Search Results (299)

Argania spinosa L. Skeels is an ecological pillar of the arid zones of South-West Morocco, currently threatened by the drastic climate change. This study investigates the effect of the combined application of compost (C) and subsurface water retention technology (SWRT) on field performances of one-(1Y) and two-year-old (2Y) argan seedlings. A randomized field trial was performed with four treatments: Control, C, SWRT, and C + SWRT. We evaluated soil properties, growth, and physiology, alongside biochemical parameters including stress markers, compatible solutes, antioxidant enzyme activities, and secondary metabolites. The results reveal the significant effect of C and/or SWRT on argan seedlings performances, particularly in 1Y subjects. The C + SWRT strongly stimulated stem elongation (246% vs. 163%), stomatal conductance (75% vs. 99%), photosynthetic efficiency (18% vs. 11%), and chlorophyll a content (80% vs. 65%) in 1Y and 2Y seedlings, respectively, compared to their corresponding controls. Under the same treatment, malondialdehyde levels were significantly reduced by 37% in 1Y seedlings and 23% in 2Y seedlings. In addition, catalase activity and soluble sugar, protein, and polyphenol content increased by 38, 43, 26, and 21%, respectively, in the younger seedlings and by 53, 51, 18, and 19%, respectively, in the elder seedlings. In terms of soil health, C + SWRT significantly enhanced total organic carbon and matter, available phosphorus, and reduced electrical conductivity. In summary, the C + SWRT application significantly improved argan plant performances, with a particularly marked effect on 1Y seedlings, which makes this combination an alternative solution to enhance the resilience of the argan tree in the era of climate change and promote the success of the reforestation program. Full article

To further improve the prediction accuracy for greenhouse crop evapotranspiration (ET) under different irrigation conditions and enhance irrigation water use efficiency, this study proposes three methods to revise the Priestley–Taylor (PT) model coefficient α for calculating ET at different growth stages: (1) considering the leaf senescence coefficient f_S, plant temperature constraint parameter f_t, and soil water stress index f_sw to correct α (MPT model); (2) combining the Penman–Monteith (PM) model to inversely calculate α (PT-M model); (3) using the machine learning XGBoost algorithm to optimize α (PT-M_(XGB) model). Accordingly, this study observed the cumulative evaporation (Ep) of a 20 cm standard evaporation pan and set two different irrigation treatments (K0.9: 0.9Ep and K0.5: 0.5Ep). We conducted field measurements of meteorological data inside the greenhouse, tomato physiological and ecological indices, and ET during 2020 and 2021. The above three methods were then used to dynamically simulate greenhouse tomato ET. Results showed the following: (1) In 2020 and 2021, under K0.9 and K0.5 irrigation treatments, the MPT model mean coefficient α for the entire growth stage was 1.27 and 1.26, respectively, while the PT-M model mean coefficient α was 1.31 and 1.30. For both models, α was significantly lower than 1.26 (conventional value) during the seedling stage and the flowering and fruiting stage, rose rapidly during the fruit enlargement stage, and then gradually declined toward 1.26 during the harvest stage. (2) Predicted ET (ET_e) using the PT-M model underestimated the observed ET (ET_m) by 8.71~16.01% during the seedling stage and the harvest stage, and overestimated by 1.62~6.15% during the flowering and fruiting stage and the fruit enlargement stage; the errors compared to ET_m under both irrigation treatments over two years was 0.1~3.3%, with an R² of 0.92~0.96. (3) The PT-M_(XGB) model achieved higher prediction accuracy, with errors compared to ET_m under both irrigation treatments over two years of 0.35~0.65%, and R² above 0.98. The PT-M_(XGB) model combined with the XGBoost algorithm significantly improved prediction accuracy, providing a reference for the precise calculation of greenhouse tomato ET. Full article

Salinity represents a major constraint on plant development and crop productivity in wheat, which represents one of the most critical sources of dietary calories worldwide. Its detrimental effects are particularly pronounced during the early stages of growth, including seed germination and seedling establishment. Salinity tolerance is a multifaceted trait governed by several interrelated mechanisms, notably ion homeostasis, osmotic adjustment, activation of enzymatic antioxidant systems, and transcriptional regulation of ion transporter genes. In the present study, contrasting wheat genotypes exhibiting differential salinity tolerance were selected from a panel of 172 accessions evaluated under salinity stress (175 mM NaCl) and control conditions (0 mM NaCl). The objectives of the current study are to confirm the underlying physiological and molecular mechanisms conferring salinity tolerance. Key physiological and molecular parameters including Na⁺, K⁺, and P homeostasis; activities of major antioxidant enzymes; and expression profiles of the salinity-responsive ion transporter genes TaAVP1 and NHX1 were quantified in six tolerant genotypes and one susceptible genotype. The tolerant genotypes exhibited higher concentrations of Na⁺ and K⁺ and elevated activities of all antioxidant enzymes, compared with the susceptible genotype. Furthermore, the tolerant genotypes showed differential expression of TaAVP1 and NHX1: both genes were upregulated in Javelin 48 and Kandahar, whereas they were downregulated in genotype 1018d. Notably, genotype Kule demonstrated the highest Na⁺ accumulation, accompanied by markedly elevated activities of all major antioxidant enzymes, with ascorbate peroxidase and glutathione reductase increasing by 9.20-fold and 2.32-fold, respectively, under salinity stress. Based on these findings, the tolerant genotypes can be categorized into two functional groups: Javelin 48, Ghati, and 1018d (characterized by high K⁺ and salinity tolerance) are better suited to soils affected by low Na⁺ salinity, whereas Kandahar, Kule, and 1049 (characterized by high Na⁺ and sodicity tolerance) are more adapted to soils with elevated Na⁺ levels. In conclusion, the tolerant genotypes exhibited distinct, coordinated mechanisms to mitigate salinity stress, underscoring the complexity and plasticity of adaptive responses in wheat. Full article

The use of biostimulants has emerged as a promising strategy for enhancing seed vigor, germination, and seedling growth. This is due to the composition of beneficial substances considered as biostimulants that modulate plant physiology and metabolism. In this context, the interest in biostimulants is growing and the use of microalgal extracts is becoming more widespread. This study aims to assess the effect of Chlorococcum sp. aqueous extracts on the germination indices and the biometric and biochemical parameters of sesame (Sesamum indicum L.). Chlorococcum sp. culture exhibited favorable growth characteristics, including high productivity, specific growth rate, and short generation time. Furthermore, analysis of the extract demonstrated that it contains a high concentration of biomolecules, which suggests significant biostimulant potential. Importantly, the results also showed a significant improvement in germination indices as well as in biochemical parameters and photosynthetic pigments in seeds treated with the highest extract concentration (2 g/L). Furthermore, improvement in biometric parameters, including radicle length as well as fresh and dry weight, was observed at low extract concentration (0.1 and 0.5 g/L). Additionally, no phytoinhibitory effects were detected. Overall, the application of microalgal aqueous extract highlights a strong potential as a sustainable and cost-effective alternative to conventional synthetic chemical fertilizers, thereby promoting the development of an environmentally friendly agricultural practice of sesame cultivation. Full article

Soil salinization, characterized by complex ionic compositions, threatens global wheat production. Current research often focuses on single salts, leaving a gap in systematic comparisons of specific salt effects. This study comprehensively evaluated six prevalent salts (NaCl, Na₂SO₄, KCl, NaHCO₃, MgSO₄, and MgCl₂) across concentrations (10–200 mmol/L) during wheat (Triticum aestivum L.) germination. By integrating ten physiological indicators with principal component analysis (PCA), membership function evaluation, and median lethal concentration (LC₅₀) calculation, we identified distinct salt-specific toxicities. Results established a clear toxicity hierarchy: MgCl₂ was consistently most toxic (LC₅₀ = 32.92 mmol/L), indicating Mg²⁺/Cl⁻ synergy, while KCl was least inhibitory (LC₅₀ = 159.66 mmol/L). PCA simplified the 10-trait dataset, extracting 1 principal component (PC, 89.29–92.35% contribution) for most salts (fresh weight as key loading, reflecting growth) and 2 PCs (95.65% cumulative contribution) for MgSO₄ (separating root-growth and germination-vigor responses), thus identifying salt-specific key evaluation traits. Building on this PCA-derived trait screening, this analysis further revealed fresh weight (FW), germination rate (GR), shoot length (SL), and simple vigor index (SVI) as core evaluation indicators, and identified distinct mechanistic pathways: while most salts caused a generalized growth inhibition reflected in biomass reduction, MgCl₂ exerted a more specific and severe inhibitory effect on shoot elongation. MgSO₄ uniquely employed dual pathways, separately affecting root and germination traits. An innovative aspect of this work is the synergistic application of three synergistic evaluation methodologies with multi-physiological parameters, which allows for the rigorous quantitative characterization of distinct salt-specific effects on both early germination and seedling growth in wheat. This laboratory-based study provides a theoretical framework and practical indicators for salt damage risk assessment and preliminary screening of salt-tolerant wheat germplasm and lays a foundation for field validation and targeted management strategies for specific saline–alkali soils. Full article

This research was conducted to investigate effects of biostimulants containing plant growth-promoting rhizobacteria and enriched biosurfactants, which were tested individually and in combination (biostimulant + enriched biosurfactant) on plant growth parameters, physiological and biochemical properties of maize seedlings under different salinity conditions (0, 100, 200 mM NaCl). In the experiment, biostimulant (B: 0.3 g/L), enriched biosurfactant (E-S: 3 mL/L), and their combination (B + E-S) were applied by foliar spray at each NaCl level. Salt stress negatively affected the growth and physiological traits of maize seedlings, while biostimulant and enriched biosurfactant improved these parameters. Under severe salinity stress (200 mM NaCl), the biostimulant, enriched biosurfactant, and their combined application markedly mitigated oxidative and osmotic damage. Compared with the untreated 200 mM NaCl group, these treatments (B, ES, B + ES) reduced proline accumulation by 65%, 52%, and 70%; hydrogen peroxide (H₂O₂) level by 53%, 39%, and 58%; and malondialdehyde (MDA) content by 72%, 50%, and 73%, respectively. These reductions indicate a substantial decrease in oxidative stress and membrane lipid peroxidation. In conclusion, biostimulant and enriched biosurfactant applications may be a promising approach to reduce the negative effects of salinity stress on maize. Full article

Despite increasing environmental concerns, there are few studies on the potential effects of polyethylene and polystyrene microplastics on feed crops. The effects of polyethylene (PE) and polystyrene (PS) microplastics with a diameter of 2 μm at different concentrations (0.1%, 0.5%, 1%, and 5%) (w/w) on the growth and development of oats were analyzed in a pot experiment, with no microplastics added as the Control (Ctrl) group. The results showed that PS microplastics exhibited a spherical morphology, whereas PE microplastics displayed an irregular morphology. PE microplastics had an inhibitory effect on oat growth, chlorophyll content, photosynthetic parameters and antioxidant enzyme activity, and this effect was concentration-dependent; specifically, the inhibitory intensity increased progressively as the concentration of PE microplastics rose. In contrast, treatments involving varying concentrations of PS microplastics elicited distinct effects on the physiological and biochemical parameters of oats. The 0.1% PS microplastics treatment significantly enhanced the net photosynthetic rate of oat leaves (by 14.0%), while the 5% PS microplastics treatment significantly reduced the seedling height (by 31.1%), the total chlorophyll content (by 34.6%), the transpiration rate (by 35.7%), the stomatal conductance (by 71.1%), and the intercellular CO₂ concentration (by 43.1%). Furthermore, a significant decrease in antioxidant enzyme activity was observed in oats after the 5% PE microplastics treatment. The activities of peroxidase (POD), catalase (CAT) and superoxide dismutase (SOD) decreased by 17.1%, 89.2% and 5.6%, respectively. At the same concentration (5%), PE microplastics exhibited a more pronounced inhibitory effect on oats compared to PS microplastics. In summary, this study demonstrates that microplastics impair photosynthesis and antioxidant capacity in oats, thereby inhibiting their normal growth and development. These findings provide a theoretical foundation and supporting data for further research into the toxicity of microplastics to oats. Full article

Cashew (Anacardium occidentale L.), native to northeastern Brazil, holds significant socioeconomic value, but its cultivation is limited by salinity, which is common in semiarid regions. This study evaluates foliar magnesium (Mg) application as a strategy to mitigate salinity stress in cashew seedlings. A greenhouse experiment was conducted with two genotypes (CCP 76 and AT01), two irrigation salinity levels (0.5 and 2.5 dS m⁻¹), and three Mg doses (0, 1, and 2 mL L⁻¹). Salinity reduced growth, physiological parameters, and stomatal conductance. Foliar Mg application, particularly at 1 mL L⁻¹, alleviated these effects by increasing root dry mass, stomatal conductance, internal CO₂ concentration, and intrinsic water-use efficiency, especially in genotype AT01. The 2 mL L⁻¹ dose showed inconsistent responses, suggesting toxicity. Overall, Mg application mitigates salinity effects in cashew, with efficiency dependent on genotype and dose, and AT01 demonstrating greater tolerance. Full article

Root pruning affects the ability of roots of Quercus variabilis Blume to absorb water and nutrients. Suillus grevillea can form a mutualistic symbiosis with Quercus variabilis Blume. A pot experiment in three compartments with two inoculation treatments (inoculation with Suillus grevillea and noninoculation control) and four different root pruning treatments (0, 1/4, 1/3, and 1/2 of the main root length pruned) was conducted. The shoot dry weight, root dry weight, shoot and root N, P and K contents, root morphological and physiological parameters of Quercus variabilis Blume seedlings, and soil properties were measured. The results showed that root pruning affected root endogenous hormone levels, root morphology, shoot and root nutrient absorption, and biomass accumulation. Compared with those without inoculation, the shoot dry weight, root dry weights, shoot and root N, and P and K contents of inoculated plants were greater, regardless of the degree of root pruning. The root length, root projection area, root surface area, root average diameter, root density, root volume, and root tip number increased in response to Suillus grevillea. The root auxin (IAA), cytokinin (CTK), gibberellin (GA), zeatin riboside (ZR), and salicylic acid (SA) contents were greater in inoculated Quercus variabilis Blume seedlings than in noninoculated plants. Inoculation with Suillus grevillea improved the soil microenvironment around the seedlings. Suillus grevillea can compensate for the adverse effects of root pruning on nutrient absorption, root morphological and physiological growth and the soil properties of Quercus variabilis Blume seedlings. Full article

Water stress is among the most important abiotic constraints affecting forest ecosystem functioning and regeneration, a phenomenon expected to intensify with climate change. It impacts photosynthesis, growth, and seedling survival, therefore threatening biodiversity and accelerating forest degradation. The use of silicon-based biostimulants has emerged as a way of mitigating the effects of water stress by improving water status and stimulating mechanical and biochemical defense. However, its effectiveness on forest tree species remains poorly explored. This study examines how potassium silicate (PS) alleviates the effects of drought on Canarium madagascariense, with the aim of improving our understanding of the resilience mechanisms of tropical forest species. To do this, an experiment with 135 two-year-old C. madagascariense saplings has been conducted, testing three irrigation levels in combination with the addition of potassium silicate (PS) at concentrations of 5 and 10 mM, via foliar spraying and soil application. Morphometric and physiological parameters were monitored, followed by the biochemical profiling of the induced responses. Linear mixed models were computed to assess the effects of the different factors on the different growth performance, physiological functioning parameters over time, and ANOVA was used for evaluating the punctual data on the biochemical compounds. Drought had a significant impact on the morphological and physiological behaviour of the seedlings. However, the application of PS modified the drought-induced changes, even at a low concentration of 5 mM. Biochemical defenses were also improved further with PS application. Hormone profiling revealed a predominance of auxins, while abscisic acid was lower in the water stress treatments under drought. Therefore, using PS could support the production of robust seedlings that are more tolerant of, and adaptive to, the challenges of climate change, making restoration more efficient. Full article

Pinus koraiensis, as a keystone tree species, possesses immense economic and ecological value. However, the present cultivation of high-quality seedlings in Pinus koraiensis plantations remains hindered by prohibitively high costs and inadequate technological advancements. Additionally, the species’ prolonged growth cycle and low yield, when compounded by issues such as excessive harvesting, may result in supply constraints. Plant growth regulators (PGRs), a class of naturally occurring or synthetically derived chemical compounds, are capable of modulating plant development and physiology. These regulators exert notable effects by enhancing root proliferation, facilitating lignification, influencing plant architecture, and augmenting yield. Owing to their operational simplicity and relatively low cost, PGR applications hold substantial promise for cultivating Pinus koraiensis seedlings with superior traits. In this study, four-year-old Pinus koraiensis seedlings were employed to evaluate the impacts of three PGRs (paclobutrazol, chlormequat chloride, and diethyl aminoethyl hexanoate), alongside varied application methods (dosage and frequency), on the growth, physiological, and photosynthetic parameters of the seedlings. The findings revealed that treatment with 1.5 g/L paclobutrazol produced the most pronounced effects across a range of indicators. Specifically, this treatment markedly enhanced growth traits (e.g., branch diameter, new shoot length, lateral branch length, aboveground fresh and dry weights, root fresh and dry weights, lateral root dry weight, and number of second-order roots), physiological attributes (e.g., increased superoxide dismutase and peroxidase activities, elevated lignin content, and reduced relative conductivity and malondialdehyde levels), and photosynthetic metrics (e.g., elevated net photosynthetic rate, stomatal conductance, transpiration rate, and maximum net photosynthetic rate), thereby constituting the optimal treatment combination. Full article

Photosynthesis is a primary plant physiological process, which can easily be affected by various environmental factors, including biotic stressors. The exogenous application of different substances like plant growth regulators might benefit this process both under normal and stress conditions. It is well known that the polyamine spermine positively modulates photosynthesis. We evaluated the effects of 5 mM spermine seed priming on photosynthesis-related parameters in wheat (Triticum aestivum L.) plants grown from Fusarium culmorum-infected seeds. Under no stress conditions, the spermine seed priming improved leaf gas exchange, chlorophyll a fluorescence, and leaf pigment content compared to the control. In non-primed seedlings exposed to the pathogen, these parameters were significantly affected. The most substantial reductions were seen in the net photosynthetic rate (56%), transpiration rate (63%), and stomatal conductance (58%). In plants cultivated from seeds primed with spermine the pathogen’s adverse effect on the assessed parameters was mitigated. Our study demonstrates the efficacy of spermine seed priming in sustaining photosynthetic activity in wheat plants exposed to biotic stress induced by Fusarium culmorum. Full article

Phytoremediation utilizing woody plants represents a promising approach for mitigating cadmium (Cd) contamination; however, the potential of ornamental species such as Punica granatum L. (pomegranate) remains insufficiently characterized. This study evaluated the growth performance, physiological responses, and Cd accumulation patterns of pomegranate seedlings exposed to increasing Cd concentrations (T1–T6) in a hydroponic system. High Cd levels (≥T4) markedly suppressed plant growth, as evidenced by reductions in biomass, root necrosis, leaf wilting, and chlorosis. Photosynthetic efficiency was severely compromised, indicated by significant declines in chlorophyll content and key chlorophyll fluorescence parameters (Fv/Fm, ΦPSII, and qP). Simultaneously, increases in the chlorophyll a/b ratio, carotenoid content, and non-photochemical quenching (NPQ) reflected the activation of photoprotective mechanisms. A reduction in stomatal conductance (G_s) and net photosynthetic rate (P_n), coupled with elevated intercellular CO₂ concentration (C_i), suggested that non-stomatal limitations were primarily responsible for photosynthetic inhibition. Cd exposure also triggered oxidative stress, as shown by increased levels of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂). In response, seedlings activated antioxidative and osmotic adjustment pathways, including elevated peroxidase (POD) activity and the accumulation of glutathione (GSH), proline, soluble proteins, and sugars. Notably, pomegranate displayed a root-based Cd sequestration strategy, with high root accumulation (bioconcentration factor, BCF > 271) and minimal translocation to aerial tissues (translocation factor, TF < 0.17). These findings demonstrate that pomegranate seedlings exhibit pronounced tolerance to Cd stress and substantial bioaccumulation capacity, supporting their potential application as ornamental woody species for phytoremediation of Cd-contaminated environments. Full article

The eutrophication of aquatic ecosystems often triggers the excessive growth of cyanobacteria, many of which release toxic metabolites such as microcystins (MCs). When irrigation water is contaminated by these compounds, adverse consequences may arise for plants as well as for animal and human health. In contrast, certain non-toxic cyanobacterial species like Limnospira platensis are increasingly regarded as valuable tools for sustainable agriculture, given their ability to enhance plant nutrition, growth, yield, and stress tolerance while also mitigating the detrimental impacts of MCs. The present work aimed to investigate the potential of L. platensis extract to enhance growth, physiological responses, and tolerance of radish (Raphanus sativus) plants stressed with Microcystis aeruginosa extract containing microcystins. Experiments were conducted in a hydroponic system under controlled environmental conditions, where radish seedlings were cultivated in perlite and exposed for 45 days to M. aeruginosa extract (10 and 40 µg/L of MCs) and L. platensis extract (0.1 and 1 g/L), applied either separately or in combination. The results showed that the application of L. platensis extract, especially at 1 g/L in combination with 40 µg/L of MCs, decreased the bioaccumulation of MCs from 8.81 to 5.35 µg/kg FW in the leaves and from 14.64 to 10.15 µg/kg FW in the taproots. In addition, it significantly stimulated radish growth and improved several biochemical parameters. In contrast, exposure to MCs at 10 and 40 µg/L negatively affected growth, chlorophyll pigments and protein contents while promoting the accumulation of malondialdehyde (MDA), polyphenols and sugars. The activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) were also increased under MCs stress, suggesting activation of the antioxidant defense system in response to oxidative damage. Combinations of MCs with L. platensis extract, especially at 1 g/L, improved antioxidant enzyme activities by significantly reducing MDA levels, biometric parameters, chlorophyll pigment, and protein and sugar contents. These results indicate that the application of L. platensis extract as a biostimulant can improve radish development, growth, and tolerance to MC-induced stress. Full article

Soil contamination is a major contemporary issue. In light of increasing efforts to align seedling production with the sustainable use and preservation of soil resources, this study aimed to explore the potential of selected plant-growth-promoting bacteria as natural alternatives to mineral fertilizers, a major soil pollutant in the forestry sector. The experiment involved inoculating one-year-old sessile oak (Quercus petraea) seedlings with multiple single bacterial treatments and a consortia derived from sessile oak rhizosphere and monitoring their effects on plant physiological parameters such as chlorophyll, carotenoid, and nitrogen content, along with selected parameters of the rapid chlorophyll a fluorescence induction curve (an OJIP curve). The results indicated that the selected bacterial strains improved specific plant physiological parameters at certain points during the monitoring period; however, further research is necessary to draw statistically significant conclusions. Although these bacteria did not directly enhance photosynthetic parameters, their potential remains evident and could be harnessed through improved application methods. Future studies should focus on identifying site conditions that support the proliferation of the introduced bacterial populations. Full article