Abstract:

The production of pear (Pyrus communis L.) nurseries is essential to providing high-quality planting material for the establishment of a successful orchard. Thus, encouraging early vegetative growth and seedling vigor during the nursery period requires optimal fertilization. Under temperate continental circumstances in northwest Romania, this study assessed the impact of various NPK fertilizer rates on the shoot fresh weight of pear nursery trees. The study was carried out in 2025 using a factorial design with two Romanian cultivars (‘Napoca’ and ‘Monica’) and four fertilization treatments (N₀P₀K₀, N₈P₈K₈, N₁₆P₁₆K₁₆, and N₂₄P₂₄K₂₄), set up in a randomized block system with five replications. At progressively higher rates of 50, 100, and 150 kg ha⁻¹, a totally water-soluble 16–16–16 fertilizer was applied. At the conclusion of the growing season, the fresh weight of the shoots was measured. The accumulation of shoot biomass was significantly and gradually impacted by fertilization. The fresh weight of the shoots rose by 29%, 45%, and 59% as compared to the unfertilized control (0.42 kg tree⁻¹) under the treatments of N₈P₈K₈, N₁₆P₁₆K₁₆, and N₂₄P₂₄K₂₄. There were no discernible cultivar-dependent variations at any fertilization level, and both cultivars showed almost equal growth responses. These findings show how strongly the growth of pear nursery shoots depends on the availability of NPK and offer helpful advice for maximizing fertilization techniques to enhance the quality of planting materials.

Abstract:

This study aimed to identify fungal species causing fruit rot of chestnut (Castanea mollissima) in Hebei Province, China and analyze the resistance differences among major cultivars. A total of 220 fungal isolates were obtained from healthy and diseased kernels, which were classified into six distinct genera. Based on both morphological and molecular analyses, these isolates were identified as Diaporthe eres (48.6% isolation frequency), Talaromyces rugulosus (22.3%), Alternaria alternata (10.5%), Mucor circinelloides (9.5%), Fusarium proliferatum (5.5%), and Rhizopus stolonifer var. stolonifer (3.6%). Among these, D. eres was firstly reported to cause fruit rot on C. mollissima in China. Moreover, disease resistance evaluation of major cultivars showed significant differences: YG, YSSF, and DBH exhibited strong resistance under both natural conditions (with 1.7% to 5.3% DI after 180 days storage) and artificial inoculation (with 33.0±0.6 to 52.6±4.0 DI); while YJ was highly susceptible (with 47.7% decay incidence and 70.5±7.2 DI). Correlation analysis revealed that the disease index was negatively correlated with sucrose and sorbitol contents, but positively correlated with stachyose and fructose contents. This study advances the understanding of postharvest chestnut fruit rot, and provide a theoretical basis for breeding resistant cultivars and developing control strategies to mitigate losses and ensure food safety.

Abstract:

Currently, inefficient fertilization practices are frequently observed in orchards in Dangshan County, which leads to substantial changes in the soil physicochemical properties and growth disorders in pear trees. This study investigated the effects of long-term fertilization on the different soil layers and aimed to establish scientific fertilization guidelines for “Dangshansuli” pear orchards. In May 2020, a total of 30 soil samples were collected from a “Dangshansuli” pear orchard that was subjected to long-term fertilization and from an unfertilized control area that had been maintained for 30 years. These samples were analyzed for their physicochemical properties, mineral elements, heavy metal content, chemical compound diversity, and allelopathic effects. Long-term fertilization considerably reduced the soil pH and increased the soil organic matter content. The contents of available potassium, exchangeable calcium, and magnesium in the fertilized soil were optimal for pear tree growth, whereas the available iron was insufficient. Although long-term fertilization led to the accumulation of heavy metals, including Cu, Hg, Ni, Cr, As, and Mn, their concentrations remained within safe limits. The number of chemical compounds detected in the fertilized soil was significantly higher than in the control. In addition, allelopathy tests indicated that 0.18 mmol·L⁻¹ octadecane exerted a strong allelopathic effect on the tissue-cultured seedlings of “Shanli” (Pyrus ussuriensis Maxim). Conclusion: These findings provide a basis for the development of optimal fertilization strategies in “Dangshansuli” pear orchards.

Abstract:

The effective management of soil water resources is a major challenge in nursery cultivation, especially for drought-sensitive species like apricot (Prunus armeniaca L.). This research examined how varying irrigation depths (0, 10, 20, and 30 mm per cycle) affect soil water consumption and plant growth in two apricot cultivars, ‘Excelsior’ and ‘Favorit’, which were grafted onto Prunus cerasifera rootstock. The study was carried out in a field nursery during the 2024 growing season. At the end of the season, total branch length was recorded, and the overall vegetative performance was assessed using the Lp-norm index. Increasing the irrigation depth consistently improved shoot development; however, the responses varied by cultivar. ‘Excelsior’ achieved its best performance at 20 mm per cycle, while ‘Favorit’ showed continued benefits from irrigation up to 30 mm, indicating its higher tolerance to limited soil moisture. Moderate levels of irrigation facilitated balanced shoot growth without leading to excessive vigor, highlighting the importance of controlled water application for enhancing water-use efficiency in nursery operations. These results offer a practical, genotype-specific approach for optimizing soil water usage and creating precise irrigation plans for apricot liner production.

Abstract: Floral volatile terpenoids are known to play important roles in plant pollination biology by attracting animal pollinators and repelling antagonists, as well as enhancing resistance to potential microbial pathogens. Terpenoid blend emitted by a flower is usually plant-lineage specific and mostly determined by a set of versatile terpene synthases (TPSs) which catalyze the final step of diverse terpenoid synthesis. The strongly scented flower of Jasminum sambac emits linalool and α-farnesene dominating the nocturnal floral VOC, yet the corresponding TPSs have not been identified. Here, we show that four TPS enzymes are responsible for the synthesis of the mixtures of volatile terpenoids in the flower, based on their highly-correlated and almost-exclusive expression in the petal, and on their enzymatic characterizations in vitro and in Nicotiana benthamiana. JsTPS01 (TPS-a) acts as a sesquiterpene synthase, producing τ-cadinol in yeast at levels that mirror its rhythmic expression in petals. JsTPS02 (TPS-b) carries a plastid-transit peptide, localizes to chloroplasts/plastids, and converts GPP to linalool with high affinity (Km = 28.2 ± 3.4 µM). JsTPS03 is a TPS-b clade member that is able to convert FPP to farnesol with a Km of 14.4 ± 5.9 μM in an in vitro assay using isolated yeast vehicles. JsTPS04 (TPS-e/f) exhibits dual targeting—cytosolic in Arabidopsis protoplasts but plastidic in J. sambac petals—and functions as a bifunctional mono-/sesqui-TPS, forming linalool from GPP (Km = 2.5 ± 0.3 µM) and trans-nerolidol from FPP (Km = 7.6 ± 0.6 µM). Transient expression in Nicotiana benthamiana leaves further confirmed its in-planta linalool production. collectively, we identified four preferentially expressed terpene synthases contribute to linalool, τ-cadinol, tans-nerolidol, and farnesol in Jasminum sambac.

Abstract:

Sweet corn (Zea mays var. saccharata) is a widely spread crop that is highly valued for its sweet taste and high nutrient content. Over the past decade, there has been an exponential increase in the area devoted to sweet corn for grain production, attributed to both its nutritional qualities and economic value. In this context, we aimed to evaluate the impact of three genotypes (Deliciosul de Bacau, Royalty F₁, and Hardy F₁) and two fertilization types (chemical and organic) plus an unfertilized control, on yield, biometrical, biochemical, and quality indicators at an experimental station during 2022–2023. The results revealed significant influences of cultivar, fertilization method, and the interaction between these two experimental factors on most of the analysed indicators. Regardless of the fertilization type, the genotype Hardy F₁ showed higher levels of photosynthetic activity, polyphenols and sucrose, leading to greater yield than that of Deliciosul de Bacau. The latter genotype and Royalty F₁ displayed the highest chlorophyll A, chlorophyll B, and lycopene contents in the grain. The results of the present research emphasize the importance of adopting and monitoring sustainable agricultural practices to enhance both the production and quality of sweet corn, particularly referring to the nutritional value, and address the growing demand for organically cultivated products within the current context of climate change.

Abstract: As a primary macronutrient, nitrogen is integral to plant growth and developmental reg-ulation; ammonium transporters (AMTs) mediate its absorption and involvement in ni-trogen metabolism. In this study, nine BcAMT genes were identified from flowering Chi-nese cabbage (Brassica campestris), which were systematically categorized into two sub-families. Their evolutionary relationships, conserved motifs, chromosomal distribution, cis-regulatory elements, and expression profiling were systematically characterized. RNA-sequencing and RT-PCR analyses demonstrated that BcAMT1.1 was abundantly expressed in roots, leaves, and stems of flowering Chinese cabbage, and was markedly up-regulated under nitrogen deficiency or low-nitrogen conditions. Subcellular location using GFP-fusion demonstrated that BcAMT1.1 localized to the plasma membrane. Func-tional assays through heterologous expression in the yeast mutant strain 31019b and transgenic Arabidopsis validated that BcAMT1.1 acted as a functional ammonium trans-porter. Compared with wildtype, overexpressing BcAMT1.1 promoted seedling growth, enhanced NH4+ influxes and NO3- effluxes under low nitrogen conditions, and signifi-cantly increased the transcription levels of key nitrogen assimilation genes (i.e., AtGLN1.1, AtGLN2, AtGDH2). Collectively, our findings enhance the fundamental understanding of BcAMT gene functions, and highlighting of BcAMT1.1 as a crucial component in nitrogen uptake and assimilation under low nitrogen conditions, and providing valuable genetic resources for improving nitrogen efficiency in vegetable crops.

Abstract: Tree fruit and nut crops are a critical component of the global economy, producing billions of dollars of value and nourishing billions of humans every year. Improved cultivars and growing practices depend upon an understanding of the molecular basis of tree traits and physiology. Over the past 20 years, the proliferation of reference genomes for tree fruit and nut crop species has transformed the study of genetics in these crops, providing a platform for resequencing analyses of large populations, enabling comparative genomic analyses between distant plant species, and allowing the development of molecular markers for use in breeding. Limitations exist, however, with reference bias and poor transferability of markers preventing widespread applicability in many instances. As third-generation sequencing has become more accurate and accessible, a greater number of reference genomes have become available, enabling higher-quality assemblies and wider sampling of genomic diversity. To facilitate the effective use of multiple closely related genomes to create a reference and comparative genomics platform, tools for the creation of pangenome graphs have been developed, allowing for singular representations of diversity within a species or even a wider genus. Pangenomic analyses at the genus-scale have been conducted for Malus and Citrus, and more tree fruit and nut species are likely to follow. As the number of genome sequences and pangenome resources increases, the importance of generating great quantities of transcriptomic and phenomic data will increase as well. This data is essential in the drive to connect genes to traits, as is needed to develop improved tree fruit and nut crops, which can satisfy global demand.

Abstract: Olive leaves are a valuable source of natural bioactive compounds, particularly poly-phenols and flavonoids, recognized for their potent antioxidant and health-promoting properties. The extraction of these high-value products has gained increasing attention due to their relevance in food sustainability and the circular economy. However, the concentration and profile of these compounds vary substantially depending on the ol-ive variety and the extraction method applied. This study evaluated the influence of extraction method and olive variety on the phenolic composition and antioxidant po-tential of olive leaf extracts from nine cultivars cultivated in Morocco. Two conven-tional extraction techniques, maceration and Soxhlet extraction, were compared for their efficiency in recovering extraction yield, total phenolic content, total flavonoid content, and total condensed tannins, along with antioxidant activity measured by DPPH and ABTS radical scavenging assays. Analyses of variance indicated that varie-tal differences were the predominant source of variation in phenolic composition and antioxidant capacity, whereas the extraction method mainly influenced yield. Soxhlet extraction enhanced phenolic recovery and antioxidant potential, while maceration favored flavonoid extraction. These findings highlight the potential of olive leaf ex-tracts derived from Manzanilla, Haouzia, Picual, and Moroccan Picholine varieties using Soxhlet as sustainable natural antioxidants for functional, cosmetic, and pharmaceutical uses.

Abstract: This study examined the effects of two apple cultivars (Gala and Jonagold), four irrigation levels (0, 10, 20, and 30 mm), and four fertilization treatments (N0P0K0, N8P8K8, N16P16K16, N24P24K24) on nursery tree density. Jonagold exhibited a slightly higher mean density (95.63% ± 4.790) compared to Gala (93.50% ± 6.195). Tree density peaked at 99.38% ± 1.295 under the 30 mm watering norm and declined with reduced irrigation, while fertilization levels showed no significant independent effect. Both cultivars achieved their highest densities under the 30 mm watering norm (Gala: 99.25% ± 1.650; Jonagold: 99.50% ± 0.827), and several cultivar–fertilizer–irrigation combinations reached 100% density. The lowest density (89.00% ± 6.944) occurred in Gala under the N24P24K24 treatment without irrigation. Overall, results indicate that irrigation, particularly the 30 mm norm, is the key determinant of maximizing nursery tree density, with select combinations enabling complete survival.

Abstract:

Excessively and randomly producing summer shoots will lead to difficulty in citrus orchard management, specially in pest and disease control. Heavy fruit load can reduce the summer shoot number. However, the mechanism is still unclear. In this study, field investigation and de-fruiting treatment confirmed that heavy fruit load reduces the number of citrus summer shoots, which is zero when the yield surpasses 3.3 kg per 125 dm³ of tree canopy. Metabolite analysis indicated that fruits at the cell expansion stage attract more soluble sugars and de-fruiting significantly increase the content of sugars and the transcript levels of sink strength-related genes, CsSUS4/5/6 to over 3.0 fold in the axillary buds. Moreover, exogenous application of some sugar-related DAMs (differently accumulated metabolites) such as sucrose obviously promoted axillary bud outgrowth. Taken together, these results confirmed that heavy fruit load plays a role in inhibiting axillary bud outgrowth or shoot branching primarily through competing for soluble sugars, which provides the basis for the inhibition of summer shoots by increasing the fruit load in citrus orchard and for the improvement of pest and disease management effectiveness.

Abstract: The effects of shortened light/dark cycles (8/4 h and 4/2 h) on the growth, productivity, and nutritional value of baby leaf vegetables (borage, fenugreek, pea, and sunflower) and microgreens (arugula, broccoli, mizuna, and radish) were evaluated under controlled environment. Control plants were cultivated under 16/8 h photoperiod. The intermittent lighting influenced the quantitative and qualitative parameters of plant growth and yield (fresh weight, robustness index, dty matter content, nutritional value) , yet plant responses were species specific. It is suggested that plant response to shortened light-dark cycles depends on their tolerance/sensitivity to circadian asynchrony, which occurs when external L/D cycles do not coincide with the endogenous circadian rhythms. In areas with time-of-use electricity rates, scheduling lighting during off-peak hours can significantly reduce production costs. It was shown that shortened light-dark cycles can serve as the basis for cost-effective lighting regimes based on electricity tariffs with peak, standatd and off-peak time bands. Thus, intermittent irradiation regime with customized periods (7/4/9/4 h) has been shown to enhance crop yield and qualty or not affect them under equivalent energy consumption while reducing lighting energy costs by 25-45% compared to conventional 16/8 h photoperiod by maximizing the use of off-peak hours.

Abstract: Diaporthe amygdali (anamorph Phomopsis amygdali) is a phytopathogenic fungus of considerable agronomic importance, responsible for branch canker in almond (Prunus dulcis) and peach (Prunus persica L.) trees, representing a major phytosanitary threat to almond cultivation in Europe—particularly in Mediterranean regions—where almond has become one of the most dynamic crops, with cultivated areas expanding rapidly as a result of new varietal introductions and improved agronomic practices. The objectives of this study were to: (i) isolate and identify fungal pathogens from infected almond samples collected in France through multilocus phylogenetic analyses (ITS, tef1-α, act, his3, tub2, cal genes) combined with morphological characterization; (ii) evaluate the susceptibility of 18 almond genotypes, using ‘Ferragnès’ and ‘Texas’ as reference standards for susceptibility and tolerance, respectively; and (iii) compare three field inoculation methods. All isolates were identified as D. amygdali. The varietal screening revealed notable resistance in cultivars ‘Ferrastar’, ‘R1877’, ‘R1413’, and ‘R1542’, whereas ‘Tuono’, ‘Guara’, ‘Ferragnès’, and ‘R1568’ were classified as susceptible. Among the inoculation techniques tested, the mycelial plug method proved to be the most consistent and reliable. The results confirm the presence of resistant genotypes, wich are useful for genetic improvement programs aimed at enancing resistance to related canker pathogens.

Abstract: Microgreens are important plants because of the nutritional, economic, environmental and social benefits. The present investigation had the objective of evaluating the proximal composition and nutritional potential of microgreens (Brassica oleracea, Brassica oleracea va. capitata, Beta vulgaris, Amaranthus) as a function of days of storage. An A*B design was used where factor A was (Types of microgreens) and Factor B was (days of storage). This study analyzed the proximate composition, pigment levels and antioxidant capacity of selected microgreens (broccoli, cabbage, beetroot and red amaranth) during a ten-day storage pe-riod. The results indicated high moisture content of up to 95.65% in cabbage, there were significant decreases in protein content with values of 4.79% in cabbage and 2.90% in broccoli, as well as in fat, which ranged from 0.69% in broccoli to 0.55% on day 10. Re-garding pigments, chlorophyll showed a decrease from 2.50 mg/g to 2.00 mg/g in broccoli, and ß-carotene was reduced from 0.77 µg/g to 0.82 µg/g. However, microgreens retained significant antioxidant capacity, with values up to 547 mg EAA/g in beet. Furthermore, the mineral analysis highlighted high levels of calcium and potassium in the broccoli micro-green with values of 880 mg/kg and 4100 mg/kg, as well as a low presence of heavy met-als, supporting its consumption as a nutritional source. These results show the need to consider storage time when evaluating the nutritional quality of microgreens.

Abstract: Urban parks serve a vital function in delivering essential ecosystem services, including biodiversity maintenance and the improvement of urban well-being. This study explores how tree stand characteristics impact the hemeroby, naturalness, and functional diversity of herbaceous cover in two parks in Dnipro, Ukraine. Utilizing structural equation modelling we identified four key gradients influencing herbaceous diversity: stand density/thinning, diversity/uniformity, cooling potential, and heating potential. Higher tree density and diversity lead to cooler temperatures and increased soil and air humidity, which in turn lessens hemeroby and promotes naturalness. Reduced light intensity under denser canopies bolsters the establishment of natural herbaceous communities. Hemeroby and naturalness also impact functional diversity, which can be divided into richness, evenness, and divergence. Environmental disturbances often reduce functional richness while increasing evenness and divergence; in contrast, greater naturalness is related to increased evenness but decreased richness. Our results highlight the importance of tree stand structure in shaping microclimate and functional diversity within urban parks. A thorough understanding of these interactions is crucial for developing park management strategies that enhance biodiversity and ecosystem stability. By merging ecological theory with urban planning, this study provides a framework for sustainable management of green spaces, ensuring lasting ecological and social benefits.

Abstract:

The lack of protocols for breaking seed dormancy, inconsistent seed quality, and abiotic stress factors such as drought impede large-scale restoration efforts of pollinator seed species. This research explores the germination response, dormancy-breaking techniques, and water stress tolerance in selected pollinator-friendly plant species with characteristics facilitating mechanized rehabilitation protocols and biodiversity enhancement. Furthermore, this study supports utilization of Multiple Seed Pellets (MSP), to facilitate mechanical sowing of pollinator seeds. Forty-two commercial seed lots representing seven plant families with 28 species were evaluated under two alternating temperature regimes (15/25°C and 20/30°C) with and without gibberellic acid (GA₃) pre-treatment. GA₃ significantly enhanced germination percentage, and reduced T₅₀ (time to 50% germination) across most seed lots. Overall, germination was higher and faster at 20/30°C than 15/25°C. Six species were further examined for dormancy-breaking responses to GA₃ and kinetin applied in a hydrogen peroxide (H₂O₂), soak. GA₃ + H₂O₂ had the greatest germination compared to other treatments. The effect of water stress on seed germination was assessed in controlled chambers at soil water potentials of −1.08, −0.75, −0.13, and 0 MPa. Milkweed species (A. incarnata, A. syriaca, and A. tuberosa) exhibited consistently high germination across a broad moisture range of -0.75 to 0 MPa. In contrast, Echinacea purpurea required high moisture levels (-0.13 to 0 MPa) for optimal germination. Monarda fistulosa and Rudbeckia hirta showed their best performance under moderate moisture conditions (-0.13 MPa). The use of GA₃ to break physiological seed dormancy offers a promising approach to enhance germination. With the utilization of MSP technology, these strategies provide scalable, practical tools to improve native seed performance and advance pollinator habitat restoration in agroecosystems.

Abstract: The objective of this study was to evaluate the changes in the fruit quality of blackcurrant ‘Tihope’ cv. during storage in regular atmosphere (RA), controlled atmosphere (CA), and in modified atmosphere packaging (MAP). Flesh firmness (elasticity), total soluble solids, titratable acidity, content of vitamin C, polyphenols, sugars, and antioxidant capacity were measured at harvest, after storage, and after shelf life (1 day at 18 °C or 2 days at 10 °C). The incidence of storage disorders and diseases was also monitored. Additionally, the sensory quality of the stored fruit was also analysed. The fruit of the 'Tihope' cultivar can be stored at 0 °C, in a regular atmosphere, up to 20 days without any negative effect on its quality. Storage in a controlled atmosphere or in MAP packaging allows the extension of the storage period of blackcurrants even up to 33 days, thereby delaying the occurrence of fruit damage and loss of firmness. After storage, vitamin C, polyphenols, sugars, and antioxidant activity remained at a high level similar to the harvest period.

Abstract:

The slow decline of citrus is a complex syndrome primarily driven by the citrus nematode (Tylenchulus semipenetrans); with unexplained modulating influences from abiotic stressors such as soil salinity and nutrient imbalances. This review synthesises existing knowledge on the physiological and biochemical mechanisms underlying this progressive economic decline; focusing on the interplay between nematode infection; abrupt reduction in root-to-shoot ratio; and consequent osmolyte dynamics; along with management implications. The pruning effects of nematode females at death; result in abrupt diversion of the root-to-shoot ratio from the normal seasonal cycle; which triggers a series of dehydration- and ion-toxicity-avoidance mechanisms; where citrus trees redistribute hyperosmotic osmolytes; which involve chemical and physiological adjustments to restore the stable seasonal root-to-shoot ratio. This review underscores the importance of maintaining a stable seasonal root-to-shoot ratio through integrated management strategies. Avoiding mechanical weeding; while maintaining light shoot pruning; strategic fertilisation with potassium supplementation; improved irrigation management and selection of dual salt-tolerant and nematode-resistant-rootstocks are crucial for sustaining orchard longevity and productivity. By integrating the proposed strategies; citrus growers can improve tree longevity; maintain fruit production; and ensure long-term orchard sustainability. In conclusion; the review highlights the necessity of a holistic; multipronged management approach to mitigate the slow decline of citrus; with future research focusing on molecular pathways that govern the root-to-shoot homeostasis by exploring breeding strategies for citrus rootstocks with enhanced resilience against both biotic and abiotic stressors.

Abstract: Global warming, with rising average temperatures and increasingly frequent extreme heat events, poses a major threat to fruit production systems and food security. Understanding how fruit trees respond to soil thermal stress is therefore critical for developing climate-resilient orchards. In this study, we investigated the physiological and growth responses of potted pear (Pyrus communis) and quince (Cydonia oblonga) plants to root-zone heating. Plants were exposed to different substrate heating regimes, and gas exchange, water status, chlorophyll content, shoot growth, and biomass allocation were assessed. Short-term extreme heating (50 °C for 36 h) caused immediate reductions in gas exchange, severe root and shoot damage, and rapid plant mortality in both species. By contrast, prolonged heating at 40/35 °C induced significant declines in gas exchange, shoot growth, and root biomass, with species-specific differences. Pear exhibited greater sensitivity than quince, showing lower shoot growth, root dry weight, and gas exchange. These findings highlight the vulnerability of pear trees to high root-zone temperatures and the limited contrast between the tested rootstocks. Accordingly, there is a clear need for targeted soil management practices that promote root growth and soil exploration to enhance orchard resilience under future climate scenarios.

Abstract: Plants exposed to combined abiotic and biotic stresses often show complex physiological responses that cannot be predicted from single stress factors. This study examined the interactive effects of temperature stress and Erwinia amylovora infection on pear (Pyrus pyrifolia) leaves using chlorophyll fluorescence analysis and RGB imaging. Photosynthetic performance remained stable under temperature stress alone at 25℃, while pathogen inoculation reduced chlorophyll content and impaired PSII energy dissipation. Disease progression, assessed by the area under the disease progress curve (AUDPC), peaked at 25℃, followed by 30℃, 15℃, 10℃, and 35℃. Distinct PSII responses were observed under combined stresses: photoprotective NPQ activity at 10 ℃, partial efficiency loss at 15 ℃, severe impairment with elevated non-regulated energy dissipation (ФNO) at 25℃, enhanced oxidative damage at 30℃, and suppressed pathogen activity with partial photoprotection at 35℃. Linear mixed-effects modeling confirmed significant main effects of temperature and infection on PSII parameters, with ФNO particularly sensitive, while three-way interactions (T:I:D) in Fm, Fv, and Fp highlighted the interdependent impact of combined stresses. These findings reveal temperature-dependent resilience strategies of pear leaves against fire blight and underscore the value of chlorophyll fluorescence for assessing tolerance mechanisms and informing cultivar selection and disease management in complex stress environments.