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1.
从菌根菌黑核菌菌丝出原生质体，并获得再生菌落。研究了预处理方法及不同水解酶组合，酶解温度和菌丝密度对原生质体产率的影响。在用胰蛋白酶预处理后，以０．８Ｍ山梨醇为渗透压稳定剂，温度为２０Ｃ，ｐＨ５．５及纤维素酶，溶解酶和浸解酶处理，可获得较高的原生质体产量。 相似文献
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几种天牛纤维素酶的来源 总被引：17，自引：3，他引：17
测定３种常见天牛：桑粒肩天牛（ＡｐｒｉｏｎａｇｅｒｍａｒｉＨｏｐｅ）、星天牛（ＡｎｏｐｌｏｐｈｏｒａｃｈｉｎｅｎｓｉｓＦｏｒｓｔｅｒ）和桔褐天牛（ＮｅｄｅｚｈｄｉｅｌｌａｃａｎｔｏｒｉＨｏｐｅ）消化道纤维素酶活性，发现几种天牛幼虫均有完整的纤维素酶体系，即Ｃ１酶、Ｃｘ酶和β－葡萄糖苷酶，能真正消化利用食物中的纤维素成分；以微晶纤维素（ＭＣ）和羧甲基纤维素钠（ＣＭＣ－Ｎａ）为碳源的选择性培养基培养几种天牛肠液，未发现纤维分解真菌及能分解ＭＣ的细菌；肠道解剖及肠组织切片未发现特殊的共生菌囊及含菌细胞；比较天牛的纤维素酶与常见真菌纤维素酶的性质相差甚远。因而认为所研究的几种天牛其纤维素酶均为其自身分泌的内源性酶而不是来源于其它生物。 相似文献
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竹刨花板上的几种真菌 总被引：1，自引：0，他引：1
在实验室里对竹刨花板上的真菌作了研究，发现竹刨花板上常见真菌有桔青霉Ｐｅｎｉｃｉｌｌｉｕｍ ｃｉｔｒｉｎｕｍＴｈｏｍ、黄曲霉Ａｓｐｅｒｇｉｌｌｕｓ ｆｌｏｕｓＬＫ．、多主枝孢Ｃｌａｄｏｓｐｏｒｉｕｍ ｈｅｒｂａｒｕｍ（Ｐｅｒｓ．）ｅｘＦｒ．艉投嗝撸校澹螅簦幔欤铮簦椋? ｓｐ．等。 相似文献
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通过对分布于欧洲的水青冈（Ｆａｇｕｓｓｙｌｖａｔｉｃａ和Ｆａｇｕｓｏｒｅｎｔａｌｉｓ）和亚洲的水青冈（Ｆａｇｕｓｊａｐｏｎｉｃａ，Ｆａｇｕｓｃｒｅｎａｔａ，Ｆａｇｕｓｌｕｃｉｄａ，Ｆａｇｕｓｅｎｇｌｅｒｉａｎａ和Ｆａｇｕｓｐａｓｈａｎｉｃａ）的地理历史资料分析和凝胶电泳法等位酶的测定，探讨欧亚大陆水青冈地理变异和遗传多样性．所测定的酶系统包括：过氧化物酶（ＰＸ１和ＰＸ２）、磷酸葡萄糖脱氢酶（ＰＧＤ）、酸性磷酸化酶（ＡＣＰ１和ＡＣＰ２）、超氧化物歧化酶（ＳＯＤ）、谷氨酸草酰乙酸转氨酶（ＧＯＴ１，ＧＯＴ２和ＧＯＴ３）、异柠檬酸脱氢酶（ＩＤＨ）、磷酸果糖异构酶（ＰＧＩ）、甲基萘醌还原酶（ＭＮＲ）、葡萄糖磷酸变位酶（ＰＧＭ１和ＰＧＭ２）和苹果酸脱氢酶（ＭＤＨ１和ＭＤＨ２）１０种酶系统．测定和分析了水青冈遗传相似性、固定指数及遗传多样性随经度、纬度和海拔高度的变化规律，讨论了水青冈起源和分布特点，为进一步研究水青冈的种间关系和地理历史进化过程提供了科学依据． 相似文献
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木霉对苗木土传病原真菌的拮抗作用 总被引：7，自引：0，他引：7
体外测定表明，木霉菌株Ｔ—１６９和Ｔ—２７９对病原菌Ｒｈｉｚｏｃｔｏｎｉａｓｏｃｌａｎｉ（立枯丝核菌）、Ｆｕｓａｒｉｕｍｏｘｙｓｐｏｒｕｍ（尖孢镰刀菌）、Ｐｙｔｈｉｕｍａｐｈａｍｉｄｅｒｍａｔｕｍ（腐霉）和Ａｌｔｅｒｎａｒｉａｔｅｎｕｉｓ（交链孢霉）在对峙培养中的拮抗系数分别为２、２～３和３。温室测定表明，用０．６％（Ｗ／Ｗ）Ｔ－１６９麸皮培养物（１０７ｃｆｕ／ｇ）处理土壤。在人工接种立枯丝核菌、尖孢镰刀菌、腐霉及交链孢霉２０ｄ后，落叶松苗木发病率分别比未用木霉处理的对照减少４９．６％、１７．４％、１８．３％和１１．７％；用Ｔ－１６９和Ｔ－２７９木霉孢子悬浮液（１０８ｃｆｕ／ｍｌ）处理落叶松种子，人工接种立枯丝核菌１９ｄ后，落叶松成苗率分别比未用木霉处理的对照增加１８．８％和１２．７％。 相似文献
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薄木镶嵌拼花装饰的构图与工艺 总被引：1，自引：0，他引：1
薄木镶嵌拼花装饰的构图与工艺唐开军（中南林学院株洲４１２００６）ＰａｔｔｅｒｎｓａｎｄＴｅｃｈｎｏｌｏｇｙｏｆＶｅｎｅｅｒＭａｔｃｈａｎｄＩｎｌａｙＤｅｃｏｒａｔｉｏｎＴａｎｇＫａｉｊｕｎ（Ｃｅｎｔｒａｌ－ｓｏｕｔｈＦｏｒｅｓｔｒｙＣｏｌｌｅｇｅ，Ｚ... 相似文献
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用Ｘ－射线微区分析方法对Ｉ－２１４（ＰｏｐｕｌｕｓｄｅｌｔｏｉｄｅｓＰ．ｎｉｇｒａ（Ｄｏｄｅ）Ｇｕｉｎｉｅｒ）和胡杨（Ｐ．ｅｕｐｈｒａｔｉｃａＯｌｉｖｅ）根和叶片样品中元素浓度和分布研究的结果表明，与盐胁迫处理和对照的Ｉ－２１４相比较，胡杨根系中具有”次生液泡”，因而Ｃｌ，Ｎａ，Ｋ和Ｍｇ离子浓度较低，而Ｃａ离子浓度较高．在不耐盐的Ｉ－２１４杨中由于不具有”次生液泡”，Ｃｌ和Ｋ离子浓度较高．胡杨中的这种结构一方面可以做为Ｃｌ离子的储存场所，另一方面可以防止Ｃｌ离子在细胞核中积聚．在盐胁迫处理条件下，相对细胞壁而言胡杨表现出较强的防止细胞核中积聚Ｃｌ离子的能力，表明胡杨在离子选择吸收和区隔化方面具有较强的功能，这将有助于解释胡杨所具有的较强的耐盐性 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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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
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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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《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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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
20.
《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