

Enhancement of germination and yield of cotton through optical seed priming: Lab. and diverse environment studies

The current study demonstrates the practical application of optical seed priming technology to improve cotton seed germination, plant growth, crop yield, and fiber quality. The hypothesis of this study is that seed irradiation with different colors of light can improve germination and cotton productivity in different environments. In the priming of cotton seeds, a wider range of the light spectrum was used, ranging from ultraviolet (UV) to red wavelengths. Various light sources such as blue LED, red LED, diode laser, UV-B, and UV-C were studied, along with different exposure times and energy densities. The exposure time ranged from 1.0 to 36.0 minutes, while the energy density doses varied from 88 to 7550 mJ cm-2, depending on the light source. In laboratory conditions, the investigation on the impact of optical seed priming on germination showed a maximum improvement of up to 180% compared to the control group. Among the different light sources and energy densities, blue LED light was found to be the most effective for enhancing cotton seed germination across different varieties. To validate the findings from the laboratory, large-scale field trials were conducted in two different environments in Pakistan, namely Tandojam and Faisalabad. The field trials demonstrated significant improvements in germination and yield, with increases of up to 37% and 74% over the control group, respectively. Once again, blue LED light emerged as the best light source for optical seed priming at the farm level. These field trials provided encouraging results, indicating the potential of the eco-friendly optical seed priming technique. The study suggests that optical seed priming can be a commercially viable technology for improving cotton seed germination, plant growth, crop yield, and fiber quality. By utilizing this technique, growers and researchers in developing countries can address the challenge of poor cotton germination and potentially enhance their agricultural productivity.

He-Ne Laser Enhances Seed Germination and Salt Acclimation in Salvia officinalis Seedlings in a Manner Dependent on Phytochrome and H2O2

In the current study the role of H₂O₂ in He-Ne laser-induced effects on seed germination and post-germinative performance of Salvia officinalis seedlings was assessed under both non-stress and saline conditions. Salinity had adverse impacts on seed germination and root length and decreased seed germination tolerance index. Seed priming with H₂O₂ and He-Ne laser impacted the seed germination and vigoration in a dose-dependent manner. The optimal effects were gathered by energy dose of 6 J/cm² laser and concentration of 5 mM H₂O₂. These pre-treatments enhanced seed germination due to increasing contents of total soluble and reducing sugars and the amylase activity in seeds and improved seedling performance under saline and non-saline conditions. Furthermore, Phy B transcripts were upregulated, salt-accrued oxidative stress was mitigated, and the activities of POD and CAT increased in seedlings primed with H₂O₂ and laser. Interestingly, applying diphenyleneiodonium (DPI as an inhibitor of NADPH oxidase activity) and N, N-dimethyl thiourea (DMTU as a H₂O₂ scavenger) arrested the upregulation of phy B gene and abolished stimulatory impact of laser priming on the aforementioned attributes under both non-stress and saline conditions. These novel findings suggest that H₂O₂ as a downstream signal modulates the impacts of He-Ne laser on seed germination, seedling performance and salt acclimation in sage seedlings, and likely phy B also is involved in these responses.

Innovating the Synergistic Assets of β-Amino Butyric Acid (BABA) and Selenium Nanoparticles (SeNPs) in Improving the Growth, Nitrogen Metabolism, Biological Activities, and Nutritive Value of Medicago interexta Sprouts

In view of the wide traditional uses of legume sprouts, several strategies have been approved to improve their growth, bioactivity, and nutritive values. In this regard, the present study aimed at investigating how priming with selenium nanoparticles (SeNPs, 25 mg L^-1) enhanced the effects of β-amino butyric acid (BABA, 30 mM) on the growth, physiology, nitrogen metabolism, and bioactive metabolites of Medicago interexta sprouts. The results have shown that the growth and photosynthesis of M. interexta sprouts were enhanced by the treatment with BABA or SeNPs, being higher under combined treatment. Increased photosynthesis provided the precursors for the biosynthesis of primary and secondary metabolites. In this regard, the combined treatment had a more pronounced effect on the bioactive primary metabolites (essential amino acids), secondary metabolites (phenolics, GSH, and ASC), and mineral profiles of the investigated sprouts than that of sole treatments. Increased amino acids were accompanied by increased nitrogen metabolism, i.e., nitrate reductase, glutamate dehydrogenase (GDH), glutamate synthase (GOGAT), glutamine synthase (GS), cysteine synthesis serine acetyltransferase, arginase, threonine synthase, and methionine synthase. Further, the antioxidant capacity (FRAP), the anti-diabetic activities (i.e., α-amylase and α-glucosidase inhibition activities), and the glycemic index of the tested sprouts were more significantly improved by the combined treatment with BABA and SeNPs than by individual treatment. Overall, the combined effect of BABA and SeNPs could be preferable to their individual effects on plant growth and bioactive metabolites.

Developmental Stages-Specific Response of Anise Plants to Laser-Induced Growth, Nutrients Accumulation, and Essential Oil Metabolism

Compared to seeds and mature tissues, sprouts are well known for their higher nutritive and biological values. Fruits of Pimpinella anisum (anise) are extensively consumed as food additives; however, the sprouting-induced changes in their nutritious metabolites are hardly studied. Herein, we investigated the bioactive metabolites, phytochemicals, and antioxidant properties of fruits, sprouts (9-day-old), and mature tissue (5-week-old) of anise under laser irradiation treatment (He-Ne laser, 632 nm). Laser treatment increased biomass accumulation of both anise sprouts and mature plants. Bioactive primary (e.g., proteins and sugars) and secondary metabolites (e.g., phenolic compounds), as well as mineral levels, were significantly enhanced by sprouting and/or laser light treatment. Meanwhile, laser light has improved the levels of essential oils and their related precursors (e.g., phenylalanine), as well as enzyme activities [e.g., O-methyltransferase and 3-Deoxy-D-arabino-heptulosonate-7-phosphate synthase (DAHPS)] in mature tissues. Moreover, laser light induced higher levels of antioxidant and anti-lipidemic activities in sprouts as compared to fruits and mature tissues. Particularly at the sprouting stage, anise was more responsive to laser light treatment than mature plants.

Red laser-mediated alterations in seed germination, growth, pigments and withanolide content of Ashwagandha [Withania somnifera (L.) Dunal]

Withania somnifera (L.) Dunal, generally well-known as Ashwagandha, is part of Indian traditional medicinal systems like Ayurveda, Siddha, and Unani for over 3000 years for treating an array of disorders. The chief bioactive component of this plant is the withanolides, a group of C₂₈-steroidal lactone triterpenoids. These compounds are present in very low concentrations and hence cell culture methods have been used to enhance their production. Low-level laser irradiation has been reported to have elicited the seed germination, agronomical characters, biosynthesis of bioactive compounds in some plants. Therefore, the objective of the study was to investigate the effect of red (He-Ne) laser irradiation on seed germination, growth characters, pigment contents and withanolide content in W. somnifera. The seeds were inoculated onto two different combinations of Murashige and Skoog (MS) media and incubated for germination. The highest germination percentage was observed in ½ MS with pH 6.5 and GA₃ presoaking followed by ½ MS with different pH. Four different doses of Helium-Neon (He-Ne) laser (10, 15, 20 and 25 J/cm²) were used to irradiate the seeds at 632.8 nm and germinated in vitro on ½ MS with pH 6.5. The maximum germination percentage, 63.88% was noted from seeds irradiated with 25 J/cm² (P = 0.04). The highest total length of 13.33 cm was observed in the seedlings irradiated with 25 J/cm² groups (P = 0.008). The highest total chlorophyll content of 329.5 μg/g fresh weight (FW) was observed for seedlings irradiated with 15 J/cm² (P = 0.02) and the highest carotenoid content of 49.6 μg/g FW was observed for 25 J/cm² treated seedlings. Further, primary root length was measured and found to be highest (11.14 cm) in seedlings irradiated with 10 J/cm² and the highest number of lateral roots were observed for 15 and 25 J/cm² groups. The significant amount of Withanolide A (WA) 0.52 μg/g dry weight (DW) and 0.60 μg/g DW was noted in 15 (P = 0.01) and 20 J/cm² (P = 0.002) groups, respectively than control. The present investigation thus reveals the positive impact of red laser on the germination of seeds, growth characters and withanolide contents under in vitro environment.

Laser light as a promising approach to improve the nutritional value, antioxidant capacity and anti-inflammatory activity of flavonoid-rich buckwheat sprouts

Buckwheat sprouts are rich in several nutrients such as antioxidant flavonoids that have a positive impact on human health. Although there are several studies reported the positive impact of laser light on crop plants, no studies have applied laser light to enhance the nutritive values of buckwheat sprouts. Herein, the contents of health-promoting minerals, metabolites and enzymes as well as the antioxidant and anti-inflammatory activities were determined in laser-treated (He-Ne laser, 632 nm, 5 mW) common buckwheat (CBW) and tartarybuckwheat (TBW) sprouts. Out of 49 targeted minerals, vitamins, pigments and antioxidants, more than 35 parameters were significantly increased in CBW and/or TBW sprouts by laser light treatment. Also, laser light boosted the antioxidant capacity and anti-inflammatory activities through inhibiting cyclooxygenase-2 and lipoxygenase activities, particularly in TBW sprouts. Accordingly, laser light could be recommended as a promising method to improve the nutritional and health-promoting values of buckwheat sprouts.

Sulfur nanoparticles mediated improvement of salt tolerance in wheat relates to decreasing oxidative stress and regulating metabolic activity

Salinity is a critical issue impairing the growth and productivity of most crop species through the mediated ionic and osmotic imbalances. As a way forward, the current study was tailored to elucidate the capacity of sulfur nanoparticles (SNPs) to amend salinity consequences on growth and physio-biochemical attributes of wheat. In a controlled experiment, wheat seeds were primed for 12 h with either 100 μM SNPs or deionized water then sown in plastic pots containing 5 kg clay-sand mixture (2:1 w/w). A week later, pots received NaCl (100 or 200 mM) as a sole treatment or in combination with SNPs and after three weeks the data of morph-bio-physiological traits were recorded. Salinity decreased growth rate, pigmentation, protein, amino acids, cysteine, ascorbate, flavonoids and phenolics content in wheat leaves. Plants pre-treated with 100 μM SNPs showed improved growth rate, pigmentation, nitrogen metabolism as well as non-enzymatic antioxidant contents as compared with salinized treatments. Neither salt nor SNP treatments affected photosynthetic performance rate (Fv/fm), however both treatments induced glutathione content. SNP treatment retrieved the undue excessive activities of catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), superoxide dismutase (SOD) and polyphenol oxidase (PPO) besides the increased level of proline caused by salt stress. Likewise, 100 μM SNPs rebalanced the declined nitrogen, phosphorus and potassium contents and decreased sodium uptake caused by salinity. On the whole, priming with 100 μM SNPs improved photosynthetic pigments, nitrogen metabolism, antioxidant status and ionic relations contributing to the enhancement of growth attributes in wheat under salinity.

Seed pretreatment with magnetic field alters the storage proteins and lipid profiles in harvested soybean seeds

The increase in crop productivity is an urgent need of the time to reduce scarcity of food in underdeveloped countries. Several biological, chemical and physical methods have been applied to promote crop yield. Application of magnetic field (MF) is an emerging physical method used to increase plant growth and yield. The reports on MF pretreatment-induced nutritional changes in harvested seeds are scarce. We previously identified the optimal frequency of MF to improve plant growth and yield as 1500 nT at 10.0 Hz. This study was aimed to investigate the effect of MF treatment on storage proteins and fatty acids in harvested soybean seeds. The results showed that MF triggered globulin production and suppressed prolamin production. However, lipid content in seeds increased, because MF exposure caused an elevation of several fatty acids including caprylic acid, palmitic acid, heptadecanoic acid, linoleic acid, lignoceric acid and eicosapentaenoic acid. This is the first report to reveal the seed pretreated MF on nutritional values of harvested seeds. This study suggests that MF treatment improves seed quality by regulating the metabolism of storage proteins and fatty acids.