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

The tomato crop has great economic and nutritional importance; however, it can be adversely affected by salt stress. The objective of this research is to quantify the agronomic and biochemical responses of tomato plants developed under salt stress with the foliar application of copper nanoparticles. Four treatments were evaluated: foliar application of copper nanoparticles (250 mg L−1) with or without salt stress (50 mM NaCl), salt stress, and an absolute control. Saline stress caused severe damage to the development of tomato plants; however, the damage was mitigated by the foliar application of copper nanoparticles, which increased performance and improved the Na+/K+ ratio. The content of Cu increased in the tissues of tomato plants under salinity with the application of Cu nanoparticles, which increased the phenols (16%) in the leaves and the content of vitamin C (80%), glutathione (GSH) (81%), and phenols (7.8%) in the fruit compared with the control. Similarly, the enzyme activity of phenylalanine ammonia lyase (PAL), ascorbate peroxidase (APX), glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT) increased in leaf tissue by 104%, 140%, 26%, 8%, and 93%, respectively. Foliar spraying of copper nanoparticles on tomatoes under salinity appears to induce stress tolerance to salinity by stimulating the plant’s antioxidant mechanisms.

https://www.mdpi.com/2223-7747/8/6/151/pdf

Responses of Tomato Plants under Saline Stress to Foliar Application of Copper Nanoparticles

Microalgal exopolysaccharides represent a potential sustainable alternative for the enhancement and protection of agricultural crops including management of both biotic and abiotic stress. In the present study, we investigated the potential of Dunaliella salina exopolysaccharides (PS) to attenuate the effect of salt stress on growth of Solanum lycopersicum, which was grown under different salinity levels (3 and 6 g L−1 NaCl). The effects of PS treatment on plant growth, osmoprotectant molecules, protein content, and antioxidant enzymes activities of tomato plants under salt stress were analyzed. A metabolomics study showed that the exopolysaccharides released by D. salina contained sulfated moiety along with carbohydrates and uronic acids. The application of sulfated exopolysaccharides on tomato plants alleviated the salt stress and mitigated the decrease in length and dry weight of the plant’s shoot and root systems, as well as that of potassium (K+), and K+/Na+ ratio. Furthermore, the increase in proline, phenolic compounds, Na+, and antioxidant enzymes (CAT, POD, SOD) activities caused by salt stress were attenuated after the exopolysaccharide treatment. GC-MS metabolomics analysis showed that PS treatment allowed the activation and/or inhibition of various metabolic pathways involved in the plant’s tolerance to stress such as jasmonic acid-dependent pathways. This study shows the potential of microalgal exopolysaccharides for enhancing tomato tolerance to salt stress and highlights the possibility of their use as plant growth biostimulants under harsh environmental conditions.

Dunaliella salina exopolysaccharides: a promising biostimulant for salt stress tolerance in tomato (Solanum lycopersicum)

Salinity stress is a severe environmental stress that affects plant growth and productivity of potato, a strategic crop moderately sensitive to saline soils. Limited studies are available on the use of combined nano-micronutrients to ameliorate salinity stress in potato plants (Solanum tuberosum L.). Two open field experiments were conducted in salt-affected sandy soil to investigate plant growth, physiology, and yield of potato in response to soil salinity stress under single or combined application of Zn, B, Si, and Zeolite nanoparticles. It was hypothesized that soil application of nanoparticles enhanced plant growth and yield by alleviating the adverse impact of soil salinity. In general, all the nano-treatments applications significantly increased plant height, shoot dry weight, number of stems per plant, leaf relative water content, leaf photosynthetic rate, leaf stomatal conductance, chlorophyll content, and tuber yield, as compared to the untreated control. Furthermore, soil application of these treatments increased the concentration of nutrients (N, P, K, Ca, Zn, and B) in plant tissues, leaf proline, and leaf gibberellic acid hormone (GA3) in addition to contents of protein, carbohydrates, and antioxidant enzymes (polyphenol oxidase (PPO) and peroxidase (POD) in tubers. Compared to other treatments, the combined application of nanoparticles showed the highest plant growth, physiological parameters, endogenous elements (N, P, K, Ca, Zn, and B) and the lowest concentration of leaf abscisic acid (ABA) and transpiration rate. The present findings suggest that soil addition of the aforementioned nanoparticles can be a promising approach to improving crop productivity in salt-affected soils.

https://www.mdpi.com/2073-4395/10/1/19/pdf

Synergetic Effects of Zinc, Boron, Silicon, and Zeolite Nanoparticles on Confer Tolerance in Potato Plants Subjected to Salinity

Soil salinization represents one of the major limiting factors of future increase in crop production through the expansion or maintaining of cultivation area in the future. High salt levels in soils or irrigation water represent major environmental concerns for agriculture in semiarid and arid zones. Recent advances in research provide great opportunities to develop effective strategies to improve crop salt tolerance and yield in different environments affected by the soil salinity. It was clearly demonstrated that plants employ both the common adaptative responses and the specific reactions to salt stress. The review of research results presented here may be helpful to understand the physiological, metabolic, developmental, and other reactions of crop plants to salinity, resulting in the decrease of biomass production and yield. In addition, the chapter provides an overview of modern studies on how to mitigate salt stress effects on photosynthetic apparatus and productivity of crop plants with the help of phytohormones, glycine betaine, proline, polyamines, paclobutrazol, trace elements, and nanoparticles. To understand well these effects and to discover new ways to improve productivity in salinity stress conditions, it is necessary to utilize efficiently possibilities of promising techniques and approaches focused on improvement of photosynthetic traits and photosynthetic capacity, which determines yield under salt stress conditions.

Strategies to Mitigate the Salt Stress Effects on Photosynthetic Apparatus and Productivity of Crop Plants

A greenhouse study was
conducted to explore the effect of various rates of potassium sulfate (K2SO4)
nanoparticles on alfalfa (Medicago
sativa L.)
growth and physiological response under salt stress. One salt-tolerant genotype
(Mesa-Sirsa) and one salt-sensitive genotype (Bulldog 505) were selected based
on germination under salt and were planted in pots containing 2 kg of sand. The
two genotypes were subjected to 0 and 6 dS·m-1 salt
levels using CaCl2·2H2O: NaCl (2:1) mixed with
Hoagland solution. Three K2SO4 nanoparticle treatments
consisting of, 1/4, 1/8, and 1/10 of the potassium (K) level in full strength
Hoagland solution (235 mg·L-1) were
applied. Adding K2SO4 nanoparticles at the 1/8 level
resulted in the highest shoot dry weight, relative yield, root length and root
dry weight in both genotypes. The different rates of K2SO4 nanoparticles affected significantly Na/K ratio and the concentrations of
Calcium (Ca), Phosphorus (P), Copper (Cu), Manganese (Mn), and Zinc (Zn) in
plant tissue. The application of K2SO4 nanoparticles at
the 1/8 rate enhanced the plant’s physiological response to salt stress by
reducing electrolyte leakage, increasing catalase and proline content, and
increasing antioxidant enzymes, activity. These results suggest that the
application of K nanoparticles may have better efficiency than conventional K
fertilizers in providing adequate plant nutrition and overcoming the negative
effects of salt stress in alfalfa.

/pdf/response-of-alfalfa-under-salt-stress-to-the-application-of-3y481rmu22.pdf

Response of Alfalfa under Salt Stress to the Application of Potassium Sulfate Nanoparticles

Salinity is a major impediment to crop production. This study was undertaken to compare the effect of seaweed extract, humic acid, and potassium sulfate nanoparticles in alleviating salt stress in Alfalfa (Medicago sativa L.). Seeds of ten alfalfa genotypes were germinated in a growth chamber at five salt concentrations (0%, 0.5%, 1.0%, 1.5%, and 2.00%). Salt concentrations above 1% reduced seed germination by more than 70% in most genotypes. One salt tolerant genotype (Mesa-Sirsa) and one salt sensitive (Bulldog 505) were selected and planted in greenhouse pots containing 2 kg of sand and subjected to two salt levels (10 and 15 dS· m-1). Four treatments consisting of 1) control (Hoagland solution, no-salt), 2) seaweed extract at 4 Kg·ha-1, 3) humic acid at 28 L· ha-1, and 4) potassium sulfate at 300 Kg· ha-1. Plant biomass was reduced under both salt concentrations in both genotypes, with a greater magnitude in the salt sensitive genotype. Application of seaweed extract resulted in higher relative water content and proline under both salt concentrations (10 and 15 dS·m-1) in the salt sensitive genotype, and lower electrolyte leakage in both salt tolerant and salt sensitive genotypes, under both salt concentrations. Seaweed extract also resulted in higher catalase and SOD activities in both genotypes under 10 dS·m-1. Catalase and SOD activities were associated with significantly (p < 0.01) reduced electrolyte leakage and increased shoot dry weight. Overall, seaweed extract seemed to have a positive effect in alleviating salt stress in alfalfa.

/pdf/effect-of-plant-growth-stimulants-on-alfalfa-response-to-1rhs6bme8u.pdf

Effect of Plant Growth Stimulants on Alfalfa Response to Salt Stress

Soil salinity and sodicity is a potential soil risk and a major reason for reduced soil productivity in many areas of the world. This study was conducted to investigate the effect of different biochar raw materials and the effects of acid-modified biochar on alleviating abiotic stresses from saline-sodic soil and its effect on biochemical properties of maize and wheat productivity. A field experiment was conducted as a randomized complete block design during the seasons of 2019/2020, with five treatments and three replicates: untreated soil (CK), rice straw biochar (RSB), cotton stalk biochar (CSB), rice straw-modified biochar (RSMB), and cotton stalk-modified biochar (CSMB). FTIR and X-ray diffraction patterns indicated that acid modification of biochar has potential effects for improving its properties via porous functions, surface functional groups and mineral compositions. The CSMB treatment enhanced the soil’s physical and chemical properties and porosity via EC, ESP, CEC, SOC and BD by 28.79%, 20.95%, 11.49%, 9.09%, 11.51% and 12.68% in the upper 0–20 cm, respectively, compared to the initial properties after the second season. Soil-available N, P and K increased with modified biochar treatments compared to original biochar types. Data showed increases in grain/straw yield with CSMB amendments by 34.15% and 29.82% for maize and 25.11% and 15.03% for wheat plants, respectively, compared to the control. Total N, P and K contents in both maize and wheat plants increased significantly with biochar application. CSMB recorded the highest accumulations of proline contents and SOD, POD and CAT antioxidant enzyme activity. These results suggest that the acid-modified biochar can be considered an eco-friendly, cheaper and effective choice in alleviating abiotic stresses from saline-sodic soil and positively effects maize and wheat productivity.

https://www.mdpi.com/2071-1050/14/13/8190/pdf?version=1657069529

Acid-Modified Biochar Impacts on Soil Properties and Biochemical Characteristics of Crops Grown in Saline-Sodic Soils

Plant Growth Stimulating Bacteria and Filter Mud Cake Enhance Soil Quality and Productivity of Mango (Mangifera indica L.)

ABSTRACT Context. The application of soil amendments to immobilise pesticide residues is a promising technology for meeting human health requirements, environmental protection and cost-effective remediation. Aims. This study aims to evaluate the effect of rice straw biochar (RB), rice straw compost (RC) and their mixtures at rates of 0.5% and 1.0% in pots, on the immobilisation of pesticides (such as atrazine, glyphosate and chlorpyrifos) in contaminated soil, using spectroscopy analysis under grown canola (Brassica napus L.) plants. Methods. Determination of immobilisation of pesticide residues by GC or HPLC and chemical properties of RB and RC and adding them at differentrates to the contaminated soil. Keyresults. The results showed that the addition of RB or RC alone or their mixtures led to a significant increase in the exchangeable Ca2+ contents, organic matter (OM), cation exchange capacity (CEC), uptake of N, P and K and dry weight of canola plants. Pesticide concentrations decreased with increasing OM, CEC, and exchangeable Ca2+ with the soil amended by RC and RB. The data indicated that adding RB at levels of 0.5% and 1.0% resulted in reductions in chloropyrifos by 43.2% and 63.1%, glyphosate by 32.8% and 77.3%, and atrazine by 21.9% and 72.2%, respectively, as compared to the control. Addition of (RC + RB) at 0.5% gave the highest pesticide immobilisation, followed (RC+RB) at 1.0%. Conclusion. These results indicate that the dominant mechanisms of pesticides immobilisation in the alkaline soils amended with RC and RB by FTIR and XRD analysis were π–π interaction, pore filling, hydrophobic effect, H-bonding, degradation as well as improvement of soil properties and dry yield of canola plants. Implications. Our results suggested the possibility of adding recycled rice straw in the form of compost or biochar to the contaminated soil to improve its properties, immobilise pesticides and increase its production capacity.

Mahmoud Samir El-Sharkawy

Papers

Response of Alfalfa under Salt Stress to the Application of Potassium Sulfate Nanoparticles

Effect of Plant Growth Stimulants on Alfalfa Response to Salt Stress

Acid-Modified Biochar Impacts on Soil Properties and Biochemical Characteristics of Crops Grown in Saline-Sodic Soils

Plant Growth Stimulating Bacteria and Filter Mud Cake Enhance Soil Quality and Productivity of Mango (Mangifera indica L.)

Compost and biochar impact on immobilisation of pesticide residues in alkaline soils under canola (Brassica napus) plants