Investigation of pulsed electromagnetic field as a novel organic pre-sowing method on germination and initial growth stages of cotton

Seed Treatment with Electromagnetic Field Induces Different Effects on Emergence, Growth and Profiles of Biochemical Compounds in Seven Half-Sib Families of Silver Birch

In the context of climate change, strategies aimed at enhancing trees' resistance to biotic and abiotic stress are particularly relevant. We applied an electromagnetic field (EMF) seed treatment to observe changes in the establishment and content of biochemical compounds in silver birch seedlings induced by a short (1 min) seed exposure to a physical stressor. The impact of EMF treatment was evaluated on seedling emergence and growth of one-year-old and two-year-old seedlings from seven half-sib families of silver birch. The effects on numerous biochemical parameters in seedling leaves, such as total phenolic content (TPC), total flavonoid content (TFC), amounts of photosynthetic pigments, total soluble sugars (TSS), level of lipid peroxidation level, antioxidant activity and activity of antioxidant enzymes, were compared using spectrophotometric methods. The results indicated that, in one-year-old seedlings, two of seven (60th and 73rd) half-sib families exhibited a positive response to seed treatment with EMFs in nearly all analyzed parameters. For example, in the 60th family, seed treatment with EMFs increased the percentage of emergence by 3 times, one-year-old seedling height by 71%, leaf TPC by 47%, antioxidant activity by 2 times and amount of chlorophyll a by 4.6 times. Meanwhile, the other two (86th and 179th) families exhibited a more obvious positive response to EMF in two-year-old seedlings as compared to one-year-old seedling controls. The results revealed that short-term EMF treatment of silver birch seeds can potentially be used to improve seedling emergence and growth and increase the content of secondary metabolites, antioxidant capacity and photosynthetic pigments. Understanding of the impact of EMFs as well as the influence of genetic differences on tree responses can be significant for practical applications in forestry. Genetic selection of plant genotypes that exhibit positive response trends can open the way to improve the quality of forest stands.

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.

Effect of high salinity and of priming of non-germinated seeds by UV-C light on photosynthesis of lettuce plants grown in a controlled soilless system

High salinity results in a decrease in plant photosynthesis and crop productivity. The aim of the present study was to evaluate the effect of UV-C priming treatments of lettuce seeds on photosynthesis of plants grown at high salinity. Non-primed and primed seeds were grown in an hydroponic system, with a standard nutrient solution, either supplemented with 100 mM NaCl (high salinity), or not (control). Considering that leaf and root K⁺ concentrations remained constant and that chlorophyll fluorescence parameters and root growth were not affected negatively in the high salinity treatment, we conclude that the latter was at the origin of a moderate stress only. A substantial decrease in leaf net photosynthetic assimilation (A_net) was however observed as a consequence of stomatal and non-stomatal limitations in the high salinity treatment. This decrease in A_net translated into a decrease in growth parameters; it may be attributed partially to the high salinity-associated increase in leaf concentration in abscisic acid and decrease in stomatal conductance. Priming by UV-C light resulted in an increase in total photosynthetic electron transport rate and A_net in the leaves of plants grown at high salinity. The increase of the latter translated into a moderate increase in growth parameters. It is hypothesized that the positive effect of UV-C priming on A_net and growth of the aerial part of lettuce plants grown at high salinity, is mainly due to its stimulating effect on leaf concentration in salicylic acid. Even though leaf cytokinins' concentration was higher in plants from primed seeds, maintenance of the cytokinins-to-abscisic acid ratio also supports the idea that UV-C priming resulted in protection of plants exposed to high salinity.

Seed priming with non-ionizing physical agents: plant responses and underlying physiological mechanisms

Seed priming has long been explored as an effective value-added potential technique that results in improved germination, reduced seedling emergence time, shortened crop duration, increased stress tolerance and eventually increased higher grain production. However, the wider applicability of water or chemical-based conventional methods of seed priming is often restricted considering its deleterious effects on post-treatment storability or agricultural pollution due to the persistence of chemicals in plant systems or in the environment. In this context, the utilization of physical methods of seed priming for enhancing plant productivity has created a new horizon in the domain of seed technology. Being eco-friendly and cost-effective approaches, priming with extra-terrestrial or physical agents such as ionizing radiation such as X-rays and gamma rays and non-ionizing radiation such as ultrasonic wave, magnetic field, microwaves, and infrared light offers many advantages along with ensuring enhanced production over conventional methods. Ultraviolet radiations, bridging between ionizing and non-ionizing radiation, are important electromagnetic waves that would also be an effective priming agent. Non-ionizing radiation has certain biological advantages over ionizing radiation since it does not generate charged ions while passing through a subject, but has enough energy to cause biological effects. Extensive research works to study the effects of various non-ionizing physical priming methods are required before their wider exploitation in agriculture. With this background, this review aims to highlight the current understanding of non-ionizing physical methods of seed priming and its applicability to combat present-day challenges to achieve agro-ecological resilience.

Seed priming as a cost effective technique for developing plants with cross tolerance to salinity stress

Salinization is one of the greatest threats in agriculture field limiting the growth and productivity of crops. Soil salinization directly affects the physiological, biochemical, and molecular functions of plants. The Plants adopt various tolerance mechanisms to combat salinity stress by involving complex physiological traits, metabolic pathways, and molecular or gene networks. Various techniques have been used to improve plant growth and productivity through genetic approach, genetic engineering and plant breeding. However, economic feasibility and ease of application can create a huge scope for priming techniques as a "stress reliever" in agricultural crop production. Seed priming is a simple, low-cost technique that enhances germination and seedling establishment by activating various physiological and metabolic processes. Priming regulates molecular mechanisms through increased expression of various stress related genes and proteins, which accelerates stress and cross tolerance. Priming memory and epigenetic changes enables the plants to withstand salinity stress by alterations in key signaling molecules, transcription factors, and change in chromatin states, that will be crucial for the second stress. In this way, priming can both mediate stress tolerance and initiate overarching stress tolerance to a wide range of stresses that further modify gene expression and enhance crop production. This review paper addresses some physiochemical, molecular and trans-generational mechanisms regulating plant adaptation and tolerance/cross tolerance to salinity in primed seeds/seedlings.

Static magnetic field treatment of seeds improves carbon and nitrogen metabolism under salinity stress in soybean

The effectiveness of magnetopriming was assessed for alleviation of salt-induced adverse effects on soybean growth. Soybean seeds were pre-treated with static magnetic field (SMF) of 200 mT for 1 h to evaluate the effect of magnetopriming on growth, carbon and nitrogen metabolism, and yield of soybean plants under different salinity levels (0, 25, and 50 mM NaCl). The adverse effect of NaCl-induced salt stress was found on growth, yield, and various physiological attributes of soybeans. Results indicate that SMF pre-treatment significantly increased plant growth attributes, number of root nodules, nodules, fresh weight, biomass accumulation, and photosynthetic performance under both non-saline and saline conditions as compared to untreated seeds. Polyphasic chlorophyll a fluorescence (OJIP) transients from magnetically treated plants gave a higher fluorescence yield at J-I-P phase. Nitrate reductase activity, PIABS , photosynthetic pigments, and net rate of photosynthesis were also higher in plants that emerged from SMF pre-treated seeds as compared to untreated seeds. Leghemoglobin content and hemechrome content in root nodules were also increased by SMF pre-treatment. Thus pre-sowing exposure of seeds to SMF enhanced carbon and nitrogen metabolism and improved the yield of soybeans in terms of number of pods, number of seeds, and seed weight under saline as well as non-saline conditions. Consequently, SMF pre-treatment effectively mitigated adverse effects of NaCl on soybeans. It indicates that magnetopriming of dry soybean seeds can be effectively used as a pre-sowing treatment for alleviating salinity stress. Bioelectromagnetics. 37:455-470, 2016. © 2016 Wiley Periodicals, Inc.

Physical Methods for Seed Invigoration: Advantages and Challenges in Seed Technology

In the context of seed technology, the use of physical methods for increasing plant production offers advantages over conventional treatments based on chemical substances. The effects of physical invigoration treatments in seeds can be now addressed at multiple levels, ranging from morpho-structural aspects to changes in gene expression and protein or metabolite accumulation. Among the physical methods available, "magneto-priming" and irradiation with microwaves (MWs) or ionizing radiations (IRs) are the most promising pre-sowing seed treatments. "Magneto-priming" is based on the application of magnetic fields and described as an eco-friendly, cheap, non-invasive technique with proved beneficial effects on seed germination, vigor and crop yield. IRs, as γ-rays and X-rays, have been widely regarded as a powerful tool in agricultural sciences and food technology. Gamma-rays delivered at low dose have showed to enhance germination percentage and seedling establishment, acting as an actual 'priming' treatment. Different biological effects have been observed in seeds subjected to MWs and X-rays but knowledge about their impact as seed invigoration agent or stimulatory effects on germination need to be further extended. Ultraviolet (UV) radiations, namely UV-A and UV-C have shown to stimulate positive impacts on seed health, germination, and seedling vigor. For all mentioned physical treatments, extensive fundamental and applied research is still needed to define the optimal dose, exposition time, genotype- and environment-dependent irradiation conditions. Electron paramagnetic resonance has an enormous potential in seed technology not fully explored to monitor seed invigoration treatments and/or identifying the best suitable irradiation dose or time-point to stop the treatment. The present manuscript describes the use of physical methods for seed invigoration, while providing a critical discussion on the constraints and advantages. The future perspectives related to the use of these approaches to address the need of seed technologists, producers and trade markers will be also highlighted.

Effects of presowing pulsed electromagnetic treatment of tomato seed on growth, yield, and lycopene content

The use of magnetic field as a presowing treatment has been adopted by researchers as a new environmental friendly technique. The aim of this study was to determine the effect of magnetic field exposure on tomato seeds covering a range of parameters such as transplanting percentage, plant height, shoot diameter, number of leaves per plant, fresh weight, dry weight, number of flowers, yield, and lycopene content. Pulsed electromagnetic field was used for 0, 5, 10, and 15 minutes as a presowing treatment of tomato seeds in a field experiment for two years. Papimi device (amplitude on the order of 12.5 mT) has been used. The use of pulsed electromagnetic field as a presowing treatment was found to enhance plant growth in tomato plants at certain duration of exposure. Magnetic field treatments and especially the exposure of 10 and 15 minutes gave the best results in all measurements, except plant height and lycopene content. Yield per plant was higher in magnetic field treatments, compared to control. MF-15 treatment yield was 80.93% higher than control treatment. Lycopene content was higher in magnetic field treatments, although values showed no statistically significant differences.

Influence of magnetic field on germination, growth and production of tomato

In the study with tomatoes, there was ivestigated the impact of extremely low frequency electromagnetic fields on seed germination of tomato (Solanum lycopersicum L.) after treatment before sowing, as well as the growth of young plants that were exposed to low frequency electromagnetic field before planting in the field when growing transplants under cover. In the experiments conducted in two consecutive years (2012 and 2013), we followed the length of seed germination period of tomato variety „Pavlína", growth of young plants expressed in plant height and root length, and the fruit size. Magnetization of seeds and young plants was carried out in laboratory conditions, plant growth was evaluated under cover prior to planting, and fruit traits were followed in field conditions where plants were grown on experimental plots (80.0 m2). The plants were grown in accordance with the standards of an agricultural practice for tomato. At the generative phase, the fruits were collected at regular intervals, and their number and weight were evaluated. Low frequency electromagnetic fields acting at the three inductance levels (20, 40 and 60 mT) and exposure of 20 minutes a day with frequency of 50 Hz, significantly positively influenced the germination, plant growth and fruit size of the studied tomato variety.