注干施药防治松材线虫的药剂筛选与林间防治效果研究

采用浸渍法测定了8种药剂对松材线虫的毒力。结果表明,阿维菌素、甲维盐和硫酸铜在较低浓度下对松材线虫即有较强的杀灭活性,其半致死浓度(LC50)分别为0.1346mg/mL、0.2965mg/mL和0.3179mg/mL。敌敌畏、二甲基硫蒽和氧化乐果的毒性次之,吡虫啉和苦参碱的毒性较弱。联合染毒测定的结果表明,联合使用对松材线虫表现出增效作用。林间试验结果表明,0.1%甲维盐和4.0%吡虫啉,1%阿维菌素和1%苦参碱2个药剂组合,可用于林间注干施药防治松材线虫,持效期可达2年。     

松材线虫罹病木的烘压处理试验

不同规格的松材线虫罹病材经 6 5℃～ 75℃ ,1 5 h热烘 ;9MPa,1 5 7℃～ 1 6 8℃ ,1 0 min液压和两种方法联合处理对松材线虫 Bursaphelenchus xylophilus和松墨天牛Monochamusalternatus都有较好的杀虫效果 ,其中 2 .8cm以下板材和 1 0 cm× 1 0 cm以下料材经 3种方法处理后 ,杀虫效果均达 1 0 0 %。     

3种生物农药对悬铃木方翅网蝽的室内毒力及解毒酶活性的影响

室内条件下采用浸叶法分别测定苦参碱、阿维菌素、苏云金芽孢杆菌(Bt)3种药剂对悬铃木方翅网蝽1,5龄若虫和成虫的毒力;采用生化方法测定3种药剂对不同虫态悬铃木方翅网蝽的羧酸酯酶(CarE)、乙酰胆碱酯酶(AChE)、谷胱甘肽S-转移酶(GST)活性影响。结果表明:3种药剂对方翅网蝽具有较好的毒杀效果,校正死亡率均随着浓度的增加而升高。1龄若虫对药剂的敏感性最强,5龄若虫和成虫的敏感性相近。3种药剂中苦参碱的毒力最高,对1,5龄若虫和成虫的LC50分别为0.1957,194.9和197.3mg·L-1;其次为阿维菌素,对不同虫态的LC50分别为10.66,420.5和472.0mg·L-1;苏云金杆菌对不同虫态的LC50分别为3.23,1414.2和6967.2mg·L-1。3种药剂处理后,悬铃木方翅网蝽不同虫态的羧酸酯酶、乙酰胆碱酯酶和谷胱甘肽S-转移酶活性均产生不同程度的诱导效应。以苏云金杆菌处理的解毒酶活性增强最明显,1,5龄若虫和成虫的3种解毒酶活性均明显高于对照;其次为阿维菌素处理,3种虫态的谷胱甘肽S-转移酶活性,1龄若虫的乙酰胆碱酯酶活性和成虫的羧酸酯酶活性明显高于对照;苦参碱处理的解毒酶活性增强最不明显,仅引起3种虫态的谷胱甘肽S-转移酶活性、1龄若虫的乙酰胆碱酯酶活性较对照显著增强。1,5龄若虫和成虫不同虫态相比,药剂处理后的5龄若虫体内解毒酶活性高于成虫和1龄若虫。     

阿维菌素乳油注干防治松材线虫病的效果

采用浸渍法测定阿维菌素乳油1 000,2 000,3 000,5 000,7 000倍液对松材线虫的毒杀效果,结果表明,阿维菌素乳油对松材线虫有较强的杀灭活性,药剂各配比液处理24 h后线虫死亡率达92%,其中,配比度低于5 000倍液的毒杀死亡率超过97%,与7 000倍液的毒杀死亡率之间差异极显著;阿维菌素乳油在林间注干防治松材线虫试验结果表明,防治效果十分显著,马尾松和湿地松注药1次,在1 a时间内未发现病害枯死木,有效地抑制了松材线虫病的发生。     

松材线虫cul-1基因的表达特性与功能

【目的】研究松材线虫Bxy-cul-1基因的表达特性和生物学功能,明确该基因在松材线虫生长发育中的作用,为从生长发育角度探索特异性的线虫种群增长控制措施提供理论基础。【方法】根据松材线虫基因组数据设计引物、克隆Bxy-cul-1基因,对Bxy-cul-1进行序列、系统发育和蛋白结构预测等生物信息学分析。利用实时荧光定量PCR技术和原位杂交技术探究Bxy-cul-1基因在松材线虫各龄期的表达水平和表达部位,明确其时空动态表达特性,采用RNA干扰技术探究该基因在松材线虫生长发育中的作用。【结果】生物信息学分析结果显示,Bxy-cul-1基因CDS全长2 292 bp,编码763个氨基酸,属于Cullin蛋白家族。原位杂交结果表明,Bxy-cul-1基因在松材线虫各发育阶段均有表达,胚胎期全胚胎表达,2龄期广泛表达,3龄期和4龄期主要在肠道、体壁肌肉和尾部表达;成虫期,Bxy-cul-1基因在雌虫的卵母细胞和阴户、雄虫的腹部、交合刺和尾部表达。实时荧光定量PCR结果显示,Bxy-cul-1基因在松材线虫2龄期表达量最高,胚胎期次之,3龄期、4龄期、成虫期表达量依次递减。对松材线虫胚胎干扰后发...     

松材线虫基因研究进展

对目前松材线虫基因水平的研究进行了概述.目前已研究过的松材线虫基因主要分为三个方面:一是应用于检疫检验的研究,主要研究的基因有rRNA基因,利用rRNA的ITS区核苷酸序列进化速度较快的特点,能准确区分松材线虫与其近缘种;二是探讨致病机理的研究,主要研究了纤维素酶和果胶酸裂解酶等在食道腺细胞中表达的酶基因,发现纤维素酶基因可能是由于基因横跨作用从细菌迁移到松材线虫基因组内,有助于研究松材线虫致病性的起源;三是对松材线虫生长发育相关基因的研究,为控制松材线虫的生长发育提供了依据.     

克线磷防治松材线虫病试验初报

为防治松材线虫病,我们于1988～1989年间,使用了三种杀线剂对松材线虫进行室内毒性测定,并选用克线磷在林间进行试验。巴丹在100ppm 时,其中线虫仍可继续存活、生长繁殖;F—001药剂在50ppm 上时,可杀死90%以上的线虫;克线磷浓度60ppm 以上时,可完全抑制线虫生长繁殖。克线磷在林间使用后,注于和根施处理的植株均比对照株死亡率降低。该药剂对防治松材线虫病有一定效果。     

松材线虫果胶酶基因Bxpel1的克隆及其生物信息学分析

以松材线虫Bursaphelenchus xylophilus转录本为模板,通过RT-PCR技术克隆果胶酶Bxpel1基因。结果表明,松材线虫果胶酶Bxpel1基因序列全长为795bp,GC含量为50.44%,编码252个氨基酸。通过Blast比对克隆的Bxpel1基因与已知序列(Gen-Bank ID:AB232908.1)的同源性达到98%。系统进化分析表明,Bxpel1基因编码产物的氨基酸序列与拟松材线虫Bursaphelenchus mucronatus,燕麦真滑刃线虫Aphelenchus avenae的Bxpel1蛋白序列具有高度同源性。Bxpel1基因编码的产物的0～25序列有可能是跨膜结构域,而其他序列均位于膜外,其二级结构主要是以无规则卷曲和β-折叠为主,信号肽的剪切位点位于第17至第18位氨基酸之间,主要在细胞外发挥生物学作用。Bxpel1基因的克隆及其生物信息学分析对进一步研究Bxpel1基因在松材线虫致病过程中的功能具有重要意义。     

松材线虫热激转录因子Bx-HSF-1基因的克隆及表达分析

【目的】通过对热激转录因子基因Bx-HSF-1的克隆和表达分析,为深入研究c GMP、TGFβ-like和Insulin/IGF等热激抗逆代谢路径提供理论基础。【方法】根据松材线虫基因组数据设计引物克隆松材线虫Bx-HSF-1基因。进一步对Bx-HSF-1进行Gene Ontology基因功能预测、系统发育分析、保守结构域分析等生物信息学分析。应用JASPAR预测Bx-HSF-1靶位点DNA序列,根据松材线虫基因组数据筛选含有该序列的靶基因,并通过蛋白质三维结构分析和分子对接验证。应用荧光定量q-PCR检测Bx-HSF-1及其靶基因在热激和低温处理条件下4个时间点的表达量,结合转录组数据对Bx-HSF-1及其靶基因的表达量相关性进行分析。采用原位杂交对Bx-HSF-1基因在松材线虫体内的表达部位进行了分析。【结果】根据基因组数据,克隆到松材线虫热激转录因子Bx-HSF-1基因长度为1 404 bp的涵盖完整蛋白编码区基因序列。结构域分析表明Bx-HSF-1基因编码蛋白质的氨基酸序列含有DNA结合结构域和亮氨酸拉链结构域。GO分析表明该基因参与延长线虫寿命、正向调控繁殖率、运动、热激反应、抗逆态幼虫发育和抗逆反应等生理过程,并具有特异DNA序列结合的分子功能。氨基酸疏水性分析表明该DNA结合结构域由3个α螺旋和4个反向平行的β折叠构成一个疏水核心,该疏水核心可以与热激元件靶位点互作。对松材线虫基因组进行BLAST比对筛选出Bx-DAF-7是Bx-HSF-1的靶基因,Bx-DAF-7基因TATA盒上游序列具有Bx-HSF-1靶位点序列。荧光定量q-PCR结果表明热激和低温处理同样促进Bx-HSF-1转录、抑制Bx-DAF-7转录,Bx-HSF-1与Bx-DAF-7的表达量负相关。原位杂交结果表明Bx-HSF-1基因在正常培养线虫体内各细胞均有微量表达,热激培养线虫前体部信号显著,峡部和肠区体壁信号较显著。【结论】本研究表明Bx-HSF-1具有特异DNA序列结合的分子功能。预测抗逆态幼虫形成基因Bx-DAF-7是Bx-HSF-1靶基因。转录组测序及q-PCR结果表明Bx-HSF-1与Bx-DAF-7的表达量负相关。Bx-HSF-1基因受温度刺激后多数体细胞内均有较高表达,特别是神经元、体壁肌肉细胞和皮下细胞中表达显著。     

乙酰胆碱干预物质对松材线虫运动行为的影响

作者通过药物干预方式研究神经递质乙酰胆碱对松材线虫Bursaphelenchus xylophilus运动行为的影响。结果表明:硫酸阿托品引起松材线虫泳动变缓,头部摆动频率和身体弯曲频率下降,随处理时间延长持续降低;运动形态出现由正常的S形变化为多节弯曲和螺旋状卷曲等异常状况;甲硫酸新斯的明引起头部摆动频率和身体弯曲频率提高、运动幅度加大等特征,同时也表现出明显的运动兴奋间歇性、短暂性及不规则扭动等特征。可见,干扰乙酰胆碱会导致松材线虫运动行为出现异常,并呈现规律性特征。     

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.     

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.     

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.     

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.     

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。     

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.     

Growth of Mixed Birch-Coniferous Stands in Relation to Pure Coniferous Stands at Similar Sites in South-eastern Norway

Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.