Tobacco is a significant economic crop cultivated in various regions of China. Arbuscular mycorrhizal fungi (AMF) can establish a symbiotic relationship with tobacco and regulate its growth. However, the influences of indigenous AMF on the growth and development of tobacco and their symbiotic mechanisms remain unclear. In this study, a pot inoculation experiment was conducted, revealing that six inoculants - Acaulospora bireticulata(Ab), Septoglomus viscosum(Sv), Funneliformis mosseae(Fm), Claroideoglomus etunicatum(Ce), Rhizophagus intraradices(Ri), and the mixed inoculant (H) - all formed stable symbiotic relationships with tobacco. These inoculants were found to enhance the activities of SOD, POD, PPO, and PAL in tobacco leaves, increase chlorophyll content, IAA content, CTK content, soluble sugars, and proline levels while reducing malondialdehyde content. Notably, among these inoculants, Fm exhibited significantly higher mycorrhizal infection density, arbuscular abundance, and soil spore density in the root systems of tobacco plants compared to other treatments. Membership function analysis confirmed that Fm had the most pronounced growth-promoting effect on tobacco. The transcriptome analysis results of different treatments of CK and inoculation with Fm revealed that 3,903 genes were upregulated and 4,196 genes were downregulated in the roots and stems of tobacco. Enrichment analysis indicated that the majority of these genes were annotated in related pathways such as biological processes, molecular functions, and metabolism. Furthermore, differentially expressed genes associated with auxin, cytokinin, antioxidant enzymes, and carotenoids were significantly enriched in their respective pathways, potentially indirectly influencing the regulation of tobacco plant growth. This study provides a theoretical foundation for the development and application of AMF inoculants to enhance tobacco growth.

Forests are increasingly impacted by climate change, affecting tree growth and carbon sequestration. Tree-ring width, closely related to tree growth, is a key climate proxy, yet models describing ring width or growth often lack comprehensive environmental data. This study assesses ERA5-Land data for tree-ring width prediction compared to automatic weather station observations, emphasizing the value of extended and global climate data. We analyzed 723 site-averaged and detrended tree-ring chronologies from two broadleaved and two gymnosperm species across Europe, integrating them with ERA5-Land climate data, CO2 concentration, and a drought index (SPEI12). A subset was compared with weather station data. For modelling interannual variations of tree-ring width we used linear models to assess parameter importance. ERA5-Land and weather-station-based models performed similarly, maintaining stable correlations and consistent errors. Models based on meteorological data from weather stations highlighted SPEI12, sunshine duration, and temperature extremes, while ERA5-Land models emphasized SPEI12, dew-point temperature (humidity), and total precipitation. CO2 positively influenced the growth of gymnosperm species. ERA5-Land facilitated broader spatial analysis and incorporated additional factors like evaporation, snow cover, and soil moisture. Monthly assessments revealed the importance of parameters for each species. Our findings confirm that ERA5-Land is a reliable alternative for modeling tree growth, offering new insights into climate-vegetation interactions. The ready availability of underutilized parameters, such as air humidity, soil moisture and temperature, and runoff, enables their inclusion in future growth models. Using ERA5-Land can therefore deepen our understanding of forest responses to diverse environmental drivers on a global scale.

The increasing demand for sustainable agricultural practices has intensified interest in soilless cultivation systems. However, hydroponics is unable to provide mechanical support for plant roots, and traditional soilless cultivation substrates mostly suffer from poor water retention capacity, rapid nutrient loss, and difficulty in precise control. Hydrogel-based soilless cultivation substrates show great potential for application due to their excellent water absorption, water retention and adjustable transparency. In this study, P(AM-co-NIPAM)/gelatin composite hydrogels with adjustable pore structures, mechanical strength and transparency were obtained by regulating the concentration of crosslinker. Soybean seedlings were grown on these substrates to evaluate the effects of hydrogel properties on root and shoot growth. The results demonstrate that hydrogels with optimized crosslink density possess superior mechanical properties, enhanced water retention capacity, and adequate transparency, facilitating both robust plant growth and high-resolution root system observation. We found that under the MBA content of 0.05 %, the hydrogel matrix could significantly promote the growth of aerial part and root system of soybean seedlings, and was conducive to the colonization of root bacteria. This work highlights the potential of controlled hydrogel matrices in soilless cultivation as a sustainable solution to improve root growth environments, enhance resource utilization, and enable dynamic root system studies. Given their adjustable structure and compatibility with plant growth, such hydrogels may also serve as promising candidates for future application in soilless crop production systems, particularly in scenarios where water and substrate optimization are critical to sustainable agricultural practices.

This study integrates a dynamic plant growth model with a three-dimensional (3D) radiative transfer model (RTM) for maize traits retrieval using high spatial-spectral resolution airborne data. The research combines the Discrete Anisotropic Radiative Transfer (DART) model with the Dynamic L-System-based Architectural maize (DLAmaize) growth model to simulate field reflectance. Comparison with the 1D RTM SAIL revealed limitations in representing row structure effects, field slope, and complex light-canopy interactions. Novel Global Sensitivity Analyses (GSA) were carried out using dependence-based methods to overcome limitations traditional variance-based approaches, enabling better characterization of hyperspectral sensitivity to changes in leaf biochemistry, canopy architecture, and soil moisture. GSA provided complementary results to assess estimation uncertainties of the proposed traits retrieval method across growth stages. A hybrid inversion framework combining DART simulations with an active learning strategy using Kernel Ridge Regression was implemented for traits estimation. The approach was validated using ground data and HyPlant-DUAL airborne hyperspectral images from two field campaigns in 2018 and achieved high retrieval accuracy of key maize traits: leaf area index (LAI, R2=0.91, RMSE=0.42 m2/m2), leaf chlorophyll content (LCC, R2=0.61, RMSE=3.89 mu g/cm2), leaf nitrogen content (LNC, R2=0.86, RMSE=1.13 x 10-2 mg/cm2), leaf dry matter content (LMA, R2=0.84, RMSE=0.15 mg/cm2), and leaf water content (LWC, R2=0.78, RMSE=0.88 mg/cm2). The validated models were used to generate two-date 10 m resolution maps, showing good spatial consistency and traits dynamics. The findings demonstrate that integrating 3D RTMs with dynamic growth models is suited for maize trait mapping from hyperspectral data in varying growing conditions.

Agricultural nanotechnology has emerged as an effective tool for enhancing crop yield and agricultural productivity amid the growing world population. Over the past ten years, application of nanoparticles (NPs) as nano fertilizers or bio-stimulants has been grown to enhance the morphological and biochemical parameters of various crops. The growth and development of edible crop is affected by soil iron deficiency, particularly in agricultural land that lacks sustainable management practices. This review evaluates effect of Iron oxide nanoparticles (IONPs) on agricultural plant growth. Iron is a micro-nutrient, which is essential for plants. The uptake of IONPs in plant mainly depends upon the exposure method i.e. foliar spray through leaves, soil treatment through roots and seed priming through pre-soaking of seeds. Their impact can be positive or negative depending on the variable conditions in the environment, application method, duration of exposure, concentration and size of IONPs. Various studies have shown that IONPs had affected the growth, seed germination, yield and quality of plants. Low concentration of IONPs resulted in increased rate of seed germination, plant biomass and photosynthetic pigments while at high concentration it causes toxicity by generating hydroxyl radicals leading to plant damage. This review provides an overview of IONPs effect on plants, seed germination, plant growth and morphology, yield and quality, their application in different plants, photosynthesis and toxicity.

Increasing drought stress due to climate warming has triggered various negative impacts on plantations in dryland areas, including growth reduction, crown dieback, and even tree mortality, with unavoidable consequences for forest ecosystems. However, how drought stress progressively led to the damage process from growth reduction to mortality for mature trees remains largely unclear, especially its varying soil moisture thresholds. Here we selected mature trees in larch (Larix principis-rupprechtii) plantations in the dryland areas of northwest China, and monitored the progressive tree responses in an extreme summer drought event in 2021, including transpiration, radial growth, leaf area index, discoloration, defoliation, crown dieback and tree mortality. The results showed strong responses of larch trees to summer drought, such as large stem shrinkage, dramatic decrease in transpiration and leaf area index, and obvious discoloration, defoliation, crown dieback and tree mortality at some sites. The intensity of tree responses mainly depended on soil moisture rather than meteorological factors and there were strong relationships between tree responses and relative soil water content (RSW) of 0-60 cm layers. Based on the trees responded to RSW, five soil drought stress levels or progressive mortality stages and their corresponding RSW thresholds were determined as following: no detectable hydraulic limitations (RSW>0.7, Level I), persistent stem shrinkage and onset of transpiration reduction (0.45<= 0.7, Level II), onset of slight discoloration and defoliation (0.35<= 0.45, Level III), onset of crown dieback and tree mortality (0.25<= 0.35, Level IV), and severe defoliation, crown dieback and tree mortality (RSW <= 0.25, Level V). This study showed that the trees responded to climatic drought were strongly regulated by soil moisture and thus were strongly site-specific. These findings will help to evaluate the degree and spatio-temporal distribution of tree damage and mortality in plantations under increasing climatic drought, particularly in dryland areas.

The pedunculate oak (Quercus robur L.) is a major tree species in Europe, but it has faced recent growth decline and dieback events in some areas resulting in economic and ecosystem losses. In the southeastern edge of its natural distribution in eastern Romania, rising temperatures since the 1980s, when a shift towards warmer and more arid conditions occurred, increased evaporative demand and triggered growth decline. We analyzed the adaptive potential of six oak stands (333 individual trees) with ages ranging between 97 and 233 years, located in three wet and three dry sites. Results showed unstable climate-growth correlations with a breakpoint after 1985 when climate warming intensified. Wet soil conditions from early spring to summer enhanced growth; on the contrary, a high evaporative demand linked to warmer conditions and greater potential evapotranspiration reduced growth, particularly in wet sites. After 1985, drought stress induced a reduction in latewood width in dry sites. The relationship between growth and summer-autumn drought intensified during the last decades in all sites. Warmer spring conditions negatively affected oak growth, particularly latewood production. Wet sites had lower resilience indices, and we also noted a post-1985 progressive reduction of growth resilience. Slow-growing trees from dry sites showed growth decline, which could be an early-warning signal of impending dieback and tree death. In contrast, fast-growing trees from wet sites showed sustained relative growth improvement, which was attributed to tree age and size effects. After 1985, the pedunculate oak is more vulnerable to drought damage in dry sites near the southeastern distribution limit in response to hotter winter-spring droughts.

Background and aimsContinuous cropping obstacles (CCOs) are frequently encountered during the cultivation of Lagenaria siceraria (L. siceraria) in the same field for many years, which is related to the secondary metabolites secreted by plants, among which vanillin is one of the factors causing CCOs of L. siceraria. This study investigated the effects of different concentrations of exogenous brassinolide (BR) on L. siceraria under CCOs.MethodsHigh-performance liquid chromatography (HPLC) was used to determine the contents of vanillin in rhizosphere soil of non-planted soil, 1-year-old, 2-year-old, and 3-year-old L. siceraria cultivation. This study investigated the effects of BR at concentrations of 0.05, 0.10, 0.20 and 0.40 mg/mL on L. siceraria under CCOs by applying 6.00 mg/mL vanillin to simulate CCOs.ResultsThe contents of vanillin in the rhizosphere soil of non-planted soil, 1-year-old, 2-year-old, and 3-year-old were 0.01, 0.03, 0.06 and 0.10 mg/g. The BR could effectively alleviate the stress imposed by vanillin and enhance the tolerance of L. siceraria to vanillin stress. When the concentration of BR was 0.20 mg/mL, the alleviation effect on vanillin stress was the most significant. Compared with the vanillin stress group, the plant height, the projected area of the root, number of tips, and total root length enhanced by 1.52, 4.21, 4.43, and 6.12 times. When the light intensity was 1200 lx, the transpiration rate and stomatal conductance increased by 68.57% and 48.00%. At the same time, the antioxidant enzyme activities had the best alleviation at 0.20 mg/mL.ConclusionThe vanillin significantly inhibited the growth of L. siceraria seedlings at elevated concentrations. Furthermore, its persistent accumulation in the soil via root exudation was identified as a contributing factor to CCOs. It was worth noting that 0.20 mg/mL BR could alleviate the damage caused by CCOs to L. siceraria seedlings.

Copper (Cu) is a toxic metal that accumulates in soil due to agricultural and industrial activities, potentially impacting plant growth and productivity. Our study examined the phytotoxic effects of Cu on Vigna radiata L. by exposing plants to a series of Cu concentrations (1, 4 and 7 mM) under controlled conditions. Growth parameters, photosynthetic performance, biochemical traits, and oxidative stress indicators were analyzed in 21-day-old Cu-treated plants and compared with control plants. The results demonstrated a concentration-dependent decline in shoot and root biomass, relative water content (RWC), pigment content, photosynthetic efficiency, carbohydrates, and lipid content. Conversely, oxidative stress markers such as malondialdehyde (MDA), electrolyte leakage, superoxide dismutase (SOD) and ascorbate peroxidase (APX) activity and proline accumulation increased significantly with increasing Cu concentrations, indicating cellular damage. Notably, protein levels increased with increased Cu concentrations, which may contribute to their tolerance to metal stress, however, it was insufficient to mitigate stress. Further research is needed to validate these findings and explore the mechanisms underlying copper stress tolerance.

Drought (D) and chromium (Cr) stress co-occur in agricultural fields due to the accumulation of excessive Cr in soils from industrial pollution and increasing frequency of water scarcity. Carrageenan (Car), a compound extracted from red seaweed, is an emerging biostimulant with multifaceted roles in plants. This study investigated the role of exogenous Car in mediating tolerance to D-, Cr-, and DCr-stress in wheat seedlings, aiming to elucidate the potential of Car in mitigating toxicity and promoting plant resilience. Wheat seedlings exposed to DCr-stress exhibited reduced growth and biomass production, along with elevated levels of reactive oxygen, carbonyl, and nitrogen species. Moreover, D-stress exacerbated Cr-toxicity, as demonstrated by principal component analysis (PCA), which showed a strong positive correlation between DCr-stress and stress marker parameters. This suggests that DCr-stress resulted in higher Cr uptake and increased oxidative damage compared to individual D-or Cr-stress, making DCr-stress more detrimental than either stress applied alone. However, Car priming ameliorated the toxic effects of DCr-stress and promoted the growth performance of DCr-stressed wheat seedlings. In PCA, the positive correlation of D + Car, Cr + Car, and DCr + Car treatments with growth and plant defense-related parameters suggests that Car-mediated improvement in stress tolerance can be attributed to reduced accumulation of toxic Cr, increased levels of total free amino acids and soluble sugars, enhanced antioxidant enzyme activity, elevated non-enzymatic antioxidant levels, higher phenolic and flavonoid content, and improved metal chelation and detoxification. Our results indicated Car is a potential and cost-effective biostimulant for managing D-, Cr-, or DCr-stress in wheat.