溶磷细菌和丛枝菌根真菌接种对南方红豆杉生长及根际微生物和土壤酶活性的影响

以南方红豆杉实生苗为材料,采用盆栽实验探讨了高效溶磷细菌草木樨中华根瘤菌(Sinorhizobium meliloti)CHW10B与丛枝菌根真菌缩球囊霉(Glomus constrictum)单独和双接种条件下,其植株生长、根际土壤可培养微生物数量、土壤酶活和土壤微生物功能多样性变化,在微生态水平揭示接种对南方红豆杉生长的影响及其机制。结果表明:(1)各接种处理对南方红豆杉幼苗均有促生长作用,接种处理苗高、地径和生物量均较对照显著增加,并以双接种促进效果最好。(2)各接种处理提高了南方红豆杉根际土壤可培养细菌、真菌和放线菌含量,增加了土壤微生物碳源利用率,改变了土壤中物种的丰富度和均一度,增加了土壤中的生物多样性。(3)各接种处理促进了南方红豆杉根际重要土壤酶(酸性磷酸酶、脱氢酶、转化酶)活力的增加,且双接种的促进作用最为明显。可见,溶磷细菌(草木樨中华根瘤菌CHW10B)和丛枝菌根真菌(缩球囊霉)具有协同作用,两者同时接种可显著提高南方红豆杉根际土壤微生物数量及土壤酶活力,提高土壤微生物碳源利用率和土壤肥力,增加土壤中的生物多样性,从而达到间接促进宿主植物南方红豆杉生长的目的。     

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。     

The complete chloroplast genome sequence of Taxus chinensis var. mairei (Taxaceae): loss of an inverted repeat region and comparative analysis with related species

Taxus chinensis var. mairei (Taxaceae) is a domestic variety of yew species in local China. This plant is one of the sources for paclitaxel, which is a promising antineoplastic chemotherapy drugs during the last decade. We have sequenced the complete nucleotide sequence of the chloroplast (cp) genome of T. chinensis var. mairei. The T. chinensis var. mairei cp genome is 129,513 bp in length, with 113 single copy genes and two duplicated genes (trnI-CAU, trnQ-UUG). Among the 113 single copy genes, 9 are intron-containing. Compared to other land plant cp genomes, the T. chinensis var. mairei cp genome has lost one of the large inverted repeats (IRs) found in angiosperms, fern, liverwort, and gymnosperm such as Cycas revoluta and Ginkgo biloba L. Compared to related species, the gene order of T. chinensis var. mairei has a large inversion of ~ 110 kb including 91 genes (from rps18 to accD) with gene contents unarranged. Repeat analysis identified 48 direct and 2 inverted repeats 30 bp long or longer with a sequence identity greater than 90%. Repeated short segments were found in genes rps18, rps19 and clpP. Analysis also revealed 22 simple sequence repeat (SSR) loci and almost all are composed of A or T.     

Chemistry of Chinese yew, Taxus chinensis var. mairei

Taxus chinensis var. mairei (Lemée et Lévl) Cheng et L.K. Fu is an evergreen tall tree ubiquitous to the southeastern region in China. The first chemical study on this species was published in 1987. Since then about 163 compounds including taxoids and non-taxane compounds were isolated from seeds, root, bark and leaves of this species. This review summarized the chemical investigation on T. chinensis var. mairei (Lemée et Lévl) Cheng et L.K. Fu in the past 20 years. T. chinensis var. mairei (Lemée et Lévl) Cheng et L.K. Fu was assigned as a variation of T. chinensis (Pilger) Rehd. in Flora of China. However, present chemotaxonomic data would suggest that these two plants might belong to two different chemotypes; further genetic investigation and comprehensive chemical studies on them are warranted to address this issue.     

Population characteristics of endangered species Taxus chinensis var. mairei and its conservation strategy in Shanxi, China

The conservation of the endemic, endangered, and first-class protected tree species, Taxus chinensis var. mairei (Lem. & H. Lev.) W. C. Cheng & L. K. Fu, is urgent in China. To assist the protection of this important medicinal plant species, the biological and ecological characteristics of its populations were investigated and analyzed in Shanxi. The study area, southeastern Shanxi, is a special region suitable for this species growth and development. The floristic composition, life form spectrum, and species diversity of T. chinensis var. mairei forests reflected the features of both warm-temperate and subtropical regions. Size classes in DBH and static life table analysis showed that the population structure of T. chinensis var. mairei was of the increase-type. Plant density, survivorship, and mortality decreased with increase in age. Distribution patterns of individuals were basically clumped and saplings tended to be distributed randomly. Disturbance from collection of leaves, branches, and stems for medicine was an important factor affecting population structure, dynamics, and distribution. The sex ratio of female/male and the efficiency of sexual reproduction were very low. The main way of reproduction for this species is vegetative propagation. Based on these characteristics, some suggestions, such as establishing nature reserves, improving population structure by cultivation and transplantation, developing seed gardens, and plantations, etc., for the conservation management of T. chinensis var. mairei and its forests in Shanxi are discussed.     

Chemical Components,Biological Activities,and Toxicological Evaluation of the Fruit (Aril) of Two Precious Plant Species from Genus Taxus

The fruit (aril) of the endangered genus Taxus plants is an abandoned herbal resource. Traditionally, people enthusiastically focus on its bark, its renewable, tremendous arils fall into the soil with seeds after they are mature. The present research investigated the fruit of two species from the genus Taxus, Taxus chinensis var. mairei, and Taxus media, with regards to their antioxidant and antihyperglycaemic activities, safety, and bioactive constituents. Results showed that T. chinensis var. mairei and T. media both had certain biological activities with T. chinensis var. mairei better in antioxidant activity and T. media better in antihyperglycaemic activity. Correlation analysis revealed that the differences in bioactivities depended on content of their mainly chemical components. The mice acute oral toxicity test indicated that the methanol extracts of the two biotypes of Taxus were safe. And nineteen compounds were tentatively assigned from the two varieties, via tandem mass spectrometry using a LC‐ESI‐Q‐TOF‐MS instrument, which included phenols, flavonoids, and terpenes. These results indicate a possible application of Taxus fruit extracts in various fields like in food industry, however, this still needs further investigations.     

Inhibitory effect of 13 taxane diterpenoids from Chinese yew (Taxus chinensis var. mairei) on the proliferation of HeLa cervical cancer cells

The inhibitory effect of 13 taxanes isolated from the Chinese yew (Taxus chinensis var. mairei) on the proliferation of human cervical cancer HeLa cells were examined using an MTT assay. Four compounds having a hydrophobic cinnamate side chain showed antiproliferative activity, which may be due to increased cell permeability.     

Effects of <i>Piriformospora indica</i> on the Respiration of <i>Taxus chinensis</i> var. <i>mairei</i> 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 <i>Taxus chinensis</i> var. <i>mairei </i>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.     

不同遮荫强度下南方红豆杉枝叶紫杉醇产量的季节变化

研究了在一个生长季节内遮荫网不同遮荫强度下对人工种植的南方红豆杉(Taxus chinensis var. mairei)枝叶生物量、紫杉醇含量和产量季节变化。结果表明,在遮荫网89％和46.4％遮光条件下,南方红豆杉枝叶生物量、紫杉醇含量及其产量随发育节律呈现明显的规律性季节变化。在遮荫网89％和46.4％遮光条件下,89％遮荫条件下南方红豆杉枝叶生物量在整个生长季节内都明显高于46.4％遮荫条件下南方红豆杉枝叶生物量;在遮荫网89％和46.4％遮光条件下南方红豆杉枝叶中紫杉醇含量在5月中旬、7月末和11月末都出现较高峰值,后者紫杉醇含量峰值都明显比前者紫杉醇的含量高;89％和46.4％遮荫网遮光条件下南方红豆杉枝叶中紫杉醇的产量都在11月末期时达到最高,后者明显高于前者。因此,生产实践中可采用46.4％遮荫网遮光,采收的最佳季节为11月末期。     

Apoptotic cell death in suspension cultures of Taxus chinensis var. mairei

Apoptotic cell death was observed in suspension cultures of Taxus chinensis var. mairei under normal cultivation conditions by using microscopy, total DNA agarose gel electrophoresis and in situ end-labeling of fragmented DNA. The morphological and biochemical changes of cells occurred mainly in the non-dividing cell clusters, indicating that the T. chinensis cells died mainly by apoptosis. There exists a close relationship between cell apoptosis and Taxol formation. Taxol concentration increased with the increase in content of apoptotic cells and reached a maximum (14.2 mg l^–1) after 23 days of culture, corresponding to a maximum ratio of apoptotic to total cells of about 13%.     

Screening of taxol-producing endophytic fungi from <Emphasis Type="Italic">Taxus chinensis</Emphasis> var. <Emphasis Type="Italic">mairei</Emphasis>

A total of 38 endophytic fungus strains were isolated from Taxus chinensis var. mairei by the aseptic technique. Genomic DNA was extracted from isolated endophytic fungi and subjected to polymerase chain reaction (PCR) analysis for the presence of the Taxus taxadiene synthase (TS) gene, a rate-limiting enzyme gene in the taxol biosynthetic pathway. Twelve out of 38 isolated endophytic fungus strains showed PCR positive for the ts gene. Subsequently, taxol and its related compounds were extracted from culture filtrates and mycelia of the PCR positive strains, separated by column chromatography, and analyzed by High Performance Liquid Chromatography and Mass Spectrum. The analysis result showed that 3 strains could produce taxol and its related compounds at the detectible level. This study indicates that molecular detection of the ts gene is an efficient method for primary screening of taxol or its related compound-producing endophytic fungi, which can improve prominently screening efficiency. Published in Russian in Prikladnaya Biokhimiya i Mikrobiologiya, 2007, Vol. 43, No. 4, pp. 490–494. The text was submitted by the authors in English.     

遮荫对南方红豆杉光合特性及生活史型影响

对浙江省富阳市种植的5年生南方红豆杉,89%遮荫的条件下生长的南方红豆杉与46.4%遮荫及自然光条件诱导50天的南方红豆杉的光合特性、光合色素及其生活史型的研究。结果表明:89%遮荫、46.4%遮荫和自然光的光补偿点分别为18.88,30.52和65.34 μmol·m^-2·s^-1,光饱和点分别为287.01,258.25和358.92 μmol·m^-2·s^-1,遮荫可以降低南方红豆杉的光补偿点和光饱和点,从而能够更好地利用弱光,同时提高光合速率,增强了南方红豆杉的光合能力,其中以89%遮荫的变化最明显。随着遮荫程度的增大,南方红豆杉叶片的叶绿素a、叶绿素b及类胡萝卜素等光合色素的含量均增大,叶绿素a与叶绿素b含量的比值减小,说明遮荫可以增加植物对光能的利用,尤其是增加了对蓝紫光的利用,提高了光合效能。研究还发现遮荫对南方红豆杉的生活史型有一定的影响,89%遮荫、46.4%和自然光的生活史型分别为V_0.836C_0.164,V_0.625C_0.375和V_0.772C_0.228,以89%遮荫的营养生长最为旺盛。因此,89%遮荫是这三种光照条件中南方红豆杉营养生长的最适条件。     

濒危植物南方红豆杉遗传多样性的RAPD分析

采用RAPD技术检测了山西南部南方红豆杉8个种群的遗传多样性。利用21个10聚寡核苷酸引物共检测出134个位点,其中多态性位点123个,占91.79%,8个种群的遗传多态位点百分率分别为67.16%(红豆峡)、67.91%(凤凰谷)、66.42%(小梯河)、66.42%(蟒河)、50.75%(历山西峡)、43.28%(云蒙山)、78.36%(长治宾馆)、50.75%(磨河)。南方红豆杉的遗传多样性分析结果显示：Shannon指数为2.180,其中31.7%的遗传多样性来自种群间,68.3%来自种群内;Nei指数为0.571,种群间的遗传分化系数(Gst)为0.181。8个种群间的遗传相似性分析结果显示：壶关红豆峡和陵川凤凰谷种群间的遗传距离最小(0.109 2),壶关红豆峡和陵川蟒河种群间遗传距离最大(0.55)。本研究结果揭示,南方红豆杉自然种群具有较高的遗传多样性,其遗传多样性不是导致该种群濒危的主要原因,导致南方红豆杉种群濒危的原因可能与南方红豆杉自然种群及群落所在生境的直接破坏及其本身生物学和生态学特性所导致的自然更新不良有着密切的联系。     

南方红豆杉生长发育及其紫杉醇含量与环境因子的关系

研究了人工种植的3年生南方红豆杉的生长发育特征及其枝叶中紫杉醇的含量,并观测了其生长环境因子的动态特征。通过对南方红豆杉的生长发育特征以及其枝叶中紫杉醇含量与生长环境因子进行相关分析发现,南方红豆杉生长发育与空气和土壤湿度呈极显著的正相关,与空气和土壤温度、土壤N和K含量、土壤有机质和土壤紧实度呈正相关,与净辐射和土壤P含量呈负相关,但相关关系不显著,说明高温、高湿以及遮荫有利于南方红豆杉的生长,且对土壤P含量有较高需求;南方红豆杉枝叶中紫杉醇含量与空气和土壤湿度、土壤N、P和K含量呈负相关,与净辐射、空气和土壤温度、土壤有机质和土壤紧实度呈正相关,但相关关系均不显著,说明高温、高光强和干旱促进南方红豆杉枝叶中紫杉醇含量的增加,且紫杉醇含量的增加对土壤中N、P和K含量有一定的需求,尤其是N和K,对P需求不大;南方红豆杉生长发育与其枝叶中紫杉醇含量呈负相关,相关关系也不显著,推测紫杉醇可能是南方红豆杉的防御物质,以促使南方红豆杉抵御高温、干旱和高光强等不良环境。     

喜树与南方红豆杉混交群落生活史型谱特征

研究了不同生境条件下喜树和南方红豆杉混交群落中喜树和南方红豆杉的生活史型谱特征。结果表明,喜树和南方红豆杉在S生活史型得分和比例均为0。喜树和南方红豆杉生活史型V主成分得分均以山地2最高,而纯林的生活史型V主成分得分最低,C也表现为山地2最高,而纯林最低。喜树种群的生活史型比例按照从山地、坡地、平地、纯林排序,V型比例逐渐上升而C型比例逐渐下降的趋势,这就构成了混交群落中喜树种群的生活史型谱。南方红豆杉种群的生活史型谱特征,主要表现为山地2和坡地V型比例最小,而C型比例最大,纯林种植中V型比例较高,而以纯林1的V型比例最高,C型比例最小。     

Translocation of isopentenyl pyrophosphate for Taxol biosynthesis in suspension cultures of Taxus chinensis var. mairei

Two inhibitors of metabolite translocators, sodium pyrophosphate (NaPP) and D,L-glyceraldehyde (DLG), respectively, were added into suspension cultures of Taxus chinensis var. mairei at the early and late growth phases to investigate the translocation of isopentenyl pyrophosphate (IPP) from cytoplasm to plastids for Taxol biosynthesis. NaPP and DLG hardly affected cell biomass and viability regardless of the phases of their introduction. The Taxol content varied less when NaPP or DLG was added at day 7 but decreased obviously when NaPP or DLG was introduced at day 14. It is thus inferred that NaPP and DLG inhibited Taxol biosynthesis by blocking IPP translocation at the late growth phase, suggesting that the translocation of IPP be involved only at the late growth phase of Taxus cells.     

Paclitaxel production using co-culture of <Emphasis Type="Italic">Taxus</Emphasis> suspension cells and paclitaxel-producing endophytic fungi in a co-bioreactor

The co-culture of the suspension cells of Taxus chinensis var. mairei and its endophytic fungi, Fusarium mairei, in a 20-L co-bioreactor was successfully established for paclitaxel production. The co-bioreactor consists of two-unit tanks (10 L each) with a repairable separate membrane in the center, culturing Taxus suspension cells in one tank and growing fungi in another. By optimizing the co-culture conditions, there was a desirable yield of paclitaxel in Taxus cell cultures. The Taxus cell cultures by co-culture produced 25.63 mg/L of paclitaxel within 15 days; it was equivalent to a productivity of 1.71 mg/L per day and 38-fold higher than that by uncoupled culture (0.68 mg/L within 15 days). The optimum conditions for co-culture in the co-bioreactor were: B5 medium, inoculating fungi when Taxus cells had grown for 5 days in the co-bioreactor, hydrophilic separate membrane in the center of the co-bioreactor, and air flow rate of 1:0.85 v/v/m in fungus cultures.     

贵州特有植物长柱红山茶种群年龄结构及空间分布格局研究

为评估贵州特有植物长柱红山茶(Camellia mairei var.lapiden)的资源现状,采用样方法对其种群年龄结构和空间分布格局进行了研究。结果表明,长柱红山茶种群年龄结构为衰退型,种群密度以中龄树>老年树>幼龄树;不同发育阶段种群的空间分布格局不同,幼龄树和中龄树均呈显著集群分布,老年树接近集群分布或随机分布;种群的3个发育阶段之空间关系不密切,均表现为负相关或不相关。长柱红山茶由于其繁殖生物学特性和受其群落之种内、种间竞争及生境异质性的影响而趋于濒危和灭绝。因此,建立长柱红山茶就地保护区和开展引种栽培,扩大其栽培种植范围以增加种群数量是保护长柱红山茶种质资源的有效措施。