Mineral Nutrition of Higher Plants, 2nd edition, H. Marschner. Academic Press, London (1995), 889, (ISBN 0-12-473543-6). Price: 29.95 Pound Sterling

In the era of climate change, global agricultural systems are facing numerous, unprecedented challenges. In order to achieve food security, advanced nano-engineering is a handy tool for boosting crop production and assuring sustainability. Nanotechnology helps to improve agricultural production by increasing the efficiency of inputs and minimizing relevant losses. Nanomaterials offer a wider specific surface area to fertilizers and pesticides. In addition, nanomaterials as unique carriers of agrochemicals facilitate the site-targeted controlled delivery of nutrients with increased crop protection. Due to their direct and intended applications in the precise management and control of inputs (fertilizers, pesticides, herbicides), nanotools, such as nanobiosensors, support the development of high-tech agricultural farms. The integration of biology and nanotechnology into nonosensors has greatly increased their potential to sense and identify the environmental conditions or impairments. In this review, we summarize recent attempts at innovative uses of nanotechnologies in agriculture that may help to meet the rising demand for food and environmental sustainability.

https://www.mdpi.com/1420-3049/24/14/2558/pdf

Applications of Nanotechnology in Plant Growth and Crop Protection: A Review

The dominance of salt water across the surface of the earth has lead to the widespread occurrence of salt-affected soils. Salt-tolerant plants (halophytes) have evolved to grow on these soils, with halophytes and less tolerant plants showing a wide range of adaptations. However, most of our crops are salt-sensitive. Consequently, salinity is an ever-present threat to agriculture, especially in areas where secondary salinisation has developed through irrigation or deforestation. Attempts to improve the salt tolerance of crops have met with very limited success, due to the complexity of the trait, both genetically and physiologically. Tolerance shows all the characteristics of a multigenic trait, with quantitative trait loci (QTLs) identified in barley, citrus, rice and tomato. Attempts to produce salt-tolerant crops have involved both the domestication of halophytes and the manipulation of existing crop species through conventional breeding programmes, the use of in vitro selection, pooling physiological traits, interspecific hybridisation, the use of marker-aided selection and the development of transgenic plants. After 10 years of research, the value of using transgenic plants to alter salt tolerance has yet to be tested in the field. The use of physiological traits in breeding programmes and the domestication of halophytes currently offer viable alternatives to the development of tolerance through the use of transgenic technologies.

Why does salinity pose such a difficult problem for plant breeders

Biochar application for the remediation of salt-affected soils: Challenges and opportunities

Drought and salt stress negatively affect soil fertility and plant growth. Application of biochar, carbon-rich material developed from combustion of biomass under no or limited oxygen supply, ameliorates the negative effects of drought and salt stress on plants. The biochar application increased the plant growth, biomass, and yield under either drought and/or salt stress and also increased photosynthesis, nutrient uptake, and modified gas exchange characteristics in drought and salt-stressed plants. Under drought stress, biochar increased the water holding capacity of soil and improved the physical and biological properties of soils. Under salt stress, biochar decreased Na+ uptake, while increased K+ uptake by plants. Biochar-mediated increase in salt tolerance of plants is primarily associated with improvement in soil properties, thus increasing plant water status, reduction of Na+ uptake, increasing uptake of minerals, and regulation of stomatal conductance and phytohormones. This review highlights both the potential of biochar in alleviating drought and salt stress in plants and future prospect of the role of biochar under drought and salt stress in plants.

Biochar soil amendment on alleviation of drought and salt stress in plants: a critical review

Antioxidant enzyme and osmotic adjustment changes in bean seedlings as affected by biochar under salt stress

Materials with a particle size less than 100 nm are classified as nano-materials. The physical and chemical properties of nano-materials can vary considerably from those of bulk materials of the same composition. Silicon (Si) still fails to get recognized as an essential nutrient for plant growth and development, however the beneficial effects in terms of growth, biotic and abiotic stress resistance have been indicated in a variety of plant species for their growth. The aim of this study was to investigate the effects of different nano-silicon rates on the growth and antioxidant activities of soybean (Glycine max L. cv. M7) under salt stress. The results showed that salinity decreased shoot and root dry weight, potassium (K+) concentration in the root and leaf; however, increased sodium (Na+) concentration, catalase, peroxidase, ascorbate peroxidase and superoxide dismutase activities, phenolic components, ascorbic acid and α-tocopherol contents, lipid peroxidation, hydrogen peroxide, and oxygen radical’s concentration. Between the treatments, 0.5 and 1 mM of nanosilicon oxide (nano-SiO2) improved shoot and root growth of seedlings. In contrast, a foliar application of SiO2 at 2 mM reduced the soybean growth. Overall, exogenous nano-silicon alleviated the salt stress by increase in K+ concentration, antioxidant activities, non-enzymatic compounds and decreasing of Na+ concentration, lipid peroxidation, and reactive oxygen species production.

Nano-silicon alters antioxidant activities of soybean seedlings under salt toxicity.

This study investigated the effects of foliar application of normal and nano-sized zinc oxide on the response of sunflower cultivars to salinity. Treatments included five cultivars (‘Alstar’, ‘Olsion’, ‘Yourflor’, ‘Hysun36’ and ‘Hysun33’), two salinity levels [0 and 100 mM sodium chloride (NaCl)], and three levels of fertilizer application. Fertilizer treatments were the foliar application of normal and nano-sized zinc oxide (ZnO). Foliar application of ZnO in either forms increased leaf area, shoot dry weight, net carbon dioxide (CO2) assimilation rate (A), sub-stomatal CO2 concentration (Ci), chlorophyll content, Fv/Fm, and Zn content and decreased Na content in leaves. The extent of increase in chlorophyll content, Fv/Fm and shoot weight was greater as nano-sized ZnO was applied to the normal form. The results show that the nano-sized particles of ZnO compared to normal form has greater effect on biomass production of sunflower plants.

Effects of foliar spray of two kinds of zinc oxide on the growth and ion concentration of sunflower cultivars under salt stress

This study investigated the effects of foliar spray of normal and nano-particles of iron sulfate (FeSO4) on the response of sunflower cultivars to salinity Treatments included five cultivars (Alstar, Olsion, Yourflor, Hysun36 and Hysun33), two salinity levels (0 and 100 mM sodium chloride (NaCl)), and three levels of fertilizer application Fertilizer treatments were the foliar application of normal and nano-particles of FeSO4 Foliar application of FeSO4 in either form increased leaf area, shoot dry weight, net carbon dioxide (CO2) assimilation rate (A), sub-stomatal CO2 concentration (Ci), chlorophyll content, Fv/Fm and iron (Fe) content and decreased sodium (Na) content in leaves The extent of increase in chlorophyll a content by foliar spray of FeSO4 nano-particles was significantly greater than normal form The results showed that the FeSO4 nano-particles increased biomass production of sunflower plants greater in comparison with normal form, although no significant difference was found bet

Effects of foliar spray of nano-particles of FeSO4 on the growth and ion content of sunflower under saline condition

Adopting conservation tillage practices such as zero tillage can enhance soil quality, compared with conventional tillage practices that disrupt soil structure. The benefits of maintaining soil structure through no tillage typically result in improved biological processes and increased microbial biodiversity. Rhizobia are considered here as an indicator for soil quality, as they are ubiquitous, present in high populations in many soils, rapidly respond to soil changes, and are crucial for legume productivity. The process of symbiotic nitrogen fixation, whereby rhizobia form a symbiotic association with leguminous plants and fix atmospheric nitrogen gas, can substantially improve agricultural system as, it has how environmental and economic costs for nitrogen supply. Tillage methods affect many soil characteristics such as aeration, structure, temperature and water use, all of which affect the microbial composition, nitrogen fixation and nodulation. This review systematically summarizes the effect of tillage systems such as conventional tillage and minimum tillage systems on nitrogen fixation by legumes. We identify that conservation tillage typically enhances nodulation and nitrogen fixation, through increased soil moisture retention and soil temperature, and increased soil microbial biomass. However, conservation tillage can lead to a reduction in soil pH and increased soil compaction, which can reduce nodulation.

Shahram Torabian

Papers

Antioxidant enzyme and osmotic adjustment changes in bean seedlings as affected by biochar under salt stress

Nano-silicon alters antioxidant activities of soybean seedlings under salt toxicity.

Effects of foliar spray of two kinds of zinc oxide on the growth and ion concentration of sunflower cultivars under salt stress

Effects of foliar spray of nano-particles of FeSO4 on the growth and ion content of sunflower under saline condition

Do tillage systems influence nitrogen fixation in legumes? A review