Nanotechnology as the Potential Tool to Mitigate Abiotic Stress
There is complexity in the response of plants to abiotic stress comprising alterations in their biology, morphology and metabolism. A series of strategies have been adopted in order to increase the tolerance against abiotic stress in plants that encompass engineering genetic varieties with distinct genetic structures capable of increasing the performance under stress conditions. Nanotechnology has been found to be an efficient and versatile technique with applications in almost all areas of science, technology and Industry. It has been reported that the application of nanoparticles has led to the enhanced germination and seedling growth along with some physiological activities such as nitrogen metabolism, carbohydrate contents, protein and a number of positive changes in gene expression demonstrating the fact that their applications in plants result in crop Improvement. It is now evident that nanostructured materials are capable of enhancing the water stress tolerance through water uptake and increasing in the root hydraulic conductance as well as differential abundance of proteins with critical roles in reduction oxidation reactions, signaling of stress hormonal pathways and ROS detoxification. Also it is known that particles in nanoscale have a high level of mobility leading to a fast transportation of nutrients to almost all parts of plants. Particularly in this case, the highly demanding solutions are required to suggest ways to increase cultivated plants adaptation potential through using nanostructured materials, especially under stressful conditions 1.
Exploring Nanotechnology to Mitigate Abiotic Stress
In particular, abiotic stresses are considered as the main constraints that adversely impact the productivity of crops and lead to consequences in plant growth process. Generally, droughts and salinity are among the most widespread and mostly occurring abiotic stresses. The growing occurrence of various abiotic stresses that are induced by anthropogenic and natural activities has risen concerns in the scientific community to find solutions in order to mitigate their adverse effects to finally enhance the crops yield potential. The reports by FAO sports the fact that there is a major challenge in finding ways to increase more food crops by around 70% for nearly 2.3 billion people in the next 30 Years. Accordingly, there is a huge need to discover and suggest novel areas of research in order to sort out the technological challenges in addressing the yielding obstacles, improving the efficiency of resources and developing sustainable and environmentally friendly technologies following the changes in environmental scenarios when the bigger population is present on Earth. There are hopes that nanobiotechnology is getting more attention and is considered as a desirable discipline to occupy this promising position leading to the mitigation of the constraints related to biotic and abiotic stress and build up a secure and sustainable future for agriculture around the globe. In addition to the widespread applications in many areas of science, nanotechnology has gates for diverse applications in agriculture and biotechnology with a lot of potential benefits in crops yield. Numerous biological, chemical and physical techniques have been introduced to obtain nanostructured metal or metal oxide. This class of nanomaterials is extensively studied to evaluate their capability in development and growth of plants as well as protecting them against abiotic and biotic stresses 2.
Nanomaterials Used to Treat Plants
It is very well known that nanomaterials have found practical and excellence applications in different fields. The most common types of nanomaterials with predominant applications comprise carbon nanotubes, fullerenes, quantum dots, dendrimers and metallic nanoparticles like Ag, Si and Au. There is evidence of naturally occurring nanomaterials resulting from diesel combustion or volcanic eruption. Chemical and biological synthesis of metallic nanoparticles has been reported taking the advantages of plants extracts that contain enzymes, sugars, proteins and chemical agents like latex, flavonoids, terpenoids, alcohol, cofactors and amines. All these compounds and agents contribute as stabilizing and reducing agents in the course of the synthesis of metallic nanoparticles responsible for a controlled synthesis to achieve definite sizes and morphologies and more importantly, they cause no pollution in the atmosphere. It is believed that nanotechnology and nanoparticles are capable of augmenting plant growth, productivity, biotic and abiotic stress tolerance and development. Plants can produce naturally mineralized nanostructured materials essential for their growth. Among all the synthesize nanoparticles so far, nanoparticles, silver nanoparticles, aluminum oxide nanoparticles, zinc oxide nanoparticles, titanium oxide nanoparticles are the most common nanomaterials that have applications in improving plants 2.
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Response of Plants to Abiotic Stress
Salinity, alkalinity, mineral toxicity, submergence and draught are among the most common abiotic stress and major factors that cause the growth of plants and crops as well as productivity to drop. In fact, plants face numerous environmental stresses in the course of their lifespan and accordingly, they develop their own defense strategy towards these abiotic stresses a different levels throughout altering and modifying physiological, biochemical and molecular pathways. In this case, plants take up distinct molecular routs in order to modify gene expressions. It’s been shown that nanomaterials are capable of leaving an impact on plants growth and regulate the biological activities of antioxidant enzymes such as SOD, CAT & POD.
Nanoparticles Impact on Abiotic Stresses as Droughts, Alkalinity and Salinity
It is very well known that water has a crucial role on survival of plants and essential factor in transporting nutrients. Therefore, water deficiencies lead to drought stress with the consequent weakening in plants vitality. It is in fact the promise of nanotechnology to get over the problem of drought dresses. The use of various concentrations of silica nanoparticles has led to improvements in plants tolerance against drought stress. Particularly, chemical and physiological responses of plants differ for different concentrations of silica nanoparticles. The effect of silica nanoparticles was confirmed to be positive on malondialdehyde (MDA), photosynthesis parameters, membrane electrolyte leakage (ELI), chlorophyll, proline contents, carbohydrate and carotenoid. Inclusion of of silicon nanoparticles on two sorghum cultivars has led to improvements in plants drought tolerance. Another major stress is salinity which has caused concerns in the scientific community to make the idea of sustainable crop production. Based on studies, it is estimated that more than 20% of cultivated land from all around the world is suffering from salinity stress and that the problem is exacerbating daily. This abiotic stress causes adverse effect on different physiological and biochemical processes that are closely associated with plant yield and growth. It has been demonstrated that silicon nanoparticles and fertilizers out of silicon have effects on morphological and physiological traits and vegetative features of basil under salinity stress. The results show a considerable increase in plants growth, chlorophyll, content and proline level in basil when treated by silicon nanoparticles which are capable of interacting with plants biological systems mechanically and chemically mainly due to their intrinsic catalytic reactivity, small size and large surface area. Studies show using silver nanoparticles with the particle size of nearly 6 nm in the plant, Spirodela polyrhiza, show activation of antioxidant system and an increase in the activity of superoxide, dismutase, catalase and peroxidase. The application of gold nanoparticles in Brassica juncea seedlings leads to a remarkable improvement in the activities of antioxidant enzymes, guaiacol peroxidase, catalase and glutathione reductase and peroxidase along with the accumulation of hydrogen peroxide and proline in plants treated by gold nanoparticles 1.
The use of nanotechnology and nanostructured materials in agricultural project has started just recently in the global level leading to developments in economical and nanotech applications to enhance biotic and abiotic stress, plant growth and so forth. Nanostructured materials have shown to enhance the stress tolerance through increasing the root hydraulic conductor and water uptake in plants. Nanoparticles can interact well with plant cells leading to a modification in plant gene expression and biological pathways to finally influence the plants growth.