Silver Nanoparticles Effects on In Vitro Germination, Growth, and Biochemical Activity of Tomato, Radish, and Kale Seedlings

Abstract

The interactions between nanoparticles and plant cells are still not sufficiently understood, and studies related to this subject are of scientific and practical importance. Silver nanoparticles (AgNPs) are one of the most commonly produced and used nanomaterials. This study aimed to investigate the influence of AgNPs applied at the concentrations of 0, 50, and 100 mg·L−1 during the process of in vitro germination as well as the biometric and biochemical parameters of developed seedlings in three vegetable species: Solanum lycopersicum L. ‘Poranek’, Raphanus sativus L. var. sativus ‘Ramona’, and Brassica oleracea var. sabellica ‘Nero di Toscana’. The application of AgNPs did not affect the germination efficiency; however, diverse results were reported for the growth and biochemical activity of the seedlings, depending on the species tested and the AgNPs concentration. Tomato seedlings treated with nanoparticles, particularly at 100 mg·L−1, had shorter shoots with lower fresh and dry weights and produced roots with lower fresh weight. Simultaneously, at the biochemical level, a decrease in the content of chlorophylls and carotenoids and an increase in the anthocyanins content and guaiacol peroxidase (GPOX) activity were reported. AgNPs-treated radish plants had shorter shoots of higher fresh and dry weight and longer roots with lower fresh weight. Treatment with 50 mg·L−1 and 100 mg·L−1 resulted in the highest and lowest accumulation of chlorophylls and carotenoids in the leaves, respectively; however, seedlings treated with 100 mg·L−1 produced less anthocyanins and polyphenols and exhibited lower GPOX activity. In kale, AgNPs-derived seedlings had a lower content of chlorophylls, carotenoids, and anthocyanins but higher GPOX activity of and were characterized by higher fresh and dry shoot weights and higher heterogeneous biometric parameters of the roots. The results of these experiments may be of great significance for broadening the scope of knowledge on the influence of AgNPs on plant cells and the micropropagation of the vegetable species. Future studies should be aimed at testing lower or even higher concentrations of AgNPs and other NPs and to evaluate the genetic stability of NPs-treated vegetable crops and their yielding efficiency.

Surface Coating-Modulated Phytotoxic Responses of Silver Nanoparticles in Plants and Freshwater Green Algae

“…Seed germination represents the first and the most crucial step for plant growth and the overall crop yield [ 105 ]. It is the most sensitive stage of plant ontogenesis, heavily susceptible to various environmental factors, such as AgNP exposure, that can modulate metabolic processes during germination and ultimately affect plant growth [ 106 ]. To assess AgNP effects on seed germination and early growth, most of the conducted studies examined germination percentage and rate, root, and shoot elongation, plant morphology, and changes in biomass [ 1 , 50 , 60 , 107 ].…”

Effect of Silver Nanoparticles on the In Vitro Regeneration, Biochemical, Genetic, and Phenotype Variation in Adventitious Shoots Produced from Leaf Explants in Chrysanthemum

“…The natural or manufactured nanomaterials are atomic or molecular aggregates, with unique and versatile physicochemical characteristics, e.g., high surface-to-volume ratio, increased catalytic activity, ability to engineer electron exchange, high reactivity, including interactions with living plant and animal cells, good electrical conductivity, or photochemical properties. These characteristics are different in comparison to material counterparts at the micrometric scale, which is directly related to the small size of nanomaterials, on a scale from 1 nm to 100 nm in one or more external dimensions or an internal structure, ensuring new applications of existing materials in various industrial sectors, biomedical sciences, pharmacology, daily life, agriculture, and biotechnology [2][3][4][5][6][7]. Silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) are the most often used nanomaterials in plant science, especially in agriculture and horticulture [5][6][7][8].…”

“…These characteristics are different in comparison to material counterparts at the micrometric scale, which is directly related to the small size of nanomaterials, on a scale from 1 nm to 100 nm in one or more external dimensions or an internal structure, ensuring new applications of existing materials in various industrial sectors, biomedical sciences, pharmacology, daily life, agriculture, and biotechnology [2][3][4][5][6][7]. Silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) are the most often used nanomaterials in plant science, especially in agriculture and horticulture [5][6][7][8]. Nanomaterials have shown high potential for the development of new crop cultivars through genetic engineering or the production of efficient agrochemicals for plant nutrition and protection from pests.…”

“…The main mechanism underlying the AgNPs phytotoxicity is the overproduction of reactive oxygen species (ROS) leading to oxidative stress in plant cells, lipid peroxidation, damage to cell membranes, proteins, and DNA [7,8,15]. Moreover, silver ions (Ag + ) released from AgNPs can interact chemically or physicochemically with nucleic acids and induce DNA damage [17].…”

“…The most often synthesized enzymatic antioxidants are superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPOX), dehydroascorbate reductase (DHAR), and glutathione reductase (GR). Anthocyanins and carotenoids are non-enzymatic antioxidants whose function is to scavenge free radicals and chelate metals under stress conditions [7,8,13,19,20]. However, beyond a limit of stress factors, the internal detoxification mechanism also fails to overcome the toxicity and ultimately leads to the activity of apoptosis in plant cells [18] or mutations in plant genetic material [6].…”