竹盲走螨、胡瓜钝绥螨对毛竹害螨的控制作用研究

应用实验种群生命表数据分析毛竹林本土优势种竹盲走螨和引进种胡瓜钝绥螨对毛竹4种害螨南京裂爪螨、竹裂爪螨、竹缺爪螨、竹刺瘿螨的控制能力。结果表明①胡瓜钝绥螨取食上述4种害螨的世代存活率分别为90．4％、77．55％、87．93％、81．63％，每雌总产卵量分别为38．12粒、45．77粒、35．59粒、30．26粒，而乡土优势种竹盲走螨取食上述4种害螨的世代存活率分别为95．23％、100％、87．7％、80．48％，每雌总产卵量分别为44．5、46．8、41．15、20．1粒；②竹盲走螨以南京裂爪螨为猎物时其内禀增长率(0．155)与引进种胡瓜钝绥螨(0．154)相近，均明显高于南京裂爪螨(0．1089)；③竹盲走螨以竹裂爪螨为猎物其内禀增长率(0．152)与胡瓜钝绥螨(0．152)相同但明显低于竹裂爪螨(0．192)；④竹盲走螨以竹缺爪螨为猎物时其内禀增长率为(0．148)明显低于引进种胡瓜钝绥螨(0．175)和其猎物(0．185)；⑤竹盲走螨取食竹刺瘿螨易大量逃跑，雌螨产卵量低，引进种胡瓜钝绥螨取食竹刺瘿螨能正常生长发育，但是其内禀增长率(0．144)明显低于其取食上述其余3种害螨的内禀增长率，产卵量高于当地种竹盲走螨，并描述1998年以来每年5—6月助迁人工繁殖的胡瓜钝绥螨控制毛竹害螨蔓延的效果。     

竹缺爪螨实验种群生命表的研究

在25℃温度条件下，用黄金间碧竹（Bambusa vulgaris cv.vittata)叶饲养竹缺爪螨（Aponychus corpuzae Rimando)，应用生存分析理论和多维矩阵模型组建竹缺爪螨种群生命表，计算得种群主要参数为：内禀增长率rm＝0．0811，净增殖率R0＝5．8368，平均世代长度T＝21．7532d，周限增长率λ=1.0845/d；并分析了种群在不同年龄的生命状态，各发育期重叠情况以及稳定的年龄一阶段分布；最后讨论了应用这2种方法组建螨类生命表的优点。     

毛竹叶螨及其天敌捕食螨的生态位研究

通过对福建南平西芹毛竹叶螨危害的毛竹林调查分析 ,结果表明 ,毛竹叶螨及其天敌对时空资源利用程度序列为 :捕食螨 (Bi =0 5550 ) >竹小爪螨 (Oligonychusurama) (Bi=0 4 467) >南京裂爪螨 (Schizotet ranychusnanjingensis) (Bi=0 30 97) >竹缺爪螨 (Aponychuscorpuzae) (Bi=0 2 875) >竹裂爪螨 (S .celarius) (Bi=0 1 674 ) >苔螨 (Bryobiasp .) (Bi=0 1 4 1 7)。捕食螨对南京裂爪螨、竹小爪螨、竹缺爪螨的时空跟随效应强 (Cij值分别为 0 574 3、0 4 830、0 4 371 )。叶螨间南京裂爪螨与竹缺爪螨对时空资源竞争最激烈 (Cij=0 60 76)。竹小爪螨与其它 4种叶螨竞争较激烈 (Cij>0 2 )。南京裂爪螨、竹小爪螨、竹缺爪螨 3种叶螨不同螨态中以竹小爪螨卵和成螨占有较大时空资源 ,其种内竞争激烈 (Cij值大 )。种间以竹缺爪螨和南京裂爪螨卵、幼若螨、竹缺爪螨幼螨与南京裂爪螨卵、竹小爪螨成螨与竹缺爪螨幼若螨竞争激烈 (Cij>0 4 )。捕食螨对 3种叶螨不同螨态的跟随效应以南京裂爪螨幼若螨、成螨、竹小爪螨成螨、竹缺爪螨幼若螨最强 (Cij>0 5) ,其余依次为竹小爪螨卵、南京裂爪螨卵、竹缺爪螨成螨、竹小爪螨幼若螨、竹缺爪螨卵     

竹子叶螨的生物学及其防治技术

危害竹子的三种主要害螨——南京裂爪螨、竹裂爪螨、竹缺爪螨,在竹叶背织网或不织网危害,都在3月出蛰、11月入蛰。竹腔注药法具有经济、安全,防效达99%以上,为最佳防治方法。     

南京地区竹锈褐斑病防治技术

近年来南京地区竹锈褐斑病大量发生,该病对竹种的观赏价值和经济价值带来了一定影响.该病病原为南京裂爪螨.对竹锈褐斑病分别进行了化学防治和生物防治:(1)利用6种药剂对竹锈褐斑病进行室内毒力测定和野外防治研究结果表明:阿维菌素对南京裂爪螨的毒力最高,LC50为0.060 mg/mL,其次为哒螨灵、腚虫脒、炔螨特、四螨嗪,甲氨基阿维菌素苯甲酸盐最低.15%阿维菌素在浓度为1.2 mg/mL时具有较好的野外防治效果.(2)利用野外发现的天敌竹盲走螨属,按照益螨∶害螨比例为 1∶10、1∶30和1∶50野外释放结果表明:林间最适释放天敌比例在1∶10～1∶30之间.     

毛竹叶化学成分对叶部主要害虫影响的通径分析

利用对竹叶可溶性糖、蛋白质、单宁和类黄酮含量的测定和毛竹叶部主要害虫种群的系统调查等资料。采用通径分析研究了竹叶4类化学成分对竹刺瘿螨、南京裂爪螨、竹缺爪螨、竹小爪螨、蠕须盾蚧和刚竹毒蛾等害虫的影响。结果表明：除竹刺瘿螨和南京裂爪螨外，竹叶化学成分对其余4种叶部害且：有着显著影响。这种影响主要表现为对各害虫种群的抑制作用；对于竹缺爪螨，直接作用以可溶性糖的影响最大，间接作用以类黄酮通过可溶性糖的影响较大；对于竹小爪螨，直接作用以单宁的影响最大，间接作用中则以类黄酮通过单宁的影响最大；对于蠕须盾蚧，直接作用以类黄酮的影响最大，间接作用以单宁通过类黄酮的影响最大；对于刚竹毒蛾，直接作用以蛋白质的影响最大，间接作用以类黄酮通过蛋白质的影响最大。     

南京裂爪螨丝膜数量消长及空间格局时序动态

林间调查分析结果表明：①南京裂爪螨丝膜数量消长与该螨种群一致，在年周期中有2个高峰期，分别是3月和9—11月，4—8月处于较底的水平；②丝膜数量与气温呈极显著相关(r＝-0．6187)；②一年中大多数时期南京裂爪螨丝膜呈聚集分布，仅5—8月呈均匀分布或接近于均匀分布，并具有明显的高度聚集分布—均匀分布—低度聚集分布—高度聚集分布周期；④丝膜的分布C值与气温及降雨量呈显著相关(r＝—0．5403，—0．4530)。     

温度、光照对南京裂爪螨的影响

南京裂爪螨 (Schizotetranychus nanjingensis Ma et Yan)常与竹缺爪螨 (Aponychuscorpuzae Rimando)、竹裂爪螨 (Schizotetranychus bambusae Recb)等害螨共同或单独在毛竹(Phyllostachys pubescens Mazel et H.de L ehaie)叶背刺吸危害 ,造成竹叶早衰、早落[1～ 3] 。有关其生活习性及其发生与部分环境因子的关系以及防治技术 ,前人已作了研究[3～ 9] ,但未见光照对其存活、发育、繁殖的影响以及温度与其存活的关系等文献报道 ,本文就此作一研究报道。1　材料与方法1 .1　温度试验设置 - 1 0℃± 1℃、2℃± 1℃、2 0℃± 1℃、2 5℃…     

竹叶螨对毛竹危害的研究

本文报道了南京裂爪螨 Schizotetranychus nanjingensis Ma et Yun、竹缺爪螨 Aponychuscorpuzae Rimando和锈螨 Eriophyes sp.的混合危害对毛竹光合作用和竹叶生长量的影响。研究结果表明 ,受害 5级竹叶片的叶绿素含量、光合作用强度和生长量分别下降 51.55%、79.6 %和 72 .6 %。新生竹叶明显变少、变小。受害程度愈重 ,表现愈明显     

西双版纳地区野生亚洲象种群年龄结构及内禀增长力研究

亚洲象种群动态是研究者和管理者关注的最基本点,是种群研究的核心内容。以个体增长率、死亡率、年龄结构和性别比例为研究指标,2015年9至2016年12月,通过跟踪调查和定点观察,采取全事件取样法和焦点动物取样法,对西双版纳地区的亚洲象种群内禀增长力进行初步研究。调查结果,共观察到17个种群的227头亚洲象,其中幼体21头、青少年体37头、亚成体68头、成体101头。研究结果表明,亚洲象种群的雌雄比为3.39∶1,年度出生率、死亡率分别为26.92%、1.32%,均生殖率(Ro)为28.096,平均世代时间(T)为37.5 a,内禀增长率(rm)为0.038 6,周限增长率λ为1.039 3,实际增长率r为0.079 3。综合亚洲象的数量、年龄结构、性别比例、出生率、内禀增长率等参数,得出西双版纳地区亚洲象种群有较强的增殖潜力,但由于种群间的相隔,互不相连,阻碍了基因交流,不利于种群的繁殖,甚至面临近交的危险。     

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.     

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.     

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.