桂花叶枯病病原菌鉴定及生物学特性研究

对桂花叶枯病病原菌进行形态鉴定及生物学特性研究结果表明,桂花叶枯病的病原菌为细极链格孢[Alter-naria tenuissima(Fr.)Wiltshire],该菌在PDBA培养基上菌丝生长量最大,在OLA上产孢量最大.碳源以糊精最适于菌丝生长,肌醇最适于产孢.氮源以蛋白胨最适于菌丝生长与产孢,而铵盐会抑制病原菌生长及产孢.缺Mg不利于菌丝生长,缺K不利于产孢,添加一定量Zn、Ve可促进菌丝生长,添加Cu、Vb2可促进产孢.pH 5-10适于菌丝生长而pH 6-11适于产孢,最适pH值分别为pH6和pH7,该菌生长适温为20℃-30℃,最适生长温度为25℃-27℃,15℃和30℃适合产孢,30℃时产孢量最大,黑暗有利于菌丝生长及产孢.桂花叶汁、蔗糖、葡萄糖、牛肉浸膏促进孢子萌发效果最好,孢子萌发适宜温度为23℃-30℃,最适为27℃,适宜湿度为98%和100%,最适为98%,适宜pH值为pH3-7,最适为pH6,分生孢子致死温度为55℃ 10 min.     

降香黄檀炭疽病菌豆类炭疽菌生物学特性

为有效防治降香黄檀(Dalbergia odorifera)炭疽病,对其病原之一豆类炭疽菌(Colletotrichum truncatum)进行了生物学特性研究。结果表明:该菌菌丝生长的温度范围为10~35℃,最适28℃;产生分生孢子的温度范围为10~35℃,最适温度30℃;分生孢子萌发的温度范围为15~30℃,最适温度28~30℃;在p H 3~12的范围内该菌均能生长,菌丝生长最适p H值为5;分生孢子在水滴中萌发率为96.67%。豆类炭疽菌可利用多种碳氮源,对蔗糖和葡萄糖利用最好,阿拉伯熟胶粉利用最差,但是产孢量却最大;对牛肉膏利用最好,硫酸铵利用效果最差,在蛋白胨和酵母粉培养基上产孢量最大;光照能加速菌丝生长和促进产孢。     

铁皮石斛炭疽病病原鉴定及其生物学特性研究

在云南省瑞丽市铁皮石斛Dendrobium officinale种植基地,发现一种铁皮石斛叶斑病。通过分离培养和接种试验,经传统形态学及ITS序列分析鉴定,采用十字交叉法和血细胞计数板法测定该病原菌的形态学特性及产孢性能。结果表明:该病病原为半知菌亚门腔孢纲黑盘孢目炭疽菌属的胶孢炭疽菌Colletotrichum gloeosporioides。菌丝生长最适温度为15～30℃,其中28℃时菌丝生长量最大,最适pH值为5～6;产孢的最适温度为25～30℃,最适pH为3～4。此菌对碳源要求不严格,能利用多种碳源,但利用能力有差异;硫酸铵、氯化铵作为氮源的培养基明显不利于菌丝生长,其他供试氮源均对该菌菌丝生长有显著促进作用。     

八角炭疽病菌哈锐炭疽菌生物学特性

哈锐炭疽菌Colletotrichum horii是在广西新发现的引起八角Illicium verum炭疽病的病原,为有效防治八角炭疽病提供病原学基础,主要研究了温湿度、碳氮源和光照对哈锐炭疽菌菌丝生长、产孢及孢子萌发的影响。结果表明:该菌菌丝生长和产生分生孢子温度为10~35℃,最适温度30℃;分生孢子在水滴中萌发率最高,为94.83%;对葡萄糖、D-木糖和蔗糖利用最好,可溶性淀粉和阿拉伯树胶粉利用最差,但能促进产孢;对牛肉膏利用最好,硫酸铵利用效果最差,产孢量最大;光照能加速菌丝生长,但不利于产孢。     

黑龙江省沙棘干缩病病原菌生物学特性的研究

对引起黑龙江省大果沙棘干缩病的病原菌-拟枝孢镰孢菌的生物学特性进行了研究,研究结果表明,病原菌生长最适温度为25℃,生长最适pH值为7,生长所需最佳碳源为麦芽糖,最佳氮源为硝酸钠和蛋白胨;病原菌产孢最适温度为25℃,最适pH为6,最佳碳源为乳糖,最佳氮源为硝酸钠.     

油茶炭疽病病原菌生物学特性研究

对引起油茶炭疽病的胶孢炭疽菌的生物学特性进行了研究.结果表明,该病菌在10~35℃的温度范围内均能生长以及分生孢子正常萌发,其中30℃最适宜菌丝生长和分生孢子萌发;在pH3.0~11.0范围内菌丝均能生长和分生孢子均可萌发,pH6.0最利于菌丝生长,pH5.0~7.0最适宜分生孢子萌发。连续光照有利于菌丝的生长,光暗交替有利于分生孢子的萌发。可溶性淀粉和尿素利于菌丝生长;乳糖和麦芽糖与谷氨酸的不利于菌丝生长。甘露醇和甘氨酸有利于产孢,半乳糖和硝酸钾不利于产孢;菌丝和分生孢子的最低致死温度为55℃,10 min。     

杨树枯萎病菌茄类镰刀菌的生物学特性

由茄类镰刀菌引起的杨树枯萎病是一种新病害,对其病原菌的生物学特性进行了初步研究.试验结果表明,病原菌Fusarium w/ani的适应性较强,在8～35℃范围内均能生长,最适生长和最大产孢量的温度为25℃,孢子萌发的适宜温度范围是25～30℃,以30℃最适,分生孢子致死温度为53℃,10 min.病原菌在pH5.91～6.98对生长和产孢较好,pH 6.98最适,当pH<4.53对菌落表现异常现象.病原菌在不同光照条件及在不同碳、氮源上均能生长,不同光照条件对其影响无显著差异;以蔗糖为其最适碳源.亚硝酸钾和硝酸钾为其最适氮源.     

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。     

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。     

枸杞根腐病病原菌的生物学特性研究

为给枸杞根腐病的有效防治提供科学依据,以甘肃省内枸杞主产区枸杞根腐病病株中分离鉴定的单隔镰孢菌为研究对象,对其在不同培养基、温度、光照、pH值、碳源和氮源上的生长状态与特性进行了观测与分析。结果表明:适于单隔镰孢菌生长的最适培养基为豆芽汁培养基;最适宜的温度范围为15~35℃,最适温度为35℃;适宜的pH值范围为4~10,最适的pH值为9;供试的4种碳源均能被其利用,其中以乳糖的利用效果为最好;该菌株能够利用供试的4种氮源,其对硫酸铵的利用效果最差;光暗交替的培养环境有利于菌丝生长,而连续黑暗的培养环境却能抑制菌丝生长。     

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.