Design and Experiment of Online Detection System for Water Content of Fresh Tea Leaves after Harvesting Based on Near Infra-Red Spectroscopy.

Fresh tea leaves continuously lose water after harvesting, and the level of water content directly affects the configuration of tea processing parameters. To address this problem, this study established an online detection system for the water content of fresh tea leaves after harvesting based on near-infrared spectroscopy. The online acquisition and analysis system of the temperature and humidity sensor signal data was developed based on LabVIEW and Python software platforms. Near-infrared spectral data, environmental temperature, and humidity were collected from fresh leaves after harvesting. Spectral data were combined with PLS (partial least squares) to develop a prediction model for the water content of fresh tea leaves. Simultaneously, data communication between LabVIEW and PLC was established, laying the foundation for establishing a feedback mechanism to send the prediction results to the main platform of the lower computer. This provides a more objective and accurate basis for the detection of fresh leaves before processing and regulation during processing, thereby effectively promoting the standardisation and intelligent development of tea-processing equipment.

Effect of Pseuderanthemum palatiferum (Nees) Radlk fresh leaf ethanolic extract on human breast cancer MDA-MB-231 regulated cell death.

Leaf extracts of Pseuderanthemum palatiferum (Nees) Radlk were investigated for their effects on human breast cancer MDA-MB-231 cell growth inhibition. Pseuderanthemum palatiferum (Nees) Radlk extracts were prepared using fresh or dried leaves and extracted by either water or 95% ethanol, respectively. Fresh leaf ethanolic extract was the most toxic to MDA-MB-231 cells measured by 3-(4,5-dimethyl)-2,5-diphenyl tetrazolium bromide assay. Fresh leaf ethanolic extract-treated MDA-MB-231 cell death was stained with propidium iodide and examined under fluorescence microscopy. Cell death was confirmed by annexin V-fluorescein isothiocyanate/propidium iodide and propidium iodide-stained cells employing flow cytometry. The mitochondrial transmembrane potential was disrupted in fresh leaf ethanolic extract-treated MDA-MB-231 cells and the percentage of cells with reduced mitochondrial transmembrane potential increased according to concentrations. Mitochondrial transmembrane potential-driven regulated cell deaths were in the form of both apoptosis and necrosis. Oxidative stress probe, 2',7'-dichlorodihydrofluorescein diacetate, was used to indicate the redox status. Dichlorofluorescein level was significantly lower at high fresh leaf ethanolic extract concentrations. Total phenolic contents were found in all Pseuderanthemum palatiferum (Nees) Radlk extracts, whereas Ca2+ level in the cytosol increased, indicating Ca2+ overload and endoplasmic reticulum stress involvement with the activation of caspase-3, -8, and -9. In conclusion, fresh leaf ethanolic extract induced human breast cancer MDA-MB-231 programmed cell death via endoplasmic reticulum and oxidative stress by activating both extrinsic and intrinsic signaling pathways.

A comparative analysis of morphology, microstructure, and volatile metabolomics of leaves at varied developmental stages in Ainaxiang (Blumea balsamifera (Linn.) DC.).

Introduction: Ainaxiang (Blumea balsamifera (Linn.) DC.) is cultivated for the extraction of (-)-borneol and other pharmaceutical raw materials due to its abundant volatile oil. However, there is limited knowledge regarding the structural basis and composition of volatile oil accumulation in fresh B. balsamifera leaves. Methods: To address this problem, we compare the fresh leaves' morphology, microstructure, and volatile metabonomic at different development stages, orderly defined from the recently unfolded young stage (S1) to the senescent stage (S4). Results and discussion: Distinct differences were observed in the macro-appearance and microstructure at each stage, particularly in the B. balsamifera glandular trichomes (BbGTs) distribution. This specialized structure may be responsible for the accumulation of volatile matter. 213 metabolites were identified through metabolomic analysis, which exhibited spatiotemporal accumulation patterns among different stages. Notably, (-)-borneol was enriched at S1, while 10 key odor metabolites associated with the characteristic balsamic, borneol, fresh, and camphor aromas of B. balsamifera were enriched in S1 and S2. Ultra-microstructural examination revealed the involvement of chloroplasts, mitochondria, endoplasmic reticulum, and vacuoles in the synthesizing, transporting, and storing essential oils. These findings confirm that BbGTs serve as the secretory structures in B. balsamifera, with the population and morphology of BbGTs potentially serving as biomarkers for (-)-borneol accumulation. Overall, young B. balsamifera leaves with dense BbGTs represent a rich (-)-borneol source, while mesophyll cells contribute to volatile oil accumulation. These findings reveal the essential oil accumulation characteristics in B. balsamifera, providing a foundation for further understanding.

Investigating the phytotoxic potential of Verbesina encelioides: effect on growth and performance of co-occurring weed species.

Allelopathy has been proposed as an efficient mechanism of invasion by plant species via growth inhibition and suppression of the resident plant community. Verbesina encelioides (Cav.) Benth. & Hook. f. ex A. Gray (golden crownbeard; Asteraceae), a native of south-western USA and Mexican Plateau, is an emerging troublesome invasive weed species of north-western states of India. We investigated the allelopathic potential of the aqueous extracts prepared from the fresh foliage and leaf litter of V. encelioides on its co-occurring species, Amaranthus viridis and Senna occidentalis. Phytotoxicity bioassay showed concentration-dependent (control < 0.5% < 1% < 2% < 4% extract) inhibition of growth and photosynthetic parameters in the test plants. Both the extracts induced ~ 50% inhibition of germination compared to control at 4% concentration. The maximum synthesis effect (collective effect on seedling length and dry weight) was observed to be - 0.69 and - 0.62 in A. viridis and - 0.68 and - 0.57 in S. occidentalis for the fresh leaf and leaf litter extracts, respectively, at 4% concentration. Also, an antagonistic concentration-dependent impact was observed on the photosynthetic pigments (total chlorophyll and chlorophyll a content) and photosynthetic efficiency. The liquid chromatography-mass spectrometry assay of leaf extracts revealed the presence of 15 allelochemicals including phenolic acids, flavonoids, phytosterols, phytophenols, dicarboxylic acid, guanidine, and triterpenes. Of these, 14 compounds were present in both fresh and leaf litter materials. However, a guanidine derivative, galegine, was only found in the fresh leaf material of the plant. The findings support the novel weapon hypothesis and suggest that V. encelioides competitively excludes its neighboring plants by virtue of allelopathic interference.

Phyllosphere antibiotic resistome in a natural primary vegetation across a successional sequence after glacier retreat.

The spread of antibiotic-resistance genes (ARGs) has posed a significant threat to human health over the past decades. Despite the fact that the phyllosphere represents a crucial pool of microorganisms, little is known about the profile and drivers of ARGs in less human interference natural habitats. In order to minimize the influence of environmental factors, here we collected leaf samples from the early-, middle- and late-successional stages across a primary vegetation successional sequence within 2 km, to investigate how the phyllosphere ARGs develop in natural habitats. Phyllosphere ARGs were determined using high-throughput quantitative PCR. Bacterial community and leaf nutrient content were also measured to assess their contribution to the phyllosphere ARGs. A total of 151 unique ARGs were identified, covering almost all recognized major antibiotic classes. We further found that there was some stochastic and a core set of the phyllosphere ARGs during the plant community succession process, due to the fluctuant phyllosphere habitat and specific selection effect of plant individuals. The ARG abundance significantly decreased due to the reduction of the phyllosphere bacterial diversity, community complexity, and leaf nutrient content during the plant community succession process. While the closer links between soil and fallen leaf resulted in a higher ARG abundance in leaf litter than in fresh leaf. In summary, our study reveals that the phyllosphere harbors a broad spectrum of ARGs in the natural environment. These phyllosphere ARGs are driven by various environmental factors, including the plant community composition, host leaf properties, and the phyllosphere microbiome.

Analysis of Characteristics in the Macro-Composition and Volatile Compounds of Understory Xiaobai White Tea.

Understory planting affects the growth environment of tea plants, regulating the tea plant growth and the formation of secondary metabolites, which in turn affects the flavor of Xiaobai white tea. The present research adopted biochemical composition determination, widely targeted volatilities (WTV) analysis, multivariate statistical analysis, and odor activity value (OAV) analysis to analyze the characteristics in the macro-composition and volatile compounds of understory white tea. The sensory evaluation results indicated that understory Xiaobai white tea (LWTs) was stronger than ordinary Xiaobai white tea (PWTs) in terms of the taste of smoothness, sweetness, and thickness as well as the aromas of the flower and sweet. Understory planting reduced light intensity and air temperature, increased air humidity, organic matter, total nitrogen, and available nitrogen contents, which improved the growth environment of tea plants. The phytochemical analysis showed that the water-extractable substances, caffeine, flavonoids, and soluble sugar contents of understory tea fresh-leaf (LF) were higher than those of ordinary fresh-leaf (PF). The phytochemical analysis showed that the free amino acids, theaflavins, thearubigins, water-extractable substances, and tea polyphenols contents of LWTs were significantly higher than those of PWTs, which may explain the higher smoothness, sweetness, and thickness scores of LWTs than those of PWTs. The 2-heptanol, 2-decane, damasone, and cedar alcohol contents were significantly higher in LWTs than in PWTs, which may result in stronger flowery and sweet aromas in LWTs than in PWTs. These results provide a firm experimental basis for the observed differences in the flavor of LWTs and PWTs.

Biochemical and physiological responses of oil palm to bud rot caused by Phytophthora palmivora.

In recent years, global consumption of palm oil has increased significantly, reaching almost 43 million tons in 2010. The sustainability of oil palm (Elaeis guineensis) cultivation has been compromised because of the bud rot disease whose initial symptoms are caused by Phytophthora palmivora. There was a significant incidence of the disease, from an initial stage 1 of the disease to the highest stage 5, that affected photosynthetic parameters, content of pigments, sugars, polyamines, enzymatic antioxidant activities, phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) and ß-(1,3) glucanase (ß-Gluc, EC 3.2.1.39). In healthy palms photosynthesis was 13.29 µmol CO2 m(-2) s(-1) in average, while in stage 5 the average photosynthesis was around 3.66 µmol CO2 m(-2) s(-1). Additionally, total chlorophyll was reduced by half at the last stage of the disease. On the contrary, the contents of putrescine, spermine and spermidine increased three, nine and twelve times with respect to stage 5, respectively. Antioxidant enzyme activities, as well as the phenylalanine ammonia-lyase and ß-(1,3) glucanase showed an increase as the severity of the disease increased, with the latter increasing from 0.71 EAU in healthy palms to 2.60 EAU in plants at stage 5 of the disease. The peroxidase (POD, EC 1.11.1.7) enzymatic activity and the content of spermidine were the most sensitive indicators of disease.