Scented green tea (Camellia sinensis) is a type of reprocessed green tea produced by scenting with flowers. To investigate the differences in the volatiles of scented green tea processed with four different flowers (Jasminum sambac, Osmanthus fragrans, Michelia alba, and Rosa rugosa), gas chromatography–ion mobility spectrometry (GC–IMS) and gas chromatography–mass spectrometry (GC–MS) were employed to detect and identify the volatile compounds in the four types of scented teas. GC–IMS and GC–MS identified 108 and 101 volatile compounds, respectively. The key characteristic volatile compounds, namely indole, linalool, β-myrcene, benzyl acetate, and ethyl benzoate (jasmine tea); cedrol, (E)-β-ionone, γ-decalactone, and dihydro-β-ionol (osmanthus tea); geraniol, phenylethyl alcohol, jasmone, methyl jasmonate, hexadecanoic acid, 4-ethyl-benzaldehyde, 2-methylbutyl hexanoate, and indole (michelia tea); and 3,5-dimethoxytoluene, (E)-β-ionone, and 2-methylbutyl hexanoate (rose tea), were identified through chemometric analysis combined with relative odor activity values (ROAVs) and sensory evaluation. This study provides new insights into the formation of aroma molecular fingerprints during green tea scenting with flowers, providing theoretical guidance for infusing distinct aroma characteristics into green tea during scented tea processing.

Low-temperature stress has become a major limiting factor for the sustainable production of forage crops and animal husbandry. This experimental study evaluated the effects of optimizing phosphorus application on the antioxidant properties and carbon-nitrogen metabolism physiology of alfalfa (Medicago sativa L.) under LT stress, aiming to provide a reference for efficient stress-resistant alfalfa production. In this study, the LT tolerant cultivar ‘Caoyuan’ (CY) and LT sensitive cultivar ‘Xinmu’ (XM) were used as plant materials, and the physiological changes of alfalfa plants under natural temperature (NT) and LT were compared under traditional phosphorus application (R1) and postponing phosphorus application (R2) treatments. The results showed that LT stress increased the accumulation of malondialdehyde (MDA) in alfalfa plants and inhibited root activity, carbon metabolism, and photosynthesis in both cultivars. The negative impacts of LT are more prevalent in XM than in CY. The postponing phosphorus application treatments enhanced root vitality as compared to the traditional phosphorus application treatments and accumulated more soluble sugar (5.6-11.2%), sucrose (8.5-14.0%), proline (7.5-11.7%), and soluble protein (8.3-11.7%) by increasing the enzyme activities related to carbon-nitrogen metabolism. Under postponing phosphorus application treatments, the enzymatic activities of antioxidants and regulation of osmotic sub-stances significantly increased in the leaves, MDA contents were decreased by 4.6-7.6%, and chlorophyll contents were increased by 4.8-8.6%, the net photosynthetic rate in alfalfa leaves increased by 5.1-7.5%. Besides, plant dry weight, root dry weight, and plant phosphorus concentration increased by 5.8-16.9%, 7.8-21.0%, and 5.1-9.9% under postponing phosphorus application treatments. In summary, split-phosphorus fertilization improved the nutrient absorption capacity of alfalfa roots compared to traditional phosphorus application treatments under LT stress. Moreover, it improved the carbon-nitrogen metabolism physiology and photosynthetic production capacity of the alfalfa plants, thus reducing the adverse effects of LT stress on the growth and development of alfalfa.

Forever Summer Hydrangea (Hydrangea macrophylla) is a common flowering plant in the Yangtze River Valley area of China, and it is widely cultivated globally (Chen et al. 2015). In July 2023, H. macrophylla leaves exhibiting visible diseased lesions were reported in a nursery in Wuhu, Anhui Province, China. The incidence reached 40% in a 0.2 ha area. The primary disease symptom was multiple irregular necrotic spots (0.5 to 1 mm in diameter) appearing on the leaves. These spots on the leaves were faded yellow around the perimeter and grayish brown in the center.). 15 leaf samples were sterilized with 75% alcohol and rinsed three times in sterile distilled water, then transferred to antibiotic-added potato dextrose agar (PDA) for incubation at 27°C. The colonies were fluffy, flocculent, or hairy, dark green, gray-green to gray-brown in color, and spreading or protruding punctate with a colorless halo on PDA. The conidiophores were brown to dark brown, smooth or rough surface, mostly unbranched, clearly differentiated, erect or curved. The conidia displayed a light brown to brown hue, lemon shape, fusiform, elongated ellipsoid or others with obvious spore markings and spore umbilicus. Genomic DNA was extracted from fungal colonies on infected leaves of three collections separately (Braun et al. 2003) and the internal transcribed spacer regions (ITS), actin (ACT) genes and partial translation elongation factor-l-alpha (EF) were amplified and sequenced using the primers ITS1/4 (Yin et al. 2012), ACT-512F/ACT-783R and EF 1-728F/986R (Carbone and Kohn 1999), respectively. DNA sequences of isolates were identical and deposited in GenBank (accession no. OR362754 for ITS, OR611929 for ACT and PP209106 for EF). The consensus sequences from ITS, EF and ACT showed 100%, 98.98% and 100% identical to Cladosporium strains (accession no. OQ186140.1, MT154169.1 and OL322092.1), respectively. To confirm the pathogenicity of the isolates, hydrangeas were planted in 15-cm pots containing commercial potting mix (one plant/pot). Three healthy plants were inoculated at the five to eight leaf stage by spraying 50 μL of the isolate conidial suspension (4 × 106 spores/mL) on healthy leaves. Three plants treated with sterile distilled water were used as controls. After inoculation, all plants were placed in a humidity chamber (>95% relative humidity, 26°C) for 48 h and then transferred to a greenhouse at 22/27°C. All inoculated leaves exhibited symptoms similar to those observed in the nursery 10 days after inoculation, while no symptoms were observed for control leaves. The fungus was re-isolated and confirmed to be C. tenuissimum. Based on the above morphological characterization and molecular identification, the causal agent for this leaf spot disease was identified as C. tenuissimum. Although C. tenuissimum has been reported to cause disease on H. paniculata in northern China (Li et al.2021), this is the first time that C. tenuissimum has been found on H. macrophylla in southern China. This new disease of H. macrophylla caused by C. tenuissimum is a threat to urban greening and is worth further investigation.

Background: Sedum, with the largest number of species in the family Crassulaceae, is a taxonomically complex genus and an important group of horticultural plants within this family. Despite extensive historical research using diverse datasets, the branching patterns within this genus and the family remain debatable. Methods: In this study, we conducted sequencing and comparative analyses of plastomes from eight Sedum species, focusing on the diversities in nucleotide, microsatellite repeats, putative RNA editing, and gene content at IR junctions. The phylogenetic inferences were further conducted at the order level—Saxifragales. Results: Our IR junction analyses of the eight investigated Sedum species detected a unique 110 bp IR extension into rps19, a feature highly conserved across Crassulaceae species, indicating a remarkably family-specific pattern. Additionally, we obtained 79 PCGs from 148 Saxifragales species and constructed a phylogenetic tree using a larger set of plastomes than in previous studies. Our results confirm the polyphyly of Sedum and reveal that S. emarginatum is more closely related to S. makinoi than to S. alfredii, which is sister to S. plumbizincicola. Furthermore, we also performed analyses of codon usage, putative RNA editing sites, and microsatellite repeats. Conclusions: These findings and the generated sequence data will enrich plastid resources and improve understanding of the evolution of Sedum, Crassulaceae, and Saxifragales.