Cotton aphid (Aphis gossypii Glover) is a harmful pest that affects cotton crops in Xinjiang, China. Afidopyropen is a new type of insecticide that exerts a strong control effect on piercing-sucking pests. In this work, Highperformance liquid chromatography (HPLC) was used to assess afidopyropen residues on different cotton parts following foliar spraying and root application. The effects of agent retention on physiological indices of cotton aphids and preventive effects were investigated. The results showed that different application methods had a strong influence on afidopyropen residues, most of which were in cotton roots, with fewer in stems and leaves. Enzyme activity analysis showed that the carboxylesterase activity of A. gossypii was significantly increased under different application methods. Foliar spraying and root application (hydroponics) of afidopyropen had rapid, potent effects against A. gossypii, while root application (soil cultivation) did not have a significant effect, but had a positive effect by day 14. Elucidation of the effects of the two application methods to the physiological indices and control of A. gossypii provide a theoretical basis for the development and promotion of integrated water-pharmaceutical technologies for afidopyropen spraying and drip irrigation in cotton fields in Xinjiang and elsewhere.

Saline-alkaline stress is a common problem in Akebia trifoliata cultivation. In this study, the enhancing effects of 5-azacytidine (5-AzaC) on the resistance of A. trifoliata to saline-alkaline stress and the underlying mechanisms were investigated. Plant height, stem diameter, biomass, root length, fresh weight of root, and root/shoot ratio of 6-month-old A. trifoliata seedlings were measured after saline-alkaline stress with or without 5-AzaC treatment. Moreover, the contents of photosynthetic pigments, malondialdehyde (MDA), H2O2, sodium, soluble sugar, and proline; activities of superoxide dismutase, peroxidase (POD), and catalase (CAT); and anatomical structures of root, stem, and leaf were assessed. Furthermore, comparative transcriptome sequencing was performed. The results demonstrated that growth and development of A. trifoliata were severely inhibited under saline-alkaline stress, suggesting that the seedlings were exposed to severe oxidative and osmotic stresses. Treatment with exogenous 5-AzaC could significantly relieve the symptoms of saline-alkaline stress in A. trifoliata. Under saline-alkaline stress, 5-AzaC could increase the stem diameter, biomass, root length, fresh weight of root, and root/shoot ratio and minimize damages to the anatomical structure. Moreover, absorption of Na+ was reduced; ionic balance was maintained; POD and CAT activities were significantly improved; proline and soluble sugar contents increased, and H2O2 and MDA contents decreased. Transcriptome analysis revealed that 5-AzaC functioned via regulating KEGG pathways such as plant hormone signal transduction, phenylpropanoid biosynthesis, photosynthesis, amino sugar and nucleotide sugar metabolism, and glutathione metabolism under saline-alkaline stress. Particularly, enhanced expression of genes from the auxin pathway in plant hormone signal transduction; the lignin synthetic pathway in phenylpropanoid biosynthesis; and photosystem II, photosystem I, photosynthetic electron transport, and F-type ATP pathway in photosynthesis may be related to 5-AzaC-induced saline-alkaline resistance. The results provided theoretical references for A. trifoliata cultivation in saline-alkaline soil and application of 5-AzaC to improve saline-alkaline tolerance in plants.

Background and aims Vascular plants and moss biocrusts are known to coexist in drylands, wherein vascular plant cover is known to be a major influencing factor for biocrusts development. Vascular plants produce litter which may affect moss biocrusts when covering them. However, to which extent the cover of litter may affect the physiology, e.g., photosynthetic activity, of moss biocrusts remains poorly understood.MethodsWe studied the effect of the litter covering on biocrust-forming mosses on the northern Chinese Loess Plateau over four-month period. We used litter from shrubs of Artemisia ordosica and Caragana korshinskii with two levels of litter thickness, and monitored moss greenness, and several indicators of moss physiological activity.ResultsLitter covering reduced moss greenness, content of chlorophyll a and b, soluble sugar, and soluble protein, suggesting a reduced photosynthetic and metabolic activity of mosses under litter cover. On the other hand, mosses covered by litter showed higher contents of malondialdehyde, proline, and catalase activity compared to those mosses without any litter cover, suggesting that litter covering increased oxidative stress in mosses and triggered a protective response against oxidative damage. Moreover, we found litter thickness exerted a more significant impact on the physiological indices of mosses than litter type.ConclusionsOur results demonstrate the detrimental effects of litter covering on the physiological activity of biocrust-forming mosses. The findings provide a mechanistic understanding of the reductions in mosses in ecosystems with high shrub cover, highlighting the importance of litter in mediating the relationships between moss biocrusts and shrub patches.

Background Bermudagrass (Cynodon dactylon) has a long history as an excellent forage grass, and salt stress will inhibit its growth and development. In order to minimize the damage, it is necessary to continuously develop innovative technologies and management strategies. Results This study evaluated the salt tolerance of new Bermudagrass strains 'FB2019R101' and 'FB2019R105' compared to commercial varieties 'Wrangler' and 'A12359' under simulated soil salinity conditions through seawater irrigation. Through correlation analysis of growth, physiological, and nutritional indicators, and principal component analysis, core indicators and weights for salt tolerance evaluation were identified. The salt-tolerant varieties were 'FB2019R101' and 'FB2019R105'. Under salinity stress, the plants of Bermudagrass varieties with salt tolerance suffered less damage as a whole, which could better regulate the osmotic balance inside and outside cells, accumulate more nutrients and have stronger ability to resist salt damage. The expression level of salt-tolerant variety CdCINV1, CdSPS1, CdSUS5, and CdSWEET6 was up-regulated under salt stress. CdCINV1, CdSPS1, CdSUS5 can promote the transformation of sucrose into glucose and fructose in Bermudagrass under salt stress, and CdSWEET6 can promote the accumulation of fructose. Conclusions 'FB2019R101' and 'FB2019R105' exhibited higher salt tolerance, with minimal impact on their biomass, physiological, and nutritional indicators under salt stress. The comprehensive evaluation revealed a salt tolerance ranking of 'FB2019R105' > 'FB2019R101' > 'Wrangler' > 'A12359'. This study provides significant reference for the bioremediation of coastal saline soils and promotes research on the application of Bermudagrass under salt stress conditions. CdCINV1, CdSPS1, CdSUS5, and CdSWEET6 can improve the salt tolerance of plants by regulating the changes of carbohydrates.

Urban ornamental shrubs have significant potential for restoring cadmium (Cd)-contaminated soil. The Cd enrichment characteristics and tolerance mechanisms of Buxus sinica and Ligustrum x vicaryi were investigated through a simulated pot pollution experiment. Specifically, the Cd content and accumulation in different plant tissues, the subcellular distribution and chemical forms of Cd in the roots, and the effects of Cd on the ultrastructure of root cells under various Cd concentrations (0, 25, 50, 100, and 200 mg kg-1) were analyzed. The results showed that: (1) As the Cd treatment levels increased, the total biomass of B. sinica gradually decreased, while L. x vicaryi exhibited a stimulation effect at low Cd concentrations but inhibition at high Cd concentrations. (2) The Cd content in different tissues of both shrubs increased with rising Cd levels. The bioconcentration factor (BCF) and translocation factor (TF) indicated that L. x vicaryi has the potential for Cd phytostabilization. (3) Cd in the roots of both shrubs was primarily present in NaCl-extractable form, and was mostly bound to the cell wall. (4) Excessive Cd caused damage to the cellular structure of B. sinica, while the cells of L. x vicaryi maintained normal morphology. (5) In both shrubs, Cd primarily bound to the cell wall through hydroxyl and amino functional groups, as well as soluble sugars. In summary, converting Cd to less active forms, immobilizing Cd in the cell wall, and providing binding sites through functional groups may be crucial resistance mechanisms for both shrubs in response to Cd stress.

Agroforestry has the potential to enhance climate change adaptation. While benefits from agroforestry systems consisting of cash crops and shade trees are usually attributed to the (shade) trees, the trees can also have negative impacts due to resource competition with crops. Our hypothesis is that leaf phenology and height of shade trees determine their seasonal effect on crops. We test this hypothesis by categorizing shade tree species into functional groups based on leaf phenology, shade tree canopy height and shade tree light (wet and dry season) interception as well as the effects. To this end, leaf phenology and the effects on microclimate (temperature, air humidity, intercepted photoactive radiation (PAR)), soil water, stomatal conductance and cocoa yield were monitored monthly during wet and dry seasons over a two-year period on smallholder cocoa plantations in the northern cocoa belt of Ghana. Seven leaf phenological groups were identified. In the wet season, highest buffering effect of microclimate was recorded under the trees brevi-deciduous before dry season. During dry season, high PAR and lowest reduction in soil moisture were observed under the trees in the group of completely deciduous during dry season. The evergreen groups also showed less reduction in soil water than the brevi-deciduous groups. In the wet season, shade tree effects on cocoa tree yields in their sub canopy compared to the respective control of outer canopy with full sun ranged from positive (+10 %) to negative (-15 %) for the deciduous groups, while yield reductions for the evergreen groups ranged from -20 % to -33 %. While there were negative yield impacts for all phenological groups in the dry season, the trees in completely deciduous during dry season group recorded least penalties (-12 %) and the trees with evergreen upper canopy the highest (-35 %). The function of shade trees in enhancing climate resilience is therefore strongly dependent on their leaf phenological characteristics. Our study demonstrates how the key trait leaf phenology can be applied to successful design of climate-resilient agroforestry systems.

Chrysanthemum, a valuable ornamental flower, has limited salinity tolerance, which restricts its cultivation in salt-stressed conditions. In this study, we investigated the salt tolerance of a population derived from the salttolerant germplasm Chrysanthemum yantaiense. The parents and 91 offspring were subjected to 300 mM NaCl concentrations for 30 days. Based on the observed changes in growth and the degree of damage caused by salt stress, 15 high-resistant, 52 moderate-resistant, and 16 low-resistant strains were identified. Two offspring (i.e., YS-58 and YS-123) with contrasting salt tolerance were subjected to 15 days of salt stress, with phenotypic, physiological, and biochemical responses assessed at 5, 10, and 15 days. YS-58 demonstrated greater resilience, maintaining higher shoot fresh weight by day 10, and exhibiting significantly less growth impairment in both aboveground and belowground by day 15 compared to YS-123. Under salt stress, YS-58 accumulated lower Na* levels in leaves, while sustaining higher K* content in roots and stems. Additionally, YS-58 showed elevated proline levels, reduced soluble sugar content, and decreased malondialdehyde (MDA) accumulation, along with enhanced superoxide dismutase (SOD) activity relative to YS-123. Understanding these mechanisms will provide insights into how chrysanthemums survive under saline conditions, potentially enabling large-scale cultivation in saline soils.

The degree of soil salinization is still on the rise. In saline environments, NaCl is the main substance that causes plant salt damage, with the toxicity of ions under salt stress primarily involving sodium (Na+) or chloride (Cl-). However, fewer studies have focused on Cl- stress. This study investigated the differences in the growth and physiology of five blueberry varieties under Cl- stress, aiming to understand the mechanisms of Cl- tolerance and the physiological responses to Cl- stress in these varieties. Five blueberry varieties ('Northland', 'PL19', 'Duke', 'Reka', and 'Bonnie') were used as test materials. This study examined the changes in growth and physiological indices of blueberry plants under different concentrations of Cl- (A1-A6: 50, 100, 150, 200, 250, and 300 mmol/L) treatments. A control treatment (CK) was included to serve as a baseline for comparison. We comprehensively evaluated the Cl- tolerance of these five varieties to screen for chlorine-tolerant varieties. This study examined the concentration-dependent changes in growth and physiological indices of blueberry plants, including plant height, leaf area, chlorophyll content, electrical conductivity, levels of soluble sugar (SS), malondialdehyde (MDA), proline (Pro), and soluble protein (SP), as well as the activities of superoxide dismutase (SOD) and catalase (CAT). The results revealed that as the Cl- concentration increased, the growth of all blueberry varieties was inhibited; plant height, leaf area, and chlorophyll content consistently declined, whereas electrical conductivity showed a steady increase. SS and MDA content exhibited a biphasic response, with an increase at lower Cl- concentrations followed by a decrease at higher concentrations. The activities of SOD and CAT in 'Duke' consistently increased with rising Cl- levels. In 'PL19' and 'Reka', chlorophyll content decreased with increasing Cl-, while their proline content rose initially and then declined. In contrast, the other varieties generally showed an increasing trend in proline content. Similarly, the soluble protein content of 'Northland' and 'PL19' increased at lower Cl- levels and decreased at higher concentrations, whereas 'Bonnie', 'Duke', and 'Reka' displayed an overall declining trend. Principal component analysis indicated that the Cl- tolerance of the blueberry varieties ranked as follows: 'Duke' > 'Bonnie' > 'Reka' > 'PL19' > 'Northland'. These findings lay a foundation for blueberry cultivation in saline-alkaline soils and support the selection and development of new, chlorine-tolerant varieties.

As an ornamentally and medicinally worthy plant, Hosta plantaginea (Lam.) Aschers. has the adapted capacity to survive cold temperate monsoon climates in Northeastern China. However, its use is limited by the soil alkalization of urban gardens. Our pre-experiment found that Hosta 'Golden Cadet' has the potential to be alkali-tolerant. Hence, tissue-cultured seedlings of Hosta 'Golden Cadet' were used as experimental material. Its related growth, physiology, and transcripts were examined to reveal the molecular mechanism of Hosta plantaginea in response to alkali stress. The results show that the development of Hosta 'Golden Cadet' was affected by alkali stress. In comparison with the control, malondialdehyde (MDA) content increased by 4.28-fold at the 24th hour, superoxide dismutase (SOD) activity increased by 49% at the 6th hour, and peroxidase (POD) activity and soluble sugar (SS) content increased by 67% and 30% at the 12th hour, respectively. The RNA-seq analysis revealed that Hosta 'Golden Cadet' gene expressions at 0 h, 6 h, 12 h, 21 h and 48 h differed after 200 mmol/L NaHCO3 treatment. During 48 h under alkali stress, 2366 differentially expressed genes were found. The transcription factors MYB, AP2/ERF, and WRKY were activated in differentially expressed genes. The KEGG analysis found that phytohormone signaling pathways, starch and sucrose metabolism, and phenylpropane production were activated in Hosta 'Golden Cadet' in response to alkali stress. In summary, Hosta 'Golden Cadet' can reduce membrane damage by improving osmoregulation and antioxidant capacity, increase sucrose and starch metabolism, and regulate phenylpropane biosynthesis by activating transcription factors and inducing related phytohormone signaling, mitigating the effects of alkali toxicity. These findings guide an investigation into the mechanism of alkali tolerance in Hosta plants, screening alkali tolerance genes, and selecting and breeding novel alkali-tolerant Hosta plantaginea cultivars.

Salicylic acid (SA) is a vital phytohormone that can mitigate the detrimental effects caused by abiotic stress in plants; however, these effects vary with SA concentrations, plant species and stress types. Although sunflowers can be cultivated on saline-alkali soil, they remain susceptible to salt stress, especially at the seedling stage. Therefore, we aimed to explore the role of SA in improving salt stress tolerance in sunflowers. Here, we conducted physiology and transcriptomic analyses to assess the effects of four SA concentrations applied through foliar spraying on sunflower seedlings under salt stress. Initially, the height and stem diameter were impeded, and the chlorophyll fluorescence parameters (such as Fv/Fm, Fv/Fo, and PIabs) decreased, but the antioxidant enzyme activity and malondialdehyde and glutathione contents increased when the seedlings exposed to salt stress (250 mM NaCl); meanwhile, the levels of most physiological indices (including plant growth, chlorophyll fluorescence, and reactive oxygen species) significantly recovered after spraying four concentrations of SA solution. Furthermore, the differentially expressed genes identified from transcriptome analysis were mainly involved in photosynthesis, plant hormone signaling, MAPK pathway, and secondary metabolite biosynthesis, which may contribute to the SA-induced response under salt stress. The key genes and TFs crucially involved in the response to salt stress and mitigating its detrimental effects were identified through K-means clustering and WGCNA. We may infer that SA can activate the self-regulatory system, thereby mitigating oxidative damage and enhancing photosynthesis and salt tolerance in plants. Overall, our results demonstrate that 1.0 mM SA is the most effective concentration for alleviating salt stress in sunflowers. This study provides initial insights into the ability of SA to alleviate salt stress and its underlying molecular mechanisms, which is valuable for both field management practices and understanding sunflower tolerance to salinity.