Key Factors of Quality Formation in Wuyi Black Tea during Processing Timing.

As the most consumed tea in the world, all kinds of black tea are developed from Wuyi black tea. In this study, quality components, regulatory gene expression, and key enzyme activity during the processing were analyzed to illustrate the taste formation of WBT. Withering mainly affected the content of amino acids, while catechins and tea pigments were most influenced by rolling and the pre-metaphase of fermentation. Notably, regulatory gene expression was significantly down-regulated after withering except for polyphenoloxidase1, polyphenoloxidase2, leucoanthocyanidin dioxygenase, chalcone isomerase, and flavonoid 3', 5'-hydroxylase. Co-expression of flavonoid pathway genes confirmed similar expression patterns of these genes in the same metabolic pathway. Interestingly, rolling and fermentation anaphase had a great effect on polyphenol oxidase, and fermentation pre-metaphase had the greatest effect on cellulase. Since gene regulation mainly occurs before picking, the influence of chemical reaction was greater during processing. It was speculated that polyphenol oxidase and cellulase, which promoted the transformation of quality components, were the key factors in the quality formation of WBT. The above results provide theoretical basis for the processing of WBT and the reference for producing high-quality black tea.

The fluoride exporter (CsFEX) regulates fluoride uptake/accumulation in Camellia sinensis under different pH.

Fluoride (F) can be absorbed from the environment and hyperaccumulate in leaves of Camellia sinensis without exhibiting any toxic symptoms. Fluoride exporter in C. sinensis (CsFEX) could transport F to extracellular environment to alleviate F accumulation and F toxicity, but its functional mechanism remains unclear. Here, combining with pH condition of C. sinensis growth, the characteristics of CsFEX and mechanism of F detoxification were further explored. The results showed that F accumulation was influenced by various pH, and pH 4.5 and 6.5 had a greater impact on the F accumulation of C. sinensis. Through Non-invasive Micro-test Technology (NMT) detection, it was found that F uptake/accumulation of C. sinensis and Arabidopsis thaliana might be affected by pH through changing the transmembrane electrochemical proton gradient of roots. Furthermore, diverse expression patterns of CsFEX were induced by F treatment under different pH, which was basically up-regulated in response to high F accumulation, indicating that CsFEX was likely to participate in the process of F accumulation in C. sinensis and this process might be regulated by pH. Additionally, CsFEX functioned in the mitigation of F sensitivity and accumulation strengthened by lower pH in Escherichia coli and A. thaliana. Moreover, the changes of H+ flux and potential gradient caused by F were relieved as well in transgenic lines, also suggesting that CsFEX might play an important role in the process of F accumulation. Above all, F uptake/accumulation were alleviated in E. coli and A. thaliana by CsFEX through exporting F-, especially at lower pH, implying that CsFEX might regulate F accumulation in C. sinensis.

Nitric Oxide Participates in Aluminum-Stress-Induced Pollen Tube Growth Inhibition in Tea (Camelliasinensis) by Regulating CsALMTs.

Nitric oxide (NO), as a signal molecule, is involved in the mediation of heavy-metal-stress-induced physiological responses in plants. In this study, we investigated the effect of NO on Camellia sinensis pollen tubes exposed to aluminum (Al) stress. Exogenous application of the NO donor decreased the pollen germination rate and pollen tube length and increased the malondialdehyde (MDA) content and antioxidant enzyme activities under Al stress. Simultaneously, the NO donor effectively increased NO content in pollen tube of C. sinensis under Al stress and could aggravate the damage of Al3+ to C. sinensis pollen tubes by promoting the uptake of Al3+. In addition, application of the NO-specific scavenger significantly alleviated stress damage in C. sinensis pollen tube under Al stress. Moreover, 18 CsALMT members from a key Al-transporting gene family were identified, which could be divided into four subclasses. Pearson correlation analysis showed the expression level of CsALMT8 showed significant positive correlation with the Al3+ concentration gradient and NO levels, but a significant negative correlation with pollen germination rate and pollen tube length. The expression level of CsALMT5 was negatively correlated with the Al3+ concentration gradient and NO level, and positively correlated with pollen germination rate and pollen tube length. The expression level of CsALMT17 showed a significant negative correlation with Al3+ concentration and NO content in pollen tubes, but significant positive correlation with pollen germination rate and pollen tube length. In conclusion, a complex signal network regulated by NO-mediated CsALMTs revealed that CsALMT8 was regulated by environmental Al3+ and NO to assist Al3+ entry into pollen tubes; CsALMT5 might be influenced by the Al3+ signal, stimulate malate efflux in vacuoles and chelate with Al3+ to detoxify Al in C. sinensis pollen tube.

MIAOME: Human microbiome affect the host epigenome.

Besides the genetic factors having tremendous influences on the regulations of the epigenome, the microenvironmental factors have recently gained extensive attention for their roles in affecting the host epigenome. There are three major types of microenvironmental factors: microbiota-derived metabolites (MDM), microbiota-derived components (MDC) and microbiota-secreted proteins (MSP). These factors can regulate host physiology by modifying host gene expression through the three highly interconnected epigenetic mechanisms (e.g. histone modifications, DNA modifications, and non-coding RNAs). However, no database was available to provide the comprehensive factors of these types. Herein, a database entitled 'Human Microbiome Affect The Host Epigenome (MIAOME)' was constructed. Based on the types of epigenetic modifications confirmed in the literature review, the MIAOME database captures 1068 (63 genus, 281 species, 707 strains, etc.) human microbes, 91 unique microbiota-derived metabolites & components (16 fatty acids, 10 bile acids, 10 phenolic compounds, 10 vitamins, 9 tryptophan metabolites, etc.) derived from 967 microbes; 50 microbes that secreted 40 proteins; 98 microbes that directly influence the host epigenetic modification, and provides 3 classifications of the epigenome, including (1) 4 types of DNA modifications, (2) 20 histone modifications and (3) 490 ncRNAs regulations, involved in 160 human diseases. All in all, MIAOME has compiled the information on the microenvironmental factors influence host epigenome through the scientific literature and biochemical databases, and allows the collective considerations among the different types of factors. It can be freely assessed without login requirement by all users at: http://miaome.idrblab.net/ttd/.

Organic amendments improved soil quality and reduced ecological risks of heavy metals in a long-term tea plantation field trial on an Alfisol.

Tea plantation can cause strong soil degradation, e.g. acidification, basic nutrient decrease and microbial diversity loss, naturally by its root activity and secondary by practically tremendous synthetic N input. Organic amendments application is considered a practical way to mitigate the above adverse consequence. However, the trade-off between agronomic and environmental effects on the application of the organic amendments is still under debate. Herein, we conducted a long-term field experiment with four treatments, including control (without and fertiliser) (CK), chemical fertiliser treatment (CF), chicken manure treatment (CM) and chicken manure combined with biochar treatment (CMB) to investigate the effects of organic amendments application on soil quality, heavy metal contamination and tea production in a tea plantation. Totally 16 plots were arranged randomly with a completely randomised design. The results showed that CM and CMB treatments improved soil nutrient, mitigated soil acidification and ameliorated soil porosity compared to CF treatment. CMB treatment displayed a relatively high tea yield and quality in three consecutive years of monitoring. However, CM and CMB treatments elevated the heavy metal (HM) potential ecological risk (RI) and Nemerow's composite index (Ps). CM treatment significantly increased available As, Pb, Cu and Zn concentrations compared to CF treatment, while CMB treatment significantly decreased available Cr and Cu concentrations and slightly decreased available Cd, Pb and Ni concentrations compared to CM treatment. But the increase of available As and Zn in CMB treatment compared to CM treatment also indicated adverse effects of biochar addition. The PLS-PM model showed HM risk had direct negative effects on tea quality. Moreover, soil fungal community revealed positive effects on tea yield and negative effects on tea quality. Overall, our study proved that CMB treatment could improve soil quality, reduce available Cr and Ni concentrations, maintain tea yield and increase tea quality.

Comparison of Bone Metastases between 18F-NaF PET/CT, 18F-NaF PET, and Planar 99mTc-MDP Bone Scintigraphy in Patients with Newly Diagnosed Nasopharyngeal Carcinoma.

Purpose: Our study aims to compare the diagnostic value of 18F-NaF positron emission tomography-computed tomography (PET/CT), 18F-NaF PET, and planar 99mTc-MDP bone scintigraphy for detection of bone metastases in patients with newly diagnosed nasopharyngeal carcinoma (NPC). Methods: Our study retrospectively analyzed 58 patients with pathologically proven NPC. They all underwent both 18F-NaF PET/CT and planar 99mTc-MDP bone scintigraphy within a 7-day interval. Bone metastases were confirmed by follow-up using PET/CT, contrast-enhanced computed tomography (CT), and magnetic resonance imaging (MRI). These three examinations were compared using per-patient-based analysis and per-lesion-based analysis. Results: 19 patients (32.7%) were classified as having bone metastatic disease in their final diagnosis. The patient-based diagnostic performances (sensitivity, specificity, and overall accuracy) were as follows: 18F-NaF PET/CT (100%, 92.3%, and 94.8%), 18F-NaF PET (100%, 53.8%, and 69.0%), and planar 99mTc-MDP bone scintigraphy (78.9%, 74.4%, and 75.9%). The overall accuracy of 18F-NaF PET/CT was significantly more favorable compared to 18F-NaF PET (p=0.002) and to planar 99mTc-MDP bone scintigraphy (p=0.044). The lesion-based diagnostic performances (sensitivity, specificity, and overall accuracy) were as follows: 18F-NaF PET/CT (98.5%, 93.9%, and 96.6%), 18F-NaF PET (98.5%, 57.1%, and 81.1%), and planar 99mTc-MDP bone scintigraphy (69.9%, 85.7%, and 76.4%). Conclusion: 18F-NaF PET/CT outperforms 18F-NaF PET or planar 99mTc-MDP bone scintigraphy in detecting bone metastases with newly diagnosed NPC on a patient-based and lesion-based analysis.

Soot Morphology and Nanostructure Differences between Chinese Aviation Kerosene and Algae-Based Aviation Biofuel in Free Jet Laminar Diffusion Flames.

Aircraft soot has a significant effect on the air quality and human health. The aim of this study is to investigate the evolution of soot morphology in free jet laminar diffusion flames between Chinese traditional aviation kerosene RP-3 and algae-based aviation biofuels. The differences in height, profile, and structural properties of soot between the RP-3 flame and biofuel flame are determined. A laboratory-made probe sampling method was applied for soot sample collection. Transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and elemental analyzers were used to analyze the collected soot particles. The average particle size of soot increases first and then decreases in both flames, and the size of biofuel primary particles is smaller than that of jet fuel RP-3 particles along the same flame height. At the flame tip, the primary particle sizes of RP-3 soot and biofuel soot are 22.7 and 15.6 mm, respectively. In comparison with the RP-3 soot, the nanostructure of biofuel soot particles along the same flame height exhibits a shorter fringe lattice, a larger fringe tortuosity, and a larger interlayer spacing, which indicate a higher degree of oxidation reactivity. Meanwhile, RP-3 soot particles have a lower H/C atom ratio and have greater intensity in X-ray diffraction, which indicates a more orderly and compact lattice structure. This study provides some references in studying the algae-based biofuel with regard to soot formation.

Water-energy-carbon nexus in China's intra and inter-regional trade.

Water consumption, energy use, and carbon emission are three related key anthropogenic impacts on the natural environment. China is the largest carbon emitter and energy consumer, with the serious unevenly distributed water resources. Therefore, investigating the water-energy-carbon (WEC) nexus is important for China's environmental footprint reduction. This study explores the relation between water utilization, energy consumption, and carbon emission in China, based on a multiregional input-output (MRIO) analysis. The WEC nexus is discussed comprehensively in consideration of the utilization of water and energy and the emission of carbon, as well as the trade to and from and the consumption activities in different sectors and provinces. Results show that water, energy, and carbon present significant consistency in production and consumption processes. Sectors with higher consumption coefficients dominate the transfer of virtual WEC. Although virtual WEC mainly transfers from less developed regions to relatively developed regions, Category 1 (i.e., WEC all import) and category 2 (i.e., WEC disaccord) present opposite results to and category 3 (i.e., WEC all export) provinces in terms of W-E and W-C nexus. The net water and energy transfers are significantly positively correlated in category 1 provinces, whereas both sides are negatively correlated in category 2 and 3 provinces. This phenomenon also exists in the relationship between net water and carbon transfers. The virtual water, as well as energy and carbon export pressures are dispersed in these export provinces. Findings of this study are expected to assist the government in decreasing the environmental footprints and achieve sustainable development in China.

Patterns of carbon footprints of main grains production in China: a comparison between main and non-main producing areas.

Understanding the spatiotemporal patterns of carbon footprints (CFs) of grains production is important to formulate regional heterogeneous greenhouse gas (GHG) mitigation strategies. This study evaluates the CFs, farm CFs (FCFs: CFs of per unit area), and production CFs (PCFs: CFs of per unit yield) of main grains production in China based on a new scale data set: agricultural statistics data of over 300 prefecture-level regions. A comparison of CFs of main grains production between main producing area (MPA) and non-main producing area (NMPA) are firstly discussed on a totally new scale. Results show that the CFs of main grains production of MPA accounts for 54-57% of country's total although the area of farmland of MPA only accounts for 42%. The PCF and FCF of rice production are higher in MPA, while those of wheat and maize production are lower in MPA. It implies that there are less GHG emission of rice (main paddy grain) productions in NMPA and less GHG emission of wheat and maize (main dryland grains) production in MPA. In additional, the PCF of rice shows growth, while that of wheat and maize shows decline from 2008 to 2017. The growth of PCF of rice is mainly driven by the rise of PCF in MPA. Findings are expected to improve the understanding patterns of China's CF of main grains production and subsequently contribute to GHG mitigation.

Moderation effect of urban density on changes in physical activity during the coronavirus disease 2019 pandemic.

Various social distancing measures were carried out in many cities worldwide during the coronavirus disease 2019 pandemic (COVID-19). These measures have led to decreased physical activity levels and higher health risks among urban populations. Strong evidence has been established that built environment characteristics can stimulate physical activity and thus improve public health during non-pandemic periods. Urban density was arguably one of the most important built environment characteristics. However, little is known about whether high urban density amplifies or attenuates the decline in physical activity during the pandemic. Based on two-wave physical activity data collected before and during the pandemic (in January and May 2020, respectively), we used moderation analysis to compare the changes in physical activity levels between people living in low- and high-density neighborhoods. Our results showed that people living in low-density areas have a smaller decrease in physical activity conducted in neighborhood, compared to those living in high-density areas. Our findings suggest that a flexible and porous urban development strategy could enhance the resilience of a city during the coronavirus pandemic and beyond.

Review of Associations between Built Environment Characteristics and Severe Acute Respiratory Syndrome Coronavirus 2 Infection Risk.

The coronavirus disease 2019 pandemic has stimulated intensive research interest in its transmission pathways and infection factors, e.g., socioeconomic and demographic characteristics, climatology, baseline health conditions or pre-existing diseases, and government policies. Meanwhile, some empirical studies suggested that built environment attributes may be associated with the transmission mechanism and infection risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, no review has been conducted to explore the effect of built environment characteristics on the infection risk. This research gap prevents government officials and urban planners from creating effective urban design guidelines to contain SARS-CoV-2 infections and face future pandemic challenges. This review summarizes evidence from 25 empirical studies and provides an overview of the effect of built environment on SARS-CoV-2 infection risk. Virus infection risk was positively associated with the density of commercial facilities, roads, and schools and with public transit accessibility, whereas it was negatively associated with the availability of green spaces. This review recommends several directions for future studies, namely using longitudinal research design and individual-level data, considering multilevel factors and extending to diversified geographic areas.

Urban greenery cushions the decrease in leisure-time physical activity during the COVID-19 pandemic: A natural experimental study.

The coronavirus disease 2019 (COVID-19) pandemic and related social distancing measures have altered the daily lifestyles of people worldwide. Although studies on this disease are emerging rapidly, less is known about the impacts of COVID-19 and urban greenery on leisure-time physical activity, which is critical to maintain health for urban residents during the pandemic. In this study, we used a natural experimental research design to identify whether urban greenery cushions the decrease in leisure-time physical activity caused by the pandemic and related social distancing measures in a high-density city. The two-wave physical activity data (before and during the pandemic) were collected for urban residents in neighborhoods with high or low levels of greenery. The results of difference-in-differences model suggest that urban greenery mitigated the decrease in physical activity during the pandemic. People who lived in greener neighborhoods experienced a lesser decrease in the leisure-time physical activity level than those who lived in less green neighborhoods. Additionally, people who lived in greener neighborhoods experienced increased levels of physical activity related to visits to country parks during the pandemic. These findings suggest that urban green spaces play a significant role in shaping physical activity and providing a refuge for the public during crises. Our study is among the first to investigate the impact of urban greenery on pandemic-induced changes in leisure-time physical activity in densely populated Asian cities, and our findings shed light on the potential protective role of urban greenery on public health during the COVID-19 pandemic and beyond.

Interaction of climate change, potentially toxic elements (PTEs), and topography on plant diversity and ecosystem functions in a high-altitude mountainous region of the Tibetan Plateau.

Potentially toxic elements (PTEs) generated from mining activities have affected ecological diversity and ecosystem functions around the world. Accurately assessing the long-term effects of PTEs is critical to classifying recoverable areas and proposing management strategies. Mining activities that shape geographical patterns of biodiversity in individual regions are increasingly understood, but the complex interactions on broad scales and in changing environments are still unclear. In this study, we developed a series of empirical models that simulate the changes in biodiversity and ecosystem functions in mine-affected regions along elevation gradients (1500-3600 m a.s.l) in the metal-rich Qilian Mountains (∼800 km) on the northeastern Tibetan Plateau (China). Our results confirmed the crucial role of PTEs dispersal, topography, and climatic heterogeneity in the diversification of plant community composition. On average, 54% of the changes in ecosystem functions were explained by the interactions among topography, climate, and PTEs. However, merely 30% of the changes were correlated with a single driver. The changes in species composition (explained variables = 94.8%) in the PTE-polluted habitats located in the warm and humid low-elevation deserts and grasslands were greater than those occurring in the dry alpine deserts and grasslands. The ecosystem functions (soil characteristics, nutrient migration, and plant biomass) experienced greater changes in the humid low-elevation grasslands and alpine deserts. Our results suggest that the processes driven by climate or other factors can result in high-altitude PTE-affected habitat facing greater threats.

A natural experiment reveals impacts of built environment on suicide rate: Developing an environmental theory of suicide.

BACKGROUND: Suicide is a global challenge. Although it is clear that socioeconomic and demographic factors influence suicide rates, we know little about the impacts of the built environment on suicide rates. METHODS: We investigated the relationship between characteristics of the built environment and suicide death rates over a 13-year period in 151 rent-only public housing communities in Hong Kong. The regulations of the public housing authority in Hong Kong constituted a natural experiment with minimal self-selection bias. We conducted hierarchical regression analyses and found that characteristics of the built environment were significantly associated with suicide rates after controlling for SES and demographic factors at the community level. RESULTS: Three significant environmental factors were identified distance to the nearest urban center, distance to the nearest Mass Transit Railway station, and gross flat area per person. CONCLUSION: These findings demonstrate a significant association between features of the built environment and suicide rates. They also suggest possible interventions that might reduce suicide through design, or redesign, of the built environment. Lastly, we propose an environmental theory of suicide based on the Interpersonal Theory of Suicide.

Multi-criteria decision making and fairness evaluation of water ecological carrying capacity for inter-regional green development.

Determining water ecological carrying capacity (WECC) is of great significance to ensure inter-regional green development. This study presents a comprehensive evaluation framework for WECC assessment in the Yangtze River Economic Zone (YREZ), China. Effects of water resources, socio-economic, and ecological elements on WECC can be evaluated based on multi-criteria decision analysis. Gini and unbalance coefficients are used for measuring the regional fairness between WECC and socio-economic development. Surface water production pressure (SWPP) and groundwater pollution risk (GPR) are further regarded as indicators for expressing water resources constraint on shale gas extraction in the YREZ. Results disclose that the average WECC level decreases from 0.439 in 2000 to 0.4007 in 2016, which is the opposite of the changing trend in the Beijing-Tianjin-Hebei Region. A high WECC level appears in Zhejiang (0.5126) with a good state, but that of Guizhou (0.3983), Anhui (0.3968), Hunan (0.3914), and Chongqing (0.3651) are at the alert state. The obstacle factors of WECC in the eastern YREZ mostly originate from socio-economic and water resource subsystems, while that in the middle and western YREZ mainly arise from water resources and ecological subsystems. Fairness analysis shows a well-matching characteristic between the overall WECC and socio-economic performances due to a majority of their Gini coefficients lower than 0.4, while a poor matching characteristic exists in terms of provincial differences owing to their varied unbalance coefficients, especially in Guizhou, Jiangsu, and Shanghai. Moreover, Chongqing with most of shale gas reserves is characterized by slight SWPP (1.0202) and GPR (0.0188), but the prospect of shale gas development in Sichuan is not optimistic due to its high SWPP (1.0846) and GPR (0.0647). Recycling of flowback and product waters can significantly lighten regional water resources pressure. This presented framework can be applied into many other Chinese cities (e.g., Beijing-Tianjin-Hebei Region) with slight modifications according to their actual situations for supporting water resource managers and government with decision making.

Measuring the Destination Accessibility of Cycling Transfer Trips in Metro Station Areas: A Big Data Approach.

Cycling is a green, sustainable, and healthy choice for transportation that has been widely advocated worldwide in recent years. It can also encourage the use of public transit by solving the "last-mile" issue, because transit passengers can cycle to and from transit stations to achieve a combination of speed and flexibility. Cycling as a transfer mode has been shown to be affected by various built environment characteristics, such as the urban density, land-use mix, and destination accessibility, that is, the ease with which cyclists can reach their destinations. However, cycling destination accessibility is loosely defined in the literature and the methods of assessing cycling accessibility is often assumed to be equivalent to walking accessibility using the same decay curves, such as the negative exponential function, which ignores the competitive relationship between cycling and walking within a short distance range around transit stations. In this study, we aim to fill the above gap by measuring the cycling destination accessibility of metro station areas using data from more than three million bicycle-metro transfer trips from a dockless bicycle-sharing program in Shenzhen, China. We found that the frequency of bicycle-metro trips has a positive association with a trip distance of 500 m or less and a negative association with a trip distance beyond 500 m. A new cycling accessibility metric with a lognormal distribution decay curve was developed by considering the distance decay characteristics and cycling's competition with walking. The new accessibility model outperformed the traditional model with an exponential decay function, or that without a distance decay function, in predicting the frequency of bicycle-metro trips. Hence, to promote bicycle-metro integration, urban planners and government agencies should carefully consider the destination accessibility of metro station areas.

The Association of Built Environment and Physical Activity in Older Adults: Using a Citywide Public Housing Scheme to Reduce Residential Self-Selection Bias.

Previous studies have documented numerous health benefits of conducting regular physical activity among older adults. The built environment is believed to be a key factor that can hinder or facilitate daily physical activity, such as walking and exercising. However, most empirical studies focusing on environment-physical activity associations exhibited residential self-selection bias with cross-sectional research design, engendering doubts about the impact of built environment on physical activity. To reduce this bias, we assessed physical activity behaviors of 720 Hong Kong older adults (≥65 years) residing in 24 public housing estates. The Hong Kong public housing scheme currently provides affordable rental flats for 2.1 million people or approximate 30% of total population. The applicants were allocated to one of 179 housing estates largely by family size and flat availability. Built environment characteristics were measured following the '5Ds' principle: (street network) design, (land-use) diversity, density, distance to transit, and destination accessibility. Multilevel mixed models were used to explore the associations between the built environment and the different domains of physical activity (transportation walking, recreational walking, and recreational moderate-to-vigorous physical activity (MVPA) while controlling for potential estate-level socioeconomic and individual confounders. We found that transportation walking was positively associated with the number of bus stops and the presence of Mass Transit Railway (MTR) stations. Recreational MVPA was positively related to the number of recreational facilities. However, land-use mix was negatively related to transportation walking, recreational walking, and recreational MVPA. The findings of this study support a threshold effect in the environment-physical activity associations. Furthermore, large-scale public housing schemes involving random or semi-random residence assignment in many cities may provide opportunities to explore built environments and physical activity behavior, with the potential to overcome residential self-selection bias.

Benzothiadiazole and B-Aminobutyricacid Induce Resistance to Ectropis Obliqua in Tea Plants (Camellia Sinensis (L.) O. Kuntz).

In order to investigate the effect of benzothiadiazole (BTH) and ß-aminobutyric acid (BABA) on the resistance of tea plants (Camellia sinensis) to tea geometrid (Ectropis obliqua), three levels each of benzothiadiazole (BTH) and ß-aminobutyric acid (BABA) were sprayed on 10-year-old tea plants. Generally PPO and PAL activities increased with low concentrations of BTH and BABA treatments. Quantitative RT-PCR revealed a 1.43 and 2.72-fold increase in PPO gene expression, and 3.26 and 3.99-fold increase in PAL gene expression with 75 mg/L BTH and 400 mg/L BABA respectively. Analysis of hydrolysis of synthetic substrates also revealed that chymotrypsin-like enzyme activity present in larval midgut extracts was not significantly inhibited by BTH and BABA. However, proteinase activity was found to be inversely proportional to the age of tea geometrid. Larvae pupation rate decreased by 8.10, 10.81 and 21.62% when tea geometrid were fed with leaves treated with 25, 50 and 75 mg/L BTH solutions, while 100, 200 and 400 mg/L BABA solutions decreased same by 8.10, 16.21 and 13.51% respectively. Also, larvae development period delayed to 23.33 and 26.33 days with 75 mg/L BTH and 400 mg/L BABA treatments respectively. The results in this study; therefore, suggest that benzothiadiazole (BTH) and ß-aminobutyric acid (BABA) play a role in inducing resistance in tea plants to tea geometrid, with the optimal effect achieved at BTH-3 (75 mg/L) and BABA-3 (400 mg/L), respectively.

[Effects of biochar on CO2 and N2O emissions and microbial properties of tea garden soils].

To clarify the effects of biochar addition (0.5%, 1.5%, 2.5%, 3.5%) on the emission of carbon dioxide (CO2) and nitrous oxide (N2O), pH and microbial communities of the tea garden soil, an indoor incubation experiment was conducted using the acidulated tea-planted soil. Results showed that the emissions of CO2 and N2O and the rate of C, N mineralization were increased in a short term after the addition of biochar compared with the control, while the promoting effect was weakened along with increasing the addition of biochar. The pH, dehydrogenase activity and microbial biomass carbon were increased in the biochar treatments. Phospholi-pid fatty acid (PLFA) with different markers was measured and the most PLFA was detected in the group in the 1.5% biochar treatment with significant differences (P<0.05) compared with the control. In addition, the higher levels of 16:0, 14:0 (bacteria), 18:lω9c (fungi), l0Me18:0 (actinomycetes) groups were observed and there were significant differences (P <0.05) in individual phospholipid fatty acid among the different treatments. Taken together, the acidulated tea-planted soil, soil microbial biomass and microbial number were improved after addition of biochar.