Search Results (128)

Climate models suggest that longer dry periods and heavier rainfall events may occur in arid and semiarid regions, which may greatly affect plant growth and propagation in these regions. Numerous studies have documented the relationship between grassland productivity and precipitation. However, the interactive effects of rainfall amount and rainfall frequency on the growth of perennial grasses with rhizomatous propagation, especially on clonal growth, have not yet been studied. In this study, the effects of three rainfall amounts and two rainfall frequencies on the vegetative traits and clonal growth traits of Leymus chinensis, a perennial rhizomatous species, were examined. Rainfall amount and rainfall frequency exhibited a significant interaction only for the root biomass ratio between the 0–20 cm and 20–40 cm soil layers. All traits (including height, aboveground biomass, root biomass, rhizome number, rhizome length, bud bank size, and daughter shoot number) increased markedly with increasing rainfall amount but showed little response to rainfall frequency. Only the root biomass in the 20–40 cm soil layer increased with an extended dry period between two rainfall events, resulting in a lower root biomass ratio between the 0–20 cm and 20–40 cm soil layers under the medium and high rainfall amount treatments. The size of the belowground bud bank was positively correlated with the daughter shoot number as well as the aboveground biomass, and the positive relationship between the bud bank size and daughter shoot number was strengthened with increasing rainfall amount, but was not sensitive to rainfall frequency. However, lower rainfall frequency significantly decreased the rhizome number per plant. These results highlight that summer rainfall amount is more important than rainfall frequency for the population growth of L. chinensis at medium and high rainfall amounts, and that lower rainfall frequency may reduce the long-term clonal growth ability of L. chinensis in the future. Our findings reveal the response mechanisms of L. chinensis productivity to climate change from the novel perspective of bud banks, which provides practical management insights for artificially established L. chinensis grasslands. This study also offers important implications for elucidating the contributions of belowground biomass production to soil carbon sequestration in grassland ecosystems. Full article

High summer temperatures can reduce growth and flower quality in standard chrysanthemum, while whole-greenhouse cooling requires substantial energy input. This study evaluated whether localized root-zone cooling could improve growth and suppress open-center malformed capitula in standard chrysanthemum ‘Baekgang’ while considering energy use. Rooted cuttings were grown in a commercial hydroponic greenhouse during summer and subjected to a non-cooled control (NC) or root-zone cooling activation thresholds of 28 °C (HT), 25 °C (MT), or 22 °C (LT). Root-zone temperature, vegetative growth, gas exchange, flower quality, open-center incidence, and electricity consumption were measured. Mean root-zone temperatures were 27.8 °C in NC, 26.6 °C in HT, 24.4 °C in MT, and 23.3 °C in LT. Root-zone cooling improved vegetative growth, particularly stem diameter and shoot and root biomass, whereas leaf-level gas-exchange parameters were not consistently affected. Open-center incidence was highest in NC (67%) and was reduced to 33%, 11%, and 33% in HT, MT, and LT, respectively. Electricity consumption was 321, 783, and 1088 kWh bed⁻¹ in HT, MT, and LT, respectively. These results indicate that moderate root-zone cooling, particularly MT, provides a practical balance between flower quality and energy use for summer chrysanthemum production. Full article

The present study aimed to characterize the vegetative growth and phenology of hop cultivars grown in successive seasons with artificial supplementation in a subtropical region. The experiment was conducted in Palotina, Paraná, Brazil (24° S) during the summer 2023–2024, winter 2024, and fall 2024–2025 growing seasons. LED lamps were used to extend the daily photoperiod to 17 h during the vegetative phase. The following hop cultivars were assessed: (a) Alpharoma; (b) Cascade; (c) Chinook; (d) Comet; (e) Dr. Rudi; (f) Hallertau Magnum; (g) Hallertau Mittelfruher; (h) Nugget; (i) Saaz; (j) Smooth; (k) Sorachi Ace; (l) Southern Cross; (m) Triple Pearl; (n) Yakima Gold; (o) Zeus. The assessed variables included plant height (Ht), hop growth rate (HGR), classification of four growth stages, number of lateral shoots, plant fresh mass, and phenology. Ht and HGR were analyzed by means of Gompertz and Gaussian regression models, respectively. The number of lateral shoots per plant and fresh mass were subjected to analysis of variance (ANOVA), and means were grouped using the Scott-Knott test (p < 0.01). Seasonal temperature fluctuations, associated with advancing age and plant establishment throughout successive cycles, acted as important modulating factors in vegetative growth and phenology. In the summer season (2023–2024), Cascade and Hallertau Magnum were characterized as early cultivars. In the winter season (2024), Chinook, Nugget, Saaz, and Zeus were classified as early cultivars, while in the fall season (2024–2025), Dr. Rudi, Sorachi Ace, and Zeus were also considered early hops. The vegetative growth Stage I was found to be critical for earliness classification. The phenological cycle variability was amplified during seasons with higher temperatures. The ‘Sorachi Ace’, ‘Triple Pearl’, and ‘Zeus’ hops were the only ones capable of completing the phenological cycle in all three harvest seasons, with ‘Sorachi Ace’ standing out due to its uniform, stable growth pattern regardless of the season. It is concluded that successive hop cultivation is technically viable for specific hop cultivars grown under subtropical conditions with supplemental lighting. Full article

Salt stress is one of the major abiotic stresses limiting the yield of agriculture production worldwide. Rice is an aquatic summer crop, while barley represents a drought winter crop. Both are classified as diploid sequenced crops within the Poaceae family, and are vital staples in the world. As a plant-specific transcriptional regulator, suppressor of gamma response (SOG) plays crucial roles in plant adaptation under abiotic stresses by repairing DNA damage pathway. However, little research has reported the function of SOGs in barley and rice. This study presents the first genome-wide identification and comparative analysis of the SOG gene family in barley and rice, two cereal crops with contrasting salt tolerance. A total of 97 HvSOGs and 74 OsSOGs were identified in the genome of barley and rice, which were divided into three subfamilies. There was significant variation between barley and rice in terms of gene structures, motif compositions, gene duplication, and cis-elements. Notably, rice may have suffered stronger purifying selection pressure than barley, whereas the proportion of SOGs with stress-related cis-elements was significantly higher in barley than in rice. The expression patterns of SOGs in barley and rice tissues under salt stress indicated that barley’s stronger salt tolerance was largely due to an energy-saving strategy in shoots. Moreover, homologous gene similarity comparison with sea barleygrass suggested that gene loss and possible functional divergence during evolution may contribute to salt sensitivity in rice. Functional validation of a differentially expressed OsSOG17 gene confirmed its positive regulatory role in salt tolerance. Our findings uncover an energy-saving strategy as a potential mechanism underlying differential salt tolerance, and functionally link a SOG gene to salt stress responses in rice. Full article

Seagrasses are vital ecosystem engineers and habitat architects in coastal environments, with Posidonia oceanica in the Mediterranean playing a crucial role as an indicator of ecological health. As an endemic and vulnerable species, P. oceanica meadows are highly susceptible to environmental degradation, underscoring the importance of non-destructive monitoring techniques. Traditional SCUBA-based surveys are accurate but resource-intensive and difficult to scale, especially for estimating shoot density and leaf length. This study applies a conservative acoustic-based approach to assess Posidonia oceanica biometrics, habitat characteristics, and ecological status along the Turkish Levant coast. The method offers a non-destructive alternative to SCUBA surveys and addresses a regional knowledge gap in Mediterranean seagrass monitoring. Acoustic data collected during winter and summer 2019 along the Turkish Levant coast were analyzed to estimate seagrass biometrics and derive ecological indicators, with validation via SCUBA observations. Results show that acoustic methods can reliably estimate shoot density, leaf area index, and canopy height. They provide broad-scale coverage and efficiency, though further refinement is required to improve calibration across depths and substrates. While acoustic methods provide broad, non-invasive coverage, they are affected by spatial and temporal variability that SCUBA surveys capture more reliably. Calibration of the POSIBIOM (vers 1.1) algorithm was based on specimens collected at 15 m depth on rocky substrates. While this provided consistent regression relationships, it may limit accuracy when extrapolated to habitats such as sand, mud, or matte. This study represents the first high-resolution, spatiotemporal mapping of P. oceanica meadows and benthic habitats along a significant portion of the Turkish Levant coast using acoustics alone. Overall, the study highlights the potential of acoustics as a scalable, non-invasive tool for seagrass monitoring. This approach contributes to ecosystem-based management and conservation strategies in the Mediterranean. Future work will focus on refining models to address bottom type- and depth-dependent acoustic responses and improve biometric accuracy. Full article

Background/Objectives: Floral bud morphogenesis is a critical developmental process determining yield potential in blueberry, yet the molecular regulatory mechanisms in leaves during this phase remain poorly understood. Methods: In this study, we employed a time-series transcriptomic approach to investigate leaf gene expression dynamics during floral bud morphogenesis in rabbiteye blueberry. Leaves were sampled at six time points spanning the critical developmental window from the cessation of summer shoot growth to bud swell and dormancy onset. Results: RNA-seq analysis generated 121.68 Gb of clean data, and weighted gene co-expression network analysis (WGCNA) identified four stage-specific modules (brown, red, blue, turquoise) significantly associated with distinct morphogenetic phases. The brown module (0–6W) was enriched in photosynthesis and hormone signaling pathways, while the red (9W) and blue (12W) modules featured protein processing, stress and hormone signaling, and carbohydrate metabolism. The turquoise module (15W) was dominated by carbon metabolism and flavonoid biosynthesis genes. Key flowering-related genes exhibited dynamic expression patterns: FT was specifically upregulated at the late stage (15W), AP2 genes peaked at mid-stage (9–12W), and COL9 showed early high expression (0–3W). Hormone-related gene analysis revealed extensive involvement of multiple pathways, with brassinosteroid (BR) signaling comprising the largest number of genes (101). Co-expression networks further identified hub genes, including FT, COL9, AP2, ERF1, SR160, LOX3-1, and transcription factor genes like MYB-related, as potential central regulators. Conclusions: Our findings demonstrate that blueberry leaves undergo a phased functional transition from a photosynthetic source to a hub for signal integration and metabolic support during floral bud morphogenesis, actively contributing to reproductive development through systemic signaling. This study provides novel insights into flowering regulation in woody perennials and establishes a foundation for marker-assisted breeding and cropping season management in blueberry. Full article

Grapevine trunk diseases, particularly Botryosphaeria dieback, pose a major threat to vineyard sustainability, a risk that is further intensified by climate variability and increasing environmental stress. This study evaluated pathogenicity and bacterial biocontrol efficacy against Neofusicoccum parvum and Diplodia seriata under vineyard conditions, analyzing the combined effects of cultivar (Vitis vinifera L. cv. Cabernet Sauvignon and Sauvignon Blanc), tissue type (young shoots and lignified arms), and phenological season (autumn/winter and spring/summer). Pathogenicity assays revealed clear tissue-age specialization: N. parvum was more aggressive in young shoots, whereas D. seriata caused the most severe vascular lesions in lignified wood. Seasonality further modulated disease expression, with higher lesion development during spring/summer, particularly for N. parvum in young shoots, while D. seriata maintained high aggressiveness in lignified tissues across both seasons. Berry assays provided a rapid initial assessment of isolate virulence but did not fully reflect pathogen behavior in woody tissue under field conditions. Biological treatments using native bacterial strains (Pseudomonas sp. AMCR2b, GcR15a, and Rhodococcus sp. PU4) significantly reduced lesion severity in V. vinifera under field conditions, although efficacy varied by tissue type and season. Biocontrol effects were generally more stable in lignified arms, and under high disease pressure, only the most robust strains maintained consistent protection, in some cases matching or surpassing the efficacy of the fungicide tebuconazole. These results show that both pathogenicity and biocontrol performance against Botryosphaeria dieback in V. vinifera under field conditions are strongly influenced by tissue type and season, supporting bacterial biocontrol as a sustainable component of integrated disease management in vineyards. Full article

To investigate how different training modes of salt stress priming affect the dynamic variation of the salt tolerance threshold (STT) in summer maize, a micro-plot experiment with staged brackish water irrigation was conducted. Based on physiological and biochemical parameters, along with shoot and root traits, a dynamic salt tolerance coefficient (α_STT) was defined to quantify STT across growth stages. The results revealed a clear two-stage adaptive response to salt stress, consisting of an initial physiological adaptation phase followed by a phenotypic adaptation phase. Different training modes induced distinct salt stress memory effects by regulating the coordination between these two stages. Among treatments, the S_1-2-3 regime—corresponding to mild (2.0 g·L⁻¹), moderate (4.0 g·L⁻¹), and severe (6.0 g·L⁻¹) salinity applied sequentially at the six-leaf, ten-leaf, and tasseling stages—exhibited the most favorable adaptive outcome, with α_STT gradually recovering to 1.0 at later stages and a concomitantly higher STT. Furthermore, a unified predictive framework was established to estimate STT dynamics, within which the process-constrained PCR-STP pathway outperformed purely data-driven pathways. Overall, our study elucidates the dynamic nature of salt tolerance in summer maize and provides a scientific basis for optimizing brackish water irrigation regimes and refining salt stress modules in crop models. Full article

Climate change has intensified summer drought and high solar radiation in Mediterranean ecosystems, generating abiotic stress that limits the establishment of riparian species. We conducted a nursery experiment to evaluate the effects of two levels of water availability and light intensity on the growth and physiological responses of two native riparian species from Mediterranean Chile: Drimys winteri and Persea lingue. A bi-factorial design combined two irrigation treatments (well-watered and water restriction) and two light intensity levels manipulated through a light protection treatment (20% shade mesh and full light exposure). Water restriction was applied gradually until 15–20% (v/v) substrate moisture, defined as maximum water restriction, followed by rehydration. Morphological variables (height, root collar diameter, and shoot-to-root ratio) and physiological traits (predawn water potential, chlorophyll fluorescence, and electron transport rate) were measured. Growth responses were affected by the light protection treatment, which promoted a significant height growth in both species. Water stress affected the global response of both species but they differed in their post-stress hydraulic recovery: P. lingue fully recovered its predawn water potential, whereas Drimys winteri did not. Our study provides measurable and quantifiable values that demonstrate the sensitivity of these species to water stress. Full article

The excessive and random production of summer shoots poses significant challenges to pest and disease management and the improvement of fruit quality in citrus orchards. Although heavy fruit load has been observed to reduce summer shoot numbers, the mechanism is not well understood. This study combined a field investigation with a de-fruiting experiment to demonstrate that significant negative correlation exists between fruit load and summer shoot numbers in citrus orchard. Metabolomic analysis further indicated that fruits at the cell expansion stage function as dominant carbohydrate sinks, attracting more soluble sugars. De-fruiting significantly elevated sugar content and upregulated the transcript levels of sink strength-related genes (Sucrose synthase, CsSUS4/5/6) by more than 3.0-fold in the axillary buds. Additionally, exogenous application of sugar-related DAMs (differentially accumulated metabolites), such as sucrose, significantly promoted axillary bud outgrowth. Taken together, our findings confirm that heavy fruit load suppresses shoot branching, primarily through competing for soluble sugars. This provides a physiological basis for managing summer shoots by regulating fruit load, offering a practical strategy to enhance citrus orchard management and the effectiveness of pest and disease control programs. Full article

Branching traits play a critical role in shaping the tree structure of fruit crops and directly influence both yield and fruit quality. Effective and well-managed branching is crucial for maximizing productivity. However, loquat trees typically exhibit weak branching ability, characterized by fewer and longer bearing shoots, along with terminal flower buds, which collectively result in lower yields per unit area. Despite their significance, research on branching characteristics in loquat remains limited. To clarify the factors influencing branching and to provide a rational and effective direction for improving the inherently weak branching performance of current loquat cultivars, we selected the loquat varieties ‘Dawuxing’ and ‘Chunhua 1’, which exhibit significant differences in leaf and branch growth. Compared to ‘Dawuxing’, ‘Chunhua 1’ has longer branches, wider stem and leaf angles, fewer lateral branches, and a looser leaf cell structure. Transcriptome analysis of terminal buds at different developmental stages revealed that differentially expressed genes in the terminal buds of central branches from the spring and summer shoots of the two cultivars were enriched in the plant hormone signal transduction pathway. Hormone-targeted metabolomics identified significant differences in the levels of abscisic acid, auxins, cytokinins, gibberellins, jasmonic acid, and strigolactones in the terminal buds of both cultivars. Through integrated analysis, two candidate genes were identified as potential regulators of branching differences between the two cultivars: EVM0025028 (EjSAPK1), SnRK2 gene a core component of the abscisic acid signaling pathway, and EVM0040331 (EjRMS3), a D14 gene involved in encoding a strigolactone receptor. These findings provide valuable genetic resources for future research on branching regulation in Eriobotrya species and offer a theoretical foundation for enhancing branching management in loquat cultivation. Full article

Juniper formations are valuable habitats for fauna and flora and play an important role in protecting the ecosystem, where they grow, from erosion and degradation. Juniper habitats are included in the European Directive 92/43. Juniperus phoenicea is of great ecological importance in Mediterranean areas, as it is often among the only species that can survive under extremely unfavorable conditions. Along with other species, it forms the habitat 2250* “Coastal dunes with Juniperus spp.” Habitat 2250* is a priority habitat, and today, it is under threat due to several factors such as coastal erosion, forest fires, etc. Therefore, the main objective of this study is to investigate the factors that affect the rooting of J. phoenicea shoot cuttings collected from plants growing in their natural habitat. Specifically, the effects of the cutting collection season and the different concentrations (0, 3, 6, and 12 g·L⁻¹) of the plant growth regulator K-IBA (indole-3-butyric acid potassium salt) on the rooting of J. phoenicea shoot cuttings in two propagation systems (mist and fog) were investigated. The shoot cuttings of J. phoenicea rooted in high percentages reaching more than 90%. The factors studied played an important role, and significant differences in the rooting ability of cuttings were found, as well as in the number and length of roots. For the optimal results, cuttings should be collected in winter and treated with 6 g·L⁻¹ K-IBA under a mist system or in summer with 3 g·L⁻¹ K-IBA under a fog system. The results of the present study can be used to make up a basic step for conservation and restoration efforts and for sustainable exploitation strategies for this valuable phytogenetic resource. Full article

High-air temperature stress inhibits the growth of hydroponic lettuce. The practical application of conventional air cooling is constrained by high cost and moderate efficacy. However, root-zone cooling represents a more promising temperature regulation strategy for vegetable production, offering advantages such as ease of integration and lower cost. This study used lettuce (Spanish Green) as the plant material under four RZT treatments: T0 (control: 24.65~31.65 °C), T1 (24.5 °C), T2 (20.5 °C), and T3 (16.5 °C). Growth parameters and nutritional quality indicators under each treatment were systematically monitored, and a comprehensive evaluation was performed using the fuzzy membership function method. All cooling treatments (T1–T3) enhanced lettuce plant height, leaf area, and shoot dry weight. According to the fuzzy membership function analysis, the T1 treatment was found to exhibit the highest overall nutritional value. Although the T0 control group displayed the poorest growth performance, with a shoot dry weight 47.24% lower than that of T1, it accumulated significantly higher levels of P, Ca, and Zn. These findings demonstrate that regulating RZT to approximately 24.5 °C synergistically enhances both biomass and quality in lettuce, providing theoretical and practical support for optimizing hydroponic production in summer conditions. Full article

This study investigated the influence of cutting techniques on the growth, development, yield, and oil quality of Cannabis sativa found in the Eastern Cape Province. The greenhouse pot experiment was conducted at Dohne Agricultural Development Institute (DADI), Stutterheim, Eastern Cape, during the winter and summer growing seasons of 2024/25. It was laid out in a Randomized Complete Design (RCD) with three treatments replicated three times. The treatments used were herbaceous shoot cutting with two different leaf area (LA) trimming amounts and sexual propagation. The parameters measured were plant height, number of branches, stem girth, number of weeks to first flowering, number of flowers, flower sex, number of weeks to 50% embar colorations, plant fresh weight, leaf and flower weights, and dry leaf and flower weights. The flower oil yield and cannabinoid composition were determined using GC-MS. The results indicate that the sexually propagated plants were taller (p < 0.05) with vigorous growth; had the highest fresh plant, leaf, and dry leaf weights; and had a higher number of male flowers overall. Herbaceous shoot cutting without LA trimming showed a significantly higher numbers of branches and flowers, as well as more rapid flowering, fresh and dry flower weights, and physiological maturity. The highest number of female flowers was recorded from cuttings, irrespective of the cutting technique. Additionally, cannabinoid concentrations in Cannabis sativa oil were influenced by the propagation techniques. In the first growing season, herbaceous shoot cutting with 50% LA trimming had the highest CBD, while in the second growing season, the sexually propagated treatment had the highest CBD concentration. Additionally, herbaceous shoot cutting without LA trimming recorded the highest Δ9-THC concentration, followed by the treatment with 50% LA trimming during the first growing season. These findings indicate that asexual propagation through cuttings is a suitable propagation choice for flower production for pharmaceutical purposes, as female-only plants can be selected. However, sexual propagation should be used for fibre production. Full article

Severe flower and fruit abscission leading to low yields makes improving fruit set and increasing production critical challenges in Macadamia cultivation. Irrigation and artificial pollination during the flowering period significantly influence the fruiting and yield of macadamia. However, the synergistic effect of these two factors on macadamia production and yield remains unclear. This study investigated the effects of irrigation and artificial pollination on fruit set and yield using 11-year-old ‘A16’ Macadamia trees. Four treatments were applied: drought (DC), drought with artificial pollination (DC + AP), irrigation (I), and irrigation with artificial pollination (I + AP). Each treatment included three biological replicates, with a total of 12 trees. We assessed fruit set and yield, analyzing underlying mechanisms by evaluating changes in pollen viability, leaf morphology, inflorescence characteristics, and leaf/inflorescence physiology. Results revealed that DC + AP, I, and I + AP treatments exhibited significantly higher pollen viability and raceme length compared to DC. The I + AP treatment also resulted in the longest summer shoot internode length. Racemes were more sensitive to drought stress than leaves. Soluble protein and soluble sugar content in racemes were significantly higher in I + AP than in I and DC + AP, and lowest in DC. The DC treatment showed significantly higher superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and malondialdehyde (MDA) contents compared to I and I + AP. Leaf physiological traits exhibited inconsistent changes across treatments. Both artificial pollination and irrigation significantly increased fruit set. Treatment efficacy ranked as follows: I + AP (102.00% increase) > DC + AP (56.00% increase) > I (14.00% increase) > DC. Consequently, the I + AP treatment achieved significantly higher yield, fruit numbers, and fruit diameters than the other treatments. In terms of yield, treatment efficacy ranked as follows: I + AP (77.72% increase) > DC + AP (41.14 increase) > I (27.54% increase) > DC. These findings provide a scientific basis for enhancing yield in high-yield Macadamia cultivation systems. Full article