Background

The expansive usage of metal oxide nanoparticles (NPs) as a potential constituent in modern nano-enabled products raises threats to environmental safety and crop production. Key lime is an economic plant enriched with secondary metabolites and imperative bioactive compounds. NPs can alter lime’s essential components, making it an ideal model for monitoring NPs’ toxicity. Hence, a comparative analysis of two synthesized metallic NPs, aluminum (Al2O3) and copper (CuO) at concentrations of 0, 100, 200, and 500 mg/L, was conducted to assess their impact on the growth and quality attributes of lime plants under controlled micro-conditions.

Results

Observations from germination, growth, physiological, biochemical, and ionomic attributes showed that Al2O3-NPs had variable effects in a concentration-dependent manner, while CuO-NPs were toxic at all concentrations. Heatmap and principal component analysis revealed that CuO-NPs instigated more pronounced toxic effects compared with Al2O3-NPs at each applied concentration, as evidenced by heightened oxidative stress symptoms. CuO-NPs exerted their toxicity by over-accumulating reactive oxygen radicals and methylglyoxal and elevating lipoxygenase activity, causing peroxidation of membrane lipids and attenuation of photosynthetic pigments. Al2O3-NPs-treated plants relatively up-regulated the pool of phenolics, flavonoids, anthocyanins, ascorbic acid, and α-tocopherol as well as stimulated the activity of enzymatic antioxidants. Ionomics analysis showed excessive copper accumulation in toxic levels (~ 15-fold), which triggered nutritional imbalance (Mg, Si, P, S, Cl, K, Ca, Fe, Cu, and Zn) and disruption of chelating molecules, nitric oxide, and hydrogen sulfide.

Conclusions

This work provides precious insights into the differential impacts of metallic NPs on the development and quality of lime plants and the underlying mechanisms involved in NPs accumulation, highlighting the possible hazards of manufactured NPs in the environment, especially for valuable plant species. However, the controlled use of NPs—particularly aluminum oxide—may offer agronomic benefits, but their application must be carefully handled to prevent toxicity.

Aluminum (Al) toxicity exhibits a challenge for growing strawberries (Fragaria x ananassa Duch), impacting their growth and nutritional value. Considerably in this study, we explored how melatonin, an endogenous plant hormone, can help alleviate Al stress in strawberry plants. The current research examined the effects of foliar spraying melatonin (0,50, and 100 ppm) on growth indicators, photosynthetic pigment levels, carbon and nitrogen assimilation, oxidative stress markers, and fruit quality attributes under Al stress (100 µM) in a controlled pot experiment conducted in a greenhouse. The results revealed that exposure to Al stress significantly reduced the adequate growth, as well as the yield and quality of fruits. Melatonin application improved plant growth parameters, especially at a concentration of 100 ppm, enhancing the levels of photosynthetic pigments and boosting carbohydrate and nitrogen metabolism. Moreover, melatonin played a role in reducing stress markers while increasing enzymatic antioxidant activities (catalase, superoxide dismutase, ascorbate peroxidase, glutathione peroxide, glutathione-S-transferase, and phenylalanine ammonia-lyase) and secondary metabolites (proline, ascorbic acid, flavonoids, reduced glutathione, and phytochelatins), while decreasing polyphenol oxidase activity as well as phenolics content, implying a role in ROS scavenging. The results underscore the promise of melatonin as a method to enhance the ability of strawberries to withstand Al toxicity and promote friendly agricultural practices in polluted soils.

This study aimed to characterize the bioactive compounds in Elaeagnus conferta Roxb. leaf extract using UPLC-QTOF-
MS
and subsequently assess its anti-obesity
effects in a murine model. The methanolic extract of Elaeagnus conferta leaves was
analyzed, identifying 13 bioactive compounds, including flavones (rutin, kaempferol 3-neohesperidoside,
and spinacetin
3-gentiobioside)
and phenolic acids (caffeic acid 3-O-
glucuronide
and 1-O-
feruloylglucose),
known for their potential anti-obesity
properties. In the in vivo study, male C57BL/6J mice were fed a high-fat
diet (HFD) and supplemented with E. conferta
extract at doses of 150 mg/kg/day and 300 mg/kg/day for 8 weeks. The administration of E. conferta leaf extract significantly
reduced body weight gain in a dose-dependent
manner, with the highest reduction observed at 300 mg/kg/day. The extract also
lowered low-density
lipoprotein cholesterol (LDL-c)
and total cholesterol (TC) while increasing brown adipose tissue (BAT)
formation. Histological analysis revealed a reduction in adipocyte size and lipid accumulation in liver tissues and white adipose
tissues, indicating improved fat metabolism. Moreover, E. conferta extract supplementation led to a significant decrease
in intra-abdominal
and epididymal white adipose tissue weights compared to the HFD group. These findings suggest that
E. conferta leaf extract exerts anti-obesity
effects by modulating lipid metabolism and adipose tissue distribution. This study
provides a scientific basis for the potential application of E. conferta as a functional food ingredient for obesity management.

Water lily (Nymphaea micrantha Guill. & Perr) is an aquatic plant that is well known for its nutritional value and medicinal
uses. The lack of adequate information regarding propagation and farming techniques has led to the low utilization
of this valuable plant. To address the knowledge gap in the use of water lily rhizomes as explants in tissue
culture, in this study, the processes of sterilization, induction, proliferation, and rooting in water lily tissue culture
are examined. Laboratory experiments were conducted to determine the best methods, materials, and concentrations
to develop an ideal method for producing water lily plants. Disinfection with 75% C2H5OH
for 2 min + 0.1%
HgCl2
for 15 min produced the best results, with a contamination rate of 30% and a browning rate of 25%, according
to the data. The results indicated that indole-3-butyric acid (IBA) is the optimal plant growth regulator for the induction
of water lily rhizomes. Medium containing 3 mg L–
1 of 6-BA was most suitable for the induction of water lily
adventitious shoots, with an induction rate of up to 80% and a yield of 2 to 8 shoots. The induction rate of water lily
adventitious shoots approached 80% in medium supplemented with 3 mg L–
1 6-benzylaminopurine (6-BA). The best
medium for inducing root development contained IBA at a concentration of 0.5 mg L–
1, which resulted in rapid root
elongation. The best tissue culture techniques identified in the present study were successful in growing full water
lily plants with good and vigorous growth from tuberous rhizomes to flowering plants. This early success in water lily
tissue culture technology provides crucial technical assistance for ex vitro preservation and water lily seedling growth.
This study offers a workable answer to one of the most significant obstacles preventing the spread of the use of water
lily culture by outlining a good technique that results in robust and healthy seedlings, which helps lower the cost
of cultivation.

The quality of green tea is influenced by soil microbes in addition to soil conditions and the Camellia sinensis cultivar.
Arbuscular mycorrhizal (AM) fungi can significantly improve soil quality and crop productivity; however, the specific AM
fungal groups that affect the catechin quality index (CQI) of green tea are not yet clear. In the present study, rhizosphere
soil samples, root samples, and fresh tea leaves from six different Camellia sinensis cultivars in Hunan Province, China,
were collected. The taxonomic diversity and community composition of AM fungi in the rhizosphere soil and roots were
investigated using high-throughput Illumina amplicon sequencing technology, and the mycorrhizal colonization rate was
assessed. The two main AM fungal genera in the Camellia sinensis roots and rhizosphere were Paraglomus and Glomus.
A higher catechin quality index (HCQI) is correlated with greater accumulation of Paraglomus in the roots of Camellia
sinensis. The tea cultivar and the available phosphorus content in the rhizosphere soil significantly affected the mycorrhizal
colonization rate and the composition of the AM fungal community within the roots. The mycorrhizal colonization rate
affected the catechin composition, consequently influencing the CQI of green tea. Furthermore, fluctuations in the proportional
presence of Paraglomus and Glomus within the roots of Camellia sinensis notably affected the CQI. In summary,
increased mycorrhizal colonization and increased prevalence of Paraglomus substantially increase the CQI of green tea.
These findings have significant implications for the application of AM fungi in the production of high-quality green tea.

Tropical rainforest soils, or latosols, are distinguished by their low pH and low fertility. In orchards, co-cultivating
grass has become popular as a way to improve soil quality and boost fruit production. Nevertheless, insufficient
information is currently available about the response of soil microbial communities in tropical rainforest orchards to
grass co-cultivation. Therefore, the present research investigates the effect of grass cultivation on the soil properties
and microbial diversity of guava (Psidium guajava L. cv Pearl) latosol orchards. Two varieties of the tropical legume
grass Stylosanthes guianensis, i.e., Reyan No. 2 and Ubon, were studied, besides the control (CK), which is without
any grass, and the natural grasses treatment (N). The study contained four treatments, i.e., S. guianensis cv. Reyan
No. 2, S. guianensis cv. Ubon, CK, and N. Soil samples from the top layer (0–20 cm) and subsoil layer (20–40 cm)
were collected to follow the changes in soil microbial biodiversity based on 16 S rDNA analysis. A total of 17,231
kinds of OTUs (Operational Taxonomic Units) were obtained, including 17,165 kinds of bacteria and 66 kinds of
Archaea. S. guianensis cv. The Ubon variety, natural grasses, and CK treatments significantly increased the soil
microbial richness and evenness in the topsoil layer compared to Reyan No. 2 variety. The β-diversity of soil
microbial community was significantly reduced in the natural grasses and Ubon variety treatments at the topsoil
layer compared to CK treatment. In the subsoil layer, natural grasses, Reyan No. 2, and Ubon treatments significantly
increased the soil microbial community based on β-diversity. The presence of natural grasses caused 49% and 42%
increases in the SOC in the top and subsoil layers, respectively, as well as remarkable increases in the available and
total soil nitrogen. The grass intercropping enhanced the levels of soil carbon and nitrogen and altered the nature of the soil’s microbial community. The diversity of soil microorganisms in the subsoil layer is significantly altered by
the shallow root systems of tropical legume and natural grasses, which have most of their roots concentrated in
the top soil layer. Overall, growing grass in tropical orchards benefits the latosolic soil microorganisms, which has
enhanced the theoretical underpinnings for using grass to improve the soil quality in latosols orchards.

Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (FOC), remains a major
constraint to global banana (Musa spp.) production, especially in tropical regions. Although
soil conditions are known to modulate disease expression, the specific physicochemical
drivers of FOC prevalence under field conditions are not well understood. This study
investigated the relationships between soil properties and the Fusarium wilt incidence
across 47 banana farms on Hainan Island, China, a tropical region dominated by highly
weathered tropical soil (latosols). The disease incidence (%PDI) and FOC abundance
were quantified, alongside key soil parameters, including the pH, organic carbon, cation
exchange capacity, and macro- and micronutrient availability. The soils were predominantly
acidic (mean pH 4.93), with low levels of organic carbon and exchangeable calcium (Ca)
and elevated levels of available phosphorus (P), potassium (K), and magnesium (Mg). The
Fusarium wilt incidence ranged from 1% to 78%, with significantly higher levels observed in
younger plantations (<5 years old). Statistical analyses revealed strong negative correlations
between the PDI and the soil pH, exchangeable Ca and Mg, and available K. Principal
component analysis further confirmed the suppressive role of the pH and base cations in
the disease dynamics. Farms older than five years exhibited better soil fertility indices
and lower disease pressure, suggesting a temporal improvement in soil-mediated disease
suppression. These findings underscore the critical role of soil acidification and nutrient
imbalances, particularly Ca, Mg, and K deficiencies, in promoting FOC pathogenicity.
Enhancing soil health offers a promising and sustainable strategy for managing Fusarium
wilt in tropical banana production systems

Sustainable water stress management in arid and semi-arid regions requires precise understanding of soil-plant interactions
when implementing biochar-based strategies. This study developed an Artificial Neural Networks (ANN) model to
predict mango productivity under drought conditions using potassium-enriched biochar (KEB), addressing a significant
knowledge gap in biochar application modeling. KEB was made by pyrolyzing a maize straw–banana peel mix (1:3)
at 500 °C for 3 h. A two-year field experiment evaluated four potassium sources, i.e., C (control), KS (K₂SO₄), KEB
(potassium-enriched biochar), and KF (potassium feldspar), under two irrigation regimes representing 80% (normal) and
50% (drought) of available soil moisture. Potassium release patterns between KEB and KS (R2 = 0.83–0.97), both superior
to other treatments. Drought stress significantly impaired soil quality, reducing mango fruit yield by 20% and decreasing
soil microbial biomass carbon (MBC) and dehydrogenase enzyme activity by 22% and 14%, respectively. However, KEB
application enhanced soil quality under water stress by improving MBC, dehydrogenase enzyme activity, and soil organic
carbon (SOC), resulting in an 82% yield increase. KEB treatment also elevated chlorophyll content, proline levels, and
soluble carbohydrates, enhancing drought tolerance through improved osmotic adjustment in mango leaves. ANN modeling
identified optimal conditions for maximizing fruit yield, with 125% KEB application providing the best results. The
model established critical threshold values: SOC (3.1 g kg− 1), MBC (365.66 mg kg− 1), chlorophyll (3.7 mg kg− 1), soluble
carbohydrates (38.25 mg kg− 1), and phosphorus (2.78 mg kg− 1). These findings highlight the dual role of KEB as a sustainable
soil amendment and the utility of ANN as a decision-support tool for precision agriculture. Integrating KEB with
intelligent modeling approaches offers a promising strategy for improving resilience and productivity in mango orchards
under water-limited conditions.

Soil organic carbon (SOC), the largest terrestrial organic carbon stored on land, plays a crucial role in regulating climate via soil carbon sequestration. Soil carbon sequestration, also known as “carbon farming” or “regenerative agriculture,” refers to various practices that manage land, especially farmland, to increase the amount of carbon stored in soils. In the soil, SOC acts as a major carbon sink by absorbing and storing atmospheric CO₂. Approximately 1,550 gigatons of organic carbon are stored in soils, accounting for about 73% of the estimated 2,110 gigatons of organic carbon in the biosphere. Also a vital component of land ecosystems, it significantly influences soil fertility, structure, and overall ecosystem health. Carbon sequestration can affect the mitigation of climate change, soil health and productivity, food security, and ecosystem services. The dynamics of SOC are regulated by the balance between inputs, including plant residues, root exudates, and microbial activity, and outputs, such as decomposition and mineralization processes These processes are governed by physical, chemical, and biological mechanisms. It also affected agricultural management like conservation tillage, crop rotation, cover crops, organic amendments (manure, compost, and biochar), and agroforestry systems. Measuring SOC is challenging due to factors like spatial variability, temporal variation, and sampling depth. Therefore, using modeling to understand and quantify soil carbon sequestration is vital for sustaining agricultural systems and directing climate policy.

Soil acidification and carbon sequestration are central challenges for sustainable agriculture, particularly across China’s extensive acidic red soil regions, which comprise 32.4% of the national soil area. This study evaluated the long-term effects of straw and manure incorporation on aluminum (Al) and iron (Fe) oxide fractions, soil organic carbon (SOC) sequestration, and crop yield in acidic red upland soil. A 33-year field experiment was conducted with four treatments: no fertilizer (CK), chemical fertilizer (NPK), NPK plus straw (NPKS), and NPK plus manure (NPKM). Soil samples were collected from three depths (0–10, 10–20, and 20–30 cm), and Al and Fe oxide fractions were quantified. Relationships among Al/Fe fractions, soil pH, and SOC were assessed using ANOVA, Pearson’s correlation, and Redundancy Analysis (RDA). Compared with CK, NPKM increased reactive Al (Alo) by 43.84%, 42.94%, and 43.06% and reactive Fe (Feo) by 132.98%, 91.54%, and 55.75% at 0–10, 10–20, and 20–30 cm, respectively. The highest carbon sequestration rate (0.21 t ha⁻¹ year⁻¹) occurred under NPKM in the 0–10 cm depth. Strong positive relationships were observed between reactive/non-crystalline Al and Fe oxides and both SOC sequestration and crop yield, particularly within the 0–20 cm depth, while SOC stock and CSR declined with depth across all treatments. These results highlight the critical role of manure in alleviating soil acidity, enhancing SOC stabilization capacity, and increasing crop productivity in acidic red upland soils. Overall, integrating organic amendments such as manure and straw substantially improves SOC accumulation and supports sustainable agricultural management in acidic red soils.