香格里拉虎跳峡镇核桃种质资源坚果表型特征多样性分析

对香格里拉虎跳峡镇79株核桃单株坚果表型特征的13个表型描述性状及8个数量性状进行测定分析和多样性研究.结果表明,该区域核桃坚果的形状、仁色的Simpson多样性指数较高,核桃拥有坚果形状表型特征描述的10种类型,表现出较大的多样性和丰富性,以扁圆球形、圆球形和长扁圆球形为主.种仁颜色主要以灰白和黄白色为主,占50.6...     

湖北麻城早熟油茶果实性状研究

湖北麻城是我国油茶主要产地之一,拥有十分珍贵的早熟油茶种质资源。为了科学评价该种质资源的多样性,以便对其进行更好的保护与开发利用,文中从该地的实生早熟油茶群体中选取50株油茶样株,分单株采集样品,对其果实成熟期、果实颜色、果实形状及果实数量性状进行了观测。结果表明:该地早熟油茶果实的成熟期为9月下旬至10月上旬;果实颜色主要有青色、红色、黄红色和青红色;果实形状有橄榄形、卵形、球形和桔形4种,其中以球形为主;果实12个数量性状的变异系数介于12.21%~42.19%之间,其中,单果籽粒数的变异系数最大;果实12个数量性状的多样性指数介于1.296~1.706之间。以上结果表明,该地早熟油茶种质资源的多样性较为丰富。     

核桃实生群体物候的观测

为给核桃抗晚霜品种的选育和晚花性状的分子辅助选择研究奠定基础,对泰安地区核桃F1实生群体的物候期进行了连续4年的观测。结果表明:核桃实生群体从3月中下旬开始萌动,3月下旬进入萌芽期,4月初至5月初随着叶片展开、新梢生长,混合芽中的雌花及枝条上的裸芽雄花陆续开放,8月下旬至10月初果实成熟,10月中下旬至11月上旬进入落叶期;核桃的物候特征是不同单株固有的遗传特性,不同年份其物候期不尽一致,但各单株上出现的先后次序是相对稳定的,而且,核桃实生群体中不同单株间的各物候时期的变异系数较高,这为晚花抗晚霜优良单株的选择提供了丰富材料。     

云南鲁甸避晚霜核桃优良单株选择

为使核桃避开晚霜危害,选育避晚霜新品种,以核桃物候期为指标,综合考虑其丰产性、坚果品质和抗逆性等来进行避晚霜核桃优良单株的选择。深入鲁甸县内9乡3镇逐乡逐村进行调查,采用群众荐优和实地调查相结合,对大约3 000棵不同树龄(均不小于15 a)的核桃树进行了调查分析,经预选、初选、复选和决选,最终选出12株避晚霜核桃优良单株,各决选优株芽萌动期与该区域主要栽培品种‘鲁甸大麻1号’相当或晚,比‘云新90303’晚25 d以上。有5个优株的芽萌动期在4月上旬,优株号分别是L161、L185、L343、L353和L455,萌芽最晚的L161,在4月16号芽才开始萌动,比‘鲁甸大麻1号’晚27 d,比‘云新90303’晚近2个月。核桃品种表现为萌芽晚这一价值特性,在鲁甸核桃生产上有较高推广应用价值。     

铁线莲品种物候期调查及分析

对28个品种的铁线莲在江苏句容的生长情况进行了物候期调查分析.结果表明,在供试的铁线莲品种中绝大部分品种是属于多年生落叶的木质藤本,常绿品种极少.在所观察的28个品种中,发芽期大都集中在2月中下旬,展叶期集中在2月24日至3月28日或是3月7日至4月11日,花苞萌动期则大部分集中在3月28日～4月26日.第1朵花的开花期在4月下旬,大部分品种的单朵花序开花持续时间较短,为5～11d,群体开花持续时间长,可从4月中下旬或5月中上旬一直持续到8月中下旬、9月中下旬或到10月中上旬不等,盛花期多在4月中下旬至5月中下旬.其中品种‘Souvenir du Capitaine Thuille ux’的群体开花持续时间最短,为4月26日至5月27日,品种‘Fireworks’的群体开花持续时间最长,从第1朵花到断断续续最后1朵花的时间为4月27日至11月21日.这28个铁线莲品种的花颜色鲜艳,有蓝色、紫色、粉红色、紫红色、白色等,且雌雄蕊多数,花的着生方式多为顶生或腋生,花瓣数基本一致,多为6瓣.种子为瘦果聚集成头状并具有长尾毛.     

黑莓与树莓品种在南京地区的物候期观测

通过定株、定期对14个黑莓、树莓品种的物候期进行观察,基本掌握了各品种在南京地区的物候期和各生育期维持的时间,为其优良品种的推广利用提供了依据.调查结果显示:不同品种黑莓与树莓各物候期存在差异,总的来看,黑莓品种一般在2月中下旬萌芽,3～4月展叶,4月中下旬至5月中下旬开花,花期平均(28.67±5.98)d,5月坐果,果实6月上旬至7月上中旬成熟,果熟期(28.78±6.44)d;树莓品种多集中在3月上中旬萌芽,4月下旬至5月上旬开花,果实5月下旬至6月下旬成熟.     

草履蚧的生物学特性及防治

草履蚧是杨树、法桐、核桃的主要害虫,在河北省邢台地区1年发生1代,以卵在寄主附近的土中越冬.翌年2月上旬至3月上旬,越冬卵孵化.4月下旬,雄虫羽化,和雌虫交配后死亡.雌虫5月下旬由树干爬到树根附近疏松的泥土中产卵,越冬卵至翌年2月～3月孵化.根据草履蚧发生规律,在防治上主要抓住若虫期,分别采用人工、阻隔及药物防治,     

四川核桃优良单株选择的研究

1966年以后,在我省重点核桃产区开展优良种质资源选择工作。按坚果品质和丰产性状等选育指标,进行优树初选、复选和决选。经多性状综合评定,筛选出12株优良单株。所选择的优良单株平均树龄27年,株产坚果21.6kg,树冠投影面积产仁量0.265kg/m^2,平均单果重12.45g,厚度1.07mm,出仁率60.25%。用这批优良单株作为无性繁殖材料,是改良我省核桃遗传品质、提高核桃生产效益的重要途径之一。     

冬樱花物候及观赏期观测

云南各地冬樱花花期有一定差异,但大都集中在12月上旬至1月中旬,紫色叶呈现期为12月下旬至1月上旬.果实成熟期为3月至4月.最佳观花期为12月中旬至1月上旬,持续时间昆明为12～15 d,思茅和景谷为10～12 d.最佳观紫色叶期为12月下旬至1月上旬,昆明为7～8 d,思茅为4～5 d.最佳现果期昆明为4月上、中旬,持续10～15 d,思茅和景谷为3月下旬至4月上旬,10～12 d.由不同地区和同一地区不同年份冬樱花物候的差异,认为冬樱花属低温春化才能开花的植物.     

滇橄榄主要栽培品种的物候期及经济性状

对云南省滇橄榄(Phyllanthus emblica Linn.)主栽品种及其栽培面积调查、物候期观测、经济性状调查、果实主要化学成分测定分析。结果表明:滇橄榄主栽品种6个("高黎贡山"糯滇橄榄、"保山1号、2号、3号、4号"余甘子和"红珍珠"滇橄榄)栽培面积17 098 hm^2;2月中旬至3月中旬萌芽,4月上旬至5月上旬开花,果实成熟期9月中旬至次年1月中旬,1月下旬至2月上旬落叶;其平方米冠影果实产量4.2～5.4 kg/m^2,果实单果质量14.9～45.9 g、可食率82.9%～90.2%,果肉Vc含量0.412%～0.523%、粗纤维1.30%～2.05%、总糖7.2%～11.1%、总酸1.51%～1.91%、可溶性固形物9.5%～13.2%、水分84%～86.8%。根据品种特性及栽培现状,提出了品种利用策略,为其产业可持续发展提供科学依据。     

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.     

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.     

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.     

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.     

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。     

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.