沙棘绕实蝇的生物学习性

[目的]沙棘绕实蝇严重危害沙棘果实,使沙棘种植地蒙受巨大经济损失。研究其生物学习性,可以为有效监测和控制沙棘绕实蝇提供理论指导。[方法]通过室内人工饲养和野外观察,研究沙棘绕实蝇的羽化、交尾、产卵、化蛹等生物学习性和野外发生动态。[结果]沙棘绕实蝇成虫在野外从6月中旬至8月上旬均可见到,发生量受天气影响较大;成虫主要集中在6:00—10:00羽化,羽化量占当日羽化量的81.3%,羽化高峰出现在8:00—9:00;化蛹时间主要集中在凌晨0:00—6:00,尤其是3:00—6:00钻出果实化蛹的幼虫数量较多,与其它时间段有明显差异;交尾时间主要集中在白天光照比较强的时间段,一天当中有两次交尾高峰,分别出现在12:00—13:00和16:00—17:00,交尾平均持续时长为239±11.86 min;沙棘绕实蝇产卵期沙棘果长径6.65±0.28 mm,宽径5.47±0.40 mm,一果只产一卵。[结论]沙棘绕实蝇在内蒙古磴口地区一年发生一代,幼虫钻蛀果实,蛹隐藏在地下,成虫期较短,防治工作应集中在成虫期进行。     

沙棘绕实蝇幼虫空间格局及其应用的初步研究

运用两种回归方法的四种聚集度指标对沙棘绕实蝇幼虫的空间格局进行了研究。结果表明,沙棘绕实蝇幼虫在其危害的沙棘林内呈聚集分布遵从负二项分布。按照ｍ－ｎ回归法,确定了理论抽样数和序贯抽样方案。     

沙棘主要钻蛀性害虫综合防治技术

对沙棘钻蛀性害虫沙棘绕实蝇、沙棘象鼻虫、红缘天牛、木蠹蛾类，采用地面喷粉、林冠喷雾、干部注药的化学防治措施与选择混交类型、平茬复壮、绝花绝果、保护天敌等营林、生态、生物防治技术，可有效地控制沙棘钻蛀性害虫的危害。     

沙棘转录因子HrWRKY53基因分离及其参与抵御绕实蝇的作用分析

【目的】明确HrWRKY53基因的生物信息学及其参与沙棘抗绕实蝇功能,为解析沙棘等胡颓子科植物抗虫机制及分子育种奠定基础。【方法】基于绕实蝇危害前后沙棘果实转录组数据,挖掘HrWRKY基因家族成员中参与绕实蝇危害的关键差异表达基因HrWRKY53,进一步分析该基因的二级结构、亲疏水性及预测磷酸化位点等。利用BLASTP检索同源性高的其他物种蛋白序列进行比对并构建系统发育树;利用qRT-PCR检测该基因的组织表达特异性,绕实蝇危害前后以及脱落酸(Abscisic acid, ABA)、茉莉酸甲酯(Methyl jasmonate, MeJA)、乙烯(Ethylene, ETH)处理下的该基因表达模式;并进一步分析响应绕实蝇危害的茉莉酸(Jasmonic acid, JA)信号途径上关键基因HrJA2、HrLOX1、HrAOS和HrAOC的表达水平,分析其与HrWRKY53基因表达的相关性。【结果】基于沙棘转录组获得HrWRKY53的开放阅读框(Open reading frame, ORF)全长为1 302 bp,编码433个氨基酸残基的蛋白,该基因含有2个WRKY保守结构域和1个C     

沙棘主要钻蛀性害虫综合防治技术

提出对沙棘钻蛀性害虫沙棘绕实蝇、沙棘象鼻虫、红缘天牛、木蠹蛾类,采用地面喷粉、林冠喷雾、干部注药的化学防治措施与选择混交类型、平茬复壮、绝花绝果、保护天敌等营林、生态、生物防治技术,在生产实践中可有效地控制沙棘钻蛀性害虫的发生危害。     

多杀菌素与碳酸铵复合微球的制备及其对沙棘绕实蝇成虫的防治效果

【目的】为克服单独使用引诱剂或农药防治沙棘绕实蝇成虫的局限性,通过采用微球包埋的方法将农药和引诱剂制成微球,使二者在林间缓慢释放,明确该药剂引诱及杀死沙棘绕实蝇的效果。【方法】以明胶和聚乳酸作为载体,多杀菌素和碳酸铵为芯材,通过溶剂挥发法制备含有杀虫剂与引诱剂的微球;碳酸铵为水溶性,多杀菌素为脂溶性,因此采用从里到外的"水溶性物质1/油溶性物质/水溶性物质2"的包埋步骤实现对引诱剂和农药的包埋;采用单因素试验设计,同时固定另外4种因素即聚乳酸、多杀菌素、明胶和反应温度,测定不同碳酸铵含量对微球理化性质的影响;采用红外光谱仪检测多杀菌素和碳酸铵是否成功包封在微球内;采用高效液相色谱法(HPLC)测定微球中多杀菌素的含量;应用凯氏定氮仪测量并计算出微球中的碳酸铵包载量;使用透析袋法测量多杀菌素的释放速率;使用手持氨检测器检测微球对氨气的缓释效果;微球的形态采用扫描电子显微镜进行观察和记录;微球的大小和粒度分布则采用激光粒度分析仪进行分析;采用生物测定方法测试微球对沙棘绕实蝇成虫的引诱和致死作用;并在野外开展无人机喷洒微球防治沙棘绕实蝇的试验。【结果】红外光谱分析显示,多杀菌素和碳酸铵被成功包封在微球内;以碳酸铵为变量时,微球中多杀菌素和碳酸铵的载药量和包封率均呈先增大后减小的趋势;微球中的多杀菌素持续释放时间约为15天,高于纯多杀菌素持续释放时间(7天),纯碳酸铵最长释放历期为6天,而微球中的碳酸铵最长缓释历期为14天,能够实现杀虫剂和引诱剂持续释放的目的;制备的4种不同含量碳酸铵形成的微球都呈球形、分散状,大小较为均匀,表面多孔,微球平均粒径60μm左右;所制备的微球对沙棘绕实蝇的毒杀和引诱作用分别与对照相比都存在显著差异(P0.05);与对照相比,沙棘绕实蝇的虫口密度平均降低约76.13%,沙棘果实的受害率平均降低约75.38%。【结论】采用多杀菌素和碳酸铵制成的微球,可达到缓释效果,具有引诱和杀死沙棘绕实蝇的作用,可用于沙棘绕实蝇的防治。     

4种药剂对沙棘绕实蝇成虫的触杀活性

目的]沙棘绕实蝇在我国新疆和内蒙古地区对沙棘果实造成重大危害,如何选取高效、易降解、低残留的农药种类成为当前沙棘绕实蝇成虫防控工作中的迫切课题。[方法]野外采集沙棘绕实蝇蛹,室内待其羽化后,雌、雄分组放置于不同浓度梯度的4种农药条件下进行触杀实验。[结果]通过KT_(50)(median knockdown time)的数据分析结果显示,同种农药同种浓度时,药物对雄性的触杀效果比雌性强,其中苦参碱在浓度为0.005 mg·m L~(-1)时,雄性KT_(50)值为39.21 h,小于雌性KT_(50)值56.13 h,但个别情况下出现对雌性触杀效果比雄性高的情况,如苦参碱在浓度为0.05 mg·m L~(-1)时,雄性KT_(50)值为15.76 h,大于雌性KT_(50)值12.39 h。通过测定4种农药对沙棘绕实蝇成虫的致死中浓度LC_(50)(median lethal dose),得出触杀作用时间为12 h时,LC_(50)分别为:印楝素7.737 mg·m L~(-1)、高效氯氟氰菊酯0.002 mg·m L~(-1)、苦参碱0.042 mg·m L~(-1)、阿维菌素0.008 mg·m L~(-1),其触杀毒力次序为:高效氯氟氰菊酯阿维菌素苦参碱印楝素;触杀作用时间为24 h时,LC_(50)分别为:印楝素6.963 mg·m L~(-1)、高效氯氟氰菊酯0.001 mg·m L~(-1)、苦参碱0.008 mg·m L~(-1)、阿维菌素0.001 mg·m L~(-1),其触杀毒力次序为:阿维菌素高效氯氟氰菊酯苦参碱印楝素;触杀作用时间为48 h时,LC_(50)分别为:印楝素0.891 mg·m L~(-1)、高效氯氟氰菊酯0.001mg·m L~(-1)、苦参碱0.002 mg·m L~(-1)、阿维菌素0.001 mg·m L~(-1),其触杀毒力次序为:阿维菌素=高效氯氟氰菊酯苦参碱印楝素。[结论]阿维菌素和高效氯氟氰菊酯对沙棘绕实成虫的触杀效果较显著,其次为苦参碱,印楝素的触杀效果不显著。     

危害沙棘种子的新象虫—沙棘象

危害沙棘(Hippophae rhamnoides L.)种子的害虫——沙棘象,隶属于象虫科(Curculionidae)象虫属(Curculio Linnaeus)为一新种。分布于陕北、渭北、关山等地,严重影响沙棘种子产量和果实利用价值。模式标本保存于中国科学院动物研究所。     

陕西省沙棘主要害虫危害特点及分析

本文在对陕西省沙棘昆虫资源进行调查的基础上,总结了陕西沙棘害虫的危害及分布特点,并对区域分布状况进行了分析,为陕西省沙棘病虫害防治及沙棘资源的开发利用提供了依据。     

沙棘象幼虫空间分布型及防治方法的初步研究

沙棘象Cruculio hippohes zhang是我国新发现的种实害虫，广泛分布于陕西、甘肃、辽宁等沙棘产区，造成果实和种子大量减产。经调查，沙棘幼虫在沙棘上的空间分布形式遵从负二项分布，属于聚集型分布，在大面积防治上可针对其分布特点进行挑治。在防治方法上可用1：5000敌杀死在成虫羽化期喷药，在冬季进行平茬可逐步杜绝虫害的发生。     

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.     

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。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.