温度对竹盲走螨实验种群生长发育与繁殖的影响

在 16、2 0、2 4、2 8、32、36℃的 6种恒温条件下 ,以竹裂爪螨各螨态为饲料 ,系统研究了温度对竹盲走螨实验种群生长发育、繁殖的影响。结果表明 ,36℃条件下竹盲走螨不能完成世代发育。在 16～ 32℃范围内 ,各螨态的发育历期随温度升高而缩短 ,卵至成螨的发育历期在 16、2 0、2 4、2 8、32℃ 5种恒温条件下分别为 16 0 1、10 80、5 81、5 12和 4 6 8d ;世代发育起点温度和有效积温分别为 10 4 4℃和 93 77d·℃。分别用王 -兰 -丁模型和逻辑斯谛模型拟合了温度与发育速率的关系 ,其中王 -兰 -丁模型能更好地反映出竹盲走螨在高温下发育受到抑制的现象。产卵期和雌成螨寿命随温度的升高而缩短。平均每雌产卵量在 2 4℃最高 ,为 31 2 6粒 ,32℃条件下仅为 9 2 0粒 ,每雌产卵量 (Y)与温度 (T)之间呈二次抛物线关系Y =- 171 6 94 2 17 2 732T - 0 0 36 3T2 (R =0 96 4 8 )。用年龄等级法分析表明 16℃、32℃条件不利于竹盲走螨种群的生长发育和繁殖。     

日本龟蜡蚧产卵、若虫孵化与寄主、温度关系的研究

日本龟蜡蚧ＣｅｒｏｐｌａｓｔｅｓｊａｐｏｎｉｃｕｓＧｒｅｅｎ雌蚧体重与产卵量之间成直线的正相关关系。在悬铃木、栀子花上危害的雌蚧身大体重，孕卵、产卵速度快，死亡率低，多年受害的黄杨雌蚧则相反。５月日均温２４．４－２６．８℃，是该蚧产卵的最适宜温度，２１－２２时气温凉爽是一天中产卵的高峰时间。卵期发育最适宜温度为２６．３０－２７．１６℃，距此适温越近，发育速率越快，小于或大于此温度范围，则卵期发育延长     

二点叶螨生物学特性的研究

在温度26±1℃,相对湿度(75±5)%条件下,室内饲养二点叶螨(Tetranychus urticaeKoch)的卵期为4 57d,幼螨期1 93d,前若螨期1 90d,后若螨期2 52d,实验种群雌成螨的平均寿命 15 96d,雌雄性比 29∶7,单雌产卵量 62 54 粒。实验种群的内禀增长力为 0 1566/d,在稳定群年龄分布中,未成熟期占总量的93 01%,成熟期占6 99%。     

竹裂爪螨天敌——余杭植绥螨的研究

余杭植绥螨是竹裂爪螨的重要天敌.室内20℃恒温饲养余杭植绥螨需21.2 d完成一个世代、28℃则10.4 d就可完成,30℃以上出现死亡.幼螨、第1若螨和雄成虫捕食量相对较少,雌成螨每天平均捕食竹裂爪螨5.5头,最多可捕食13头,雌成螨期最多可捕食165头.雌成螨捕食量大,发育即加快,产卵量增加,产卵期延长,卵粒个体也加大.一头雌成螨一生产卵量7～15粒,卵产于竹叶背面基部茸毛丛中或竹裂爪螨的丝网内.余杭植绥螨随竹裂爪螨种群数量的消长而消长,竹裂爪螨在浙江有二个明显的高峰期,其每个高峰期5～7 d后,余杭植绥螨也出现明显的高峰期;而余杭植绥螨每次高峰期后6～9 d,竹裂爪螨发生量就明显下降.     

山楂叶螨种群动态及其危害研究

１５ａ的研究结果表明：在冀中南部果产区,山楂叶螨种群消长呈单峰曲线,不同年份或同一年份不同果园的发生高峰不同,梨、桃园发生在６月下旬至７月中旬,苹果园发生在６月中旬至８月上旬。发生高峰的温湿度界限指标是旬日均温度２６．１４±２．１１℃,日均相对湿度６１．６７％±８．９２％;在发育起点温度（９．２℃）与界限指标温度范围内,种群增长与有效积温呈高度正相关,符合线性函数ｌｏｇｙ＝－３．５５７４＋２．５１９５ｌｏｇｘ,在果园和树冠内的种群空间分布属聚集型;山楂叶螨危害苹果、梨、桃树造成早期落叶的螨口指标分别是叶均３１．７９、３２．３４、１９．４７头（均指雌成螨）,叶片被害指数分别为６１．２７％、６０．０７％和５８．０１％。     

枣树红蜘蛛在自然变温下有效积温的研究

该文对枣粮间作地中枣树红蜘蛛──截形叶螨的卵、幼螨、前若螨、后若螨４个虫期在自然变温下的有效积温进行了研究，结果表明，卵的发育起点温度１４．８±１．５６℃，有效积温为３９．３５６３日度；幼螨发育起点温度为１１．５±２．７３℃，有效积温为２７．８４日度；前若螨发育起点温度为１１．０±２．０８９℃，有效积温为４２．１３４７日度；后若螨发育起点温度为１２．８±１．８７℃，有效积温为３７．１日度；世代发育起点温度为１１．２±１．８３６℃，有效积温为１１６．２４４６日度。年发生１３代。     

温度对麻疯树柄细蛾生长发育和繁殖的影响

为明确温度对麻疯树柄细蛾Stomphastis thraustica Meyrick生长发育和繁殖的影响,研究了不同温度下(19～37℃)麻疯树柄细蛾各虫态生长发育、存活和繁殖等生物学特性。结果表明:在19～34℃范围内,各虫态的发育历期随温度的升高而缩短。37℃时,卵不能孵化。在25℃下雌虫和雄虫平均寿命最长,分别为5.94 d和5.22 d。在25～34℃范围内,温度对雌虫产卵量无显著影响,但平均产卵量(44.4粒/雌)明显高于低温区19～22℃的平均产卵量(16.9粒/雌)。卵、幼虫、蛹和世代的发育起点温度分别为8.391,6.312,8.014,8.874℃,世代有效积温为294.183日度。     

竹缺爪螨生物学特性及其发生与环境的关系

研究结果表明,竹缺爪螨（ Ａｐｏｎｙｃｈｕｓｃｏｒｐｕｚａｅ Ｒｉｍａｎｄｏ） 营两性或孤雌生殖,孤雌生殖产雄卵;雌螨日产卵１ ～２ 粒,一生平均产卵９－８ 粒;林间自然性比为２－３５∶１ ;该螨以雌成螨和卵滞育,１１ 月中旬入蛰,３ 月上旬出蛰;在一定温度范围内,各螨态发育历期随温度升高而变短,从卵到成螨产卵有效积温为２８０－７６ 日度,发育起始温度为１３－３２ ℃。该螨还可取食苦绿竹（ Ｄｅｎｄｒｏｃａｌａｍ ｕｓｂａｓｉｈｉｒｓｕｔａ） 、长毛米筛竹（ Ｂａｍｂｕｓａ ｐａｃｈｉｎｅｎｓｉｓ） 、半耳箬竹（ Ｚｎｄｒｏｃａｌｍｕｓｌｏｎｇｉａｕｒｔｕｓ） ,并完成其生活史,在麻竹（ Ｄｅｎｄｒｏｃａｌａｍｏｐｓｉｓｌａｔｉｆｌｏｒｕｓ） 、毛金竹（ Ｐｈｙｌｌｏｓｔａｃｈｙｓｎｉｇｒａ） 上不能存活,在苦绿竹上完成１ 代需１８－４ ｄ;降雨的冲刷及浸水对幼、若、成螨存活影响较大,短期浸水对卵孵化影响不大,浸水１ ｄ 后卵孵化率降至３０－６５ ％ 。利用灰色关联度（Ｔｈｅ Ｇｒａｙ Ｓｅｑｕｅｎｃｅ） 方法分析湿度、气温、降雨量、天敌４ 个因子对该螨种群消长的影响,结果表明,４ 个因子对幼、若、成螨数量消长的关联序为湿度＞ 降雨量＞ 天敌     

杨潜叶跳象生态学特性的研究

通过定点观测,研究了杨潜叶跳象生态学特性,结果表明,杨潜叶跳象卵孵化率为82．1％,幼虫成活率93．1％,羽化率53．3％,性比为1：1。卵期发育起点温度11．65℃±0．18℃,有效积温8．27±1．28日度。幼虫期发育起点温度14．53±0．45℃,有效积温31．54±7．16日度。预蛹—蛹期发育起点温度16．80±0．31℃,有效积温24．76±3．41日度。     

松天牛小首螨的研究Ⅰ.生物学特性

【目的】松天牛小首螨是新发现的对松褐天牛卵具有寄生和致死作用的微型螨类,研究阐明其生物学特性,为利用该螨防治松褐天牛提供基础依据。【方法】通过室内饲养、显微观察和控制性试验,研究松天牛小首螨的行为习性、寄生率、发育历期、繁殖力和寿命等。【结果】松天牛小首螨属携播螨类,成螨附着在松褐天牛成虫胸腹部,在天牛产卵时沿产卵器爬行到刻槽中寄生天牛卵。该螨营两性生殖,雌成螨寄生天牛卵后腹部膨大形成膨腹体,若螨在母体膨腹体内完成发育,成螨自膨腹体胎生,1个膨腹体通常只产1～2头雄螨,其余均为雌螨。雄成螨先自膨腹体爬出并停留在旁,雌成螨自膨腹体爬出后即寻找雄成螨交尾,交尾过程持续3～6 s。松天牛小首螨对松褐天牛卵的平均寄生率为80.85%,被寄生的松褐天牛卵均干瘪、死亡。温度对该螨发育历期、雌成螨寿命和膨腹体大小均有显著影响,随着温度升高其发育历期和雌成螨寿命均显著缩短。该螨在17℃下的平均发育历期为6.9天,在33℃下为2.2天,其发育起点温度为(10.44±0.09)℃,有效积温为(46.28±0.28)d·℃;雌成螨在15℃下的平均寿命为70.3天,在30℃下为10.7天;雌螨膨腹体体积在21...     

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.     

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.     

Key Habitats in the Norwegian Production Forest: A Case Study

This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes.