桑叶褐斑病病原菌的生物学特性研究

通过对桑叶褐斑病病原菌在不同种类培养基培养、不同氮源与碳源、不同温度等6种条件下培养6天后，测定菌落直径，观察菌丝颜色和菌落形态，分析了桑褐斑病病原菌的生物学特性。结果表明，在室内培养条件下，不同的营养成分、 pH值、温度、光照都对菌丝的生长有影响。病原菌菌丝生长的最适宜培养基是燕麦片培养基，适宜生长温度范围是20～30℃，最适生长温度为25℃，光照对菌丝生长无显著影响，最适pH值为9～10，最适碳源为α-乳糖，最适氮源为尿素，菌丝在55℃水浴10 min后则不能生长。     

桑树轮纹病病原菌的分离鉴定及其生物学特性研究

2012年6～8月,通过对桑树轮纹病病原菌分离、田间致病性测定、病原菌形态观察,将该病原菌鉴定为桑膝节霉,并对此病病原菌的生物学特性进行了研究。结果表明,不同培养基配方、温度、酸碱度、碳源、氮源、光照对桑树轮纹病病原菌菌丝的生长有一定影响,菌丝生长的最适宜培养基是理查培养基,最适温度是25℃,最适pH值是7.0,最适碳源为葡萄糖,最适氮源为蛋白胨,光照对菌丝生长无显著性差异,菌丝的致死温度和时间分别为85℃和10 min。对该病病原菌生物学特性研究为云南首次报道,对桑树轮纹病的防治具有一定的参考价值。     

冬枣黑斑病菌生物学特性的研究

通过对冬枣黑斑病菌的生物学特性研究,结果表明,菌落在玉米培养基、燕麦培养基、土豆培养基上均生长良好,其中在玉米培养基上生长最快;菌丝生长最适温度25℃,孢子萌发最适温度为28℃;菌落在不同光照条件下生长良好,差异不显著;菌丝生长适宜pH值为6～9,最适pH值为6～7.0,孢子萌发的最适pH值为7.0;不同营养条件下,孢子萌发差异不显著。     

浙江景宁云锦杜鹃叶斑病病原菌鉴定及生物学特征研究

为明确浙江省景宁县上山头云锦杜鹃Rhododendron fortunei叶斑病Cercospora rhododendri病原菌的种类及其生物学特性,采取组织分离法获得菌株DJ-1,采用柯赫氏法则验证试验证明该病原菌为云锦杜鹃叶斑病致病菌,通过形态学和分子生物学技术鉴定该病原菌为芦笋拟茎点霉Phomopsis asparagi。对病原菌生物学特性的研究结果表明,不同培养条件对该病原菌的菌丝生长、分生孢子产生量均有显著影响(P0.05);在马铃薯葡萄糖琼脂培养基中菌丝生长最为适宜,该病菌可以利用多种碳源和氮源,最佳碳源和氮源为甘露醇和甘氨酸;病菌分生孢子产生的最佳培养基为马铃薯葡萄糖琼脂和马铃薯蔗糖琼脂培养基,最佳碳源为葡萄糖和果糖,最佳氮源为甘氨酸;当pH为8.0时,病原菌菌丝及分生孢子产生量为最佳;光照12 h+黑暗12 h交替条件下菌丝及产孢量为最佳;病原菌菌丝致死温度为60℃,10 min,分生孢子致死温度为55℃,10 min。本研究为芦笋拟茎点霉在浙江省内引起云锦杜鹃叶斑病的首次报道。     

橡胶树炭疽病病原菌Colletotrichum laticiphilum生物学特性研究及防治药剂筛选

对橡胶树新发现病害病原菌Colletotrichum laticiphilum的生物学特性进行初步研究并开展室内筛选防治药剂,旨在为该病害的防治提供理论依据。通过单因子变量试验,研究病原菌最适生长条件。菌丝最适生长培养基为土豆琼脂培养基,最适生长温度为26℃,最适合生长pH值为6,菌丝致死温度为50℃、10 min,分生孢子致死温度为51℃、10 min。该病原菌能利用多种碳源和氮源,碳源以可溶性淀粉的利用率最高,牛肉浸膏为最适氮源,在24 h光照条件下更有利于菌丝生长。采用菌丝生长速率法测定室内毒力,结果表明:4种杀菌剂对病原菌的毒力存在明显差异,其中咪鲜胺和丙环唑的毒力最强,EC_(50)分别为0.1286 mg/L、0.5208 mg/L。     

杜松枯梢病的初步研究

根据柯赫氏证病法则和病原菌形态特征证明杜松枯梢病是由桧色二孢Diplodia juniperi Wes-tend.引起的.病原菌的适生温度15～35℃,最适温度30℃,温度低于20℃生长缓慢,低于15℃时完全停止生长.菌丝在pH值5.8～8.2之间均能生长,最适pH为6,偏酸更好.不同的碳源对生长无显著影响,乳糖为最佳碳源.蛋白胨为最佳有机氮源,硝酸钙为最佳无机氮源.     

油松枯枝病病原菌生物学特性研究

该文采用室内纯培养的方法,对油松枯枝病病原菌不同的培养基、温度、碳源、pH值进行培养试验,结果显示：PDA培养基最适合病原菌的生长,其次是燕麦片琼脂培养基（OA）、松针煎汁琼脂培养基（PA）和玉米粉琼脂培养基（CA）,在玉米粉琼脂培养基（CA）上几乎不能生长;病原菌对蔗糖碳源利用较好,其次为葡萄糖、D-果糖和乳糖,对麦芽糖的利用最差;菌落在pH5．0～10．0均能生长,在pH5．0～7．0时生长较好,为最适生长范围,pH6．0菌丝生长速度最快;病原菌在10～30℃均能形成可见菌落,20～25℃生长较好,其中25℃为最适生长温度,大于35℃时不能生长。     

杨叶枯病病原菌生物学特性初步研究

杨叶枯病Alternaria alternate（Fr．）Keissler是一种发生普遍且危害严重的杨树叶部病害。该菌的生长发育温度在5～35℃,菌丝和分生孢子的最适生长温度在20～30℃之间,孢子的致死温度为52℃,菌丝的致死温度为55℃。在pH3～10之间的培养基上均可生长,以pH值6～8为最佳。有无光照处理对菌丝生长差异明显,以黑暗与日光灯交替处理病原菌生长较快。在PDA培养基黑暗条件下培养该菌生长良好,其次是胡萝卜汁培养基,但在琼脂加水培养基上产孢效果最好。     

南洋楹溃疡病病原菌生物学特性研究

研究了不同培养基、碳氮源、温度、pH及光照条件对南洋楹溃疡病病原菌可可毛色二孢Lasiodiplodia theobromae菌丝生长的影响。结果表明:该菌的最适培养基为PDA,最适碳源、氮源分别是葡萄糖和蛋白胨,菌丝最适生长温度为25℃,最适pH为5~7,在12∶12光暗交替条件下生长最好。     

人参锈腐病病原菌生物学特性研究

为探究引起人参锈腐病致病菌的生物学特性,以人参锈腐病病株根部分离的菌株为试材,采用菌丝生长速率法研究了不同培养基、温度、p H值、光照、碳、氮条件对该菌菌丝生长的影响及其致死温度。结果表明:最适合该菌生长的培养基为改良马丁氏,其次是PDA;最适温度为20℃;最适生长pH值为7;在12 h光暗交替条件下菌丝生长最快;最适菌落生长碳源为甘露醇;最适氮源为硝酸钾;致死温度55℃。研究结果可为人参锈腐病发病规律的研究和病害防治提供科学依据。     

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.