黑龙江省沙棘干缩病病原菌生物学特性的研究

对引起黑龙江省大果沙棘干缩病的病原菌-拟枝孢镰孢菌的生物学特性进行了研究,研究结果表明,病原菌生长最适温度为25℃,生长最适pH值为7,生长所需最佳碳源为麦芽糖,最佳氮源为硝酸钠和蛋白胨;病原菌产孢最适温度为25℃,最适pH为6,最佳碳源为乳糖,最佳氮源为硝酸钠.     

桦树枯枝病病原菌的生物学特性研究

桦树枯枝病病原菌拟茎点霉Phomopsissp．生物学特性的研究表明,该菌在8～30℃范围内均能生长,最适温度为20-30℃;在pH值5．8～8．2间均能生长,偏酸环境最佳;不同光照条件和碳源对生长无显著影响,但光照有利于产孢;在无碳源条件下也能生长,以蔗糖为最佳碳源;菌丝体在生长发育时,以蛋白胨为最佳有机氮源,以硝酸钙为最佳无机氮源;在尿素中几乎不生长。     

桑树轮纹病病原菌的分离鉴定及其生物学特性研究

2012年6～8月,通过对桑树轮纹病病原菌分离、田间致病性测定、病原菌形态观察,将该病原菌鉴定为桑膝节霉,并对此病病原菌的生物学特性进行了研究。结果表明,不同培养基配方、温度、酸碱度、碳源、氮源、光照对桑树轮纹病病原菌菌丝的生长有一定影响,菌丝生长的最适宜培养基是理查培养基,最适温度是25℃,最适pH值是7.0,最适碳源为葡萄糖,最适氮源为蛋白胨,光照对菌丝生长无显著性差异,菌丝的致死温度和时间分别为85℃和10 min。对该病病原菌生物学特性研究为云南首次报道,对桑树轮纹病的防治具有一定的参考价值。     

桑叶褐斑病病原菌的生物学特性研究

通过对桑叶褐斑病病原菌在不同种类培养基培养、不同氮源与碳源、不同温度等6种条件下培养6天后，测定菌落直径，观察菌丝颜色和菌落形态，分析了桑褐斑病病原菌的生物学特性。结果表明，在室内培养条件下，不同的营养成分、 pH值、温度、光照都对菌丝的生长有影响。病原菌菌丝生长的最适宜培养基是燕麦片培养基，适宜生长温度范围是20～30℃，最适生长温度为25℃，光照对菌丝生长无显著影响，最适pH值为9～10，最适碳源为α-乳糖，最适氮源为尿素，菌丝在55℃水浴10 min后则不能生长。     

东北红豆杉根腐病病原鉴定及生物学特性

东北红豆杉Taxus cuspidata幼苗期易发根腐病。通过形态学和分子生物学相结合的方法对东北红豆杉根腐病病原菌进行鉴定,并在实验室内纯培养条件下对病原菌进行生物学特性研究。结果表明:东北红豆杉根腐病病原菌为茄腐皮镰孢菌Fusarium solani(Mart.)App.et Woll.,病原菌菌丝生长最适碳源为蔗糖,最适氮源为蛋白胨,最适pH值为6.0,菌丝生长适宜温度为20~35℃,最佳光照条件为12∶12光暗交替。     

杨树枯萎病菌茄类镰刀菌的生物学特性

由茄类镰刀菌引起的杨树枯萎病是一种新病害,对其病原菌的生物学特性进行了初步研究.试验结果表明,病原菌Fusarium w/ani的适应性较强,在8～35℃范围内均能生长,最适生长和最大产孢量的温度为25℃,孢子萌发的适宜温度范围是25～30℃,以30℃最适,分生孢子致死温度为53℃,10 min.病原菌在pH5.91～6.98对生长和产孢较好,pH 6.98最适,当pH<4.53对菌落表现异常现象.病原菌在不同光照条件及在不同碳、氮源上均能生长,不同光照条件对其影响无显著差异;以蔗糖为其最适碳源.亚硝酸钾和硝酸钾为其最适氮源.     

石榴疮痂病病原菌生理学特性研究

该文对来源于危害石榴枝干部和果实部的疮痂病病原菌Dothiorella sp.菌株的生理学特性进行了系统研究。研究结果表明：两菌株的菌丝体在5～40℃范围内均可生长，最适温度为25～30℃；在pH3～11均可生长，最适酸碱度为pH4，pH6～7时生长较为迅速；在不同碳源中，多糖生长最好，其次为单糖、二糖；在不同氮源中，以牛肉膏和蛋白胨生长最好；分生孢子在多糖中萌发最好，其次为单糖、二糖；而在氮源中以硫酸铵萌发最好；分生孢子萌发的最适温度为30℃，最适湿度为100％。两菌株问没有显著差异。     

桦树枯枝病病原菌的生物学特性研究

桦树枯枝病病原茵拟茎点霉Phomopsis sp.生物学特性的研究表明,该茵在8～30℃范围内均能生长,最适温度为20～30℃;在pH值5.8～8.2间均能生长,偏酸环境最佳;不同光照条件和碳源对生长无显著影响,但光照有利于产孢;在无碳源条件下也能生长,以蔗糖为最佳碳源;茵丝体在生长发育时,以蛋白胨为最佳有机氮源,以硝酸钙为最佳无机氮源;在尿素中几乎不生长.     

桉树轮斑病原菌生物学特性分析

采用平板培养法和液体培养法研究桉树轮斑病原菌(Pilidiella eucalyptorum)的生物学特性,为桉树轮斑病的监测及防治技术提供理论基础。结果表明,该菌菌丝在10～35℃及pH 2～12的环境里均能生长,最适温度为28℃,最适pH值为6;6 h/18 h紫外光光暗交替与12 h日光灯光暗交替有利于菌丝生长;乳糖和蔗糖是菌丝生长最佳碳源;蛋白胨和酵母粉是菌丝生长最佳氮源;分生孢子在20～30℃均可萌发,以28℃萌发率最高;在饱和湿度且有水滴条件下分生孢子萌发率最高;病原菌菌丝和分生孢子的致死温度分别为48和50℃。     

铁皮石斛炭疽病病原鉴定及其生物学特性研究

在云南省瑞丽市铁皮石斛Dendrobium officinale种植基地,发现一种铁皮石斛叶斑病。通过分离培养和接种试验,经传统形态学及ITS序列分析鉴定,采用十字交叉法和血细胞计数板法测定该病原菌的形态学特性及产孢性能。结果表明:该病病原为半知菌亚门腔孢纲黑盘孢目炭疽菌属的胶孢炭疽菌Colletotrichum gloeosporioides。菌丝生长最适温度为15～30℃,其中28℃时菌丝生长量最大,最适pH值为5～6;产孢的最适温度为25～30℃,最适pH为3～4。此菌对碳源要求不严格,能利用多种碳源,但利用能力有差异;硫酸铵、氯化铵作为氮源的培养基明显不利于菌丝生长,其他供试氮源均对该菌菌丝生长有显著促进作用。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.