适合陕北枣区的良种选择研究

本文对陕北枣区现有的75个枣品种，选用13个性状指标。进行综合判别，初选出16个优良品种，其中制于品种6个、鲜食品种5个，兼用品种5个，结合陕北的气候特征和生产现状，主要研究了陕北良种的物候期、结实性状和果实品质。最终选出适合陕北栽培的优良（1）制干品种为中阳木枣、方木枣、猗头枣、赞皇大枣和骏枣；（2）鲜食品种为梨枣，牛奶脆枣、狗头枣；（3）加工蜜枣用的品种为扁圆团枣，赞皇大枣和方木枣。     

武威枣树新品种引进筛选试验

通过在武威地区引进河南灰枣、骏枣、七月鲜、大王枣、早脆王、龙枣、胎里红、黑珍珠、蜜蜂罐、小口枣等11个品种,进行高接换优试验,结果表明:嫁接成活率均达到了80%以上。通过对其物候期、适应性和抗逆性、果实性状及生长结果表现情况进行对比分析和比较筛选,结果表明:在武威表现优良的品种有4个,即:河南灰枣、骏枣、大王枣、七月鲜。其中:七月鲜为早熟品种,骏枣和大王枣为中熟品种,河南灰枣为晚熟品种。     

枣树品比试验研究

在湖南省茶陵县,对来自7个省(区)枣产区的22个地方枣树良种进行品比试验,结果表明,尖枣、灌阳长枣、相枣、团枣和圆枣单株产量高,幼树期枣头连续结果能力强,果吊比高,果大,树体生长好,是适宜南方地区推广的早实丰产优良品种,其他品种产量普遍较低,多数树体生长不良,有些北方品种还出现明显的矮化趋势,应因地制宜控制发展或不发展。     

3个枣品种抗旱性综合评价及抗旱指标的筛选

在4种不同的水分胁迫处理条件下,对大平顶枣、金铃圆枣、三星大枣的12个抗旱指标进行了测定,并运用隶属函数值法对3个枣品种抗旱性进行了综合评价。结果表明,3个枣品种的抗旱性大小顺序为:三星大枣金铃圆枣大平顶枣。运用灰色关联分析法,对3个枣品种的抗旱性与12个抗旱指标相关性进行的关联度分析结果表明:叶片相对含水量、胞间CO2浓度可作为重要的抗旱评价指标。     

30个制干枣品种在新疆库尔勒地区的引种

为升级换代适应新疆发展的制干枣品种,以引进新疆的30个枣品种为研究对象,初步筛选出适宜新疆枣产业发展的制干枣品种。对各品种的主要物候特性、树体发育进行定株观测,采用因子分析法对果实品质进行综合评价与排序。结果表明:完熟期最早的品种为新乐大枣,最晚的是万荣楼疙瘩枣;树体发育良好、树势较强的品种为陕西面枣、鲁枣5号和新乐大枣;果实品质综合评价较优的品种为新郑大枣、轱辘枣、金丝1号、驴粪蛋、鲁枣12号。各品种的物候表现与树体发育情况均说明所引品种能够适应新疆气候和立地条件。综合分析各品种的树体生长状况、单株产量以及果实品质,认为新郑大枣、轱辘枣、驴粪蛋、鲁枣5号和鲁枣4号能够较好地适应新疆气候和立地条件,并且具有较优的丰产性和果实品质,可以进一步作为中试制干品种进行栽培推广。     

抗枣疯病枣树品种及品系的选择

测定了6个枣树品种的1个酸枣品种对枣疯病的抗性及河北太行山区主栽品种婆枣的45个单株对枣疯病的抗性。利用连续两年嫁接病皮的方法测定了采自山西果树研究所中国枣树基因库的5个枣树品种砘子枣、马牙枣、长红枣、哈蟆枣、壶瓶枣及河北唐县的婆枣和酸枣两个品种的抗病性。通过四年的跟踪观察，以上7种枣树的发病率分别是100％、78．5％、66．67％、0％、0％、100％、80％。结果表明，壶瓶枣和蛤蟆枣对枣疯病具有高度抗性。利用连续3年2次嫁接病皮和1次嫁接病枝的方法测定了采自河北太行山区七县的婆枣45个单株112株根蘖苗的抗病性，经4年观测，结果有3个单株6根蘖苗经过三次测定苗木未疯，表现出了很强的抗性。     

制干及干鲜兼用枣品种在甘肃沿黄灌区引种试验评价

以引进成功的12个制干及干鲜兼用枣树品种4年生枣树及其枣果为试材,测定其树高、冠径、单株产量、单果质量、果核质量、可食率、含糖量、含酸量、糖酸比、Vc含量、微量元素铁含量、枣果口感、抗裂果性和抗病虫性等14个指标;采用因子分析法对其进行数据处理分析、综合评价和优良度排序。结果表明:提取的前5个主因子的累计贡献率达到92.50%,前5个主因子可以作为评价引进枣品种适应性及枣果品质性状的综合指标。12个品种综合得分及优良度排序,从好到差依次是:骏枣、新郑灰枣、金昌一号、壶瓶枣、赞皇大枣、晋赞大枣、金谷大枣、灰枣、阜星大枣、新星枣、悠悠和新星无核。该结果与各品种在甘肃沿黄灌区引种栽培适应性及其枣果品质的感官评价结果基本一致,说明因子分析法在引种栽培适应性及其枣果品质的综合性状比较和优良品种选择中有较大的应用参考价值。在甘肃沿黄灌区栽培制干及干鲜兼用枣品种,推荐选择大果型的骏枣、壶瓶枣、金昌一号、金谷大枣和中果型的新郑灰枣。     

武威绿洲灌区红枣引种栽培试验

为了比较不同枣树品种的生长结果特性,采用完全区组试验设计,在武威平川灌区就陕西笨枣、耙齿枣、骏枣、临泽小枣、山东躺枣、民勤小枣进行了对比试验,连续7年测定了其每m2树冠投影产量、果吊比、二次枝枣股数、枣头二次枝数、单果质量和单株产量,以其平均值作为枣树品种生产特性的评价指标.结果表明:除骏枣外,其它4个品种的综合性状优...     

忻州市的枣树资源分布及品种布局

介绍了忻州市枣树主要乡土栽培品种－油枣,大枣，黑腰枣，定襄小枣，芽枣，故城小枣，绵枣和主要引种栽培品种－交城骏枣，太谷壶瓶枣，运城犁枣的分布特性等，并根据忻州市两个枣树基地的气候特征，提出了适合于各基地发展的枣树品种。     

不同枣品种花粉的形态特征和萌发特性

为调控枣花芽分化,为丰产栽培提供理论指导,以鸡蛋枣、以色列1号枣、以色列3号枣、引-10枣、中秋酥脆枣5个枣品种为试材,采用纤维素酶法、电镜扫描、琼脂培养法对其进行花粉量、花粉形态、花粉萌发特性的研究。结果表明:(1)5个枣品种单药花粉量为311~1 115,其中以色列3号枣的花粉量最少,中秋酥脆枣的花粉量最多;(2)5个枣品种的花粉形态为长椭圆形或细长椭圆形,具3条狭长萌发沟,极端不汇合,表面为网状雕纹;(3)不同品种花粉萌发对培养基中硼酸及蔗糖浓度具有选择性,以色列1号枣、引-10枣、鸡蛋枣的最适硼酸质量浓度为10.0 mg/L,以色列3号枣、中秋酥脆枣的最适硼酸质量浓度分别为30.0、50.0 mg/L。引-10枣、鸡蛋枣的最适蔗糖质量分数分别为20%、15%,以色列3号枣、中秋酥脆枣的最适蔗糖质量分数为10%。以色列1号枣在各种培养条件下,平均萌发率为2.04%,属于雄性高度不育品种。     

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。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

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.