Identification of ‘Candidatus phytoplasma ziziphi’ associated with persimmon (Diospyros kaki Thunb.) fasciation in China

Persimmon (Diospyros kaki Thunb.) trees, with fasciation symptoms (PF), were observed in an orchard located in suburban Tai'an, Shandong Province, China. A specific fragment of the phytoplasma 16S rRNA gene, approximately 1.2 kb in length, was amplified from two symptomatic plants via nested polymerase chain reaction, while no fragment was obtained from healthy controls. The two samples (PF1 and PF2) resulted with 99.5% nucleotide sequence identity. Phylogenetic and restriction fragment length polymorphism (RFLP) analysis of 16S rRNA gene sequences revealed that PF1 was a member of ribosomal subgroup B of the elm yellows group (16SrV), and PF2 may represent a novel subgroup within the 16SrV group, designed as 16SrV‐I. This is the first report of phytoplasmas of the 16SrV group associated with persimmon fasciation disease.     

Inoculation of ectomycorrhizal fungi contributes to the survival of tree seedlings in a copper mine tailing

To advance our understanding of the effects of inoculation with ectomycorrhizal fungi (EMF) on seedling colonization in mine wastelands, we conducted a field experiment in a copper tailing. Six-month-old seedlings of Japanese red pine (Pinus densiflora) and oak (Quercus variabilis) separately inoculated with three EMF species (Pisolithus sp., Cenococcum geophilum, Laccaria laccata) were transplanted to the copper tailing. The survival rates of tree seedlings were monitored monthly, and growth (biomass and height), contents of nutrients and heavy metals (K, P, Ca, Mg, Cu, Zn), and mycorrhizal infection rates of seedlings were determined 6 months after planting. Oak seedlings exhibited higher survival rates than pine seedlings after 6 months of growth on the tailing. EMF inoculations of pine seedlings significantly enhanced their survival, growth, and nutrient uptake. In contrast, EMF inoculations of oak seedlings improved growth only in terms of biomass. Additionally, EMF inoculation caused pine seedlings to accumulate more Cu and Zn in roots compared to non-inoculated seedlings, whereas inoculation inhibited the accumulation of heavy metals in shoots. However, similar results were not observed in oak seedlings. Observations of roots indicated that the rates of mycorrhizal infection of both tree species had dramatically declined at harvest time. In conclusion, ectomycorrhizal symbioses can improve the survival and performance of pine seedlings in mine tailings. The present study provided direct evidence of the importance of EMF inoculation of seedlings to the reforestation of mine wastelands.     

竹笋象危害对竹材物理力学性质的影响

对受笋万纹象(Otidognathus rubriceps Chevrolot)、一字竹笋象(O.davidis Fairmaire)、大竹笋象(Cyrtatrachelus longimanus Fabricius)危害后断梢毛竹、竹腔注药防治后毛竹、正常毛竹3种竹材进行竹材抗弯强度、抗弯弹性模量和顺纹抗拉强度测定结果表明,与正常毛竹相比较,受竹笋象危害断梢毛竹差异显著,3个竹材物理力学性质指标分别下降了43.79%、39.01%、29.28%,竹腔注药防治后毛竹3个指标下降了13.87%、10.95%、9.01%,但差异不显著,不影响竹材的使用价值.     

Impacts of forest management on liana diversity and community structure in a tropical forest in Ghana: implications for conservation

We studied the impacts of liana cutting as a forest management tool on liana diversity(species richness,Shannon diversity index) and community structure(diameter distribution, basal area, species dominance) in the Asenanyo Forest Reserve, Ghana. Two types of silviculturally treated forests were studied: Logging treated(LT)and Tropical Shelterwood System(TSS) treated forests. An untreated primary forest was included as a control, resulting in three forest management systems. Lianas with diameter C2 cm were identified in ten 40 9 40 m2 plots within each management system. Liana cutting significantly reduced liana species richness, Shannon diversity index, and basal area in the LT forest after two decades.However, liana species richness and basal area werecomparable in the TSS treated and untreated forests, indicating significant recovery in the former after over six decades. S?rensen similarity index of liana species composition between the untreated forest and each of the treated forests was moderate. Our findings suggest that liana cutting most likely influenced the dominance of some liana species. In view of the adverse impact of blanket liana cutting on liana diversity, selective liana cutting is recommended as a means of controlling liana numbers while maintaining liana diversity.     

Characterizing long-term forest disturbance history and its drivers in the Ning-Zhen Mountains,Jiangsu Province of eastern China using yearly Landsat observations (1987–2011)

Forest losses or gains have long been recognized as critical processes modulating the carbon flux between the biosphere and the atmosphere. Timely, accurate and spatially explicit information on forest disturbance and recovery history is required for assessing the effectiveness of existing forest management. The major objectives of our research focused on testing the mapping efficacy of the vegetation change tracker (VCT) model over a forested area in China. We used a new version of VCT algorithm built upon the Landsat time series stacks (LTSS). The LTSS consisted of yearly image acquisitions to map forest disturbance history from 1987 to 2011 over the Ning-Zhen Mountains, Jiangsu Province of east China. The LTSS consisted of TM and ETM+ scenes with different projections due to distinct data sources (Beijing remote sensing ground station and the USGS EROS Center). The validation results of the disturbance year maps showed that most spatial agreement measures ranged from 70 to 86 %, comparable with the VCT accuracies reported for many places in USA. Very low accuracies were identified in 1995 (38.3 %) and 1992 (56.2 %) in the current analysis. These resulted from the insensitivity of the VCT algorithm to detect low intensity disturbances and also from the mis-registration errors of the image pairs. Major forest disturbance types existing in our study area were identified as agricultural expansion (39.8 %), urbanization (24.9 %), forest management practice (19.3 %), and mining (12.8 %). In general, there was a gradual decreasing trend in forest cover throughout this region, caused principally by China’s economic, demographic, environmental and political policies and decisions, as well as some weather events. While VCT has largely been used to assess long term changes and trends in the USA, it has great potential for assessing landscape level change elsewhere throughout the world.     

浅谈德国的“近自然森林经营”

从德国“可持续”森林利用的不同概念、德国不同森林认证体系“经营标准(Management Standards)”的比较实例、德国森林经营和“近自然森林经营”筒史、德国森林资源状况和森林资源的变化、德国有关森林资源的几个基本理念与“近自然森林经营”的主要特征、德国哥廷根市有林“近自然森林经营”实例等6个方面,简要介绍了德国的“近自然森林经营”。     

试论科学发展观对林业发展的重大意义

党中央提出的科学发展观对林业发展有着极为重要的意义。文章从重视人的主体性、森林经营利用多元化、森林经营管理开放性和森林永续利用等四个方面,分别阐述了以人为本,全面、协调、可持续发展对林业的指导意义。     

湘西虎杖抑菌成分提取及其抑菌活性研究初报

以乙醇作溶剂,对湘西虎杖抑菌活性物提取条件进行研究,通过抑菌实验得到最佳提取条件为A3B2C3,即90%乙醇、60℃、3h, 该条件下的提取物对细菌生长的抑制活性最强,但对酵母菌无明显的效果,对三种受试细菌的最小抑菌浓度(MIC)为0.25~ 0.5g/ml。提取物经85℃、100℃,15 min 或pH2~8 处理后仍具有较强的抑菌活性,其乙酸乙酯萃取物对三个菌都有较强的抑菌活性。     

广东省林木种质资源现状及其保护利用策略

文章概述了林木种质资源的重要作用,着重分析了广东省林木种质资源的现状及其保护利用中存在的主要问题,并提出了保护利用的有效措施和建议。     

观赏凤梨催花栽培试验

文章对4个观赏凤梨常规品种进行不同催花剂、不同乙烯利浓度、不同处理温度的催花试验及基质对植株生长影响的试验。结果表明：乙烯利对凤梨催花效果显著,开花株率最高,花穗高度短;催花处理时的平均温度越高,诱导花芽发育的时间越短;各品种对乙烯利不同浓度的催花表现不同,在500,600,700mg／L浓度范围。彩苞凤梨开花率随乙烯利浓度的升高而降低,大红星凤梨、擎天凤梨和虎尾凤梨的开花率则随乙烯利浓度的升高而增高。基质以树皮80％＋松林下表土20％栽培效果最佳。