树干注药后吡虫啉在枣树不同部位的传导分布动态

为了阐明吡虫啉在金丝小枣树体内的传导机理,在树干滴注林果注干杀虫剂后,测定其不同方位叶片、枝条木质部及韧皮部中的吡虫啉含量。结果表明,经树干滴注杀虫剂后,吡虫啉在枣树叶片、枝条木质部及韧皮部组织中均具有良好的传导、分布性能,随着时间的延长,枣树叶片、枝条木质部及韧皮部中的吡虫啉含量均表现出先上升后下降的变化趋势;注药后21 d、15 d、15 d枣树叶片、枝条木质部及韧皮部中的吡虫啉含量分别达到最高值0.90 mg/kg、1.03 mg/kg、0.83 mg/kg。然后逐渐降低,均于用药70 d后变化趋于平缓,而注药后85 d时,枣树叶片、枝条木质部及韧皮部中的吡虫啉含量分别为0.79 mg/kg、0.54 mg/kg、0.64 mg/kg,仍处于较高水平;枣树不同部位吡虫啉平均含量由大到小依次为叶片、枝条木质部、枝条韧皮部,叶片中的吡虫啉平均含量为0.70 mg/kg,比枝条木质部和韧皮部分别增加25.00%和45.83%,木质部平均含量为0.56 mg/kg,比韧皮部含量增加16.67%;树冠上层叶片、上层枝条木质部及上层枝条韧皮部中的吡虫啉平均含量分别达到0.78 mg/kg、0.58 mg/kg、0.49 mg/kg,均高于下层的含量,说明吡虫啉在树体内传输时纵向传导能力较强。枣树经树干滴注吡虫啉后,药效持续时间长,可有效防治枣树生长期内的主要害虫。     

树干涂抹吡虫啉、乙酰甲胺磷复配剂在枣树树冠内的传导分布

采用高效液相色谱测定了吡虫啉、乙酰甲胺磷复配剂经树干涂抹后在枣树树冠中的传导分布动态。结果表明:树干涂抹吡虫啉、乙酰甲胺磷复配剂在枣树体内具有良好的传导性能,药剂进入树体木质部后随蒸腾液流向上纵向运输,使树冠上层叶片中药剂含量最高;同时又存在横向运输,使树冠其他部位也有药剂分布。吡虫啉、乙酰甲胺磷复配剂在枣树树冠叶片内残留期较长,涂药后85d药剂在叶片中的含量分别为0.84、1.02ug/g。     

树干注药技术防治红松球果害虫的无公害农药筛选

该文对树干注药防治红松球果害虫的农药种类和用药剂量进行筛选,对注药方法、注药时机、药剂在树体内的传导速率以及对树体主要生理指标的影响做了探讨.结果表明:20％吡虫啉可溶液剂防效最佳,在树干胸径0.6 mL/cm和0.9 mL/cm剂量条件下,强力注药方法防治15d后效果分别为66.35％和69.19％,蒸腾作用加快,有利于药剂的快速传导和富集.7月防治效果明显高于6月,防治10 d后树冠的药剂富集就可以达到较高的杀虫效果.内吸性药剂对树体的生理指标影响较小,同对照氧化乐果相比,吡虫啉和噻虫啉均提高了针叶的蛋白和叶绿素含量,有一定的促进作用,在注药30 d后,树体生理指标基本恢复正常.打孔注药防治球果害虫切实可行.     

从C、N、P化学计量特征分析雷竹氮素克隆整合分株年龄效应

[目的]研究雷竹不同年龄分株叶片C、N、P化学计量特征对氮素克隆整合的响应机制,探讨雷竹林施肥的适宜立竹年龄,为雷竹林精准化、减量化施肥提供参考。[方法]以1年生和2年生雷竹分株组成的克隆整合单元为研究对象,通过给不同年龄分株竹腔注射¹⁵NH₄¹⁵NO₃的方法,设置3个氮素添加水平(低浓度N,4.07 mol·L^-1;中浓度N,8.13 mol·L^-1;高浓度N,12.20 mol·L^-1),测定各处理1年生、2年生立竹叶片在时间梯度上的C、N、P含量,分析雷竹不同年龄分株间氮素整合方向及传输效率等差异。[结果]雷竹克隆分株间存在强烈的氮素传导功能,1年生立竹会部分传输氮素至2年生立竹,而2年生立竹会将氮素大量传输至1年生立竹,即2年生立竹的氮素传导能力显著强于1年生立竹,同时具有一定的时间效应和氮素浓度效应,氮素浓度过低或过高均会减弱分株间氮素传输能力,试验的中浓度N是整合功能显著变化的"拐点"。1年生、2年生立竹氮素处理均能提高相...     

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。     

树干注药后阿维菌素在枣树体内的传导分布及消长动态

为了明确树干滴注林果注干杀虫剂后阿维菌素在枣树体内的分布动态,以金丝小枣Ziziphus jujube树为试材,采用高效液相色谱法,测定不同高度不同方位叶片、枝条木质部和韧皮部及枣果中的阿维菌素含量。结果表明:树干注药后,阿维菌素在枣树体内具有良好的吸收、传导性能,其总残留量在树体不同部位的含量随时间推移均呈现先上升后下降的趋势,至注药70 d后各部位总含量分布趋于稳定。各个取样时期,阿维菌素含量从大到小依次为叶片,枝条木质部,枝条韧皮部;用药2 d时,三者间差异达到最大值,后期三者间差异逐渐减小;树冠上层叶片、枝条木质部和韧皮部中阿维菌素含量较树冠下层高,以上层南部最高。注药后105 d时枣果中的阿维菌素含量为0. 008 mg/kg,显著低于0. 01 mg/kg的标准,建议用阿维菌素注干药剂防治枣树害虫时,注药时间距枣果采收期一般应大于105 d。     

含硒、锗保健笋培育试验初报

通过对立竹基部竹腔注入亚硒酸钠或锗的溶液后,该竹所生产的竹笋体内硒或锗总量有明显增加,红哺鸡竹、白哺鸡竹、黄杆乌哺鸡竹、雷竹所生产的笋含硒总量平均达到0.64×10-6,相当于陕西省紫阳富硒茶含硒量(平均值为0.65×10-6).其中,竹笋内有机硒的含量为(0.031 ～ 0.234)×10-6;试验表明,不同竹种具有不同的富集硒和锗的能力,应选择适宜的注射溶液浓度和竹子品种,以生产富硒或富锗竹笋,使之符合人体的最佳需要.     

雷竹主要器官Se的分配与富集累积规律研究

在浙江省富阳市主产雷竹的7个乡镇的8个试验点生长正常的雷竹林和春建乡的2年生雷竹林中分别对雷竹主要器官Se的富集累积和同一竹鞭系统内立竹间Se的转移累积规律进行了研究.结果表明:在雷竹主要器官中,以叶片的Se含量最高,平均值为0.132 8mg·kg-1(干重),其次是竹笋,平均值为0.067 0 mg·kg-1(干重);其它器官之间差异较小,且硒含量极低;雷竹竹鞭硒含量与其它器官(竹笋、叶片、竹枝、竹秆)硒含量之间又均达到显著和极显著线性相关;在同一竹鞭系统内,一竹株茎秆注射亚硒酸钠后,另一未茎秆注射亚硒酸钠的竹株叶片的硒含量有明显的增加,证明了硒可在同一竹鞭系统内的立竹间传递.     

注射竹力学性质测试初报

注射竹,是指用竹腔注射法防治竹螟而被注射化学农药的竹子。该法具有操作简单、防治效果好、不污染环境,并适宜在高山密林中工作等优点。近年来,许多毛竹产区在竹子虫害防治中得到较广泛的应用。据嘉兴地区统计,1980年采用注射法防治竹螟面积达1万余亩。但在推广过程中,许多群众耽心注射化学农药后,是否会降低竹材的力学性质和使用价值。为此我们进行了注射竹力学性质的测定。现将初步结果整理如下。     

不同竹材制备活性炭的孔结构特性比较研究

分别以毛竹、淡竹、甜竹及雷竹四种竹材为原料,以KOH活化法制备高比表面积活性炭,比较研究了不同竹种活性炭的比表面积及孔隙结构.研究结果表明:4种不同的竹种经活化后比表面积淡竹为2 327 m2·g-1、雷竹为2 045 m2·g-1、甜竹为2 102 m2·g-1、毛竹为2 233 m2·g-1;总孔容分别为淡竹1.27 m3·g-1、雷竹1.09 cm3·g-1、甜竹1.14 cm3·g-1、毛竹1.24 cm3·g-1.4种不同的竹质活性炭都含有大量的微孔和中孔,其中中孔率分别为淡竹58.3%、雷竹26.6%、甜竹56.1%、毛竹60.4%.且其孔径分布较集中,主要分布在0.5～7nm范围内.从总体上看这4个竹种经活化后比表面积和孔容差别不大,都达到高比表面积活性炭的要求范围,都可以作为制备高比表面积活性炭的原材料.     

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。     

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.     

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.     

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.