Impact of LFGD (Ar+O2) plasma on seed surface, germination, plant growth, productivity and nutritional composition of maize (Zea mays L.)

Exploring the effects of non-thermal plasma pre-treatment on coriander (Coriander sativum L.) seed germination efficiency

This study investigates the effects of non-thermal plasma (NTP) treatment on the germination characteristics of coriander seeds (Coriandrum sativum L.). Different germination factors, water imbibition rate and changes in mass, were analyzed. The results indicate that a suitable duration of NTP treatment (180 s and 300 s) enhances seed germination characteristics, whereas prolonged exposure (420 s) leads to adverse effects. Furthermore, shorter NTP exposures (180 s) improved water absorption and surface properties of seeds, while longer exposures (420 s) caused mass loss and compromised seed vigor. Overall, the findings demonstrate the significance of optimizing NTP treatment conditions for enhancing seed germination characteristics.

From seed to sprout: Unveiling the potential of non-thermal plasma for optimizing cucumber growth

Background and aims

Numerous strategies for enhancing seed germination and growth have been employed over the decades. Despite these advancements, there continues to be a demand for more effective techniques, driven by the growing global population. Recently, various forms of non-thermal atmospheric pressure plasma have garnered attention as environmentally friendly, safe, and cost-effective methods to enhance the agricultural and food sectors. This study explores the remarkable impact of non-thermal plasma (NTP) treatment on cucumber (Cucumis sativus L.) seed germination.

Methods

A cost-effective, custom-designed power supply operating at line frequency was used for treating seeds, with exposure times ranging from 1 to 7 min. Various germination parameters, including water contact angle measurements, mass loss, water imbibition rate, and seedling length, were evaluated to assess the impact of plasma treatment on seed germination.

Results

Cucumber seeds exposed to NTP treatment for 3 min and 5 min durations showed significant germination improvements, notably a 57.9 ± 4.25 % higher final germination percentage, 14.5 ± 3.75 % reduced mean germination time, and a remarkable 90.6 ± 4.64 % increase in germination index compared to the control. These results suggest that NTP treatment enhanced seed coat permeability, triggered essential biochemical processes, and expedited water absorption and nutrient assimilation, ultimately fostering faster and more synchronized germination.

Conclusions

Our findings underscore the potential of NTP as an innovative approach to improving seed germination in agricultural practices.

Germination and Growth of Plasma-Treated Maize Seeds Planted in Fields and Exposed to Realistic Environmental Conditions

In this study, we applied an inductively coupled, radio frequency oxygen plasma to maize seeds and investigated its effects on seedling emergence, plant number at tasseling, and crop yield of maize in realistic field conditions. Maize seeds of seven different hybrids were treated over two harvest years. In addition to plasma-treated seeds, a control sample, fungicide-treated seeds, an eco-layer, and a plasma and eco-layer combination, were planted. Seedling emergence, plant number at tasseling (plants/m2), and yield (kg/ha), were recorded. In the first harvest year, results were negatively affected by the presence of an insect pest. In the second harvest year, plant number and yield results were more uniform. In both years, for two and three hybrids, respectively, the highest yield arose from plants from plasma-treated seeds, but the differences were only partially significant. Considering our results, plasma treatment of maize seeds appears to have a positive effect on the yield of the plant.

Non-Thermal Plasma: A Promising Technology for the Germination Enhancement of Radish (Raphanus sativus) and Carrot (Daucus carota sativus L.)

Cold plasma is an innovative and promising technology that is developing in a variety of fields, and recently it has been getting a lot of attention in the agricultural industry. The influence of cold atmospheric pressure plasma (CAPP) exposure on germination parameters and vigor of radish (Raphanus sativus) and carrot (Daucus carota sativus L.) seeds was investigated in the present study. A custom-designed plasma driver utilizing 11.32 kV rms and 50 Hz was used for the generation of the discharge. Seeds were treated using a dielectric barrier discharge (DBD) in an argon atmosphere at exposure periods of 1–4 minutes. The estimate of plasma parameters was done using optical emission spectroscopy and electrical measurements. Germination-related measures such as the final germination percentage, germination index, germination value, coefficient of velocity of germination, vigor index, and chlorophyll content were all improved in the case of CAPP-treated seeds as compared to control seeds. Similarly, CAPP treatment changed the in vitro radical scavenging capabilities, total phenolic, and total flavonoid levels of the seedlings. Our results indicated that the seeds being treated by CAPP for 3 minutes seemed to have a favorable impact on seed germination and sprouting development.

A study to examine the ageing behaviour of cold plasma-treated agricultural seeds

Cold plasma (low pressure) technology has been effectively used to boost the germination and growth of various crops in recent decades. The durability of these plasma-treated seeds is essential because of the need to store and distribute the seeds at different locations. However, these ageing effects are often not ascertained and reported because germination and related tests are carried out within a short time after the plasma-treatment. This research aims to fill that knowledge gap by subjecting three different types of seeds (and precursors): Bambara groundnuts (water), chilli (oxygen), and papaya (oxygen) to cold plasma-treatment. Common mechanisms found for these diverse seed types and treatment conditions were the physical and chemical changes induced by the physical etching and the cold plasma on the seeds and subsequent oxidation, which promoted germination and growth. The high glass transition temperature of the lignin-cellulose prevented any physical restructuring of the surfaces while maintaining the chemical changes to continue to promote the seeds germination and growth. These changes were monitored over 60 days of ageing using water contact angle (WCA), water uptake, electrical conductivity, field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS). The vacuum effect was also investigated to separate its effect from cold plasma (low pressure). This finding offers a framework for determining how long agricultural seeds that have received plasma treatment can be used. Additionally, there is a need to transfer this research from the lab to the field. Once the impact of plasma treatment on seeds has been estimated, it will be simple to do so.

Enhancement of Wheat Seed Germination, Seedling Growth and Nutritional Properties of Wheat Plantlet Juice by Plasma Activated Water

Previous studies have shown the great potential of using plasma-activated water (PAW) on improving agriculture seed germination, however, information on the influence of PAW on crop plantlet juice remains scanty. In this research, the effect of PAW generated by atmosphere pressure Ar-O₂ plasma jet for 1-5 min on wheat seed germination, seedling growth and nutritional properties of wheat plantlet juice was investigated. Results revealed that all PAWs could enhance wheat seed germination and seedling growth in 7 days by improving the germination rate, germination index, fresh weight, dry weight and vigour index, and especially that PAW activated for 3 min (PAW-3) showed the best overall performance. In addition, the application of PAWs enhanced the nutritional properties of wheat plantlet juice from those grown for 14 days by improving total soluble solids, protein content, photosynthetic pigments, total phenolic content, antioxidant activity, enzyme activity, free amino acids and minerals content, and the best enhancement was also observed in PAW-3. It was concluded that PAWs would be an effective technique to enhance the growth and nutritional properties of crop sprouts, which could be served as functional foods in many forms.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s00344-022-10677-3.

Biochemical and Physiological Plant Processes Affected by Seed Treatment with Non-Thermal Plasma

Among the innovative technologies being elaborated for sustainable agriculture, one of the most rapidly developing fields relies on the positive effects of non-thermal plasma (NTP) treatment on the agronomic performance of plants. A large number of recent publications have indicated that NTP effects are far more persistent and complex than it was supposed before. Knowledge of the molecular basis and the resulting outcomes of seed treatment with NTP is rapidly accumulating and requires to be analyzed and presented in a systematic way. This review focuses on the biochemical and physiological processes in seeds and plants affected by seed treatment with NTP and the resulting impact on plant metabolism, growth, adaptability and productivity. Wide-scale changes evolving at the epigenomic, transcriptomic, proteomic and metabolic levels are triggered by seed irradiation with NTP and contribute to changes in germination, early seedling growth, phytohormone amounts, metabolic and defense enzyme activity, secondary metabolism, photosynthesis, adaptability to biotic and abiotic stress, microbiome composition, and increased plant fitness, productivity and growth on a longer time scale. This review highlights the importance of these novel findings, as well as unresolved issues that remain to be investigated.

Cold Atmospheric Pressure Plasma Treatment of Maize Grains-Induction of Growth, Enzyme Activities and Heat Shock Proteins

Zea mays L. is one of the most produced crops, and there are still parts of the world where maize is the basic staple food. To improve agriculture, mankind always looks for new, better methods of growing crops, especially in the current changing climatic conditions. Cold atmospheric pressure plasma (CAPP) has already showed its potential to enhance the culturing of crops, but it still needs more research for safe implementation into agriculture. In this work, it was shown that short CAPP treatment of maize grains had a positive effect on the vitality of grains and young seedlings, which may be connected to stimulation of antioxidant and lytic enzyme activities by short CAPP treatment. However, the prolonged treatment had a negative impact on the germination, growth, and production indexes. CAPP treatment caused the increased expression of genes for heat shock proteins HSP101 and HSP70 in the first two days after sowing. Using comet assay it was observed that shorter treatment times (30-120 s) did not cause DNA damage. Surface diagnostics of plasma-treated grains showed that plasma increases the hydrophilicity of the surface but does not damage the chemical bonds on the surface.