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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。 相似文献
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桑树轮纹病病原菌的分离鉴定及其生物学特性研究 总被引：1，自引：0，他引：1
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。 相似文献
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《浙江林业科技》2020,(2)
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。 相似文献
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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 总被引：1，自引：0，他引：1
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。 相似文献
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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。 相似文献
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南洋楹溃疡病病原菌生物学特性研究 总被引：1，自引：0，他引：1
《中国森林病虫》2017,(6)
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。 相似文献
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杨叶枯病病原菌生物学特性初步研究 总被引：1，自引：0，他引：1
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。 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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Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and
also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the
amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter
bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K
was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed
significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week−1 for leaves and from 0.0225 to 0.0633 week−1 for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed
during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly
between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species
provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient
enrichment capacity and slower decomposition rates which would minimize leaching losses.
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):118-130
The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions. 相似文献
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Steven Maranz Amadou Niang Antoine Kalinganire Djeneba Konaté Bocary Kaya 《Agroforestry Systems》2008,72(3):231-239
Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional
data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral
contents and B1 and B2 vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising
germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B1 88 mg 100 g−1, B2 187 mg 100 g−1, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal
diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties
to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations. 相似文献
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《Wood material science & engineering》2013,8(2):76-84
Abstract Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists. 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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Astra Zaluma Lauma Bruna Darta Klavina Natalija Burnevica Kristine Kenigsvalde Andis Lazdins Talis Gaitnieks 《Forest Pathology》2019,49(6)
Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered. 相似文献