Cr~(+3)元素在平菇栽培中的应用研究

采用不同浓度的CrCl3.6H2O于平菇栽培期间进行拌料处理,研究铬对平菇生长的影响,试验结果表明:采用0.01~100mg/L的CrCl3.6H2O拌料能够有效地促进平菇菌丝的生长及产量的提高,当浓度达500mg/L时则会抑制平菇的菌丝生长和降低子实体的产量。同时,各处理组随着培养料中CrCl3.6H2O量的增加,平菇子实体内富铬量也随之增大。从CrCl3.6H2O拌料对平菇的菌丝生长、子实体的产量以及富铬量的安全性综合考虑,采用CrCl3.6H2O于平菇栽培期间进行拌料处理的浓度以1~10mg/L为最佳。     

吸水保水剂在平菇生产上的应用研究

试验结果表明,采用不同量的吸水保水剂于平菇栽培期间进行拌料处理,在试验范围内,添加吸水保水剂的各栽培配方在菌丝生长及产量上的作用有所不同,其中以含量为1%吸水保水剂的配方表现最好,显著地促进了平菇的菌丝生长及产量提高。     

绿风95在平菇栽培中的应用研究

选用几种不同浓度的绿风95于平菇栽培期间进行培养料处理，其结果表明，在试验范围内，不同浓度的绿风95对平菇的生长发育影响存在一定的差异，其中以2ml/L的绿风95处理作用效果最好，明显地促进了平菇的菌丝生长和产量提高．     

不同硒源处理对竹荪子实体营养成分的影响

研究通过对比不同硒源处理中竹荪Dictyophora echinovolvata硒子实体营养成分含量差异,探讨不同硒源对竹荪子实体中营养成分含量的影响。试验设置纳米硒、富硒氨基酸液肥、螯合硒3种硒源,每种硒源选择5、10 mg/L 2种施用浓度。结果表明:施用5 mg/L的富硒氨基酸液肥利于促进竹荪子实体中蛋白质的合成,施用5 mg/L的富硒氨基酸液肥、10 mg/L螯合硒利于竹荪子实体中粗多糖的合成,施用10 mg/L纳米硒利于竹荪子实体中硒元素的吸收存储,施用10 mg/L的螯合硒和纳米硒竹荪子实体中氨基酸总量较大,施用5 mg/L纳米硒可以有效提高竹荪子实体中风味氨基酸占氨基酸总量的比例,施用10mg/L螯合硒、5 mg/L纳米硒后可以有效提高竹荪的抗氧化功能。     

东北地区大球盖菇优良菌株筛选试验

以引进的4个大球盖菇菌株为对象,观察在母种培养基、原种培养基以及栽培种培养基上菌株的菌丝生长状况,在栽培料上进行了产量试验。结果筛选出2个适宜东北地区栽培的大球盖菇优良菌株,其菌丝生长均匀、浓密,生长势强,生长速度快,产量高,子实体丛生,菌盖酒红色,菌柄粗壮。     

光照和赤霉素对平菇子实体发育的影响

通过开展试验探究了不同光照强度和赤霉素(GA3)浓度对平菇子实体发育的影响。结果表明:光照和GA3会对平菇子实体的出菇时间、产量和品质等方面产生影响,其中以250lx的光照强度和50mg/L的GA3处理效果最佳。光照强度为250lx时,平菇出菇时间最早,且菌体生长快,菌盖直径最大,肉厚,且色泽雪白,品质最好;GA3为50mg/L时,平菇出菇时间比对照组提早了4d,且品质不变。     

植物生长调节剂在平菇栽培中的应用研究

平菇栽培期间，采用一定浓度的油菜素内酯、爱多收、三十烷醇对培养料进行单一和混合处理，试验结果表明：三种植物生长调节剂的单一和两两混用对平菇均有明显的增产效果，其中单一处理的效应在总体上优于混合处理，并以浓度 2×10~（－6）的爱多收拌料为最优。     

微量元素锌在金针菇培养中的应用研究

采用单因素完全随机设计，于金针菇培养期间用不同浓度的硫酸锌溶液对培养料进行处理，研究微量元素锌对金针菇的茵丝生长、子实体产量及其多糖含量、富锌量等的影响。试验结果表明：0．1～100mg／L的硫酸锌处理对茵丝生长均有促进作用，以10mg／L处理的茵丝生长速度最快；10mg／L和100mg／L的硫酸锌处理对子实体具有明显的增产效果；不同浓度的硫酸锌溶液处理均可提高金针菇子实体多糖及其富锌量，以100mg／L处理的多糖含量最高、富锌量最大。采用不同浓度的硫酸锌溶液对培养料进行处理时浓度以100mg／L为佳。     

雷州半岛地区林下栽培平菇栽培料配方试验

在雷州半岛地区进行林下平菇栽培试验,栽培料中用不同量的桉树木屑代替棉籽壳,以获得适宜林下栽培平菇的栽培料配方.结果表明:桉树木屑可以替代部分棉籽壳进行林下栽培平菇,桉树木屑52％、棉籽壳26％、米糠20％、蔗糖1％、石膏粉1％是较适宜的配方,应用该配方可以明显提高平菇的菌丝生长速度和鲜菇产量,其生物转化率为102.5％,比对照高出10.3％.     

微量元素硒在猴头菇栽培中的应用研究初探

采用不同浓度的亚硒酸钠溶液对培养料进行处理,以探讨其对猴头菇的菌丝生长、子实体产量及其多糖含量的影响。试验结果表明:采用1mg/L和10mg/L的处理对菌丝生长有促进作用,并可显著提高子实体产量;不同浓度的亚硒酸钠溶液处理对猴头菇子实体多糖含量都有增加,以10mg/L和100mg/L的处理表现较好,分别比对照提高12.53%和11.41%;采用亚硒酸钠溶液对猴头菇的培养料进行处理时浓度以10mg/L为佳。     

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.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

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.     

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。     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

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.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

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.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

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.     

Modelling of adequate pretwist for obtaining straight timber

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.