Armillaria ostoyae in managed coniferous forests in Kastamonu in Turkey

Although several Armillaria species have been reported in Turkey, there is little information about their ecology in Turkish forests. In this study, we investigated five forest stands, approximately 5–74 ha in size, in Kastamonu province in the Black Sea Region of Turkey for the presence of Armillaria species in stumps and logs. The stands were mixed Abies nordmanniana ssp. bornmülleriana and Pinus sylvestris forests managed using a selective cuttings system; the proportion of fir in the total number of stems and stumps ranged from 36 to 98%. Based on sequence analysis of the internal transcribed spacer and intergenic spacer regions of the rDNA, all rhizomorphs sampled from the stumps and logs were of Armillaria ostoyae. The size of the genets was estimated with random amplified microsatellites analysis of the isolates and ranged from single stumps to approximately 450 m². One to seven genets were found in each stand. These results indicate that the genets had arisen from spores and vegetative spread was limited on most sites.     

上海中央公园特大银杏树白蚁防治探讨

通过对上海松江中央公园内65株特大银杏树白蚁为害情况的调查,发现该公园银杏受害率为100%,其中存在活白蚁的银杏占总量的56.9%,采用毒土处理、粉剂疗法、建立白蚁监测点等措施,经过两次灭杀,活白蚁的灭杀率达到92.3%和93.3%,从而使存在活白蚁银杏树的比例从56.9%下降到2.7%,白蚁发生情况明显降低。       

我国食品中农药残留研究进展

随着人们安全健康意识提高,食品中农药残留问题更加受到重视,本文综述了样品预处理研究进展及农药残留快速检测技术研究进展,并简单分析介绍各种方法的优缺点。     

建平半干旱地区石质山地造林技术研究

研究了不同植物在石质山地的造林成活率、土壤化学性质随造林年限的变化和造林措施对土壤化学性质和植物胸径、树高年净生长量的影响。结果表明：不同植物在石质山地的成活率在21%～85%之间,其中白榆和沙打旺的成活率分别为81%和85%,而小叶杨、刺槐、栾树的成活率均在70%左右;植被能明显提高石质山地不同土层的有机质、全N、P2O5含量,但提高程度随土层深度、养分种类和造林年限的不同而不同;在同一土层,生物复合肥料、菌剂和保水剂均显著提高土壤有机质含量（p〈0.01）并显著降低土壤P2O5含量（p〈0.01）;只有保水剂可引起土壤全K含量的明显升高;生物复合肥料、菌剂和保水剂均显著提高白榆、小叶杨、刺槐、栾树树高和胸径的年净生长量,但保水剂的提高程度最高。     

植物DNA甲基化研究进展

植物经常暴露在各种生物和非生物的胁迫之下,这些胁迫会影响植物的生长发育和繁殖并最终导致植物死亡。为了抵御不利的环境条件,植物已经进化出复杂而精细的网络来感知胁迫并激活防御系统。为此,植物激活许多信号转导通路,这些信号转导通路可以改变一些胁迫响应基因的表达,从而引起植物形态、生理和生化的改变以适应逆境。DNA胞嘧啶甲基化是高等真核生物的主要表观遗传机制之一,在维持基因组稳定性和调节基因表达方面起着关键作用。表观遗传变异比遗传变异更为灵活。一旦环境条件发生变化,为了适应新的环境植物都会发生表观遗传的改变。许多研究表明DNA甲基化参与植物的发育和应激反应。基于相关研究对DNA甲基化进行了综述,对植物逆境胁迫有重要意义。     

木材碳封存研究进展

碳封存可以分工业封存和生物封存, 工业封存包括地质封存、海洋封存、矿石碳化以及工业循环利用, 这些方法能快速回收CO₂, 但工艺流程技术复杂, 成本较高。木材碳封存是生物碳封存的一种类型, 树木光合作用吸收的碳主要存贮在木材中。运用木材密度、微密度等检测仪器, 通过确定木材密度变化, 结合其含碳率来计量木材的碳封存过程以及封存过程中碳的分配格局, 同时研究其与环境因子的相关性, 可以为研究森林的碳吸收动态提供便捷的方法和科学的依据。     

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha^?1, of which 1700?ha^?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha^?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.     

Changes in micropores in dry wood with elapsed time in the environment

To investigate the changes in microstructures of wood with elapsed time in the environment, CO₂ adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years. The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption and/or temperature variation in the environment.     

Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha^?1), and 36% were at least satisfactory (≥1300 ha^?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.     

Deposits in heartshakes in wood

Summary  The heartshakes of some species can contain deposits of inorganic, metal organic, resinous or organic compounds in a pure or concentrated condition. The type of deposit in different genera is discussed. Morphological and chemical examinations have been made of the deposits in the heartshakes ofIntsia bijuga, Dacrydium spp.,Anisoptera curtisii, Pinus elliotii andOrites excelsa. The deposits were of a benzenoid or terpenoid nature or aluminium succinate.I thank Mr. R. Wearne for organic analyses     

浅色松香酯的研究进展

松香酯是松香的重要改性产品之一，广泛应用于各个领域，但目前松香酯颜色较深，不能满足用户的要求。因此开发研制浅色松香酯是一个重要的课题。本文从松香原料、催化剂、添加剂、酯化工艺等方面探讨了浅色松香酯的研究进展。     

舟山黑松林群落物种多样性特征研究

通过样方法对舟山长岗山森林公园中的黑松林进行群落调查,每个样地大小为20 m×20 m。结果表明:和同一生境的其他乔木相比,黑松的径级分布呈正态分布趋势,小径级的黑松明显偏少;常绿阔叶林和松阔混交林的乔木种类比较丰富,分别达11.33和9.92种,几乎是黑松林的物种丰富度的2倍;和常绿阔叶林不同的是,黑松林林下植被物种丰富,常见伴生种有枫香(Liquidambar formosana)、白栎(Quercus fabri)、麻栎(Q.acutissima)和黄檀(Dalbergia hupeana),继续封育可加速向松阔混交林演替,以提高其乔木层生物多样性。     

南京地区桂花品种资源调查研究

列出了南京地区现有桂花品种资源３０种，且对各品种特征作了记载与描述。     

Deposits in heartshakes in wood

Summary Crystalline or almost pure organic compounds can be formed either alone or with two or three related compounds in juxtaposition in shakes in central heartwood. The compounds may not always be present in the more complex extractives formed at the heartwood periphery. The largest amounts of deposits are in the innermost or widest portion of the shake. No evidence could be found of a source of substrate, energy or specific enzymes necessary for the selective biosynthesis of these deposits. They are considered to be formedin situ by an undetermined mechanism during enlargement of the shake.     

油橄榄氮素营养研究进展

氮作为植物生长的一种必需元素一直以来都是人们研究的热点问题。本文通过查阅相关文献资料,分别从N素营养对于油橄榄光合作用、抗盐性、果实产量和橄榄油品质及土壤环境等方面的影响进行了综述,以期能在油橄榄的生产中合理施用N肥、提高产量和经济效益提供参考。     

Research advance in wood composites in China

Inthe21stcentury,thewoodsupplyinChinawillcontinLJetobelessthanthedemand,soChinawillneedtousewoodasetfectivelyasPossible.Theuseotwoodcompositesisaveryefficientwaytosavewood.ChinalackssLJfficientforeststomeetitsdemandforwood,especiallyinfinequalitywoods.BecauseofChina'spopulationandfiberdemand,efficientuseofwoocJismoreimportanttoChinathanthattosomeothercoLJntries.However,Chinawasneitherconvincedofthisandnordiditpayattentiontothestudyofwoodcompositesbeforethe1970's.FacingthewoodcrisisChinaf…     

植物中miRNA的研究进展

miRNA是长度约19~25个核苷酸的内源性具有调控功能的非编码单链小RNA分子,可通过识别靶基因的裂解位点,并在转录后水平对靶基因进行裂解,从而对靶基因起负调控,以控制蛋白编码基因的表达,研究表明miRNA在植物的多个生物学过程中发挥重要作用。该研究就miRNA及其靶基因的获得和验证以及在植物中的生物学功能进行总结。     

被子植物性别分化的研究进展（英文）

被子植物的性别分化对遗传多样性、子代和环境适应有着巨大的贡献。在自然界中广泛存在单性花物种,单性花形成是避免自交、促进异交、保持遗传多样性和避免雌雄功能干扰的重要途径。单性花物种分布于不同的进化分支上表明被子植物性别分化可能存在性别多样性的进化途径和复杂的调控网络机制。因此,性别分化机制研究具有重要的理论意义和实际应用价值。性别分化和表达研究涉及形态学、生物化学、细胞学和分子遗传学等研究领域,在查阅近年来国内外文献的基础上,本文主要从4个方面对性别分化相关研究进行系统总结:1)单性花形成源于两性花祖先,主要是通过两性花中性器官缺失或者退化2条系统进化途径形成。从花着生部位和结构来看,单性花分为雌雄异花同株和雌雄异花异株,而且单性花的外部形态结构具有多样性;以花发育过程中划分的发育阶段来看,单性花的表型特征形成于4个发育阶段,即阶段0(性器官原基出现之前)、阶段1(性器官原基发育早期)、阶段2(减数分裂之前)和阶段3(减数分裂之后),而且已有处于发育阶段0、1和3物种的性别调控机制被发现和证实。2)赤霉素、生长素和乙烯等六大类植物激素在性别分化调控过程扮演着重要的角色,赤霉素主要具有促进雄蕊发育,而生长素、细胞分裂素和乙烯主要是促进心皮的生长,同时,已有相关激素的调控机制被阐明,如乙烯合成途径调控性别分化。3)了解不同类型单性花性器官缺失或者败育的遗传分子基础,整合已经鉴定的各物种中与性别相关或者性别决定基因,阐述DNA甲基化和小分子RNA等表观遗传调控性别形成的机制以及XY系统、X[DK]∶A系统和ZW染色体系统调控性别分化的模式。4)环境因素如温度、光照以及矿质营养等对植物性别分化的影响。本文旨在对于现有基于性别分化的相关研究进行总结,对单性花发育的不同调控机制进行回顾和梳理,了解性别分化的最新研究现状和成果,促进对性别表达途径及其系统发育进化的理解,为性别分化的调控机制提供理论基础和依据,也为进一步探索植物性别分化新思路提供参考。     

寒地城市居住区冬季植物景观探讨

寒地城市冬季漫长 ,如何创造良好冬季植物景观是居住区外环境建设的重要问题 ,文章探讨发挥寒地植物冬季景观特色 ,从植物形成景观的基础形态、干皮颜色、果实等 ,到形成景观 (配置 ,色彩 ,结构 ,认识 ,管理 )等 ,为寒地居住区环境建设提供参考