Inappropriate fertilization and poor management practices in citrus orchards can cause soil acidification, which may result in potential proton (H+) toxicity to citrus roots. It has been reported that boron (B) can mediate H+ detoxification in citrus; however, the mechanisms remain limited. Herein, a hydroponic experiment was employed to unravel the alleviation mechanism of B on H+ toxicity at pH 4 in trifoliate (Poncirus trifoliate (L.) Raf.) seedlings. H+ toxicity reduced cytoplasmic pH from 7.2 (control) to 6.9 and vacuolar pH from 5.6 (control) to 5.4. This severely damaged the plasma membrane (PM) and inhibited root activity by 35%. However, B supplementation restored cytoplasmic pH to 7.1 and vacuolar pH to 5.6, enhancing root activity by 52% and reducing membrane permeability (relative conductivity decreased by 28%). Mechanistically, B upregulated phosphorylated-type adenosine triphosphatase activity by 14%; conversely, it suppressed vacuolar-type adenosine triphosphatase hyperactivity by 9% to stabilize vacuolar pH. Furthermore, B restored PM integrity by increasing phospholipid (40%), glycolipid (50%) and sulfhydryl group (28%) content, critical for membrane structure and function. It is concluded that B can alleviate root growth inhibition induced by H+ toxicity via increasing the content of key components of PM, which not only repairs the damaged PM but also maintains cellular pH homeostasis through enzyme regulation. The improvement of citrus growth correspondingly safeguards the production capacity.

Cadmium (Cd) is a hazardous trace contaminant that naturally occurs in soil and poses a global concern due to its severe impacts on human health and ecological security. In plants, tremendous efforts have been made to use some cost-effective, non-toxic, and organically made key growth regulators that partake in coping plants against adverse environmental conditions. However, the role of sorghum water extract (SWE) in attenuating the noxious effect of Cd stress is still limited in various crops including maize. In this study, different growth attributes, and physiological and biochemical indices of Cd-exposed (0, and 500 mu M) maize plants were analyzed to confirm the protective role of SWE at different concentrations (0%, 2.5%, 5%, 7.5%, and 10%). However, Cd application decreased maize growth such as plant length, number of leaves, number of roots, leaf area and biomass, and deteriorated the photosynthetic pigments such as carotenoids, chlorophyll a and b contents, decreased nutrient uptake, especially calcium and potassium ions and increased reactive oxygen species such as hydrogen peroxide. Though, medium supplementation of SWE at 10% level followed by 7.5% improved plant growth indices (plant length, number of leaves, number of roots, leaf area and biomass), nutrient uptake (calcium, potassium, nitrate, phosphate, and sulfate) and defense responses (ascorbic acid, phenolics, flavonoids) that can be attributed to enhanced physiological functioning and hermetic responses of maize plants to potential allelochemicals present in SWE. The present research highlights that the integration of these allelochemicals can be a promising approach in the future for sustainable agriculture and for keeping the environment safe at low costs.

Salt stress is a relative concept, excessive sodium ions can inhibit the normal growth and development of mulberry seedlings through osmotic stress, oxidative damage and ion imbalance. Calcium as a second messenger to regulate the process. Therefore, calcium should also be taken seriously in experimental design. The experiment was conducted by setting different salt concentrations (0, 50, 200 mmol L- 1) and exogenous calcium contents (0, 2.5, 5, 10, 20 mmol L- 1) on mulberry seedlings in hydroponics. The effects of exogenous calcium on nutrient accumulation, distribution and stoichiometric characteristics of mulberry seedlings under salt stress were studied. Results showed that salt stress reduced mulberry growth, but exogenous calcium reversed this effect, when the concentration of exogenous calcium was 10 mmol L- 1 the biomass and nutrient accumulation of mulberry seedlings could reach the maximum, and there are significant differences with other treatments (p < 0.05). And salt stress shifted the calcium absorption focus from leaves to trunks. Exogenous calcium mitigation on mulberry stoichiometry under salt stress shows initial decrease then increase, the N: P ratio showed that salt treatment could change the P stress to N stress in mulberry seedlings. Meanwhile, there was a significant positive correlation between the biomass of each organ with C: P and N: P (p < 0.01, 0.001), but a extremely significant negative correlation between the biomass with others stoichiometric ratios (p < 0.001). According to the results of leaf stoichiometric ratio and correlation analysis, the optimum application amount of exogenous calcium in mulberry seedlings under salt stress was 10 mmol L- 1. This research offers a theoretical foundation for salt-alkali soil fertilization and has significant implications for soil salinization management.

Nitrogen deposition and drought significantly influence plant growth and soil physicochemical properties. This study investigates the effects of nitrogen deposition and water stress on the growth and physiological responses of Quercus dentata, and how these factors interact to influence the overall productivity. Two-year-old potted seedlings were selected to simulate nitrogen deposition and water stress. Nitrogen was applied at rates of 0 kgha-1year-1 (N0) and 150 kgha-1year-1 (N150). The levels of water stress corresponded to 80% (W80), 50% (W50), and 20% (W20) of soil saturation moisture content. High nitrogen (N150) significantly increased stem elongation and stem diameter by enhancing photosynthetic parameters, including P n (W80) and G s (W50), and maintained higher water use efficiency. Under drought conditions, nitrogen enhanced leaf water content, stabilized electrical conductivity, regulated antioxidant enzyme activity, and increased the accumulation of proline. However, under severe drought, nitrogen did not significantly improve biomass, highlighting the critical role of water availability. Additionally, increased nitrogen levels enhanced soil enzyme activity, facilitated the uptake of crucial nutrients like K and Zn. Mantel tests indicated significant correlations between soil enzyme activity, water use efficiency, and leaf Fe content, suggesting that nitrogen deposition altered nutrient uptake strategies in Q. dentata to sustain normal photosynthetic capacity under water stress. This study demonstrates that nitrogen deposition substantially enhances the growth and physiological resilience of Q. dentata under W50 by optimizing photosynthetic efficiency, water use efficiency, and nutrient uptake. However, the efficacy of nitrogen is highly dependent on water availability, highlighting the necessity of integrated nutrient and water management for plant growth.

In China, high copper (Cu) and low organic matter often occur in some citrus orchard soils. However, the underlying mechanisms by which humic acid (HA) stimulates growth and mitigates Cu toxicity of citrus seedlings are unclear. After being treated with 0, 0.1, or 0.5 mM sodium humate and 0.5 or 400 mu M CuCl2 (Cu excess) for 24 weeks, sweet orange [Citrus sinensis (L.) Osbeck cv. Xuegan] seedlings were used to examine the impacts of HA-Cu interactions on seedling growth, nutrient uptake, leaf pigments, and photosynthetic performance that was revealed by chlorophyll a fluorescence transient. Copper excess reduced root, stem, and leaf dry weight (DW) by 42.4%, 65.4%, and 61.6%, respectively at 0 mM HA, and by 17.3%, 25.4%, and 31.4%, respectively at 0.5 mM HA; and that the levels of Cu in leaves, stems, and roots declined with elevating HA supply. Copper excess caused some rotten and dead fibrous roots at 0 mM HA, but not at 0.5 mM HA. Adding HA lowered Cu uptake per root DW (UPR), the levels of Cu in leaves, stems, and roots, and the competition of Cu2+ with Mg2+ and Fe2+, and therefore mitigated root impairment caused by Cu excess. The HA-mediated alleviation of root damage caused by Cu excess increased the uptake per plant and UPR of nitrogen, potassium, magnesium, phosphorus, calcium, sulfur, boron, and manganese, and therefore alleviated Cu excess-induced decline in seedling growth, impairment to leaf photosynthetic electron transport chains, and decrease in leaf pigments. For 0.5 mu M Cu-treated seedlings, adding HA promoted seedling growth by improving root nutrient uptake and leaf photosynthetic performance. Cu excess aggravated the impacts of HA supplementation on seedling growth, leaf photosynthetic performance, and root nutrient uptake.

Root knot nematode (RKN), Meloidogyne incognita, , is considered a major soil-borne pathogen that can cause severe yield losses for vegetables and diverse crops. Usually, reducing of M. incognita damage is mainly relies on the application of nematicides and good agricultural practices. However, the use of synthetic nematicides is restricted due to concerns about their impact on the environment and human health. As a result, the use of alternative strategies is becoming necessary to combat RKN resistance. This study evaluates the antagonistic impact of the root mutualistic fungus Piriformospora indica on M. incognita. . It also assesses its influence on the nutritional status, photo-synthesis, antioxidant enzyme activity, endogenous abscisic acid (ABA) levels, and selected ABA related-responsive genes in cucumber plants. Roots of cucumber seedlings were inoculated with P. indica and the second-stage juveniles (1000 J2 per plant). The results demonstrated that P. indica significantly reduced M. incognita invasion in roots, resulting in a 24% reduction in root galling and 42.6% decline in final population. Inoculating plants with both P. indica and RKN increased performance of root fresh and dry weight, as well as improved photochemical efficiency of PSII (Fv/Fm), photosystem II efficiency (PSII), catalase (CAT), peroxidase (POD), and superoxide dis-mutase (SOD). Furthermore, P. indica colonization, either alone or in combination with M. incognita, , significantly improved number of fruits per plant, average fruit weight, the plant's marketable yield, and leaf nutrient content (N, P, K and Mg), Moreover, there was an increase in IAA content combined with a decrease in ABA content in roots of dual inoculation plants, if compared to M. incognita infested plants. The highest ABA content was recorded in the root of RKN-cucumber plants. The decline in ABA content due to P. indica treatment was consistent with the modulation of ABA pathway genes, specifically PP2C, PYL1, RK2,1, and RK2,2. The mixed of P. indica and M. incognita led to a decrease in the expression of PP2C, PLY1, RK2,1, and RK2,2 in comparison to the control group. These results indicate that P. indica application could help reduce the negative effects of RKN on important crops.

Context: Arbuscular mycorrhizal fungi (AMF) have been extensively applied as biofertilizers in wheat to promote crop productivity. However, variability in AM root colonization, grain yield, and nutrients was observed among wheat genotypes and according to AM genotype and environment. Objectives: We hypothesized that wheat response to AM inoculation is more affected by genotype than environment; the response is driven by increases in AM abundance and community structure changes, and not by modification of composition. Methods: We inoculated an indigenous AM consortium on four old genotypes (Bianco Nostrale, Andriolo, Abbondanza, Sieve) and one modern variety (Bologna) of bread wheat for two years. The effect was evaluated by assessing grain yield, nutrients, and quality of processed products (flour and breadsticks), while the AM abundance and the community composition and structure in roots were characterized, at two plant growth stages, using morphological and molecular tools. Results: The functional traits of AMF and plant were better explained by inoculation than by genotype or environment (33 %, 17 %, 4 % of total explained variance), although significant interactions environment x genotype and genotype x inoculation were highlighted. Consistent increases in AM abundance in Sieve and Bologna were associated with positive changes in grain yield and nutrients, supporting the good responsiveness of these genotypes with inoculated AMF, while the plant response of other genotypes was shaped by air temperature and rainfall. However, we did not find significant correlations between changes in AM colonization and mycorrhizal response ratio, with the exception of P and K. After inoculation, AM community composition was similar in all wheat genotypes, but the structure greatly differed among genotypes in interaction with inoculation and plant growth stage. These changes were significantly related to wheat productivity. A Septoglomus taxon, present in the inoculum, was the best predictor of wheat performance. The characterization of the community structure at early crop development and maturity allowed the identification of fast and latest active AM colonizers. Our results showed for the first time that AM inoculation affect the rheological parameters and nutraceuticals of processed products, although the response was modulated by genotype. Conclusions: The selection of responsive wheat genotypes is fundamental for the positive outcome of inoculation. The positive effects on wheat productivity and field persistence of the inoculated AMF support the use of indigenous consortia that have low impacts on resident AMF. Significance: Our findings advance the understanding of the facilitative mechanisms that underlie compatibility between AMF and wheat genotypes.

With the rapid population explosion, the demand for food sources will continue to rise. The use of chemical fertilizers in disproportionate quantities to meet the food demand has caused nutrient imbalances and losses in the soil. Using chemical fertilizer excessively often finds its way to water resources and leads to water pollution. Hence, alternative measures must be adopted to achieve sustainable agricultural production systems rather than the conventional practice of chemical fertilization. In this context, applying nanoformulation and/or nanofertilizer draws attention to its ability to improve crop production and fertilizer use efficiency without causing damage to the environment. Nano-inorganic and nano-organic fertilizers help to transport nutrients gradually in a sustainable way at a specific dose to the crops, thereby enhancing the rate of nutrient absorption by the crop plants. Many reports indicate that using nanofertilizer has reduced nutrient (e.g., P, Zn) acquisition by crops in deficient soils. In this review, the recent advances in nanoformulations as fertilizers are highlighted. It focuses mainly on applying nano-macronutrients, nano-micronutrients, nano-biofertilizer, nano-vermicompost, and nanobiochar in different crops for yield and growth enhancement, better nutrient use efficiency, and sustainability of soil health. The potential additional benefits and precise concerns are also discussed for sustainable agricultural production.

Aim: To determine the optimum level of phosphorus for higher yield and phosphorus uptake by groundnut at different planting densities. Methodology: A field experiment was laid out in randomized block design with factorial concept during Rabi seaon 2019-20 to study the phosphorus uptake by groundnut under high density plantation (22.5 x 10 cm - 4.44 lakh ha(-1) ; 20 x 7.5 cm - 6.66 lakh ha(-1) ; 22.5 x 5 cm - 8.88 lakh ha(-1) with graded levels of phosphorus (25, 37.5, 50 and 62.5 kg P2O5 ha(-1) ). Results: The present study revealed that 4.44 lakh ha registered lower phosphorus uptake and application of 62.5 kg P2O5 ha recorded a higher uptake of phosphorus and soil available nitrogen, phosphorus, and potassium. Interaction was significant only in influencing pod yield. Higher pod yield was recorded in the population density of 4.44 lakh ha applied along with 50 kg P2O5 ha , followed by 6.66 lakh ha applied with 62.5 kg P O ha(-1) . Interpretation: The results indicate that for better nutrient uptake and higher pod yield of groundnut, farmers should prefer a planting density of 6.66 lakh ha(-1) with an application of 62.5 kg P2O5 ha(-1) .

Plant growth-promoting rhizosphere bacteria (PGPR) are increasingly considered as highly efficient bioagents. They confer for instance better salt tolerance to host plants while improving soil enzyme activities and microbiome diversity, which are indicators of soil biological health and fertility. Here, the aim was to investigate the efficiency of native bacteria from saline rhizosphere of Hordeum marinum, in alleviating the adverse effects of salinity in this facultative halophyte with fodder potential. Following identification and characterization for salt tolerance capacity and in vitro plant growth promoting potential, the bacteria strain Bacillus pumilus, was selected for its ameliorative effects on H. marinum when cultivated under NaCl salinity (200 mM) in a greenhouse experiment. Salinity significantly restricted growth, induced oxidative stress and disturbed the mineral nutrition of H. marinum, whereas inoculation with B. pumilus significantly restored growth, as leaf elongation rate and plant dry weight. Similarly, the highest accumulation of K+, N and P were observed in inoculated plants challenged with salinity. This was concomitant with reduced MDA and H2O2 levels, thereby preventing oxidative damage in H. marinum plants cultivated under salt stress. Furthermore, B. pumilus strain also overcame salt impact via indirect mechanisms by activating soil enzymes (dehydrogenase, beta-glucosidase and acid phosphatase) and microbial biomass C production. Overall, our data further highlight the environmental significance of microorganisms inhabiting extreme environments like sabkhas as promising agents for biological approaches aiming at saline soil rehabilitation and improving plant productivity when challenged with salinity, due to their beneficial effect on both plant and the rhizosphere.