云杉花粉生活力及贮藏方法试验研究

对内蒙古林科院树木园内引种的一些品种云杉从雄花生长期花粉量与花粉活力的关系以及花粉贮藏方法等方面进行了试验研究,结果表明:云杉属各品种花粉散粉从开始到结束需10 d左右,在散粉盛期花粉生活力最高,同时花粉量也最大,此时也是杂交制种的最佳时期;不同的云杉种对蔗糖培养基浓度要求不同,多数品种云杉以15%的蔗糖浓度培养基花粉管萌发较好,而欧洲云杉以12%的蔗糖浓度培养基效果最佳;贮藏方法对花粉的生活力有很大影响,在云杉花粉保存过程中温度是主要条件,冷冻好于冷藏,不宜常温保存。     

江南油杉花粉离体萌发的适宜条件与萌发特征

以江南油杉(Keteleeria fortunei var. cyclolepis)花粉为研究对象,采用液体培养法,通过单因素试验设计研究不同培养基组分、pH值和温度对花粉萌发的影响。结果表明,江南油杉花粉在无蔗糖、无H_3BO_3及无CaCl_2的培养基中均能萌发,但萌发率较低。添加蔗糖、H_3BO_3和CaCl_2均可显著促进花粉萌发和花粉管生长,但高浓度的蔗糖、H_3BO_3和CaCl_2均会抑制花粉萌发和花粉管生长。pH值和培养温度均对江南油杉花粉的萌发影响显著,培养基最适pH值为6.5,花粉萌发的最适温度为25℃,过高或过低均会抑制花粉萌发。综合萌发率和花粉管长度,江南油杉花粉萌发的最适培养基为250 g/L蔗糖+200 mg/L H_3BO_3+100 mg/L CaCl_2,pH值为6.5,置于25℃光照培养96 h,萌发率为42.4%。     

牛角瓜花粉离体萌发研究

为了探讨牛角瓜花粉离体萌发的最适条件及培养基成分,以2年生牛角瓜新鲜花粉为试材,研究了不同溶液对牛角瓜花粉块壁解离效果的影响情况;还采用离体培养法,研究了不同培养温度和培养时间、不同培养基组分对牛角瓜花粉萌发率和花粉管生长的影响情况。结果显示:以10%的Na OH溶液将牛角瓜花粉块处理10 min的解离效果最好;牛角瓜花粉离体萌发的最适温度为30℃,在此温度条件下培养6 h后其花粉萌发率基本稳定,培养12 h后其花粉管生长最好;蔗糖对牛角瓜花粉萌发率及花粉管长度的影响均较大,硼酸对花粉萌发率及花粉管长度的影响均较小;牛角瓜花粉萌发和花粉管生长的最适培养基为20%蔗糖+0.1%硼酸+5 mg/L氯化钙+15 mg/L 6-BA,在此培养基上并在30℃的温度条件下培养6 h,其花粉萌发率达到94.77%,花粉管长度为11.07 mm。     

小黑杨花粉离体萌发和细胞学分析

采用花粉离体培养法,研究不同的液体培养基组分、温度、pH值对小黑杨花粉萌发的影响。结果表明:在单因子试验中,蔗糖、H3BO3和CaCl2在一定的浓度范围内对小黑杨花粉萌发及花粉管生长起促进作用,但超过一定浓度时则起抑制作用,温度和pH值也是如此。在正交试验中,蔗糖、H3BO3、CaCl2、温度和pH值对小黑杨花粉萌发均有极显著的影响,小黑杨花粉萌发最适的培养基为150g·L-1蔗糖+20mg·L-1H3BO3+40mg·L-1CaCl2,在21℃和pH6.0条件下,花粉的萌发率可以达到46.23%,花粉管生长状态良好。细胞学观察结果表明:小黑杨成熟花粉为2-细胞型,随着培养时间的延长,花粉萌发率逐渐提高,花粉管不断伸长。     

培养条件对紫丁香花粉离体萌发的影响

以紫丁香盛花期的新鲜花粉为材料,采用单因素试验,研究了培养基、pH值、培养温度、培养时间对紫丁香花粉离体萌发和花粉管生长的影响。结果表明:花粉萌发和花粉管生长的最适培养基pH值为6.0,其花粉萌发率为32.45%,花粉管长度为0.350mm,最佳培养温度为25℃,最佳培养时间为1.5～2h。     

月月竹的花粉萌发力及贮藏力研究

对南京林业大学竹种园的开花竹种月月竹进行了花粉萌发力及贮藏力等方面的研究,结果表明:月月竹花粉在不同浓度的蔗糖硼酸培养基中培养萌发率不同,以20%的蔗糖浓度 0.001%硼酸培养基培养3h花粉萌发最好;一天之中以上午9时的萌发率最高;不同贮藏方法对花粉的萌发力有较大影响,月月竹花粉保存过程中不干燥好于干燥,-5℃保存萌发力相对较好,总之,月月竹花粉不耐贮藏,一般48 h内失去生活力。     

西南桦花粉离体萌发的适宜条件与萌发特征

应用各种浓度蔗糖、蔗糖 硼酸培养基于系列温度下开展西南桦花粉萌发对比试验,研究了蔗糖、硼酸浓度对西南桦花粉离体萌发的影响,筛选出适合西南桦花粉萌发培养基的适宜组分和适宜培养温度,并应用4个单株的花粉对其萌发特征进行了初步研究.结果表明:蔗糖基本培养基上添加硼酸能够显著促进西南桦花粉萌发;西南桦花粉离体萌发的合适培养基为15%蔗糖 200 mg·kg-1硼酸,适宜培养温度为30℃;在此条件下培养3 h后花粉萌发率基本稳定,培养7 h后花粉管长度也趋于稳定.     

二乔木兰花粉萌发特性及其保存方法的研究

通过使用不同的培养基,采用液体培养法研究了蔗糖、硼酸和钙离子对二乔木兰花粉萌发的影响。将所用花粉分为两组,组1于8:00采集,组2于16:00采集,结果表明:一定浓度的蔗糖、硼酸和钙离子对花粉的萌发有较大的促进作用,但超过一定浓度时则起抑制作用,二乔木兰花粉萌发的最适培养基为30 g·L~-1蔗糖 100mg·L~-1硼酸 500 mg·L~-1Ca~2 ,在该培养基内,组1花粉的萌发率为46．21%±1．86%,花粉管长度为1156．25Um;组2花粉的萌发率仅为14．22%±1．86%,花粉管长度为1022um。此外,在其离体萌发过程中,二乔木兰花粉存在花粉管双萌发的现象。用不同的花粉保存方法保存二乔木兰花粉后,发现干燥处理后于-18℃下保存的花粉活性最高,30d后仍有6．92%±0．75%的萌发率,而于常温25℃下保存的花粉10d后就基本失活,说明低温干燥保存是保存二乔木兰花粉活性的有效途径。     

日本海棠花粉最佳离体萌发培养基筛选及萌发过程研究

为给观赏海棠杂交育种提供参考依据,采用单因素和正交试验方法,对日本海棠花粉离体萌发培养基进行了筛选,对其花粉活力展开了研究,探讨并观察了观赏海棠花粉离体萌发条件和花粉萌发过程。单因素试验结果表明:当蔗糖、硼酸、硝酸钙的处理浓度分别为10%、0.02%(其萌发率与0.04%浓度处理的无显著差异)、0.02%(其萌发率与0.01%浓度处理的无显著差异)时,日本海棠的平均花粉萌发率及花粉管长度最高值分别达到55.2%与853.11μm、54.4%与595.07μm、37.6%与713.74μm,显著高于同一试验因素下的其余各处理。正交试验结果表明:10%蔗糖+0.02%硼酸+0.04%硝酸钙的组合培养基为日本海棠离体萌发的最适培养基,以此培养基培养的日本海棠其平均花粉萌发率与花粉管长度分别达到70.1%和777.02μm,显著高于除以(10%蔗糖+0.01%硼酸+0.03%硝酸钙)组合培养基处理以外的其他组合培养基处理。在日本海棠花粉离体萌发过程中,培养第1个小时内花粉未萌发,培养2~4 h的花粉萌发率和花粉管生长速率均达到最高值,分别达23.4%/h及259.01μm/h,培养8 h后,其萌发速率趋于平稳,培养12 h后,其花粉管生长速度趋于平稳。研究结果表明,日本海棠离体萌发的最佳培养基为(10%蔗糖+0.02%硼酸+0.04%硝酸钙)组合培养基,以此组合培养基培养2~4 h其花粉萌发率与花粉管生长速率均最高。     

大叶相思花粉离体萌发适宜条件及活力检测方法

【目的】对大叶相思花粉离体萌发适宜条件以及花粉活力不同检测方法进行研究,为今后进一步开展人工控制授粉、选育优良的马大杂交新品种提供基础。【方法】采回花穗的次日10:00之后,使用毛笔刷法收集大叶相思花粉;通过不同培养温度、不同蔗糖浓度和不同硼酸浓度处理后进行花粉离体萌发,筛选适宜大叶相思花粉离体萌发的条件;采用过氧化物酶法、I_2-KI法以及花粉管离体萌发法对大叶相思花粉进行活力测定,探讨大叶相思花粉有效的活力测定方法。【结果】大叶相思花粉在28℃下培养,其花粉平均萌发率为71.99%,花粉管平均长度为5.3 D(1 D=1倍的花粉粒长度),花粉管平均条数为6.2条,显著高于其他培养温度的处理。当培养基中含有200 g·L~(-1)蔗糖时,大叶相思花粉萌发率为84.96%,其花粉管平均长度为5.8 D,花粉管平均条数为6.2条,显著高于含有其他蔗糖浓度的处理。在含有300 mg·L~(-1)硼酸的培养基中培养大叶相思花粉,其平均萌发率为75.32%,花粉管平均长度可达4.8 D,平均花粉管条数为5.4条,显著高于在其他硼酸浓度下的处理。大叶相思花粉在培养温度30℃、200 g·L~(-1)蔗糖、300 mg·L~(-1)硼酸的培养基中萌发率为98.26%,花粉管长度均可达到10倍复合花粉粒的长度,最多可萌发出10条花粉管,显著高于其他处理。培养3 h的大叶相思花粉,萌发率为65.74%;培养6 h时,其萌发率为90.55%;培养24 h后,其萌发率趋于稳定,达到最高值98.26%。过氧化物酶法检测的花粉活力为99.67%,I_2-KI法检测的花粉活力为99.00%,花粉管离体培养法检测的花粉活力为98.15%,3种方法检测的花粉活力无显著差异。【结论】大叶相思花粉在不同的离体培养处理下,其萌发情况均不相同且差异显著,最佳离体萌发条件为200 g·L~(-1)蔗糖+300 mg·L~(-1)硼酸,培养温度为30℃,萌发率为98.26%。过氧化物酶法、I_2-KI法以及花粉管离体培养法检测的花粉活力无显著差异。研究结果可为今后开展大叶相思的花粉收集、贮藏及活力测定等研究,以及开展人工控制授粉选育优良马大杂种相思新品种等研究提供重要依据。     

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.     

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。