油茶人工高效杂交技术

为提高油茶杂交效率,大量创制新种质,以蕾期授粉为基础,通过对原有杂交技术的改进提出一套油茶人工高效杂交技术.基本步骤为:选处于松蕾阶段的母本花蕾,剪除全部花瓣和雄蕊,然后用父本的雄蕊直接对去雄后母本进行授粉,最后套袋标记.通过试验表明,该方法适用于种内不同品种间杂交组合的规模化配制,每杂交1朵花可获得杂交种子1.29～5.13粒;同时,还可以克服种间杂交的不亲和性,本试验获得了13粒宜春白皮中子与茶梨的杂交种子.     

林木杂交育种研究的发展

1林木杂交育种研究的回顾英国学者A．Henry是在林木改良中率先提倡杂交的开拓者，他1921年开展了杨树、栎类和白腊树等的种间杂交，并第一个育成杨树人工杂交品种。美国在1925年以后开展了针叶树种的种间杂交。30年代前苏联也开展了杨、栎、落叶松、松类的种间杂交有种。20年代丹麦和英国发现日本落叶松和欧洲落叶松天然杂种的优势，出现了建立落叶松杂交种子园的设想。针对当时多数树种或者种间杂交困难、或者得到的少量优良种间杂种没法投入生产的问题，有人曾提出用F1植株相互交配生产种子，或把F1植株无性繁殖应用于生产的思想。这一…     

不同杂交方法对63×69杨杂种种实发育的苗木生长的影响

意大利杨树六个无性系Ⅰ—72/58、Ⅰ—69/55、Ⅰ—63/51、Ⅰ—214、Ⅰ—45/51和加龙引种我省业已开花.1980年春我所进行人工有性杂交,获得杂种,播种又得到一批杂交苗木.现将不同杂交方法对69×63杨杂种种实发育和苗木生长影响简报如下:一、杂交方法以63杨为母本,69杨为父本,采用以下三种杂交方法:1.温室切枝杂交 1980年3月4日从大树上采集花枝,在温室内进行水培.4月2—4日连续3次进行人工授粉.5月11—26日朔果成熟.     

嫁接在杨树远缘杂交育种上的应用研究

为了在吉林省西部地区选育出耐盐碱性强,又能无性扦插育苗进行快速繁殖的杨树新品种,选用了白杨派的银新杨作母本与青杨派的小叶杨为父本进行远缘杂交育种,但两派之间杂交不亲和。为解决这一问题,进行了先嫁接再杂交的育种方法。试验表明,此方法在一定程度上提高了远缘杂交的结实率,而且杂种苗具有明显的父母本双亲的性状,为杨树新品种培育开辟了新的途径。     

云南松不同组合杂交种苗期生长分析

为详细了解云南松杂交育苗及苗期生长情况,对云南松51个杂交组合和19个半同胞苗木的苗高和地径生长性状进行了测定与分析,结果表明,38个云南松种内杂交种幼苗苗高与地径生长差异大部分达到极显著水平,有15个种内杂交种的苗高生长值超过了总体平均值,有18个种内杂交种的地径生长值超过了总体平均值;云南松种内杂交相同母本的不同杂交组合类别之间的苗高和地径生长差异大部分达到极显著水平,有11个类别杂交种的苗高和地径生长均显著高于半同胞苗木的生长性状;13个云南松与思茅松种间杂交种幼苗苗高与地径生长差异均达到极显著水平,有7个种间杂交种的苗高和地径生长均超过了总体平均值;云南松与思茅松种间杂交种的苗高总体均值约是云南松种内杂交种苗高总体均值的1.4倍,二者的地径生长均值基本接近;云南松与思茅松种间杂交相同母本的不同杂交组合类别之间的苗高生长差异均达到极显著水平,地径生长差异不显著,有4个类别杂交种的苗高和地径生长均显著高于半同胞苗木的生长性状。     

杂交榛子斜干定植高密度带状压条技术

<正>杂交榛子是辽宁省经济林研究所以平榛做母本、欧洲榛做父本通过远缘杂交培育而成的种间杂交种,也是目前我国唯一在生产上大量推广应用的榛子栽培种。杂交榛子由于栽培管理容易,经济效益较高而     

锥栗无性系间杂交种实性状变异分析

为选育出早实、优质、丰产的锥栗品种,试验设4个杂交组合,进行无性系间杂交,对杂交种实性状进行测量分析.结果表明,杂交种实盛果期相对延迟,25×15的杂交种实栗果显著大于其它组合;经聚类分析,除25×15与母本25号最短距离较短外,其它杂交种实与亲本最短距离均较远;不同授粉类型对杂交种实性状有极显著影响,其中组间差异显著大于组内,说明杂交种实稳定性较强,这为杂交选育提供有利条件.     

沙棘的杂种优势及杂交种子园营建

通过多种杂交试验,确知"蒙古沙棘×中国沙棘"有明显杂种优势。在这一杂交类型范围内,亲本材料不同,杂种后代的性状表现有别。亲本的品质好,性状整齐一致,则后代分化幅度小,经济价值高。在所作过的杂交试验中,以"乌兰沙林"作母本,以中国沙棘冀北种原优树雄株作父本,表现最好。利用这一亲本组合,可直接建立用于生产杂交种子的杂交种子园。杂交种的生态适应幅度优于双亲,而且主要经济性状,较中国沙棘有大幅度提高。还可用杂交种再与大果无刺沙棘雄株建立复合杂交种子园,进一步提高杂交种的遗传品质。     

杨山牡丹和牡丹种间杂交后代的DNA分子证据

以杨山牡丹作母本，分别以牡丹品种‘赵粉’(Paeonia suffruticosa Andr.cv.‘Zhao Fen’)和‘紫二乔’(P.suffruticosa cv.‘Zi Er Qiao’)作父本，进行人工杂交，获得了杂交后代。利用DNAISSR标记技术构建的亲子代DNA指纹图谱显示，在杂交后代中检测到了分别来自双亲的特征带。建立起来的专用于牡丹研究的ISSR标记技术方法可以用于牡丹杂交种的苗期快速鉴定。     

影响杨树切枝杂交产种量和质量因素

对杨树切枝杂交中母本枝条营养状况与杂交结籽率和种子品质进行典型相关分析结果表明,母本枝条保留花芽数和枝条粗是影响杂种产量的主要因素;种子品质与枝条营养状况相关不密切。     

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.     

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。     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.     

Key Habitats in the Norwegian Production Forest: A Case Study

This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes.