Effect of Prosopis (mesquite) invasion and clearing on vegetation cover in semi-arid Nama Karoo rangeland,South Africa

The Nama-Karoo is the largest of the three biomes that comprise the semi-arid Karoo-Namib ecoregion of southern Africa. Large tracts of Nama-Karoo rangeland have been invaded by alien leguminous trees of the genus Prosopis. We assessed the impact of Prosopis invasion and clearing on vegetation cover in heavily grazed Nama-Karoo rangeland on two sheep farms in the Beaufort West district of the Western Cape province of South Africa. Our results suggest that, below critical threshold cover levels, Prosopis trees do not affect indigenous vegetation and add to overall rangeland vegetation cover. However, once Prosopis cover exceeds critical thresholds, the trees begin to negatively impact on indigenous vegetation (especially grasses) and overall vegetation cover. In addition, our data suggest that vegetation cover recovers after Prosopis clearing, being temporarily higher than pre-invasion levels possibly as a result of enhanced post-invasion soil fertility. Lastly, our results suggest that Prosopis trees reduce rangeland erosion potential at low cover and increase it after they exceed critical threshold cover. Information about thresholds of Prosopis impact can be used to direct clearing efforts for maximum benefit when resources are limited.     

叶用型沙棘育种研究--“蒙×中”沙棘F1代雄株变异特性与选优标准的研究

通过对蒙古沙棘亚种优良品种与中国沙棘亚种优良类型F1代雄株的变异特性分析,建立了选择优 良单株的标准,为叶用型沙棘选择育种提供了科学依据。     

湖北省国家珍稀濒危植物区系地理研究

经调查研究与统计，湖北省自然分布的国家珍稀濒危植物有５８种。论述了该地区国家珍稀濒危植物的属和种的区系地理分布特点，并提出了开发利用珍稀濒危植物资源的建议。     

Antimycotic Screening of 58 Malaysian Plants against Plant Pathogens

Ethanolic extracts of 58 Malaysian plants belonging to 24 different families were screened for antifungal activity against seven plant pathogens using the filter paper disc diffusion technique. Two varieties of Piper betle, showed strong activity against all the pathogens tested (Colletotrichum capsici, Fusarium pallidoroseum, Botryodiplodia theobromae, Alternaria alternata, Penicillium citrinum, Phomopsis caricae-papayae and Aspergillus niger), with inhibition diameters significantly (P<0·01) bigger than 2·5 mg ml⁻¹ prochloraz or 10 mg ml⁻¹ clotrimazole. The minimum inhibitory concentrations of the ethanolic extracts of P. betle against these plant pathogens ranged between 0·01 mg ml⁻¹ and 1 mg ml⁻¹. Thirty-four other plants (Kucing gala, Limau batik, Bertholletia excelsa, Bixa orellana, Caesalpinia pulcherrima, Cerbera odollam (fruits and leaves), Colocasia gigantea, Curcuma domestica, Curcuma manga, Derris eliptica, Elephantopus scaber, Eleusine indica, Eugenia polyantha, Euphorbia hirta, Euphorbia tirucalli, Gardenia florida, Hedyotis auricularia, Hibiscus rosa-sinensis, Juniperus chinensis (three varieties), Lawsonia inermis, Lecythis ollaria, Mentha arvensis, Mimusops elengi, Ocimum sanctum, Phyllanthus niruri, Piper nigrum, Piperomia pellucida, Pedilanthus tithymaloides, Polygonum minus, Spondias dulcis, Solanum nigrum, Tinospora tuberculata) showed selective antifungal activity, while 21 species were inactive.     

宿主植物对AM真菌生长发育的影响

研究了宿主植物对丛枝菌根(Arbuscular mycorrhizae,AM)真菌(Glomus mosseae)生长发育的影响。结果表明:温室条件下,4种宿主植物都能与丛枝菌根真菌共生,综合比较菌根长度、根外菌丝量及孢子数3项指标,高粱敖杂1号对真菌的生长发育最为有利。宿主植物菌根长度及根中的可溶性糖质量分数与根外孢子数呈显著正相关,而宿主植物中磷质量分数与菌根真菌的生长发育没有显著的相关性。说明不同宿主植物甚至同种宿主植物不同基因型的品种与丛枝菌根真菌的共生状况不同,宿主植物的菌根长度及根中可溶性糖质量分数对菌根真菌的生长发育有显著影响。     

基于组织培养技术的姜科植物快繁体系的研究进展

为解决姜科植物繁殖系数低、种性退化等问题,扩大姜科植物的繁殖规模,提高品种自身抗逆性和增产潜力,有效建立姜科植物的离体快繁体系,总结了基于植物组织培养技术的部分姜科植物离体快繁体系构建过程中外植体的选择与消毒处理、丛生芽和愈伤组织的诱导、增殖与分化和生根培养条件,阐述了姜科植物离体快繁体系建立过程中存在的问题及解决方案,同时对植物组织培养在姜科植物中的应用进行了展望,以期为姜科植物产业的健康、快速发展提供参考。     

Development and identification of glyphosate-tolerant transgenic soybean via direct selection with glyphosate

Glyphosate-tolerant soybean is the most widely planted genetically modified crop worldwide. However, soybean remains recalcitrant to routine transformation because of the low infection efficiency of Agrobacterium to soybean and lack of useful selectable markers. In this study, several Agrobacterium strains and cell densities were compared by transient expression of the GUS gene. The results showed that Agrobacterium strain Ag10 at cell densities of OD_(600) of 0.6–0.9 yielded the highest infection efficiency in Agrobacterium-mediated soybean cotyledonary node transformation system. Meanwhile, a simple and rapid method was developed for identification of glyphosate tolerance in putative T_0 transgenic plants, consisting of spotting plantlets with 1 μL Roundup~?. The whole cycle of genetic transformation could be shortened to about 3 mon by highly efficient selection with glyphosate during the transformation process and application of the spot assay in putative T_0 transgenic plantlets. The transformation frequency ranged from 2.9 to 5.6%. This study provides an improved protocol for development and identification of glyphosate-tolerant transgenic soybeans.     

基于高通量测序技术分析2种菌草根际土壤真菌群落多样性

为了解福州菌草基地巨菌草和绿洲一号2种菌草的根际土壤真菌群落多样性,采用Illumina Miseq高通量测序技术和生物信息学方法,对菌草根际土真菌的多样性及群落结构进行分析。结果表明：从3份土壤样本中获得525 292条ITS序列,在97%序列相似性基础上可划分为7267个可操作分类单元（OTU）。真菌群落的丰富度指数（ACE）以菌草非根际土最低,绿洲一号根际土略高于巨菌草根际土;而多样性指数（Shannon-Wiener和Simpson）菌草根际土高于非根际土,绿洲一号根际土略高于巨菌草根际土。3份样品的优势菌门为子囊菌门（Ascomycota）、担子菌门（Basidiomycota）、接合菌门（Zygomycota）、壶菌门（Chytridiomycota）、球囊菌门（Glomeromycota）;优势菌纲为散囊菌纲（Eurotiomycetes）、粪壳菌纲（ Sordariomycetes）、座囊菌纲（Dothideomycetes）、伞菌纲（Agaricomycetes）、锤舌菌纲（Leotiomycetes）、圆盘菌纲（Orbiliomycetes）、银耳纲（Tremellomycetes）、粘膜菌纲（Wallemiomycetes）;优势菌属为篮状菌属（Talaromyces）、深黄伞形霉属（Umbelopsis）、枝孢菌属（Cladosporium）、暗双孢菌属（Cordana）、镰刀菌属（Fusarium）、隐球菌属（Cryptococcus）、淡紫紫霉属（Purpureocillium）、赤霉菌属 （Gibberella）、灵芝属（Ganoderma）。研究结果表明,菌草根际土真菌群落多样性高于非根际土,为进一步更好地利用菌草提供理论参考依据。     

外源5-氨基乙酰丙酸对低温胁迫下茶树叶片光合及生理特性的影响

通过对陕茶1号（耐低温型）和金牡丹（低温敏感型）2个茶树品种在冬季自然低温胁迫下喷施不同浓度（0、10、30、50 mg·L^-1）的外源5-氨基乙酰丙酸（5-aminolevulinic acid,ALA）,探究外源ALA对低温胁迫下茶树叶片光合荧光特性及生理特性的调控作用。结果表明,适宜浓度的外源ALA对低温胁迫下茶树叶片净光合速率、气孔导度、胞间CO₂浓度、蒸腾速率、PSⅡ最大光化学效率及PSⅡ潜在活性具有促进作用,能够提高水浸出物、咖啡碱、游离氨基酸、儿茶素类物质、茶氨酸、可溶性糖、可溶性蛋白等生理活性物质含量的累积;外源ALA能够提高低温胁迫下茶树光合作用的能力并改善茶叶品质,其中50 mg·L^-1的ALA处理能有效提高陕茶1号应对低温胁迫的能力,10 mg·L^-1和30 mg·L^-1的外源ALA对金牡丹应对低温胁迫具有较好的缓解效用。     

翁源青云山自然保护区维管束植物区系特征分析

青云山省级自然保护区位于韶关翁源县的东南部,本研究在查阅文献、历史标本的基础上,对本区进行全面踏查、标本采集并鉴定,从而进行植物物种多样性编目和区系分析。结果表明：青云山自然保护区有维管束植物1336种（含种下分类单位）,其中石松类和蕨类植物132种,隶属于62属24科,裸子植物6种,隶属于4属4科,被子植物1198种,隶属于588属148科;本区的表征科主要以樟科（Lauraceae）、壳斗科（Fagaceae）、冬青科（Aquifoliaceae）等为主。植物区系地理组成复杂,主要以热带、亚热带为主,且热带、亚热带的过渡性质明显。从中国特有种的分布情况来看,该地区与湖南南部、广西东北部、江西西南部联系较为紧密,体现了南岭山脉植物区系的一致性与整体性;珍稀濒危植物共计48种;植被具有中亚热带向南亚热带过渡的特征。青云山自然保护区植物物种丰富度高、植被类型多样,建议将园洞、青山口等珍稀濒危植物分布较集中的地区列为优先保护区域。