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不同寄主植物“树皮”从外向内皆由周皮、皮层、次生韧皮部构成,但是在每层结构中,不同寄主之间存在一定的差异。大叶千斤拔的周皮最薄,光叶合欢的皮层最薄。在栾树和苏门答腊金合欢的周皮中,局部地方木栓层显著加厚,滇刺枣的木栓层角质化呈点状分布。滇刺枣石细胞纤维层最厚,共有4层,聚果榕、苏门答腊金合欢的皮层中未见连续的石细胞纤维层。苏门答腊金合欢的韧皮部最薄,聚果榕的韧皮部最厚,栾树周皮到次生韧皮部的最小距离最短,苏门答腊金合欢到韧皮部的最大距离最短。苏门答腊金合欢筛管在单位面积的分布密度最大。在筛分子具功能区,大叶千斤拔、栾树、滇刺枣射线为单列,偶有多列;聚果榕、光叶合欢、久树射线单列、双列、多列并存;苏门答腊金合欢射线为多列。文中还从寄主植物的韧皮部厚度、节管密度等解剖特征研究了不同寄主树对紫胶蚧的固虫密度和死亡的影响。 相似文献
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采用主分量分析、聚类分析等方法研究7种寄主植物氨基酸含量与紫胶蚧关系,结果显示：(1)不同寄主植物和是否被寄生的枝条之间,氨基酸含量存在差异。(2)当寄主植物枝条与久树1年生枝条氨基酸含量相近时,能产生较厚的胶被;偏离久树1年生枝条氨基酸含量越远,紫胶蚧在该寄主植物上的死亡率、怀卵量越高。(3)紫胶蚧寄生后久树枝条中氨基酸总量减少了35％左右,天门冬氨酸、苏氨酸、丝氨酸、苷氨酸、丙氨酸、缬氨酸、异亮氨酸、亮氨酸、酪氨酸、苯丙氨酸的含量也都存在不同程度减少,但久树枝条中蛋氨酸、组氨酸、赖氨酸、精氨酸、色氨酸含量比未放虫枝条中高。其他寄主植物放虫枝条中也有不同种类的氨基酸含量比未放虫枝条中升高或降低的现象。 相似文献
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以紫胶蚧优良寄主植物久树为研究对象，采用比较研究法研究了其种子育苗技术、造林技术、枝条利用及紫胶蚧在寄主植物上生物学特性。研究结果：破壳处理可极大提高种子发芽率，一般在开春(3月)采用容器育苗，雨季初期(6-7月上旬)造林；造林地应选择土层深厚、土壤通透性好的山坡中、下部，阳坡效果更好；雨季前松土除草和追施氮肥相结合，可明显促进幼树生长；久树是紫胶蚧最优良寄主植物，冬、夏代放养结果稳定，既适于保种又适宜产胶，寄主植物每年可利用1次。 相似文献
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蚧壳虫是林木三大顽固性害虫之一。其对杨树的危害方式主要是以若虫和雌成虫群集固定在杨树的主干和枝条上吸食养分为害,自小枝到主枝均可受害,2～3年生枝受害最重,发生严重时整个枝条被虫体覆盖,并可重叠成层,远看像涂了一层白蜡。污染叶面和枝条,堵塞气孔、皮孔,影响光合作用。被害处由于不能正常生长发育而凹陷,使受害枝条的皮层凹凸不平,发育不良,树势衰弱,枯枝增多,枝条严重被害后,逐渐干枯,风季造成大批风折,使整株早衰至全株死亡。由于蚧壳虫类体表常披有蜡质物或有蚧壳覆盖,如用药物对它直接喷洒,一般农药难以奏效,且以刺吸式口器取食,吸取植株的汁液,因而对林木造成极大的危害,给防治工作带来一定困难。新疆克拉玛依市开发区在生产上采用人工防治、生物防治与化学防治相结合的综合治理过程中,总结出一套较理想的防治方法。 相似文献
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杨树天牛,为蛀干性害虫,常见有星天牛、光肩星天牛、黄斑星天牛、桑天牛、云斑天牛等。
光肩星天牛在江南多为1年1代11月在树干隧道内或皮下越冬．并于翌年4月下旬用木屑作室化蛹。,6月中旬至7月中旬为成虫羽化盛期．7月上旬初孵幼虫先啃食树皮下韧皮部组织．7～9月成虫飞翔并取食枝条顶端叶脉及嫩枝皮。成虫最喜欢在直径4～10厘米的枝和干上产卵, 相似文献
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胶蚧属一新种及其生物学研究初报(同翅目:胶蚧科) 总被引：2，自引：0，他引：2
本文记述1969年自云南省寄生在粗糠柴枝条上的胶蚧属(Laccifer)一新种取名为田胶蚧(Laccifer ruralis sp.n.)。此种长期以来因在外部形态上与紫胶蚧(Laccifer LaccaKerr.)相似,所以一直被误认为两者是同一种,或认为是因为寄主不同或分布不同地区所发生的变异。通过在福建省南靖(同一地区)生长的南岭黄檀(同一寄主)上田胶蚧的生物学观察以及形态方面的比较,我们认为它与紫胶蚧是同域生活的近缘种。现将该新种的形态和生物学介绍如下。新种的正模和副模标本均保存在中同科学院动物研究所。 相似文献
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我省江淮及淮北地区杨树天牛危害以光肩星天牛和桑天牛为主.光肩星天牛在我省一般为一年1代,极少为两年1代.上一年11月间以不同龄期幼虫在隧道内或皮下越冬,当年4月下旬在隧道末端向四周扩散,用木屑作成化蛹室,6月中旬至7月中旬为成虫羽化盛期,7～9月为成虫飞翔期,取食枝条顶端叶脉及嫩枝皮,7月上旬初孵幼虫先啃食树皮下韧皮部组织,排出红褐色粪便.桑天牛在我省一般为两年1代,幼虫钻蛀杨树髓心形成直通的虫道,且排粪孔多,等距离排列在同一方位,可蛀至根部深处.成虫取食枝条皮部,以后边取食边产卵. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):427-435
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. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(3):206-217
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. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1):53-61
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. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1):15-27
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. 相似文献
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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。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):472-479
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. 相似文献
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Srisuda Thippayarugs Banyong Toomsan Patma Vityakon Viriya Limpinuntana Aran Patanothai Georg Cadisch 《Agroforestry Systems》2008,72(2):137-148
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. 相似文献
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A. Rigueiro-Rodríguez M. R. Mosquera-Losada E. Gatica-Trabanini 《Agroforestry Systems》2000,48(3):245-256
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. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(2):166-178
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. 相似文献