Taxus Chinensis Var Research Articles

Taxus chinensis var. mairei (Lemée et Lévl) Cheng et L.K. Fu overcomes the resistance to osimertinib in EGFR-mutant non-small-cell lung cancer via suppression of ERK1/2-related cholesterol biosynthesis

Ethnopharmacological relevanceAcquired resistance to osimertinib limits its clinical efficacy in non-small cell lung cancer (NSCLC) with EGFR mutations. The widespread recognition of Taxus chinensis var. Mairei (Lemée et Lévl) Cheng et L.K. Fu (Chinese yew) as a natural anti-cancer medication is well-established. However, the specific contribution of Taxus chinensis var. Mairei (Lemée et Lévl) Cheng et L.K. Fu in addressing resistance to osimertinib is still uncertain. Aim of the studyBased on the biological behaviors and lipid metabolism, we investigated whether aqueous extract of Taxus chinensis var. Mairei (Lemée et Lévl) Cheng et L.K. Fu (AETC) could enhance the antitumor effect of osimertinib in NSCLC with an investigation on the precise mechanisms. Materials and methodsThe effect of AETC on enhancing osimertinib sensitivity was assessed via cell viability measurements, levels of reactive oxygen species (ROS), apoptosis, and lipid levels. Western blotting was used to verify the mechanisms of AETC responsible for overcoming the resistance to osimertinib via ERK1/2 overexpression and knockdown models. In vivo validation was conducted using subcutaneous xenografts from osimertinib-resistant cells in nude mice. ResultsOsimertinib-resistant cells exhibited altered cholesterol biosynthesis, which was induced by ERK1/2 activation. The combination of AETC and osimertinib can synergistically decrease the levels of ROS in cells, enhance apoptosis, and inhibit the growth of osimertinib-resistant cells. Mechanistic experiments demonstrated that AETC can downregulate the key regulators of cholesterol biosynthesis by regulating ERK1/2, inhibiting the endogenous synthesis rate of cholesterol, and suppressing the level of lipids in osimertinib-resistant cells and xenograft tumors when combined with osimertinib, ultimately reversing resistance to osimertinib. ConclusionsThe resistance to osimertinib is significantly influenced by cholesterol biosynthesis, highlighting its pivotal role in this context. AETC can enhance osimertinib sensitivity via ERK/SREBP-2/HMGCR-mediated cholesterol biosynthesis. These results provide a promising therapeutic target and potential treatment option for resistance to osimertinib.

Remark: Evaluation of the Habitat and Potential of Taxus chinensis var. mairei in the Jiangnan Hilly Region

Taxus chinensis var. mairei is an endangered tree species endemic to China; it has important ornamental, timber, and medicinal value. In this work, based on a MaxEnt model, the Jiangnan hilly region was used as the study area, and geographic, climatic, soil, and vegetation data were synthesized to simulate the present area of suitable habitat for T. chinensis; the key environmental factors that constrain its habitat expansion were also explored. Additionally, the potential future distribution of this species under different climate-change scenarios was predicted. The results showed that the six variables making the highest contribution to T. chinensis habitat suitability were the precipitation of the warmest quarter (14.2%), precipitation seasonality variation coefficient (9.1%), aspect (8.2%), altitude (8%), maximum temperature of the warmest month (7.4%), and base saturation (6.6%). Ideal areas have middle elevations, northeastern or northwestern slopes, warmest quarterly precipitation of 508.3–629.2 mm, maximum temperature in the warmest month of 34.6–35.9 °C, and relatively moist soil. The current area of suitable habitat is 6.09 × 105 km2, of which the area of high suitability is 7.56 × 104 km2; this is mainly concentrated in the southwestern part of Hunan, the southwestern part of Jiangxi Province, and the northern part of Zhejiang. Under the SSP2-4.5 climate scenario, the area of high habitat suitability increases; under both the SSP1-2.6 and SSP5-8.5 climate scenarios, the suitable habitat area expands similarly. The direction of the center-of-mass migration of T. chinensis under different climate scenarios is somewhat different from that caused by the uncertainty of human activities and climate warming. This paper clarifies the distribution of suitable habitat and future potential for T. chinensis in the Jiangnan hilly region, providing a theoretical basis for habitat management of this species.

Development and evaluation of high permeability liposomes for improving anti-melanogenic activity of taxus chinensis fruit polysaccharide

Taxus chinensis var. mairei fruit polysaccharide (TMFP) is a natural resource with effective hypoglycemic and anti-tumor properties. However, its impact on melanogenesis remains largely unexploited. This study explores the anti-melanogenic activity of TMFP using in vitro and in vivo models. It was found that TMFP can safely and effectively eliminate melanin and inhibit tyrosinase activity without cytotoxicity. More specifically, the inhibitory effect of TMFP on melanin synthesis was verified in zebrafish embryos. In addition, nine formulations of TMFP-Liposomes were prepared to improve drug transdermal absorption, and TMFP-Liposome E was determined as the optimal formulation after characterization and transdermal comparison experiments. Most importantly, in vivo skin whitening experiments gave that TMFP-Liposome E has better skin whitening activity than control, model, blank liposomes, TMFP aqueous, and arbutin groups. The cell viability and animal safety tests confirmed the good biosafety of TMFP-Liposome E. Overall, this research suggests that TMFP may serve as a potential therapeutic agent for skin diseases and a potent whitening agent for cosmetic use. TMFP-Liposome E may enhance the therapeutic effect of melanin through improved transdermal absorption.

Comparative study of the antibacterial effects of wound secretions of different cultivars of Chinese fir.

The bark of Chinese fir (Cunninghamia lanceolata), the largest afforestation tree species in the forest areas of southern China, is susceptible to injuries and bites from small animals. The population of small animals has recently increased owing to improvements in the ecological environment across various forested areas, thus increasing the incidence of injuries in the bark of Chinese fir. Following such injuries, the bark secretes light yellow or milky white secretions, the function of which remains unclear. The present study aimed to reveal the antibacterial effect of exudates of different Chinese fir cultivars on five bacterial species. The research involved three-year-old plantations of Taxus chinensis var. koraiensis and Yangkou3 and three-year-old container plantations of Taxus chinensis var. pendula, Yang 061, and Yang 020. The antibacterial effects of exudates were analyzed using the filter paper diffusion method. The minimum inhibitory concentration for each secretion and the bacterial inhibition zone were determined. The exudates of the different Chinese fir bark exhibited notable antibacterial effects on Bacillus subtilis, Salmonella paratyphi B, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus. However, the extent of these antibacterial effects varied among the different Chinese fir cultivars, as the minimum inhibitory concentrations (MICs) of the exudates against the five bacterial species varied. The mean MIC of Pseudomonas aeruginosa was lower potency, whereas that of Escherichia coli was the lowest. Notably, the antibacterial efficacy of the exudates was mainly influenced by the composition of the secretions rather than the number of secretions, with organic acid compounds and terpenoids potentially contributing to the antibacterial effects against E. coli and Bacillus subtilis, respectively. This study demonstrates the antibacterial effect of wound secretion of different Chinese fir cultivars, highlighting their varying efficacy on different bacterial species. Moreover, the antibacterial ability of the exudates of the strains was mainly determined by the composition of the wound secretions, and there was no noticeable relationship with the number of wound secretions. The results of this study offers a theoretical basis for screen Chinese fir cultivars with high-disease-resistant.

Neuroprotective α-pyrones from Nigrospora oryzae, an endophytic fungus residing in Taxus chinensis var. mairei

Endophytes coevolve with plant hosts and thus are more probable to acquire the character (in favor) of producing undescribed bioactive metabolites. Consequently, the topic has been intensely investigated for over two decades, but endophytic metabolites with neuroprotective effect remain scarce. The study presents the discovery of eight undescribed (named solanapyrones U–Z and prosolanapyrones A and B) and six known pyrones (solanapyrones A–C and E–G) from the culture of Nigrospora oryzae, an endophytic fungus associated with Taxus chinensis var. mairei. The structures and absolute configurations of undescribed pyrones were elucidated by extensive spectroscopic analysis, modified Mosher's method, and induced circular dichroism (ICD) spectrum. Solanapyrones A and B and an undescribed pyrone (solanapyrone U) were demonstrated to be more neuroprotective than clenbuterol in inducing bone marrow mesenchymal stem cells (bMSCs) to secret nerve growth factor (NGF). The work updates the pyrone chemodiversity in nature and extends the biofunction repertoire of solanapyrone-related polyketides.

Insights from multi-omics integration into seed germination of Taxus chinensis var mairei

The transition from deep dormancy to seed germination is essential for the life cycle of plants, but how this process occurs in the gymnosperm Chinese yew (Taxus chinensis var mairei), the natural source of the anticancer drug paclitaxel, remains unclear. Herein, we analyse the transcriptome, proteome, spatial metabolome, and spatial lipidome of the Chinese yew and present the multi-omics profiles of dormant and germinating seeds. Our results show that abscisic acid and gibberellic acid 12 homoeostasis is closely associated with gene transcription and protein translation, and the balance between these phytohormones thereby determines if seeds remain dormant or germinate. We find that an energy supply of carbohydrates from glycolysis and the TCA cycle feed into the pentose phosphate pathway during seed germination, and energy supplied from lipids are mainly derived from the lipolysis of triacylglycerols. Using mass spectrometry imaging, we demonstrate that the spatial distribution of plant hormones and phospholipids has a remarkable influence on embryo development. We also provide an atlas of the spatial distribution of paclitaxel C in Chinese yew seeds for the first time. The data from this study enable exploration of the germination mechanism of Chinese yew seeds across several omics levels.

Rapid Characterization of Male and Female Taxus chinensis by Near-Infrared (NIR) Spectroscopy and High-Performance Liquid Chromatography (HPLC) with Orthogonal Partial Least Squares—Discriminant Analysis (OPLS-DA)

Taxus chinensis var. mairei (T. chinensis) is a dioecious plant that is important in traditional Chinese medicine. However, information about male and female T. chinensis is absent. To establish a simple, rapid, and reliable method for the qualitative identification of male and female T. chinensis, near-infrared spectroscopy (NIR) and high-performance liquid chromatography (HPLC) with the orthogonal partial least-squares discriminate analysis (OPLS-DA) mode was performed. NIR and discriminant analysis (DA) were employed for the first time to distinguish male and female T. chinensis. Meanwhile, HPLC also was optimized to determine the contents of the bioactive ingredients 10-deacetyltaxol (10-DAT) and paclitaxel of T. chinensis. Herein, the results of the validation showed that the DA model using NIR had a correct differentiation of nearly 100% for male and female T. chinensis. Moreover, the HPLC results indicated that the content of paclitaxel and 10-DAT was higher in female plants than in males. Additionally, based on the HPLC content results of male and female T. chinensis, the OPLS-DA successfully distinguished male and female T. chinensis. Thus, combining HPLC and OPLS-DA to initially differentiate between males and females allowed further quantitative and qualitative analysis of male and female T. chinensis. This method provides an approach to the identification and quality control of traditional Chinese medicine.

Nigrospora musae Causing Taxus chinensis var. mairei stem blight in Sichuan, China.

Taxus chinensis var. mairei is the endemic, endangered, and first-class protected tree species in China. This species is considered as an important resource plant because it can produce Taxol which is an effective medicinal compound against various cancers (Zhang et al., 2010). Stem blight was observed in two plant nurseries in Ya'an (102°44'E,30°42'N), Sichuan province in April 2021. The symptoms first appeared as round brown spots on the stem. As the disease progressed, the damaged area gradually expanded into an oval or irregular shape, which was dark brown. About 800 square meters of planting area were investigated and the disease incidence was up to approximately 64.8%. Twenty obviously symptomatic stems which exhibited the same symptoms as above were collected from 5 different trees in the nursery. To isolate the pathogen, the symptom margin was cut into small blocks (5 x 5 mm), and the blocks were surface sterilized in 75% ethanol for 90 s and 3% NaClO solution for 60 s . Finally incubated on Potato Dextrose Agar (PDA) at 28℃ for 5 days. Ten pure cultures were isolated by transferring hyphal and the three strains (HDS06, HDS07 and HDS08) were selected as representative isolates for further study. Initially, colonies on the PDA of three isolates were white and cotton-like, and then gradually turned gray-black from the center. After 21 days, conidia were produced and were smooth-walled, single-celled, black, oblate, or spherical, measuring 9.3 to 13.6 × 10.1 to 14.5 μm in size (n = 50). Conidia were present at the tip of conidiophores on hyaline vesicles. These morphological features were generally consistent with those of N. musae (Wang et al., 2017). To validate the identification, DNA were extracted from the three isolates, followed by the amplification of transcribed spacer region of rDNA (ITS), the translation elongation factor EF-1 (TEF-1), and the Beta-tubulin (TUB2) sequences with the respective primer pairs ITS1/ITS4 (White et al., 1990), EF-728F/EF-986R (Vieira et al., 2014) and Bt2a/Bt2b (O'Donnell et al., 1997) .The sequences were deposited in GenBank with the accession numbers ON965533, OP028064, OP028068, OP060349, OP060353, OP060354, OP060350, OP060351 and OP060352, respectively. Phylogenetic analysis of combined ITS, TUB2, and TEF genes using the Mrbayes inference method showed that the three isolates clustered with Nigrospora musae as a distinct clade (Fig. 2). Combine with morphological characteristics and phylogenetic analysis, three isolates were identified as N. musae. 30 2-year-old healthy potted plants of T. chinensis were used for pathogenicity test. 25 of these plants were inoculated by injecting 10 μL of the conidia suspension (1 × 106 conidia/mL) into stems and then wrap around the seal to moisturize. The remaining 5 plants were injected with the same amount of sterilized distilled water as a control. Finally, all potted plants were placed in a greenhouse at 25°C and 80% relative humidity. After 2 weeks, the inoculated stems developed lesions similar to those observed in the field, whereas controls were asymptomatic. N. musae was re-isolated from the infected stem and identified by both morphological characteristics and DNA sequence analysis. The experiments repeated three times showed similar results. As far as we know, this is the first report of N. musae causing T. chinensis stem blight in the world. The identification of N. musae could provide a certain theoretical basis for field management and further research of T. chinensis.

Effects of seasonal temperature regimes on embryo growth and endogenous hormones of Taxus chinensis var. mairei seeds.

Seed dormancy is a mechanism that prevents seeds from germinating at times of the year when conditions are unfavorable, that is, when the chance of seed survival is low. Determining the seasonal dynamics of seed dormancy is important for exploring how plant regeneration is adapted to the environment. We studied the seed dormancy status of Taxus chinensis var. mairei, an endangered species in China, under simulated seasonal temperature regimes. The embryo length, embryo-to-seed (E:S) ratio, and percentage of seeds with a split seed coat increased when seeds were stratified at spring and autumn temperature regimes. The abscisic acid (ABA) content decreased during stratification at simulated seasonal temperatures, but no obvious pattern in the content of gibberellic acid (GA) and indole acetic acid (IAA) was observed. The GA-ABA and IAA-ABA ratios increased during stratification. These results suggest that T. chinensis var. mairei seeds have morphophysiological dormancy, and that the seasonal dynamics of seed dormancy break are controlled by endogenous hormones and their balances, which was confirmed by the results of a field experiment. Our study provides useful information for understanding the natural population regeneration and propagation of this threatened species.

Fermentative Production of Diacylglycerol by Endophytic Fungi Screened from Taxus chinensis var. mairei.

Diacylglycerol (DAG) production by microbial fermentation has broad development prospects. In the present study, five endophytic fungi which could accumulate DAG were screened from Taxus chinensis var. mairei by using potato dextrose agar plate and flask cultivation in potato dextrose broth culture medium. The strains were biologically identified based on morphological features and semi-quantitative PCR. The identification results indicated that the five strains belonged to different genera: Fusarium annulatum (F. annulatum, coded as MLP41), Trichoderma dorotheae (T. dorotheae, coded as MLG23), Colletotrichum aeschynomenes (C. aeschynomenes, coded as MLY23), Pestalotiopsis scoparia (P. scoparia, coded as MLY31W), and Penicillium cataractarum (P. cataractarum, coded as MLGP11). The crude lipids from the strains and their corresponding triacylglycerol, 1,2-DAG, and 1,3-DAG fractions separated via thin-layer chromatography were mainly composed of palmitic acid, stearic acid, oleic acid, and linoleic acid, which in total accounted for higher than 94% of the content. The effects of fermentation conditions on the DAG productivity were discussed, and the yields of DAG were determined based on the 1H NMR spectra of crude lipids. The highest total DAG yields of F. annulatum, T. dorotheae, C. aeschynomenes, P. scoparia, and P. cataractarum were 112.28, 126.42, 189.87, 105.61, and 135.56 mg/L, respectively. C. aeschynomenes had the strongest potential to produce DAG. The results showed that this may be a new promising route for the production of DAG via fermentation by specific endophytic fungi, such as C. aeschynomenes.

Promotion Effects of Taxus chinensis var. mairei on Camptotheca acuminata Seedling Growth in Interplanting Mode

Wild Camptotheca acuminata Decne (C. acuminata) resources are becoming endangered and face poor growth. Preliminary investigation results found that the growth of C. acuminata in an artificial mixed forest of Taxus chinensis var. mairei (Lemee et Levl.), Cheng et L. K. Fu (T. chinensis var. mairei) and C. acuminata was significantly higher than that in pure forests. Understanding the reasons for the above differences can help create a mixed forest of T. chinensis var. mairei and C. acuminata to solve the problem of depleting C. acuminata resources. In this study, the growth and soil indexes under two different modes (C. acuminata/T. chinensis var. mairei interplanted and monocultured C. acuminata seedlings) were compared. The results showed that plant height, basal diameter, photosynthesis rate and chlorophyll content of C. acuminata under the interplanting mode were higher than those under monoculture. The growth rates of plant height and basal diameter that were calculated from interplanted specimens increased by 25% and 40%, respectively, compared with those from specimens that were monocultured. Photosynthetic rates from different light intensities under interplanting were higher than those in seedlings under monoculture. The contents of chlorophylls a and b and total chlorophyll under interplanting were 1.50, 1.59, and 1.47 times higher than those under monoculture, respectively. The numbers of bacteria and fungi in the interplanted culture were higher than those in the monoculture. Furthermore, the differences in microbial diversity under different planting modes were analyzed via the amplicon sequencing method. Soil enzyme activities increased under interplanting compared with that in the monoculture. Taxane allelochemicals were detected in the range of 0.01–0.67 μg/g in the interplanting mode from April to September. T. chinensis var. mairei may increase the establishment and productivity of C. acuminata seedlings under interplanting mode through improvements in enzyme activity, changes in microorganism population structure, and release of allelochemicals.

Aqueous extract of Taxus chinensis var. mairei targeting CD47 enhanced antitumor effects in non-small cell lung cancer

Immunoglobulin protein CD47 is overexpressed in malignant tumor cells, allowing them to evade host immunity mainly by inhibiting macrophage-mediated phagocytosis. Taxus chinensis var. mairei (TC) exhibits high antitumor efficacy with low toxicity and notable cost-effectiveness. However, it is unknown whether aqueous extract of TC (AETC) is an immunomodulator that mediates antitumor efficacy. In this study, we aimed to elucidate the critical role of CD47 degradation in the treatment of AETC in non-small cell lung cancer (NSCLC) cells. A mouse Lewis lung carcinoma model was developed to determine whether the administration of AETC, as an anti-CD47 antibody, in combination with anti-PD-1 could synergistically inhibit tumor growth and promote a peripheral immune response. AETC treatment downregulated CD47 levels in NSCLC cells and Lewis tumor xenograft mice. Furthermore, treatment enhanced immunity against NSCLC by triggering CD47 ubiquitination and degradation, promoting macrophage-mediated tumor cell phagocytosis, and activating CD8+ T cells. The present study empirically demonstrated, for the first time, that AETC exerts antitumor properties as an immunomodulator. Our findings present AETC as a promising alternative or adjuvant treatment in lung cancer therapy.

Allelopathy of Taxus chinensis var. mairei on Camptotheca acuminata seedling growth and identification of the active principles

ABSTRACT The root extracts and root exudates from the Taxus chinensis var. mairei had significant promote effects on growth of Camptoteca acuminata seedlings. Four taxane chemicals, cephalomannine, 10-deacetylbacatin III, paclitaxel and 7-Epi-10-deacetyl-paclitaxel, were isolated from T. chinensis var. mairei root extracts and their structures were identified by spectroscopic analysis. The chemicals were detected in T. chinensis var. mairei root exudates, rhizosphere soils, and their concentrations ranged from 0.01 to 5.90 μg/g. At an approximate concentration determined in T. chinensis var. mairei root exudates, all four chemicals significantly promoted the growth of C. acuminata seedlings. Therefore, four chemicals from T. chinensis var. mairei root exudates may act as allelochemicals accelerating growth of C. acuminata seedling. There were significant relationships between growth of C. acuminata seedlings, soil properties, enzyme activities and microbial community under allelochemicals’ application. The results provide a reference for in-depth understanding of C. acuminata and T. chinensis var. mairei interactions.

C:N:P stoichiometric characteristics of the soil–vegetation system of three rare tree species growing on Mount Fanjing in Southwest China

The aim of this study was to understand the C:N:P stoichiometry of three rare tree species that grow at different elevations of Mount Fanjing Nature Reserve in Guizhou Province, China. We analyzed the C, N and P stoichiometry of new stems, leaves and soil of two coniferous species, Abies fanjingshanensis and Taxus chinensis var. mairei , and of the hardwood tree Davidia involucrata . The total-C, total-N, hydrolyzed-N and available-P contents of the forest soils were higher at higher altitudes, with median values for A. fanjingshanensis forest soil > T. chinensis var. mairei soil > D. involucrata soil. The C:N, C:P and N:P ratios of soil in A. fanjingshanensis stands were the largest, and significantly higher than those of soils in T. chinensis var. mairei and D. involucrata stands. The C content of stems and leaves of the coniferous tree species was higher than that of the hardwood tree species. The N:P ratio of stems and leaves ranged from 0.06 to 0.22. The total-C, total-P and total-N of soil explained 37.5%, 11.0% and 8.0%, respectively, of the variance in C, N and P content and stoichiometry of plant stems and leaves. The total-C content of soil was positively correlated with the C and P contents of plant leaves, the C:N ratio and the C content of plant stems. Except for the total-C content of the soil–vegetation system, in general, the stoichiometric characteristics of N and P of soils and plants in the study area were not significantly correlated. Correlations between C, N, and P nutrients and the stoichiometric characteristics of the soil–vegetation system of the different forest types and environments varied. In the reserve environment, the growth of T. chinensis var. mairei and D. involucrata was restricted by N limitation in the soil. Our findings could provide basic data for the management and protection of rare plants growing on Mount Fanjing.

The Taxus genome provides insights into paclitaxel biosynthesis

The ancient gymnosperm genus Taxus is the exclusive source of the anticancer drug paclitaxel, yet no reference genome sequences are available for comprehensively elucidating the paclitaxel biosynthesis pathway. We have completed a chromosome-level genome of Taxus chinensis var. mairei with a total length of 10.23 gigabases. Taxus shared an ancestral whole-genome duplication with the coniferophyte lineage and underwent distinct transposon evolution. We discovered a unique physical and functional grouping of CYP725As (cytochrome P450) in the Taxus genome for paclitaxel biosynthesis. We also identified a gene cluster for taxadiene biosynthesis, which was formed mainly by gene duplications. This study will facilitate the elucidation of paclitaxel biosynthesis and unleash the biotechnological potential of Taxus.

Aqueous extract of Taxus chinensis var. mairei regulates the Hippo-YAP pathway and promotes apoptosis of non-small cell lung cancer via ATF3 in vivo and in vitro

Taxus chinensis var. mairei (TC) is a traditional Chinese ornamental and medicinal plant, the leaves and twigs of which are used in anti-tumor therapy in southern China. However, the mechanism and role of aqueous extract of TC (AETC) in promoting apoptosis in non-small cell lung cancer (NSCLC) cell lines has remained unclear. In this research, we observed that AETC inhibited the suppression of the proliferation of NSCLC cells and highly inhibited the proliferation of NCI-1975 cells. Furthermore, AETC exerted minimal inhibitory effects on normal human lung epithelial cells and induced apoptosis in NCI-1975 and A549 cells. The findings of RNA sequencing, qRT-PCR, western blotting, and immunofluorescence showed that upregulated ATF3 expression and ATF3 gene knockdown, respectively, increased and decreased the anti-tumor effects of AETC associated with Hippo pathway inhibition and decreased YAP degradation. Furthermore, AETC reduced the tumor volume and weight in nude mice; upregulated ATF3, p-MOB1, and p-YAP (Ser397); and actively regulated cleaved PARP and cleaved caspase-9/8/3. These findings suggest that AETC induced NSCLC cell apoptosis via the ATF3-Hippo-YAP pathway in vivo and in vitro. We also found that AETC is non-toxic to normal cells and nude mice. Thus, AETC might represent a promising adjuvant for anti-tumor therapy against NSCLC.

Ancient and Famous Trees Risk Assessment in Changting Based with Multi-Level and Multi-Dimensional Indicator System

According to the results of the second census of ancient and famous trees and field investigation in Changting County, Through VTA method and AHP method, the multi-level and multi-dimensional evaluation index system of risk degree of ancient and famous trees was constructed. The results show that: The higher weight of growth factors are the main trunk diseases and insect pests, abnormal cracks in the main trunk, hollow trunk, branch diseases and insect pests, abnormal cracks in the branches, dangerous dead branches, root diseases and insect pests, leaf diseases and insect pests. The growth space of tree roots is the most important factor in environmental factors. Among the anthropogenic factors, the most important ones are the artificial dumping of pollutants and the lack of professional management. Hazard index of Taxus chinensis var. mairei is maximum, followed by Schima superba, Cinnamomum camphora and Liquidambar formosana. The most dangerous indicators are the professional level of managers, lack of professional management, V-angle trunk and plant parasitism. Through the risk assessment, this paper seeks for the key points of management and protection of ancient and famous trees, aims at solving problems and reducing the risk of ancient and famous trees, so as to promote the management and protection of ancient and famous trees.

南方红豆杉水浸提液对喜树种子发芽和幼苗生长的化感作用

化感作用是影响人工混交林种间关系的重要因素之一。已有研究表明：喜树南方红豆杉混交对喜树生长有明显促进作用，并从混交改善混交林地微气候角度解释了这种促进作用，但未从种间化感作用角度探讨这种作用。为了探究南方红豆杉是否对喜树具有潜在的化感促进作用，从而更全面了解喜树南方红豆杉混交林种间关系，考察了不同浓度（25、50 g/L和100 g/L）的南方红豆杉（Taxus chinensis var.mairei）鲜叶、凋落叶、枝和根水浸提液对喜树（Camptotheca acuminata）种子发芽和幼苗生长的影响。结果表明：（1）南方红豆杉凋落叶浸提液对喜树种子发芽和幼苗生长无显著影响（P>0.05），而鲜叶、枝和根浸提液对喜树发芽和幼苗生长均具有不同程度的促进作用（P<0.05），且作用强度大体与浓度呈正相关；（2）100 g/L的南方红豆杉鲜叶、枝和根浸提液浸泡的喜树种子，其发芽率比对照组分别提高8.1%、14.9%和25.6%；（3）南方红豆杉鲜叶浸提液只有在高浓度（100 g/L）时，对喜树幼苗基径生长具有促进作用（P<0.05），而对其株高、全株干重和净光合速率无显著影响；南方红豆杉根和枝浸提液对喜树幼苗株高、基茎、干重和净光合速率均具有促进作用（P<0.05），与对照组相比，100 g/L的根和枝浸提液浇灌喜树幼苗，可以使喜树幼苗株高分别提高14.2%和8.4%，基径分别提高19.0%和15.3%，干重分别提高23.1%和15.9%，净光合速率分别提高11.6%和6.1%。研究结果表明，在喜树南方红豆杉混交林中，南方红豆杉对喜树的正向化感作用可能是促进喜树生长的重要因素之一。;Allelopathy is one of the important factors that affect the interspecific relationship of artificial mixed forest. Previous studies have shown that Taxus chinensis var. mairei has a significant promoting effect on the growth of Camptotheca acuminata in the mixed forest of T. chinensis var. mairei and C. acuminata, which was explained from the perspective of improving the microclimate of mixed forest land, but not from the perspective of interspecific allelopathy. In order to explore whether T. chinensis var. mairei has potential allelopathy promoting effect on C. acuminata, so as to understand more comprehensively the interspecific relationship of T. chinensis var. mairei and C. acuminata mixed forest, the effects of water extracts from fresh leaves, litter leaves, branches and roots of T. chinensis var. mairei with different concentrations (25 g/L, 50 g/L, and 100 g/L) on seed germination and seedling growth of C. acuminata were studied in this study. The results showed that (1) the litter extract of T. chinensis var. mairei had no significant effect on seed germination and seedling growth of C. acuminata (P>0.05), but the fresh leaves, branches and roots extracts had the promoting effects on C. acuminata germination and seedling growth in different degrees (P<0.05), and the intensity was positively correlated with the concentration of extracts. (2) The germination percentage of C. acuminata seeds soaked in 100 g/L extracts of fresh leaves, branches and roots from T. chinensis var. mairei was 8.1%, 14.9% and 25.6% higher than that of the control group, respectively. (3) The fresh leaves extract of T. chinensis var. mairei could promote the basal diameter growth of C. acuminata seedlings at high concentration (100 g/L) (P<0.05), but had no significant effect on plant height, total dry weight and net photosynthetic rate regardless of extracts concentration. The root and branch extracts of T. chinensis var. mairei had the promoting effects on plant height, basal stem, dry weight and net photosynthetic rate of C. acuminata seedlings (P<0.05). Compared with the control group, 100 g/L of root and branch extracts could increase the height of C. acuminata seedlings by 14.2% and 8.4%, the basal diameter by 19.0% and 15.3%, the dry weight by 23.1% and 15.9%, and the net photosynthetic rate by 11.6% and 6.1%, respectively. The results showed that the positive allelopathy of T. chinensis var. mairei to C. acuminata may be one of the important factors to promote the growth of C. acuminata in the mixed forest of the two trees.

Effects of Piriformospora indica on the Respiration of Taxus chinensis var. mairei under Water Stress

Seedlings of Taxus chinensis var. mairei were used as experimental materials to study the adaptation of Piriformospora indica to this plant under water stress. The materials were divided into two groups, namely, with or without inoculation with P. indica. Each group was subjected to four different levels of water stress. Vitality and physiological and biochemical indexes of the roots of T. chinensis var. mairei were regularly measured. Under water stress, T. chinensis var. mairei had significantly decreased root vitality; root vitality was higher in inoculated roots than in uninoculated roots. Under intense water stress, the inoculated roots had a higher soluble sugar content than the uninoculated roots. Under water stress, T. chinensis var. mairei experienced decreased activity of aerobic respiratory metabolic enzymes. The activity of anaerobic respiratory metabolic enzymes and alcohol dehydrogenase initially increased and then decreased, whereas that of lactate dehydrogenase increased. The inoculated roots had a higher activity of respiratory metabolic enzymes than the uninoculated roots. As water stress was further intensified, the roots had significantly decreased activity of aerobic respiratory metabolic enzymes and significantly increased activity of anaerobic respiratory metabolic enzymes. The activity of respiratory metabolic enzymes decreased faster in the uninoculated roots than in the inoculated roots. This study demonstrated that Piriformospora indica plays a positive role in enhancing the antihypoxic ability of T. chinensis var. mairei, thereby alleviating plant damage due to water stress.

Comparison of Morphological and Anatomical Characteristics of Taxus chinensis var. mairei Seedlings Root under Waterlogging Stress in Different Substrates

Four different ratios of river sand, ceramic pellets, vermiculite and perlite (1:1), and field soil were selected as the substrates in this experiment, and four gradient levels of root waterlogging, half waterlogging, full waterlogging and normal were set to investigate the effects of different gradients of waterlogging stress on the root morphology of Taxus chinensis var. mairei seedlings under different substrates. In this study, the root anatomical structure of Taxus chinensis var. mairei under different waterlogging stress was observed by the paraffin section method. The roots of T. chinensis var. mairei were diarch, with no pith and resin canals. There was a large number of tannins in the pericycle of the aerial adventitious roots of seedlings adapted to waterlogging. Also, the endodermis has obvious casparian strip thickening, and there were 4-5 layers of large parenchymatous cells in the close to the inner side of the pericycle in the vascular cylinder, which could increase the storage capacity, and transport capacity of the root. Under the treatment of root waterlogging stress, the development of plant roots in the mixed substrate of vermiculite and, perlite was the earliest. Under half waterlogging stress, T. chinensis var. mairei seedlings treated with various substrates all could better adapt to the environment of waterlogging stress. Under the stress of fully waterlogging, the roots of seedlings planted in river sand substrate developed secondary growth.