薄壳山核桃果实性状的遗传变异与相关性研究

为了选育适应我国种植的薄壳山核桃优良品种,研究薄壳山核桃实生后代的遗传变异规律,对南京中山植物园周边地区树龄在55～60a的249株薄壳山核桃实生后代果实的9个性状方面的遗传变异情况进行了调查与分析。结果表明:果实质量变异度最大,变异系数为26.67%,其它性状变异度都较小,变异系数在7.12%～12.91%之间;果实性状的变异表现为连续变异,属于数量性状遗传;果实性状的分布表现为正态分布规律,偏倚系数较小;果实性状多数指标的相关性显著,其中果实质量与果壳厚度、果实含油率分别与出仁率和种仁含油率呈极显著正相关性,果实质量和果壳厚度分别与出仁率、果实含油率呈极显著负相关性;根据果实性状间的相关性,建立起相关回归模型,决定系数在0.99以上,回归测验的F值达到了6880,均远高于极显著临界值,模型准确可靠。     

薄壳山核桃区域试验

对中国亚热带林业研究所提供的12号、32号、99号、103号、104号薄壳山核桃和新平华森果业有限公司提供的金华、绍兴等薄壳山核桃品种进行栽培试验,采取嫁接改造和抚育管理等技术措施,调查定植后的薄壳山核桃苗木的物候、幼树的树高和冠幅以及结果树的树高、冠幅、单株产量等,测定果实性状及内含物指标。试验结果表明,薄壳山核桃品种在试验区生长结果正常,果实经济性状好,坚果具有壳薄、出仁率高、含油率高等特点,建议规模化推广优良品种,并加强提质增效技术推广运用,培养技术人才,促进增产增收。     

薄壳山核桃良种‘巴顿’选育研究

为筛选出适宜云南栽培的早实薄壳山核桃优良品种,以35个引种品种为材料,按照优良品种的选育程序和标准,进行初选、复选、决选、区域性试验和生产性试验。结果表明:经过系列良种选育试验后筛选鉴定出优良性状突出并稳定的品种‘巴顿’。‘巴顿’平均单果重4.8 g,壳薄,出仁率56.86%,仁含油率73.2%,油酸含量69.94%,亚油酸含量20.38%,适宜在云南省海拔1600~1800 m的中、北亚热带气候区域栽培。本研究结果丰富了云南薄壳山核桃发展中可供选择的良种,为我国薄壳山核桃产业发展的技术研究提供一定的理论依据。     

湘南地区优良千年桐雌株初步选择与评价

【目的】建立千年桐优株选择综合评价体系,进行千年桐优株的准确评价,为千年桐育种奠定理论基础。【方法】以湘南地区实生繁殖的进入盛果期的5 000 hm2千年桐为选优林分,根据单株结果数、单株产果量、树体大小、树形、果实聚集度等表型指标初步确定565株千年桐,通过复选确定40株备选优树,再从40株备选优树中筛选出优株。根据对单株结果量、单株产果量、冠高比、冠形指数、鲜果单果质量、鲜果出籽率、干籽出仁率、种仁含油率、病虫害程度、果熟一致性、果实聚集度11个性状指标,进行了聚类分析和综合评价,建立了千年桐优树综合评价体系。【结果】利用综合评价法,从40株备选优树选出了19株优树,然后对19株优树进行聚类分析,结果为三类,其中Ⅰ类4株、Ⅱ类5株、Ⅲ类10株;Ⅰ类优树的单株结果量、单株产果量的均值分别为1 181个、29.68 kg,是Ⅱ类优树均值的1.63、1.62倍,是Ⅲ类优树的1.65、1.71倍,是40株备选优树的1.87、1.85倍。Ⅰ类优树的鲜果单果质量、鲜果出籽率、干籽出仁率、种仁含油率的均值分别为41.63 g、51.20%、59.97%、59.75%,是Ⅱ类优树均值的1.14、1.03、1.01、1.11倍,是Ⅲ类优树均值的1.16、1.35、1.12、1.17倍,是40株备选优树均值的1.14、1.23、1.15、1.17倍。Ⅰ类优树4株可作为嫁接繁殖的采穗母树,可进一步作为目标优树。【结论】基于综合评价法筛选出的优树为千年桐优良无性系选育打下了基础。     

高州油茶果实性状变异分析

为选育适应广东省种植的高州油茶优良品种,对高州油茶实生后代果实的19个性状的变异规律进行研究。结果表明:高州油茶果实的各个性状在单株间、单果间、样地间均有不同程度的差异。在样地内单株间果实各性状的变异均达到了极显著水平;在样地间有15个果实性状的变异达到显著水平或极显著水平;综合单果间、样地内单株间及总体株间的变异规律,各果实性状根据其变异程度由高到低排列基本遵循如下规律:烘干种仁质量、晒干种仁质量,烘干籽质量、晒干籽质量、鲜籽质量,鲜果含油率、鲜果质量、单果籽粒数、果皮厚度,鲜果出籽率、烘干果出籽率、晒干果出籽率,晒干籽出仁率、烘干籽出仁率,种仁含油率、纵径、横径、果径均值,果形指数。     

施用钾肥对油茶果实性状的影响

为了明确钾肥对油茶(Camellia oleifera Abel.)果实性状的影响,本文以长林27号为材料开展试验。结果表明,钾肥用量对油茶果茎和单果质量有提高但是影响不显著。钾肥有利于油茶出籽率和出仁率的提高,180g/株钾肥处理下出籽率和出仁率均达到了最高,分别比对照提高了16.5%、15.2%。钾肥处理对种仁含油率影响不显著,但是能够显著提高鲜果的含油率。180g/株钾肥处理下,鲜果含油率达到最高。综合考虑钾肥对油茶果实性状等指标的影响,最适合油茶果实生长的钾肥用量为180g/株。     

薄壳山核桃品种果质性状变异及选择改良研究

对南京地区引种的21个薄壳山核桃品种果实单果重、出仁率、出油率,果型指数性状进行测定分析.结果表明,各性状均有显著的遗传变异,具有明显的改良潜力.相关分析未发现性状间有相互制约的关系.通过综合性状改良,由综合坐标评定法选出Mahan,Wictita,Sioux,Pawnee,Elliott,Shawnee等6个优良新品...     

黑河地区优良榛子选育研究

从黑河地区野生榛子和俄罗斯大果榛子实生苗中筛选出生长健壮、果实饱满、无病虫害的18株优树,经过多年对其生物学特性、果实性状等相关数据调查,结果表明:编号为1207的榛树优株综合性状最好,出仁率最高,为41.2%,适宜在本地繁育及栽培推广。     

长白山区核桃楸果实性状优株选择、保存研究

以长白山区210株核桃楸果实性状为材料,对其果实性状变异进行分析,编制了选优标准,并在进一步调查基础上筛选出优良个体。结果表明:核桃楸单果重、果仁和出仁率三个果实性状在单株间达到差异极显著水平(P0.01);核桃楸果实性状选优标准为单果重11.7 g,果仁重1.81 g,出仁率16.16%;筛选出59个优株,并营建了多点子代林,为其遗传改良奠定了基础。     

豫南引种18个薄壳山核桃无性系黑斑病抗性调查

为给豫南地区筛选适合的、对黑斑病抗性较强的薄壳山核桃主栽品种和配置授粉品种提供参考，采用田间调查方法和感病率、病情指数指标，对豫南引进的18个薄壳山核桃无性系果实的黑斑病发病情况进行调查分析。结果表明：18个薄壳山核桃无性系对黑斑病的抗性存在差异，其中6号、11号、13号、20号、21号、25号、35号、64号、132号、“波尼”为高抗病无性系，28号、C12号、C29号为中抗病无性系，5号、104号、C10号为低感病无性系，29号为中感病无性系，1号为高感病无性系；相关性分析表明，薄壳山核桃黑斑病的发生与无性系的树体性状、果实性状和无性系之间有一定的相关性，发病率和病情指数与冠幅呈显著负相关、与地径、树高呈负相关；与果实长度、单核质量呈正相关，与果实宽度、单株核产量呈一定负相关；与不同无性系之间有相关性。从18个无性系的抗病性、核果质量和产量性状差异综合评判，13号、64号、“波尼”、25号、132号等5个无性系可以作为豫南地区抗黑斑病较强的薄壳山核桃无性系推广。     

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.     

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.     

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.     

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.     

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。