Effects of silicon nanoparticles and conventional Si amendments on growth and nutrient accumulation by maize (Zea mays L.) grown in saline-sodic soil.

Salinity is one of the major abiotic stresses in arid and semiarid climates which threatens the food security of the world. Present study had been designed to assess the efficacy of different abiogenic sources of silicon (Si) to mitigate the salinity stress on maize crop grown on salt-affected soil. Abiogenic sources of Si including silicic acid (SA), sodium silicate (Na-Si), potassium silicate (K-Si), and nanoparticles of silicon (NPs-Si) were applied in saline-sodic soil. Two consecutive maize crops with different seasons were harvested to evaluate the growth response of maize under salinity stress. Post-harvest soil analysis showed a significant decrease in soil electrical conductivity of soil paste extract (ECe) (-23.0%), sodium adsorption ratio (SAR) (-47.7%) and pH of soil saturated paste (pHs) (-9.5%) by comparing with salt-affected control. Results revealed that the maximum root dry weight was recorded in maize1 by the application of NPs-Si (149.3%) and maize2 (88.6%) over control. The maximum shoot dry weight was observed by the application of NPs-Si in maize1 (42.0%) and maize2 (7.4%) by comparing with control treatment. The physiological parameters like chlorophyll contents (52.5%), photosynthetic rate (84.6%), transpiration (100.2%), stomatal conductance (50.5%), and internal CO2 concentration (61.6%) were increased by NPs-Si in the maize1 crop when compared with the control treatment. The application of an abiogenic source (NPs-Si) of Si significantly increased the concentration of phosphorus (P) in roots (223.4%), shoots (22.3%), and cobs (130.3%) of the first maize crop. The current study concluded that the application of NPs-Si and K-Si improved the plant growth by increasing the availability of nutrients like P and potassium (K), physiological attributes, and by reducing the salts stress and cationic ratios in maize after maize crop rotation..

Synthesis, characterization and antifungal potential of titanium dioxide nanoparticles against fungal disease (Ustilago tritici) of wheat (Triticum aestivum L.).

Nanoparticles (NPs) preparation using a green as well as environmentally acceptable processes has achieved a lot of attention in recent decade. The current study compared the synthesis of titania (TiO2) nanoparticles synthesized from leaf extracts of two plant species (Trianthema portulacastrum, Chenopodium quinoa) and traditional approach by chemical preparation. The effects of no calcination on the physical characteristics of TiO2 NPs as well as their antifungal effects were examined and compared with the already reported calcinated TiO2 NPs. The produced TiO2 NPs were evaluated using high-tech techniques such as X-ray diffraction (XRD), scanning electron microscope, energy dispersive spectroscopy (EDX), and elemental mapping. TiO2 NPs prepared by sol-gel technique (T1) and prepared from extractions from leaves of T. portulacastrum (T2), and C. quinoa (T3) were either calcinated or non calcinated and tested against fungal disease (Ustilago tritici) of wheat for antifungal efficacy. The -peak (2θ) at 25.3 was confirmed by XRD to be connected with the anatase (101) form in both cases but before calcination, NPs were lacking the rutile and brookite peaks. The results showed that all types of TiO2 NPs examined had good antifungal activity against U. tritici, but those made from C. quinoa plant extract have good antifungal activity against disease. TiO2 NPs which are produced by the green methods (T2, T3) have the highest antifungal activity (58%, 57% respectively), while minimal activity (19%) was recorded when NPs were synthesized using the sol-gel method (T1) with 25 µl/mL. Non calcinated TiO2 NPs have less antifungal potential than calcined TiO2 NPs. It can be concluded that calcination may be preferred for efficient antifungal activity when using titania nanoparticles. The green technology may be used on a larger scale with less damaging TiO2 NP production and can be utilized against fungal disease on wheat crop to reduce crop losses worldwide.

Effect of soil texture and zinc oxide nanoparticles on growth and accumulation of cadmium by wheat: a life cycle study.

Cadmium (Cd) is getting worldwide attention due to its continuous accumulation in agricultural soils which is due to anthropogenic activities and finally Cd enters in food chain mainly through edible plants. Cadmium free food production on contaminated soils is great challenge which requires some innovative measures for crop production on such soils. The current study evaluated the efficiency of zinc oxide nanoparticles (ZnONPs) (0, 150 and 300 mg/kg) on the growth of wheat in texturally different soils including clay loam (CL), sandy clay loam (SCL), and sandy loam (SL) which were contaminated with were contaminated with 25 mg/kg of Cd before crop growth. Results depicted that doses of ZnONPs and soil textures significantly affected the biological yields, Zn and Cd uptake in wheat plants. The application of 300 mg/kg ZnONPs caused maximum increase in dry weights of shoot (66.6%), roots (58.5%), husk (137.8%) and grains (137.8%) in CL soil. The AB-DTPA extractable Zn was increased while Cd was decreased with doses of NPs depending upon soil textures. The maximum decrease in AB-DTPA extractable Cd was recorded in 300 mg/kg of ZnONPs treatment which was 58.7% in CL, 33.2% in SCL and 12.1% in SL soil as compared to respective controls. Minimum Cd concentrations in roots, shoots, husk and grain were found in 300 mg/kg ZnONPs amended CL soil which was 58%, 76.7%, 58%, and 82.6%, respectively. The minimum bioaccumulation factor (0.14), translocation index (2.46) and health risk index (0.05) was found in CL soil with the highest dose of NPs. The results concluded that use of ZnONPs significantly decreased Cd concentration while increased Zn concentrations in plants depending upon doses of NPs and soil textures.

Synthetic algocyanobacterial consortium as an alternative to chemical fertilizers.

The use of unregulated pesticides and chemical fertilizers can have detrimental effects on biodiversity and human health. This problem is exacerbated by the growing demand for agricultural products. To address these global challenges and promote food and biological security, a new form of agriculture is needed that aligns with the principles of sustainable development and the circular economy. This entails developing the biotechnology market and maximizing the use of renewable and eco-friendly resources, including organic fertilizers and biofertilizers. Phototrophic microorganisms capable of oxygenic photosynthesis and assimilation of molecular nitrogen play a crucial role in soil microbiota, interacting with diverse microflora. This suggests the potential for creating artificial consortia based on them. Microbial consortia offer advantages over individual organisms as they can perform complex functions and adapt to variable conditions, making them a frontier in synthetic biology. Multifunctional consortia overcome the limitations of monocultures and produce biological products with a wide range of enzymatic activities. Biofertilizers based on such consortia present a viable alternative to chemical fertilizers, addressing the issues associated with their usage. The described capabilities of phototrophic and heterotrophic microbial consortia enable effective and environmentally safe restoration and preservation of soil properties, fertility of disturbed lands, and promotion of plant growth. Hence, the utilization of algo-cyano-bacterial consortia biomass can serve as a sustainable and practical substitute for chemical fertilizers, pesticides, and growth promoters. Furthermore, employing these bio-based organisms is a significant stride towards enhancing agricultural productivity, which is an essential requirement to meet the escalating food demands of the growing global population. Utilizing domestic and livestock wastewater, as well as CO2 flue gases, for cultivating this consortium not only helps reduce agricultural waste but also enables the creation of a novel bioproduct within a closed production cycle.

Eco-friendly biopesticides derived from CO2-Fixing cyanobacteria.

There is currently an escalating global demand for the utilization of plant and natural extracts as pesticides due to their minimal health risks. Cyanobacteria are highly valuable organisms with significant potential in agriculture and are of great interest for the development of agrochemical agents as biopesticides. The flexibility and adaptability of Cyanobacteria to various environmental conditions are facilitated by the presence of specialized enzymes involved in the production of biologically active diverse secondary metabolites, including alkaloids, lipopolysaccharides, non-protein amino acids, non-ribosomal peptides, polyketides, terpenoids, and others. This review focuses on the metabolites synthesized from cyanobacteria that have demonstrated effectiveness as antibacterial, antiviral, antifungal agents, insecticides, herbicides, and more. The potential role of cyanobacteria as an alternative to chemical pesticides for environmental conservation is discussed.

Alleviating lead-induced phytotoxicity and enhancing the phytoremediation of castor bean (Ricinus communis L.) by glutathione application: new insights into the mechanisms regulating antioxidants, gas exchange and lead uptake.

Heavy metals pollution represents a serious issue for cultivable lands and ultimately threatens the worldwide food security. Lead (Pb) is a menacing metal which induces toxicity in plants and humans. Lead toxicity reduces the photosynthesis in plants, resulting in the reduction of plant growth and biomass. The excessive concentration of Pb in soil accumulates in plants body and enters into food chain, resulting in health hazards in humans. The phytoremediation is eco-friendly and cost-efficient technique to clean up the polluted soils. However, to the best of our Knowledge, there are very few reports addressing the enhancement of the phytoremediation potential of castor bean plants. Therefore, the present study aimed to investigate the potential role of glutathione (GSH), as a promising plant growth regulator, in enhancing the lead stress tolerance and phytoremediation potential of castor bean plants grown under lead stress conditions. The results indicated that Pb stress reduced the growth, biomass, chlorophyll pigments and gas exchange attributes of castor bean plants, causing oxidative damage in plants. Pb stress induced the oxidative stress markers and activities of antioxidant enzymes. On the other hand, the application of GSH reduced oxidative stress markers, but enhanced the growth, biomass, photosynthetic pigments, gas exchange attributes, Pb accumulation and antioxidant enzymes activities of lead-stressed castor bean plants. Both Pb uptake and Pb accumulation were increased by increasing concentrations of Pb in a dose-additive manner. However, at high dose of exogenous GSH (25 mg L-1) further enhancements were recorded in the Pb uptake in shoot by 48% and in root by 46%; Pb accumulation was further enhanced in shoot by 98% and in root by 101% in comparison with the respective control where no GSH was applied. Taken together, the findings revealed the promising role of GSH in enhancing the lead stress tolerance and phytoremediation potential of castor bean (Ricinus communis) plants cultivated in Pb-polluted soils through regulating leaf gas exchange, antioxidants machinery, and metal uptake.

The excessive concentration of Lead (Pb) in soil accumulates in plants body and enters into food chain, resulting in health hazards in humans. Phytoremediation is eco-friendly and cost-efficient technique to clean up the polluted soils. However, to the best of our knowledge, there are very few reports addressing the enhancement of the phytoremediation potential of castor bean plants. Therefore, the novelty of this research is that this research studied the potential role of glutathione (GSH), as a promising plant growth regulator, in enhancing the lead stress tolerance and phytoremediation potential of castor bean plants grown under lead stress conditions. The results indicated that Pb stress reduced the growth, biomass, chlorophyll pigments and gas exchange attributes of castor bean plants, causing oxidative damage in plants. Pb stress induced the oxidative stress markers and activities of antioxidant enzymes. On the other hand, the application of GSH reduced oxidative stress markers, but enhanced the growth, biomass, photosynthetic pigments, gas exchange attributes, Pb accumulation and antioxidant enzymes activities of lead-stressed castor bean plants. Taken together, the findings revealed the promising role of GSH in enhancing the lead stress tolerance and phytoremediation potential of castor bean plants cultivated in lead-polluted soils.

Anticancer Activity of Cordia dichotoma against a Panel of Human Cancer Cell Lines and Their Phytochemical Profiling via HPLC and GCMS.

The current study was conducted to examine the in vitro anticancer potential of Cordia dichotoma (bark, leaves, pulp and seed). The plant material was collected from UT of J&K and methodical bioassays were carried out on ten human cancer cell lines (Michigan Cancer Foundation-7 (MCF-7), M.D. Anderson-Metastatic Breast (MDA-MB-231), Neuroblastoma-2a (N2A), SH-SY5Y, U-251, HCT-116, SW-620, A-549, MIA PaCa-2, Panc-1) from five different origins (breast, CNS, colon, lung, pancreas) respectively. Methanolic extracts were produced and fractions were then obtained from the extracts and evaluated for cytotoxicity. Mechanistic assays, HPLC, and GCMS profiling were performed on the highest active fraction. The Sulforhodamine B (SRB) assay determined the in vitro cytotoxicity. The findings revealed that the bark portion had in vitro cytotoxicity against the A-549 human lung cancer cell line. To our knowledge, this is the first study to show that the plant's bark has anticancer properties and induced chromatin condensation, confirmed cell death via ROS generation, and significantly decreased colony formation in A-549 cell line from lung origin in a dose-dependent manner. Furthermore, HPLC and GCMS investigations indicated the presence of a number of bioactive molecules such as gallic acid (144,969.86) uV*sec, caffeic acid (104.26) uV*sec, ferulic acid (472.87) uV*sec, vanillic acid (13,775.39) uV*sec, palmitic acid (18.34%), cis vaccenic acid (28.81%), etc. and one of the compounds was reported for the first time from the bark. As a result of its promising efficacy, it may become an essential cancer chemopreventive or chemotherapeutic medication for patients with lung carcinoma.

Effect of gibberellic acid and titanium dioxide nanoparticles on growth, antioxidant defense system and mineral nutrient uptake in wheat.

Nanoparticles (NPs), as a novel source of industrial materials, have been extensively used in recent years which ultimately ends up in soils and may cause toxic effects on plants. Gibberellic acid (GA), phytohormone, has ability to minimize abiotic stresses in plants. The role of GA in minimizing titanium dioxide (TiO2) NPs stress in plants is still unknown. In current study, soil was spiked with TiO2 NPs (0, 100, 200, 400, 600 mg/kg) while GA was foliar-sprayed at different concentrations during wheat growth. The findings revealed that TiO2 NPs increased the growth, chlorophyll contents, and nutrient (P, K, Fe, Mn) concentrations in tissues till 400 mg/kg and then decrease was observed at 600 mg/kg level of NPs whereas the values of these parameters were higher compared to control irrespective of NPs levels. The NPs enhanced the antioxidant activities (SOD, POD, CAT, APX) and reduced the oxidative stress (EL, H2O2, MDA) in leaves over the control. Foliar GA further improved the growth, yield, nutrients and antioxidant activities while minimized the oxidative stress compared to respective sole NPs- treatments. The interactive effects of NPs and GA were dose dependent. The results proved that studied doses of TiO2 NPs were not toxic to wheat plants except the highest level (600 mg/kg) used and GA positively affected the yield of wheat under TiO2 NPs application. The GA can be used to improve crop growth in the presence of NPs which, however, needs further investigation at higher doses of TiO2 NPs in various crops.

Salinization of the soil solution decreases the further accumulation of salt in the root zone of the halophyte Atriplex nummularia Lindl. growing above shallow saline groundwater.

Water use by plants in landscapes with shallow saline groundwater may lead to the accumulation of salt in the root zone. We examined the accumulation of Na+ and Cl- around the roots of the halophyte Atriplex nummularia Lindl. and the impacts of this increasing salinity for stomatal conductance, water use and growth. Plants were grown in columns filled with a sand-clay mixture and connected at the bottom to reservoirs containing 20, 200 or 400 mM NaCl. At 21 d, Na+ and Cl- concentrations in the soil solution were affected by the salinity of the groundwater, height above the water table and the root fresh mass density at various soil depths (P < 0.001). However, by day 35, the groundwater salinity and height above the water table remained significant factors, but the root fresh mass density was no longer significant. Regression of data from the 200 and 400 mM NaCl treatments showed that the rate of Na+ accumulation in the soil increased until the Na+ concentration reached ~250 mM within the root zone; subsequent decreases in accumulation were associated with decreases in stomatal conductance. Salinization of the soil solution therefore had a feedback effect on further salinization within the root zone.

The defensive role of silicon in wheat against stress conditions induced by drought, salinity or cadmium.

In the crust of earth, silicon (Si) is one of the two major elements. For plant growth and development, importance of Si remains controversial due to the widely differences in ability of plants to take up this element. In this paper, pot experiments were done to study Si roles in improving salt, drought or cadmium (Cd) stress tolerance in wheat. Up to full emergence, all pots were watered at 100% field capacity (FC) every other day with nutrient solution without any treatments. Fifteen days after sowing, pots were divided into four plots, each with 40 pots for no stress (control) and three stress treatments; drought (50% FC), salinity (200 mM NaCl) and cadmium (2 mM Cd). For all plots, Si was applied at four levels (0, 2, 4 and 6 mM). Under no stress condition, Si applications increased Si content and improved growth as a result of reduced electrolyte leakage (EL), malondialdehyde (MDA) and Na+ contents. Under stress conditions, Si supplementation conferred higher growth, gas exchange, tissue water and membranes stabilities, and K+ content, and had limited MDA and Na+ contents and EL compared to those obtained without Si. Compared to those without Si, enzyme (e.g., superoxide dismutase, catalase and peroxidase) activity was improved by Si applications, which were linked with elevated antioxidants and osmoprotectants (e.g., free proline, soluble sugars, ascorbic acid and glutathione) contents, might providing antioxidant defense against abiotic stress in wheat. The level of 4 mM Si was most effective for mitigating the salt and drought stress conditions, while 6 mM Si level was most influentially for alleviating the Cd stress condition. These results suggest that Si is beneficial in remarkably affecting physiological phenomena and improving wheat growth under abiotic stress.

Synergistic effect of biochar with gypsum, lime, and farm manure on the growth and tolerance in rice plants under different salt-affected soils.

Soil salinization and sodication harm soil fertility and crop production, especially in dry regions. To combat this, using biochar combined with gypsum, lime, and farm manure is a promising solution for improving salt-affected soils. In a pot experiment, cotton stick biochar (BC) was applied at a rate of 20 t/ha in combination with gypsum (G), lime (L), and farm manure (F) at rates of 5 and 10 t/ha. These were denoted as BCG-5, BCL-5, BCF-5, BCG-10, BCL-10, and BCF-10. Three different types of soils with electrical conductivity (EC) to sodium adsorption ratio (SAR) ratios of 2.45:13.7, 9.45:22, and 11.56:40 were used for experimentation. The application of BCG-10 led to significant improvements in rice biomass, chlorophyll content, and overall growth. It was observed that applying BCG-10 to soils increased the membrane stability index by 75% in EC:SAR (2.45:13.7), 97% in EC:SAR (9.45:22), and 40% in EC:SAR (11.56:40) compared to respective control treatments. After BCG-10 was applied, the hydrogen peroxide in leaves dropped by 29%, 23%, and 21% in EC:SAR (2.45:13.7), EC:SAR (9.45:22), and EC:SAR (11.56:40) soils, relative to their controls, respectively. The application of BCG-10 resulted in glycine betaine increases of 60, 119, and 165% in EC: SAR (2.45:13.7), EC: SAR (9.45:22), and EC: SAR (11.56:40) soils. EC: SAR (2.45:13.7), EC: SAR (9.45:22), and EC: SAR (11.56:40) soils all had 70, 109, and 130% more ascorbic acid in BCG-10 applied treatment, respectively. The results of this experiment show that BCG-10 increased the growth and physiological traits of rice plants were exposed to different levels of salt stress. This was achieved by lowering hydrogen peroxide levels, making plant cells more stable, and increasing non-enzymatic activity.

Health risk assessment of heavy metals in saffron (Crocus sativus L.) cultivated in domestic wastewater and lake water irrigated soils.

Irrigation of crops with domestic wastewater (DW) is a common practice in developing countries like India. However, domestic wastewater irrigation poses a risk of migration of toxic heavy metals to edible parts of crops, which requires serious measures to prevent their uptake. In this study, the effect of DW irrigation in comparison with Sarbal Lake water (SLW) and borewell water (BW) on soil characteristics and cultivated saffron (Crocus sativus L.) was investigated. For this purpose, samples of water, soil, and saffron (corm, petal, and stigma) were collected from the suburban area of Pampore, Srinagar district, Jammu and Kashmir, India. The results showed that DW irrigation had the maximum significant (p < 0.05) influence on the physico-chemical and nutrient characteristics of the soil, followed by SLW and BW irrigation, respectively. The growth and yield parameters of saffron were also significantly (p < 0.05) increased in the case of DW irrigation as compared to SLW and BW. The quality ranking of the cultivated saffron was found to be in accordance with the ISO standard (III: BW and II: DW and SLW). On the other hand, DW irrigation showed a significant increase in heavy metal contents (mg/kg) of saffron plant parts such as As (0.21-0.40), Cd (0.04-0.09), Cr (0.16-0.41), Cu (7.31-14. 75), Fe (142.38-303.15), Pb (0.18-0.31), Mn (15.26-22.81), Hg (0.18-0.25), Ni (0.74-1.18), Se (0.13-0.22), and Zn (3.44-4.59), followed by SLW and BW. However, the levels of heavy metals did not exceed the FAO/WHO safe limits. Bioaccumulation factor (BAF), dietary intake modeling (DIM<0.006496), health risk assessment (HRI<0.028571), and target hazard quotient (THQ<1) analyses showed no potential health hazard associated with the consumption of saffron irrigated with DW and SLW. Therefore, the results of this study provide valuable insights into the optimization of irrigation sources for saffron cultivation.

Effects of agro based organic amendments on growth and cadmium uptake in wheat and rice crops irrigated with raw city effluents: Three years field study.

Cadmium (Cd) accumulates in the vegetative tissues of rice and wheat crops, posing a serious threat in the food chain. A long-term field experiment was conducted to investigate the effects of rice husk biochar (RHB), farm manure (FM), press mud (PrM), and poultry manure (PM) on the growth, yield, and economics of wheat and rice crops grown with sewage water. The results showed that RHB increased wheat plant height (27%, 66%, 70%), spike-length (33%, 99%, 56%), straw yield (21%, 51%, 49%), and grain yield (42%, 63%, 65%) in year-1, year-2, and year-3, than respective controls. For rice crop, RHB showed the maximum increase in plant height (64%, 92%, 96%), spike length (55%, 95%, 90%), straw yield (34%, 53%, 55%), and grain yield (46%, 66%, 69%) each year (2019-2021), compared to their respective controls. The Cd immobilization was increased by the application of RHB while other treatments followed FM > PrM > PM > control in each year of wheat and rice crops. For year-1, benefit-cost ratio remained maximum with the application of FM while for the 2nd and 3rd years in sequence, RHB proved more economical than other treatments and consistently produced wheat and rice with lower Cd concentration than FM, PrM, and PM in grains. This long-term experiment suggested that the application of organic amendments consistently increased biomass of rice and wheat and decreased the Cd concentration in tissues. The RHB remained more effective compared with FM, PrM, and PM in terms of yield, low Cd accumulation and economics of rice and wheat crops.

Residual efficiency of iron-nanoparticles and different iron sources on growth, and antioxidants in maize plants under salts stress: life cycle study.

Exogenous application of iron (Fe) may alleviate salinity stress in plants growing in saline soils. This comparative study evaluated the comparative residual effects of iron nanoparticles (FNp) with two other Fe sources including iron-sulphate (FS) and iron-chelate (FC) on maize (Zea mays L.) crop grown under salt stress. All three Fe sources were applied at the rate of 15 and 25 mg/kg of soil before the sowing of wheat (an earlier crop; following the sequence of crop rotation) and no further Fe amendments were added later for the maize crop. Results revealed that FNp application at 25 mg/kg (FNp-2) substantially increased maize height, root length, root dry weight, shoot dry weight, and grain weightby 80.7%, 111.1%, 45.7%, 59.5%, and 77.2% respectively, as compared to the normal controls; and 62.6%, 81.3%, 65.1%, 78%, and 61.2% as compared to salt-stressed controls, respectively. The FNp-2 treatment gave higher activities of antioxidant enzymes, such as superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase compared to salt stressed control (50.6%, 51%, 48.5%, and 49.2%, respectively). The FNp-2 treatment also produced more photosynthetic pigments and better physiological markers: higher chlorophyll a contents by 49.9%, chlorophyll b contents by 67.2%, carotenoids by 62.5%, total chlorophyll contents by 50.3%, membrane stability index by 59.1%, leaf water relative contents by 60.3% as compared to salt stressed control. The highest Fe and Zn concentrations in maize roots, shoots, and grains were observed in FNp treatment as compared to salts stressed control. Higher application rates of Fe from all the sources also delivered better outcomes in alleviating salinity stress in maize compared to their respective low application rates. The study demonstrated that FNp application alleviated salinity stress, increased nutrient uptake and enhanced the yield of maize grown on saline soils.

The Effect of Short-Term Heating on Photosynthetic Activity, Pigment Content, and Pro-/Antioxidant Balance of A. thaliana Phytochrome Mutants.

The effects of heating (40 °C, 1 and 2 h) in dark and light conditions on the photosynthetic activity (photosynthesis rate and photosystem II activity), content of photosynthetic pigments, activity of antioxidant enzymes, content of thiobarbituric acid reactive substances (TBARs), and expression of a number of key genes of antioxidant enzymes and photosynthetic proteins were studied. It was shown that, in darkness, heating reduced CO2 gas exchange, photosystem II activity, and the content of photosynthetic pigments to a greater extent in the phyB mutant than in the wild type (WT). The content of TBARs increased only in the phyB mutant, which is apparently associated with a sharp increase in the total peroxidase activity in WT and its decrease in the phyB mutant, which is consistent with a noticeable decrease in photosynthetic activity and the content of photosynthetic pigments in the mutant. No differences were indicated in all heated samples under light. It is assumed that the resistance of the photosynthetic apparatus to a short-term elevated temperature depends on the content of PHYB active form and is probably determined by the effect of phytochrome on the content of low-molecular weight antioxidants and the activity of antioxidant enzymes.

Foliar application of silicon-based nanoparticles improve the adaptability of maize (Zea mays L.) in cadmium contaminated soils.

Heavy metals (HMs) especially cadmium (Cd) absorbed by the roots of crop plants like maize have emerged as one of the most serious threats by causing stunted plant growth along with disturbing the photosynthetic machinery and nutrient homeostasis process. A trial was conducted for inducing Cd stress tolerance in maize by exogenous application of silicon nanoparticles (SiNPs) using five doses of SiNPs (0, 100, 200, 300, and 400 ppm) and three levels of Cd (0, 15, and 30 ppm) for maize hybrid (SF-9515). The response variables included morphological traits and biochemical parameters of maize. The results indicated that Cd level of 30 ppm remained the most drastic for maize plants by recording the minimum traits such as shoot length (39.35 cm), shoot fresh weight (9.52 g) and shoot dry weight (3.20 g), leaf pigments such as chlorophyll a (0.55 mg/g FW), chlorophyll b (0.27 mg/g FW), total contents (0.84 mg/g FW), and carotenoid contents (0.19 µg/g FW). Additionally, the same Cd level disrupted biochemical traits such as TSP (4.85 mg/g FW), TP (252.94 nmol/g FW), TSAA (18.92 µmol g-1 FW), TSS (0.85 mg/g FW), and antioxidant activities such as POD (99.39 min-1 g-1 FW), CAT (81.58 min-1 g-1 FW), APX (2.04 min-1 g-1 FW), and SOD (172.79 min-1 g-1 FW). However, a higher level of Cd resulted in greater root length (87.63 cm), root fresh weight (16.43 g), and root dry weight (6.14 g) along with higher Cd concentration in the root (2.52 µg/g-1) and shoot (0.48 µg/g-1). The silicon nanoparticles (Si NPs) treatment significantly increased all measured attributes of maize. The highest value was noted of all the parameters such as chlorophyll a (0.91 mg/g FW), chlorophyll b (0.57 mg/g FW), total chlorophyll contents (1.48 mg/g FW), total carotenoid contents (0.40 µg/g FW), TSP (6.12 mg/g FW), TP (384.56 nmol/g FW), TSAA (24.64 µmol g-1 FW), TSS (1.87 mg/g FW), POD (166.10 min-1 g-1 FW), CAT (149.54 min-1 g-1 FW), APX (3.49 min-1 g-1 FW), and SOD (225.57 min-1 g-1 FW). Based on recorded findings, it might be inferred that higher levels of Cd tend to drastically reduce morpho-physiological traits of maize and foliage-applied silver nanoparticles hold the potential to ameliorate the adverse effect of Cd stress on maize.

Effect of farmyard manure, elemental sulphur and EDTA on growth and phytoextraction of cadmium by spider plants (Chlorophytum comosum L.) under Cd stress.

Cadmium (Cd) contamination is considered as a widespread concern at global scale which is serious threats to human health. Phytoremediation is an eco-friendly approach which can remove or immobilize Cd from the soil. Different organic and inorganic amendments can potentially enhance Cd phytoremediation efficiency but the comparison of farmyard manure (FM), elemental sulphur (S) and ethylenediaminetetraacetic acid (EDTA) for Cd phytoremediation through spider plants (Chlorophytum comosum L.) remained unanswered. The present study evaluated the efficiency of S (0.1 and 0.2%), EDTA (0.1 and 0.2%, represented as EDTA-0.1 and EDTA-0.2) and FM (0.5 and 1%, represented as FM-0.5 and FM-1) for remediation of Cd contaminated soils (50 and 100 mg kg-1, represented as Cd-50 and Cd-100) through spider plants. Results depicted that the highest shoots and roots dry biomass was found in FM treated plants followed by S, EDTA and control except in EDTA-0.2 treatment in which the lowest values of these parameters were observed. Application of FM-1 significantly increased the shoot dry weight (120%), root dry weight (99%), as well as photosynthetic attributes in Cd-50 as compared to control. Application of EDTA-0.2 increased the bioavailable fraction of Cd than control and the maximum increase was observed in Cd-100. The highest Cd concentrations in shoot and roots were found in EDTA treated plants followed by S, control and FM irrespective of Cd and amendment levels. Maximum Cd in roots (109%) and shoots (156%) was recorded in plants grown in Cd-100 with EDTA-0.2 than control. The maximum bioaccumulation factor, translocation index, harvest index and root to shoot translocation were observed with EDTA than control and other treatments. EDTA along with spider plants may enhance the uptake of Cd but lower biomass production in the highest dose of EDTA may questioned the efficiency of EDTA.

Rice straw based silicon nanoparticles improve morphological and nutrient profile of rice plants under salinity stress by triggering physiological and genetic repair mechanisms.

The agricultural sector is facing numerous challenges worldwide, owing to global climate change and limited resources. Crop production is limited by numerous abiotic constraints. Among them, salinity stress as a combination of osmotic and ionic stress adversely influences the physiological and biochemical processes of the plant. Nanotechnology facilitates the production of crops either directly by eradicating the losses due to challenging environmental conditions or indirectly by improving tolerance against salinity stress. In this study, the protective role of silicon nanoparticles (SiNPs) was determined in two rice genotypes, N-22 and Super-Bas, differing in salinity tolerance. The SiNPs were confirmed through standard material characterization techniques, which showed the production of spherical-shaped crystalline SiNPs with a size in the range of 14.98-23.74 nm, respectively. Salinity stress adversely affected the morphological and physiological parameters of both varieties, with Super-Bas being more affected. Salt stress disturbed the ionic balance by minimizing the uptake of K+ and Ca2+ contents and increased the uptake of Na+ in plants. Exogenous SiNPs alleviated the toxic effects of salt stress and promoted the growth of both N-22 and Super-Bas, chlorophyll contents (16% and 13%), carotenoids (15% and 11%), total soluble protein contents (21% and 18%), and the activities of antioxidant enzymes. Expression analysis from quantitative real-time PCR showed that SiNPs relieved plants from oxidative bursts by triggering the expression of HKT genes. Overall, these findings demonstrate that SiNPs significantly alleviated salinity stress by triggering physiological and genetic repair mechanisms, offering a potential solution for food security.

Exogenous application of low and high molecular weight organic acids differentially affected the uptake of cadmium in wheat-rice cropping system in alkaline calcareous soil.

Anthropogenic cadmium (Cd) in arable soils is becoming a global concern due to its harmful effects on crop yield and quality. The current study examined the role of exogenously applied low molecular weight organic acids (LMWOAs) including oxalic acid (OxA), tartaric acid (TA) and high molecular weight organic acids (HMWOAs) like citric acid (CA) and humic acid (HA) for the bioavailability of Cd in wheat-rice cropping system. Maximum increase in root dry-weight, shoot dry-weight, and grain/paddy yields was recorded with HA for both crops. The HA significantly decreased AB-DTPA Cd in contaminated soils which remained 41% for wheat and 48% for rice compared with their respective controls. The minimum concentration of Cd in roots, shoots and grain/paddy was observed in HA treatment in both crops. The organic acids significantly increased the growth parameters, photosynthetic activity, and relative leaf moisture contents for both wheat and rice crops compared to that with the contaminated control. Application of OxA and TA increased the bioavailability of Cd in soils and plant tissues while CA and HA decreased the bioavailability of Cd in soils and plants. The highest decrease in Cd uptake, bioaccumulation, translocation factor, immobilization, translocation, harvest, and health risk indices were observed with HA while maximum increase was recorded with OxA for both wheat and rice. The results concluded that use of HMWOAs is effective in soil Cd immobilization being maximum with HA. While LMWOAs can be used for the phytoextraction of Cd in contaminated soils having maximum potential with OxA.

Dose optimization of silicon for boosting arbuscular mycorrhizal fungi colonization and cadmium stress mitigation in maize (Zea mays L.).

The foliar applied silicon (Si) has the potential to ameliorate heavy metals, especially cadmium (Cd) toxicity; however, Si dose optimization is strategically important for boosting the growth of soil microbes and Cd stress mitigation. Thus, the current research was performed to assess the Si-induced physiochemical and antioxidant trait alterations along with Vesicular Arbuscular Mycorrhiza (VAM) status in maize roots under Cd stress. The trial included foliar Si application at the rate of 0, 5, 10, 15, and 20 ppm while Cd stress (at the rate of 20 ppm) was induced after full germination of maize seed. The response variables included various physiochemical traits such as leaf pigments, protein, and sugar contents along with VAM alterations under induced Cd stress. The results revealed that exogenous application of Si in higher doses remained effective in improving the leaf pigments, proline, soluble sugar, total proteins, and all free amino acids. Additionally, the same treatment remained unmatched in terms of antioxidant activity compared to lower doses of foliar-applied Si. Moreover, VAM was recorded to be at peak under 20 ppm Si treatment. Thus, these encouraging findings may serve as a baseline to develop Si foliar application as a biologically viable mitigation strategy for maize grown in Cd toxicity soils. Overall, the exogenous application of Si helpful for reducing the uptake of Cd in maize and also improving the mycorrhizal association as well as the philological mechanism and antioxidant activities in plant under cadmium stress conditions. Also, future studies must test more doses concerning to varying Cd stress levels along with determining the most responsive crop stage for Si foliar application.