Rhizoctonia solani AG4同一融合群内不同分离物对杉苗致病力的研究

ＲｈｉｚｏｃｔｏｎｉａｓｏｌａｎｉＡＧ４同一融合群内不同分离物对杉苗致病力的研究朱天辉（四川农业大学林园学院）ＲｈｉｚｏｃｔｏｎｉａｓｏｌａｎｉＡＧ４是杉苗猝倒病的主要病原［７］，多在４～６月危害，因发病时期不同可出现４种症状类型［３］。此病原是一种...     

毛白杨腐烂病发生规律及防治

1　腐烂病的症状杨树腐烂病 (ｖａｌｓａｓｏｒｄｉｄａ)又称烂皮病 ,主要发生在树干及枝条上 ,表现为干腐和枝枯两种类型。1.1　干腐型主要发生在主干 ,大枝及树干分杈处 ,发病初期为暗褐色水渍状斑 ,略肿胀 ,病部皮层组织腐烂变软 ,用手压之有水渗出 ,以后病斑失水 ,树皮便干     

枣缩果病研究进展

对枣缩果病病原的种类、症状类型、侵染途径、影响发病因素、防治方法等方面的研究进展进行了综述。迄今已报道过的病原菌有6种真菌和2种细菌,病原菌在枣树皮、枣枝、枣头、枣叶、枣吊等部位皆可越冬;病原主要借助风雨作用传播,通过伤口或自然孔口传病;从花期开始整个生长期地上部各器官都可侵染,其中在叶和枣花上不表现症状,果实上到近成熟期才开始表现症状;果实症状主要有铁皮和缩果两种类型,果实症状发展可分为晕环、水渍、提前着色、萎缩、脱落5个阶段;发病程度受气候、地势、土壤类型、栽培条件和间作物种类、品种、树龄、枝龄、树势、枣果成熟度等多种因素的影响;防治措施包括加强枣园综合管理,提高树体抗病能力及化学农药防治等。针对枣缩果病研究中的问题,提出了今后的研究方向。     

苹果树腐烂病发生与防治

一、症状 腐烂病主要为害果树的枝干，幼树和苗木也可被害。受害皮层腐烂坏死，其症状表现有溃疡和枯枝两种类型。以溃疡型为主。     

胶孢炭疽菌在斯里兰卡热带水果的寄主范围

从斯里兰卡的２３种水果作物上分离到胶孢炭疽菌（Ｃｏｌｌｅｔｏｔｒｉｃｈｕｍｇｌｏｅｏｓｐｏｒｉｏｉｄｅｓ），在这之前。未有该菌在斯里兰卡的榴莲、山竹了、蒲桃和红毛丹以及其它１１种经济价值较小的果树上的记载。胶孢炭菌侵染果树树苗（特别是芒果和红毛丹）的症状曾被认为是生理失调所致，这可造成高达４０％的苗木损失。所以，推荐通过隔离该菌接种体的主要来源来保护这些树苗。     

苗木猝倒病的防治

<正>猝倒病也称立枯病,在我国各地苗圃普遍发生,幼苗死亡率很高,严重的达50%以上,是许多针阔叶树幼苗的主要病害。1症状病害多在4～6月间发生,因发病时期不同,可出现四种症状类型。(1)种腐型:播种后,土壤潮湿板结,种芽出土前被病菌侵入,破坏种芽的组织,未出土就引起腐烂,地面表现为缺苗。     

花椒流胶病病原的初步研究

花椒流胶病是花椒树枝干上的重要病害,引起枝干皮层组织流胶,树势衰弱,寿命缩短。该病害在我国北方花椒种植区普遍发生。按其流胶部位和表现症状的不同可分成四种类型,即基腐型流胶、干腐型流胶、枝腐型流胶和伤口流胶。经病原分离和回接试验,证明引起前三种类型流胶的病原分别是三种真菌(种名待定),即镰刀菌(Fusarium sp)、茎点霉(Phoma sp)、复端孢(Cephalothecium sp)。伤口流胶是椒树受伤组织的一种生理反应。     

六种竹子节长模型及其特性的研究

本文研究了雅竹（Ｐｈｙｌｌｏｓｔａｃｈｙｓｖｉｖａｘ）、斑苦竹（ｐｌｅｉｏｂｌａｓｔｕｓｍａｃｕｌａｔｕｓ）、满山爆竹（Ｓｉｎｏｂａｍｂｓａｌａｅｔａ）、孝顺竹（Ｂａｍｂｕｓａｍｕｌｔｉｐｌｅｘ）、大节竹（Ｉｎｄｏｓａｓａｃｒａｓｓｉｆｌｏｒａ）和茶秆竹（Ａｒｒｎｄｉｎａｒｉａａｍａｂｉｌｉｓ）６个竹种的节长变化规律，发现其共有两种节长变化类型．可用不同的模型去拟合，拟合效果良好．同时，应用数学分析的方法，对这两类节长模型的特性作了探讨．     

欧美杨枯萎病症状和病原初探

通过对欧美杨枯萎病野外林间症状的调查 ,发现本病在林间存在两种症状类型。按两种症状类型分别作分离 ,一种类型多数只分离到FusariunOxysporum ,而另一种症状类型多数同时分离到FusariunOxysporum和XanthomonasPopuli,用分离物作接种试验 ,能致病 ,再分离与接种物一致。初步表明 ,F Oxysporum和X Populi都是杨树枯萎病的病原菌 ;对林间两种不同症状类型是否由F Oxysporum单独所致还是由F Oxysporum和X Populi复合侵染致病 ,本文进行了初探     

不同类型国家林业管理体制的启示及借鉴

不同类型国家林业管理体制的启示及借鉴Ｅｎｌｉｇｈｔｅｎｍｅｎｔｆｒｏｍｔｈｅｆｏｒｅｓｔｒｙｍａｎａｇｅｍｅｎｔｗｓｔｅｍｓｉｎｄｉｆｆｅｒｅｎｔｃｏｕｎｔｒｉｅｓ￥／／谭俊（黑龙江省大兴安岭林业调查规划院加格达奇市１６５０００）１不同类型国家的林业...     

TAXONMIC SIGNIFICANCE OF SYMPTOM CHARACTERISTICS AND AECIOSPORES SURFACE STRUTURE OF PINE NEEDLE RUST

INTRoDUrnoNRneneedlerustdiseasecausedbyCo-leosPoriumsPP.seriouslyharmspinetreesthatarelessthanloyearsold.Sincel847,LeviellsetuPCoIeosPoriumgenus,sofarintheworld,morethan9Ospeieshavebeendescribed.AInOngthem,8speCiesareautoec1ous,1speciesarendcI-OCyclic,and3speciesaredenti-cyclic,theremainingareheteroeciousI7'l6l.fuStorically,theclassificahonofColeosPo-riumisnotveryclear.lntfadihonalclassifica-hon,genusofCoIeosPorilunwasdecidedbythemorpholOgyofteliosPOres,andspecieswasdecidedbyaltem…     

松树分子标记辅助育种研究进展

松树是世界上森林生态系统和人工林的重要树种,松树的遗传改良开展早,进展快,成效大.分子标记技术为缩短育种周期,提高育种效率提供了有力的工具.本文回顾了世界上松树分子标记遗传图谱构建、比较遗传作图、数量性状位点定位和标记辅助选择的研究进展.已经构建遗传连锁图的林木有13个属,近40个树种,其中松树占40%,而大多数松树遗传图谱仍然是不完整的,不能覆盖全基因组;比较遗传作图显示松属树种具有高度的遗传保守性;数量性状位点(QTL)定位表明,大多数性状的遗传基础存在着主效基因,为开展分子标记辅助选择提供了良好的基础.杂种松部分重要性状的遗传控制中存在着树种效应,对标记辅助选择和育种策略的制订具有指导意义.     

松材线虫病的潜伏侵染及松墨天牛传播新途径

在南京用松材线虫接种 7种松树 ,于第 2a在无任何症状的松树的接种点上方 10cm处取样 ,分离线虫。结果表明松材线虫病的潜伏侵染现象比较普遍。在不同的松树品种上潜伏侵染现象有所差异。感病黑松和赤松很快死亡 ,只有在接种量小的情况下才有潜伏侵染现象发生。抗病性强的火炬松和湿地松感病后潜伏侵染现象比较普遍 ,并且样品中的线虫量也较高。而抗病性中等的马尾松和刚松感病后潜伏侵染现象的普遍性及样品中的线虫量均处于中等。短针松接种松材线虫后既不枯死 ,也无潜伏侵染现象。松墨天牛传播松材线虫的试验结果表明 ,未携带松材线虫的松墨天牛成虫在松材线虫病松枝上取食后 ,再到健康松枝上取食 ,有传播松材线虫的可能。这些结果表明在松材线虫病新病区清理病死木时 ,应采取早期诊断技术 ,把未表现症状的松树一起清除 ,以达到防治目的。     

The R. R. Reynolds Research Natural Area in Southeastern Arkansas

The R. R. Reynolds Research Natural Area is a 32-ha pine-hardwood forest in southeastern Arkansas, U.S.A., that originated from diameter-limit cutting of the virgin forest before 1915. In 1935, these 32 ha were reserved from timber management. Between 1937 and 1993, eight inventories were taken of all living trees > 9-cm DBH, using 2.5-cm DBH classes within three species groups: Pinus spp., Quercus spp., and other hardwoods. In 1994, all standing dead snags of pines and hardwoods > 9-cm DBH were inventoried by 2.5-cm DBH classes. During 56 years, thc overstory pine-hardwood ratio remained stable in terms of relative basal area, but pine density decreased with a commensurate increase in hardwood density. In 1993, pines represented 63% of basal area but only 23% of stem density. Just before the 1993 inventory, a pine bark-beetle infestation developed on the area, and within one year the pines lost about 2.5 m2/ha in basal area and had 180% more snags than were contributed by hardwoods. The overstory pine component is decreasing in density as a result of natural senescence and the allogenic effects of bark beetles. Hardwood species are expected to eventually dominate the forest because shade-intolerant pine regeneration will not develop to maturity beneath the closed hardwood canopy which can be altered only by catastrophic natural disturbances or anthropogenic intervention.     

Responses of water-stressedPinus thunbergii to inoculation with avirulent pine wood nematode (Bursaphelenchus xylophilus): Water relations and xylem histology

The effect of water-stress conditioning on water relations and histological features ofPinus thunbergii Parl. inoculated with avirulent isolate ofBursaphelenchus xylophilus (Steiner and Buhrer) Nickle, pine wood nematode, were investigated. Pines were kept under 8 days cycle of severe water stress. One-half of the water-stressed pines died as a result of infection by avirulent pine wood nematode and water stress tended to induce increased susceptibility and/or decreased resistance of pines to avirulent pine wood nematode. In dead pines, the water conducting function of xylem was lost, and all of the parenchyma cells died. In surviving pines, the xylem hydraulic conductivity and the xylem water content were significantly reduced (12 to 23% and 77 to 83%, respectively) compared to controls. Safranin dye perfusion of excised axis stem segments indicated that the water conductance was limited to the very narrow peripheral area of xylem. Embolism caused by cavitation in the tracheids occurred in the central part of xylem and in that dysfunctional region of the xylem the axial parenchyma cells surrounding the epithelial cells, and ray parenchyma cells partly degenerated but the epithelial cells survived. The disruption of tracheid shape observed in surviving pines indicates that avirulent pine wood nematode temporarily disturbed cell division of the cambium. Considering the differences in responses between dead pines and surviving pines after inoculation with avirulent pine wood nematode, the death of water-stressed pines apparently resulted from death of cells, in particular the vascular cambium and the loss of xylem hydraulic function by cavitation.     

竹材梯度结构对弯曲力学性能的影响

竹材梯度结构对力学性能影响显著,尤其是在弯曲应力下,更呈现明显的非对称行为。文章对竹材梯度结构进行详细解析,提取了维管束形状、纤维鞘面积、维管束梯度变化规律等多个梯度因子,然后对其弯曲力学性能进行测试,解析竹材梯度结构因子与弯曲力学性能之间的关系,阐明梯度结构对弯曲力学的影响机制。结果发现,毛竹维管束沿径向梯度分布的曲线属于下凹型曲线,梯度分布指数n=2.28;从竹青到竹黄,维管束长径比呈现明显下降的趋势,靠近竹青侧的维管束长径比较大,靠近竹黄侧的维管束长径比较小,形状更趋近于圆形;对比了竹黄侧加载和竹青侧加载2种模式下的竹材弯曲力学性能,当竹青侧受压、竹黄侧受拉的情况下,竹材的弯曲韧性最好;当竹青侧受拉、竹黄侧受压的情况下,竹材的弯曲模量最大。     

建德松树枯死原因剖析及治理

建德市有松林面积5．57万hm^2,占有林地面积的35．6％，占总蓄积的46．7％，近几年，枯死松树日趋严重，已影响自然景观和生态平衡，经多年调查研究表明，主要原因是松毛虫为害，高虫口松褐天牛，超强度割脂和日本松干蚧传入等因素造成，必须采取相应措施才能制遏制。     

Short-term effects of hexazinone applications on woody species diversity in young loblolly pine (Pinus taeda) plantations

Data from four studies determining the susceptibility of woody plant species to foliar applications of several rates of liquid hexazinone (Velpar L®) were used to examine the short-term effects of the herbicide on woody species diversity in young loblolly pine plantations. Woody species diversity, as measured by four similarity measures between pretreatment and post-treatment species importance or diversity, decreased significantly with increasing hexazinone rate. Woody species shown to be among the most susceptible (sumacs (Rhus spp.) and oaks (Quercus spp.)), and least susceptible (loblolly and other pines, and Vaccinium spp.) to hexazinone in previous herbicide screening trials decreased and increased in importance, respectively. Differences in similarity measures between the no-hexazinone treatment and the 1.0 × hexazinone rate (1.2 to 1.5 kg a.i./ha depending on the study location) 2 years after herbicide application were small.     

Field ready: Development of a rapid LAMP-based colorimetric assay for the causal agent of white pine blister rust,Cronartium ribicola

The invasive fungal pathogen Cronartium ribicola causes white pine blister rust which is considered one of the most destructive diseases of five-needle (white) pines in North America. The disease has a life cycle that requires two hosts: white pines and Ribes spp., although other non-Ribes species, including Castilleja and Pedicularis, have been demonstrated as alternate hosts as well. Detection of this disease can be difficult because of the ephemeral nature of sporulation on pine hosts with ambiguity in other symptoms, and the alternate hosts for C. ribicola can also be an alternate host for other pine rust species. We used the previously published C. ribicola genome and species-specific real-time PCR assay to develop a field-ready loop-mediated isothermal amplification (LAMP) specific colorimetric assay for this pathogen. Specificity results across regionally identified pine rust pathogens showed the assay is highly specific to C. ribicola and can detect as little as 40 pg of pathogen DNA. We also developed a simple DNA extraction method that works with several tissue types (bark/phloem, aeciospores, and urediniospores/telia) to prepare the DNA samples for the LAMP assay. The DNA extraction and LAMP assay take ~70 min to complete and require a relatively small investment in equipment. This tool enables quick and efficient detection of white pine blister rust.     

高产脂马尾松、普通马尾松枝、叶的精油与抽出物的初步分析

通过热水蒸煮法测得高产脂马尾松的枝条精油含量高于普通马尾松，而针叶精油含量，两种类型的马尾松无大的差别；枝条精油含量较针叶低．气相色谱分析表明：两种类型的马尾松的精油在组成成份上无大的差别，枝、叶相比，枝条精油的构成成份少．生物检定表明：两种类型的马尾松精油对紫花苜蓿的种子的发芽及幼苗的生长都具有一定的影响，并存在一定的差别。用四种不同极性的溶剂（正己烷、苯、乙醚、甲醇）对枝、叶进行逐次抽出，其中甲醇的抽出物含量最高，针叶的抽出物含量高干枝条的抽出物含量。