雷公藤总甙对马尾松毛虫生物活性的影响

以无水乙醇为溶剂,用连续回流渗漉法从雷公藤生药中提取出粗提物。经乙酸乙酯纯化后得红褐色的浸膏,经检测为总萜内酯（T1）。就其杀虫活性和作用方式进行了较系统的生物测定。结果表明：T1对马尾松毛虫具有强的拒食、麻醉和毒杀作用,毒杀中浓度LC50为1548．50mg／L,拒食中量AFD50为12．25μg／条,麻醉中量ND50为103．98μg／g,无触杀作用;T1不仅抑制马尾松毛虫幼虫的生长发育．还影响其蛹的羽化和卵的孵化及初孵幼虫存活;抑制中浓度EC50为952．65mg／L;在T1浓度10～10000mg／L之间,马尾松毛虫蛹不完全羽化率为43．3％～63．3％。其卵的不能孵化率为12．0％～84．0％,孵化的幼虫存活率为0．0％～95．6％。     

花椒蚜虫防治试验

选用5种杀虫剂，每种3个浓度，对花椒蚜虫进行室内毒力测定，结果显示：25％的赛丹乳油和25％的蛾蚜灵可湿性粉剂对蚜虫有较强的杀伤效果，林间防治试验结果表明，上述2种药剂对花椒蚜虫防效在91．98％～97．06％之间，且防治成本低，环境污染小。     

褐边绿刺蛾幼虫生物农药防治试验

通过生物农药苦参碱、森乐及印楝素3种农药对褐边绿刺蛾幼虫室内毒力测定和田间防治试验,结果表明苦参碱对褐边绿刺蛾幼虫的致死中浓度LC50较低,仅为0．398mg／l;生物农药苦参碱、森乐及印楝素均可用于防治园林植物上的褐边绿刺蛾幼虫,0．5％苦参碱水剂600倍溶液,森乐可湿性粉剂2000倍溶液,印楝素乳油2000倍溶液均能取得较好的防治效果,综合分析室内毒力测定和田间防治试验,以印楝素乳油防治效果相对较好。     

梨豹蠹蛾防洽技术研究

孵化期用8％绿色威雷400倍、25％灭幼脲Ⅲ号1000倍、Bt乳剂500倍、定虫隆1500倍喷雾，护林神3号12kg／hm^2喷粉；蛀叶柄期每cm胸径树干注射20％吡虫啉可溶性液剂10倍液0．8mL，并辅以清除刚蛀入叶和有越冬幼虫的枝干以及合理水肥，能有效防控梨豹蠹蛾，迅速恢复核桃产量。     

广东木榄+桐花树群落上的白缘蛀果斑螟和荔枝异形小卷蛾研究

白缘蛀果斑螟和荔枝异形小卷蛾是红树林木榄＋桐花树群落上的重要害虫,在广东省局部区域的红树林保护区,已经对木榄造成严重危害。白缘蛀果斑螟1年完成4代,第1至第3代虫历时48～66d,越冬代历时180d;荔枝异形小卷蛾1年完成5代,第1至第4代虫历时39～44d,越冬代历时188d。白缘蛀果斑螟和荔枝异形小卷蛾幼虫均危害木榄的花萼和胚轴,荔枝异形小卷蛾能够迁移到桐花树上危害桐花果实。在木榄＋桐花树群落上,白缘蛀果斑螟成虫占54％,荔枝异形小卷蛾成虫占46％。林间世代重叠,以幼虫和蛹越冬。在4月下旬～5月中旬,受害花萼和受害胚轴数量有一个高峰期,而7月上旬－10月中旬,则有一个明显的低值期。白缘蛀果斑螟和荔枝异形小卷蛾种群数量消长规律与受害花萼和受害胚轴的数量变化规律成正相关,前者同样也出现一个高峰期和一个低值期。白缘蛀果斑螟和荔枝异形小卷蛾与捕食性蜘蛛数量的比例为1：0．30,捕食性蜘蛛的捕食作用不明显。     

几种无公害农药防治松针小卷蛾试验

利用百虫杀、惠新净、阿维烟剂、灭幼脲4种无公害农药对松针小卷蛾Epinotia rubiginosana(Herrich-Schaeffer）初龄幼虫进行了防治试验。试验结果为阿维烟剂对松针小卷蛾的防治效果是74．9％，其最适用药量为225mL/hm^2。     

静电喷雾与非静电喷雾防治森林害虫对比试验

采用静电喷雾机进行了静电喷雾和非静电喷雾2%噻虫啉微胶囊悬浮剂和3%高渗苯氧威乳油防治马尾松毛虫Dendrolimus punctatus(Walker)、杨小舟蛾Micromelalopha troglodyta Graeser及杨扇舟蛾Clostera anachoreta(Fabricius)幼虫对比试验。结果表明:在同一药剂浓度下,林间防效静电喷雾明显优于常规喷雾;2%噻虫啉微胶囊悬浮剂4 000倍液和3%高渗苯氧威乳油3 000倍液可作为静电喷雾防治马尾松毛虫2～3龄幼虫和杨小舟蛾及杨扇舟蛾2～4龄幼虫的推荐使用浓度。     

蛋白质沉淀剂对杨小舟蛾谷胱甘肽S-转移酶的部分纯化

用硫酸铵和聚乙二醇（PEG）沉淀技术对杨小舟蛾幼虫谷胱甘肽S-转移酶（GSTs）进行了纯化研究。结果表明：通过硫酸铵沉淀，杨小舟蛾GSTs活性主要分布在40％～60％沉淀段，比活力为174．41nmol／（min·mg），纯化倍数为1．39。在5种PEG（PEG400、PEG2000、PEG4000、PEG6000和PEG20000）中，PEG20000的纯化效果最好。杨小舟蛾PEG20000沉淀的GSTs活性峰主要分布在10％～15％沉淀段，GSTs比活力＆454．14nmol／（min·mg），纯化倍数达到15．50。因而，PEG20000沉淀对于杨小舟蛾幼虫GSTs的纯化效果优于硫酸铵。     

银杏外种皮乙醇提取液对蔬菜害虫的毒力研究

为了探讨银杏外种皮对蔬菜害虫的室内毒力效果，采用非选择性拒食和毒杀作用方法研究银杏外种皮乙醇提取液室内对蔬菜害虫的毒力。结果表明：银杏外种皮乙醇提取液的稀释倍数与菜粉蝶5龄幼虫的拒食率呈现较好的负相关性，菜粉蝶5龄幼虫50％拒食率所需的银杏外种皮乙醇提取液的质量浓度为0.63mg/mL。100倍稀释的银杏外种皮乙醇提取液对蔬菜菜粉蝶3龄幼虫、黄曲条跳甲成虫和美洲斑潜蝇幼虫毒杀作用的死亡率分别为25．00％、32．50％和36．67％。说明银杏外种皮乙醇提取液对菜粉蝶5龄幼虫有很好的拒食作用，而对蔬菜害虫的毒杀作用效果不明显。     

六种药剂对榆黄毛萤叶甲的毒力测定

以叶片药膜法和喷雾法室内测定6种化学药剂对榆黄毛萤叶甲Pyrrhalta maculicollis(Mots.)成虫及幼虫的毒力。结果表明:叶片药膜法和喷雾法处理3龄幼虫,2.5%溴氰菊酯EC的致死中浓度LC_(50)分别为0.21,0.18 mg/L,5%高效氯氰菊酯EC的LC_(50)分别为0.36,0.52 mg/L,5%氯氰菊酯EC的LC_(50)分别为0.41,0.56 mg/L,均表现出杀虫的高效性;叶片药膜法处理成虫,2.5%溴氰菊酯EC,5%高效氯氢菊酯EC,5%氯氰菊酯EC,2.8%阿维菌素EC,3%甲维·氟铃脲EC,40%啶虫脒SP的LC_(50)依次为0.23,1.18,1.64,5.76,8.60,9.55 mg/L。6种药剂对榆黄毛萤叶甲幼虫及成虫均具有良好的杀虫效果。     

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.