Zinc (Zn) is an indispensable micronutrient for plant growth and metabolism, yet its bioavailability in soil is often limited. Recent advances in nanotechnology offer potential strategies to improve nutrient delivery through green-synthesized nanoparticles (NPs). The present study investigates the cytological, enzymatic and other metabolic responses of Vicia faba plants treated with green-synthesized zinc oxide NPs (ZnO NPs) compared with bulk zinc sulfate (ZnSO4). First, ZnO NPs were green synthesized from Sorghum bicolor leaves extract giving a size of 23.6 nm. Germination bioassay and pot experiment were conducted using different concentrations of ZnO NPs and ZnSO4 (25, 50, and 100 mg L− 1). Concerning the germination bioassay, cytological observations revealed differential effects on mitotic index, chromosomal behavior and number of aberrant cells indicating ZnO NPs-mediated modulation of cell division while high concentrations of both ZnO NPs and ZnSO4 caused cell abnormalities. Both ZnO NPs and ZnSO4 primarily boosted protein and carbohydrate content, and enzyme activities of amylase and protease in the V. faba seedlings. In the pot experiment, all growth, photosynthetic and gas exchange parameters were increased with Zn supplements except for the higher doses and the more enhancement for ZnO NPs. Biochemical assays demonstrated enhanced activities of carbonic anhydrase, nitrate reductase and antioxidant enzymes, including superoxide dismutase, catalase, and peroxidase, alongside altered levels of proline due to ZnO NPs application compared to bulk ZnSO4. Zn determination in shoots and roots revealed that Zn absorption was higher in plants treated with ZnSO4 at all tested concentrations which was accompanied by elevated levels of electrolyte leakage and lipid peroxidation. Metabolic changes further reflected ZnO NP-induced regulation of oxidative stress responses and cellular homeostasis by maintaining membrane stability and water content. Overall, the findings suggest greater phytotoxicity in plants subjected to ZnSO4 compared with ZnO NPs, likely due to the accumulation of dissolved Zn ions absorbed into plant tissues. These findings emphasize the role of green-synthesized ZnO NPs as sustainable growth regulators, offering novel insights into their cytological and biochemical impact on higher plants.

A field experiment was conducted during the wheat-growing season on a clay-loam soil to investigate the interaction between irrigation management, sowing dates, and winter wheat productivity. A split-plot design tested three planting dates (PD₁: 15 November, PD₂: 30 November, PD₃: 15 December) and three irrigation levels (Irr₁: five irrigations, Irr₂: four, Irr₃: three irrigations). Results revealed that early sowing (PD₁) under full irrigation (Irr₁) maximized grain yield (6.8 tons/ha) and 1000-grain weight (49.3 g) but required the highest water applied (5,608 m³/ha). Conversely, PD₃ with reduced irrigation (Irr₃) conserved water (3,282 m³/ha) but incurred yield penalties (4.6 t/ha grain). Critically, PD₂ under Irr₂ achieved 94% of PD₁’s yield with 18% less water, highlighting its viability for balancing productivity and sustainability. Water productivity (WP) improved under water-saving strategies, with PD₃Irr₃ yielding the highest WP (1.41 kg/m³). The findings underscore that planting date (mid-November) is more suitable for yield than maximal irrigation, offering actionable strategies for farmers in water-scarce regions to enhance climate resilience while safeguarding food security.

The effects of nitrogen (N) fertilizer (0, 45, 90, and 135 kg N/fad), phosphorus-potassium (PK) application (0 vs. recommended rate: 31 kg P₂O₅ + 24 kg K₂O/fad), and wheat and maize composts on maize growth, yield, nutrient dynamics, and nitrogen economy were examined in a two-year field study. With increases of 4.3–12.9% and 8.0–9.2% over seasons, respectively, maize compost considerably increased grain yield (15.8 ard/fad) above wheat compost (15.2 ard/fad) and control, according to results from a split-plot design with four replicates. While the effects of phosphorus (P) differed by season, both composts increased the percentages of nitrogen (N) and potassium (K) in leaves and grains. While ear characteristics, yield components, and nutrient content in leaves and grains were increased by increasing N rates up to 135 kg/fad, nitrogen utilization efficiency (NUE: 25.11 to 16.41 kg grains/kg N) and recovery (29.24% to 23.76%) were decreased. While effects on ear morphology and P content were mixed, PK fertilization greatly increased yield, crude protein, and N and K in grains. At 45 kg N/fad, recovery and N efficiency were at their best. Combining compost with moderate N and PK inputs increased sustainability and productivity, indicating that balanced fertilization (45 kg N/fad + PK) and maize compost are good ways to maximize maize production and control nutrients.

Environmental stress causes significant crop damage by constraining its productivity. Previous data shows that phytohormones regulate plant growth and development and play an important role in managing plant responses against abiotic stresses. Melatonin (MEL) is a versatile organic signaling molecule with a small molecular weight and potentially defends plants against these stresses. The present review discusses the biosynthesis mechanism and signaling of MEL in plants based on recent research. Here, the review focuses on MEL's role in combating several abiotic stresses, such as temperature (heat and cold), drought, salinity, and heavy metal stress in plants. Lastly, the interaction between Mel and other phytohormones in controlling these responses is also reviewed.

Nanotechnology shows potential to promote sustainable and productive agriculture and address the growing population and food demand worldwide. Recently, there has been an increase in interest in using nanoparticles (NPs) in agriculture. The current investigation aimed to examine the effects of two different NPs, SiO2 or TiO2 as foliar spray or root dipping treatment on tulsi (Ocimum sanctum L.) to identify the optimal concentration of SiO2 and TiO2 NPs that influence the growth, physiology, and biochemical processes of tulsi. The findings suggest that the treatment of SiO2 or TiO2 NPs led to an increase in peltate glandular trichomes (PGTs) density and diameter, chlorophyll content, photosynthesis, gas exchange traits, and elemental status; which led to enhancement of shoot and root length, fresh and dry mass of shoot and root, leaf area and leaf per plant. The application of SiO2 or TiO2 NPs led to the stimulation of enzyme activity responsible for maintaining carboxylation/decarboxylation homeostasis (carbonic anhydrase), nitrogen metabolism (nitrate reductase), Calvin cycle (RuBisCo), and TCA cycle (succinate dehydrogenase and fumarase). In addition, SiO2 or TiO2 NPs also played a crucial role in preserving a balance between reactive oxygen species (ROS) and the scavenging system by maintaining elevated activities of antioxidant enzymes involved in ROS detoxification. In the comparison between the two modes of treatment foliar treatment exhibited a more promising response compared to root dipping. SiO2 and TiO2 NPs increased Ocimum sanctum growth, physiology, and biochemical traits, with foliar application showing superior effects over root dipping. These NPs improve photosynthesis, enzyme activity, and antioxidant defense, making them promising for sustainable agriculture. Future studies should focus on long-term impacts, optimal dosages, and environmental safety to ensure their effective use in crop production.

A field study on maize growth in sandy soils found that applying 5 tons/fad of compost significantly enhanced plant growth and grain yield. Increasing the nitrogen (N) rate up to 135 kg N/fad also, led to a notable increase in plant and grain yield and resulted in early flowering. The application of phosphorus and potassium (PK) at a rate of 15.5 kg P2O5 + 48 kg K2O/fad led to early flowering and significantly increased grain yield. Furthermore, the application of PK fertilizer led to an increase in the nitrogen and phosphorus content of grains in both growing seasons. The concentration of proline, which serves as an endogenous osmoprotectant against biotic stress, also increased. The suggested PK fertilizer level (15.5 kg P2O5 + 48 kg K2O/fad) resulted in a notable rise in the CP% in grains. The research further revealed that the uptake of nitrogen in grains increased in response to higher nitrogen levels, with the maximum nitrogen utilization efficiency being 25.11 kg of grains/ kilogram of applied nitrogen.

In this study, we examined the role of zinc oxide nanoparticles (ZnO NPs) on the growth facet, photosynthetic attributes, lipid peroxidation, electrolyte leakage (EL), and antioxidant activity of basil plants following growth subjected to different levels of sodium chloride-induced salinity [1.0 (control), 2.0, 3.0, 4.0, and 5.0 deci Siemens per meter (dSm–1)]. The foliage of 30-day-old plants was sprayed with an aqueous solution of ZnO NPs [(1.5/2.0 parts per million (ppm)]. Treated plants sampled at 75 days after sowing showed a concentration-dependent response against salinity for all studied growth, photosynthetic attributes, and other biochemical parameters. All growth parameters decreased with increasing salt levels in the soil. However, a direct relationship was observed for lipid peroxidation, EL, and all antioxidant stress markers, and all these parameters increased with the increased salinity levels in the soil. Moreover, ZnO NPs alone (1.5 or 2.0 ppm) or as a follow-up treatment with salinity (2.0 dSm–1 + 1.5 or 2.0 ppm ZnO, 3.0 dSm–1 + 1.5 or 2.0 ppm ZnO, 4.0 dSm–1 + 1.5 or 2.0 ppm ZnO, and 5.0 dSm–1 + 1.5 or 2.0 ppm ZnO) enhanced all the growth and photosynthetic parameters and protected the plants against salinity by reflecting the enhanced activity of antioxidants and decreasing EL and lipid peroxidation. The results of this study confirmed the ameliorating role of ZnO NPs against salt stress and screened out an effective dose of ZnO NPs (2.0 ppm) for growing Ocimum basilicum plant species in saline soil.

Abstract The present study was conducted to evaluate the impact of Cu-induced toxicity on the growth, yield parameters, and Cu accumulation in the seeds of black cumin (Nigella sativa L.) plants. In this experiment, plants grown in earthen pots filled with 3 kg of garden soil were contaminated with different dilutions (1.5, 2.0, 2.5, 3.0, 3.5, 4.0) of Cu in millimoles (mM), except for the control. Growth, yield, and Cu bioaccumulation parameters were recorded and analyzed at the harvesting stage. Results revealed that all doses of Cu show a considerable negative effect on the growth and yield parameters of black cumin as the concentration of Cu increased in the soil and reduced all of the growth parameters significantly (p ≤ 0.05). With each Cu dose, the levels of chlorophyll a and b in the tissues of fresh leaves decreased significantly (p ≤ 0.05). Fruit and seed yield also decreased significantly (p ≤ 0.05) from the lower to the higher dose of Cu (1.5 mM to 4.0 mM). Cu bioaccumulation levels in the seeds of all treated plants (Control to 4.0 mM Cu) are under the threshold limit for Cu set by the Food Safety and Standards Authority of India (FSSAI) and World Health Organization (WHO) for spices and are safe for human consumption. Finally, due to the low seed yield in Cu-contaminated soil, it is advised to farmers that Nigella sativa should not be grown in Cu-contaminated soil to avoid economic loss. Graphical Abstract

This study was designed to evaluate the pre-reproductive and reproductive responses of Linum usitatissimum L. (flax, linseed plant) to different levels of Pb in the soil. Flax seeds were sown in garden soil-filled earthen pots and treated with three different levels of lead as lead chloride (150, 450, and 750 mg Pb kg(-1) soil) except control, and each treatment was replicated three times. Growth and reproductive parameters and photosynthetic pigments were significantly reduced (p <= 0.05) for all treatments. Quantitatively, Chlorophyll b content decreased more than chlorophyll a and the amount of proline content in the leaves increased in lockstep with the increase of Pb levels in the soil. Pb was found in substantial amounts in the roots, shoots, and seeds. The pattern of Pb accumulation in different organs was root > shoot > seeds. Pb levels in seeds obtained from 750 mg Pb kg(-1) soil-treated plants exceeded the permissible limits. Biological concentration factor (BCF), biological accumulation coefficient (BAC) and translocation factor (TF) values showed that roots of L. usitatissimum absorbed and accumulated a substantial quantity of Pb but translocated only a fraction of that to the shoots. Therefore, L. usitatissimum L. can be used in phytostabilization rather than phytoextraction of Pb. Novelty statement This manuscript evaluates the potential of flaxseeds to cause biomagnification of lead (Pb) in the human body when grown under different concentrations of Pb and assessment of the risk posed to consumer health in a food chain. This study also provides insight to evaluate the uptake and extraction efficiency of Linum usitatissimum L. to remediate the Pb-polluted soil and use of Pb contaminated plant products (stem fibers and linseed oil) in an ecofriendly manner.

Cowpea (Vigna unguiculata L.) is an important legume well grown in semiarid and arid environment. Hydrogen peroxide solutions (0.1, 0.5, 1.0, and 1.5 mM) have been used to optimize growth and photosynthetic performance of cowpea plant at two growth stages [30 and 45 DAS (days of sowing)]. Foliar application of H2O2 at 0.5 > 1.0 mM solution at 29 DAS optimally promoted the photosynthetic attributes [leaf chlorophyll content, net photosynthetic rate (PN), water use efficiency, and maximum quantum yield of PSII (Fv/Fm)] and growth performance [root and shoot length; fresh and dry weight] of plants where the responses were more significant at the later growth stage. It was favored by activity of enzymes as carbonic anhydrase [CA; E.C. 4.2.1.1] and nitrate reductase [NR, E.C. 1.6.6.1] and those of antioxidant enzymes viz. peroxidase [POX; EC 1.11.1.7], catalase [CAT; EC 1.11.1.6], and superoxide dismutase [SOD; EC 1.15.1.1] and leaf proline content. Strengthened root system and antioxidant activity, particularly leaf proline level appeared to be the key factor for efficient photosynthesis and growth responses.

Excess cadmium accumulation in shoot decreases the photosynthetic attributes and the activity of carbonic anhydrase (CA; E.C. 4.2.1.1) thereby retarding plant growth metabolism, in a cultivar dependent manner. Two mustard (Brassica juncea) varieties were treated with increasing cadmium doses (0, 25, 50 or 100 mg CdCl2 kg−1 of soil) in the soil in a net house. The photosynthetic features, activity of CA, and the yield attributes were recorded in association with morphological characters. A clear-cut difference in these features was noted among the varieties, where Varuna excelled in its resistance to the cadmium toxicity with better growth and yield, at harvest.

The presence of cadmium in the soil above a particular level is proposed to check not only plant growth but also productivity and fruit quality. Therefore, in the present study investigations are directed to evaluate the effect of four levels of cadmium (3, 6, 9, 12 mg kg(-1)) in interaction with two analogs of brassinosteroids on the growth, fruit yield and quality of tomato. Under greenhouse conditions plants were analyzed for antioxidant system activity and photosynthetic assimilation efficiency. Cd stressed plants exhibited poor growth and biological yield. The metal also had a negative impact on the antioxidant system of the resulting fruits. However, the follow up application of BRs (10(-8) M) neutralized the damaging effects of the metal on the plants. (c) 2012 King Saud University. Production and hosting by Elsevier B.V. All rights reserved.

Ten cultivars of tomato were subjected to different cadmium (Cd2+) concentrations, to find out their degree of tolerance towards these metal ions during the tomato ontogeny. Seeds of tomato cultivars (i.e. `K-25', 'K-21', 'NTS-9', 'Kaveri', 'NBR-Uday', 'Swarnodya', 'Sarvodya', 'NBR-Uttam', 'Malti' and 'S-22') were soaked in 0, 50, 100 or 150 mu M of Cd2+ for 0, 4, 8 or 12 h. Despite substantial varietal differences, increases in Cd2+ concentration and the soaking duration caused a linear decrease in growth and a reduced activity of catalase and peroxidase for all varieties. Variety 'K-25' was found to be the most resistant cultivar as it possessed maximum activity of antioxidative enzymes reflecting one of the possible reasons to overcome stress conditions. However, the seeds of 'S-22' could not germinate in the presence of even the lowest Cd2+ concentration.

Seeds of five wheat ( Triticum aestivum ) cultivars (PBW-373, UP-2338, DL-LOK-01, DL-373, and HD-2338) were sown in earthen pots and 10-day-old seedlings were exposed to 0, 50, and 100 μM of nickel (Ni) in the form of nickel chloride. At the 20-day stage, seedlings were sprayed with 0.01 μM of 28-homobrassinolide (HBL). The results of the experiment at the 30-day stage revealed a decline in the dry mass per plant, leaf area, leaf water potential, and net photosynthetic rate with concomitant decline in the activities of various enzymes (viz . carbonic anhydrase and nitrate reductase) with an increasing concentration of Ni. However, an increase in proline content and the activities of catalase, peroxidase, and superoxide dismutase was observed as a result of an increase in Ni concentration. Moreover, the treatment of these stressed plants with HBL enhanced the activities of carbonic anhydrase and nitrate reductase, catalase, peroxidase, and superoxide dismutase. The proline content in the leaves also increased, which is known to act as an osmolyte and reactive oxygen species scavenger. The toxic effects generated by Ni were ameliorated by HBL through an improved antioxidant system and osmolyte. Moreover, improvement of photosynthetic parameters and growth characteristics further strengthen our belief that HBL acted as a potent stress alleviator.

Cobalt (Co) affords both beneficial as well as toxic effects to plants. The present study was performed with an aim to find out the varietal differences among five tomato cultivars against the Co induced changes in growth, photosynthesis, nitrate reductase (E.C.1.6.6.1), carbonic anhydrase (E.C.4.2.1.1), antioxidative enzymes i.e. peroxidase (E.C.1.11.1.7), catalase (E.C.1.11.1.6), superoxide dismutase (E.C.1.15.1.1) and that of proline content. Seeds of tomato (varieties, K-25, NTS-9, NBR-Uday, Sarvodya, and Malti) were soaked in 0, 100, 200 or 300 µM CoCl2 for 0, 4, 8, 12 h (shotgun approach) and sampled at 30 days after sowing. All the varieties showed significantly different response to different treatment combinations. Despite substantial varietal difference, increased Co concentration caused concomitant decrease in growth, photosynthesis and the activity of nitrate reductase and carbonic anhydrase. However, the activity of antioxidant enzymes and that of proline content increased with the increased concentration of Co as well as duration of soaking in all the varieties. Out of the varieties, K-25 possessed maximum antioxidative enzyme and proline content that represent its most resistant nature against the toxic effect of Co. The order of susceptibility/sensitivity was K-25 > NTS-9 > NBR-Uday > Sarvodya > Malti.

The present study was conducted with an aim to gain better insight of brassinosteroid generated response on the effects of cadmium on photosynthetic machinery and active oxygen metabolism in two tomato cultivars (K-25 and Sarvodya). These tomato cultivars were subjected to graded cadmium levels in soil (0, 3, 6, 9 or 12mgkg−1 soil) with their foliage being sprayed with 0 or 10−8M of 28-homobrassinolide/24-epibrassinolide (HBL/EBL) at 59d stage. The results suggested that photosynthetic parameters, leaf water potential and activity of several enzymes (nitrate reductase and carbonic anhydrase) decreased significantly in both the cultivars, to a lesser extent in K-25 than Sarvodya with the increasing levels of cadmium in the soil. However, the activity of antioxidant enzymes and proline content increased in response to metal treatment as well as the application of brassinosteroids (HBL/EBL). Overall, exogenous application of brassinosteroids improved the activity of photosynthetic machinery and that of antioxidant defense system in both the cultivars, and also nullified the damaging effect of metal on these parameters.

Ten-days-old seedlings of mung bean (Vigna radiata cv. ‘T-44’) were exposed to salicylic acid (SA) and/or temperature and/or NaCl stresses. The treated seedlings were sampled at 18 days after sowing (DAS) to assess the change in growth pattern, photosynthetic attributes, quantum yield of PSII (Fv/Fm), activity of antioxidative enzymes i.e. peroxidase (POX), catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR) and the activity of nitrate reductase and carbonic anhydrase. The plants exposed to temperature and/or saline stress exhibited a reduction in growth, photosynthesis, and the activity of nitrate reductase and carbonic anhydrase. However, treatment with SA both in the presence or absence of stresses significantly improved the values for the above mentioned parameters. Moreover, the activities of antioxidative enzymes and proline content increased in response to both SA and the stress(s). The interaction of salinity and temperature stress with SA treatment had an additive effect enhancing significantly the values by 107.3% (POX), 37.2% (CAT), 37.5% (SOD), 55.3% (GR) and 65.3% (proline content) over control. SA treatment significantly affected the membrane stability index (MSI) under stressed as well as unstressed conditions resulting in a significant enhancement, 27% more than the MSI of plants exposed to a combined temperature and salinity stress. It may therefore be concluded that SA plays an important role in signaling pathways of plants leading to resistance against temperature and/or salinity stresses. _____________________________________________________________________________________________________________