青榨槭外植体消毒方法初步研究

以青榨槭带芽茎段为外植体,研究了取材时间、消毒剂种类以及处理时间对外植体灭菌效果的影响。结果表明,0.1%、0.2%升汞处理5 min或7 min的污染率显著低于1%次氯酸钠处理20 min或30 min;75%酒精浸60 s后,用0.1%的升汞消毒7 min和0.2%的升汞消毒5 min或7 min的处理间没有显著差异,其中75%酒精浸60 s后用0.1%的升汞消毒7 min的消毒效果最好,外植体污染率和存活率分别为1.9%和90.4%。4月中旬至7月中旬取材的外植体污染率均低于5%,而存活率均达90%以上,为青榨槭茎段外植体取材的最佳时期。     

麻栎组织培养外植体选择与灭菌方法

麻栎组织培养外植体选择与灭菌方法试验表明：以麻栎播种苗幼苗茎段和大树嫩枝作为外植体进行组培效果较好;播种苗幼苗茎段的最佳灭菌方法是：70%酒精30 s→无菌水洗3次→0.1%升汞2 min→无菌水洗3次;大树嫩枝的最佳灭菌方法是：70%酒精30 s→无菌水洗3次→0.1%升汞5 min→无菌水洗3次;幼苗茎段外植体和大树嫩枝外植体的最佳取材时间是4月,接种后的外植体污染率和死亡率低于其他月份,而芽的萌发率高于其他月份。     

桤叶唐棣外植体灭菌试验研究

为确定桤叶唐棣组织培养的外植体最佳灭菌方案,以桤叶唐棣当年生、带腋芽茎段为外植体,采用0.1%HgCl、5%NaCl对外植体进行不同时长消毒处理试验,结果表明:0.1%HgCl灭菌在12 min内,5%NaClO灭菌在30 min内,都是随着消毒时间的增加污染率降低、褐化率升高;0.1%HgCl灭菌≤10 min,5%NaClO灭菌≤25 min,成活率随消毒时间延长而升高,之后都又下降;0.1%HgCl灭菌10 min是最佳灭菌方法,成活率达38%。     

蓝莓外植体不同取材时间灭菌方法研究

选用兔眼蓝莓"灿烂"当年生半木质化带腋芽茎段做外植体,从3月下旬至6月下旬共7次取材,根据外植体木质化程度的不同,选取不同的消毒试剂和消毒时间,为筛选出不同取材时间最适合的灭菌方法进行了实验,结果表明:"灿烂"最佳的取样时期是4月份,最佳灭菌方法是将茎段分为嫩部及半木质化部两部分,嫩部用0.1%升汞灭菌6～7 min最佳,其污染率为4.4%～6.7%,褐化率为6.7%～11.1%,萌芽率达到84.5%～86.7%;半木质化部用0.1%升汞灭菌10～11 min最佳,其污染率为4.4%～13.3%,褐化率为2.2%～6.7%,萌芽率达到84.5%～88.9%。     

红叶榆叶梅组织培养初步研究

本试验以红叶榆叶梅(Amygdalus triloba(Lindl.)Ricker)带芽茎段为外植体,分别采用75%酒精(15~60s),0.1%升汞(6~12min)进行消毒。对不同取材部位(顶芽以下1~9茎节),不同激素(6-BA,NAA,ZT)和浓度的培养基进行研究。结果表明:在0.1%升汞处理时间8min时,最适宜的75%酒精灭菌时间为45s;而在0.1%升汞处理10min时,污染率最低且存活率最高。茎段选择稍硬枝茎段(顶芽以下4~6茎节),具有较高的存活率和萌发率。6-BA1.0mg/L+NAA 0.15mg/L+ZT0.15mg/L的培养基中,萌发率达到35.83%,萌芽苗生长状况较优。建议使用稍硬枝茎段(顶芽以下4~6茎节)作为红叶榆叶梅组织培养的外植体,使用75%酒精45s+0.1%升汞10min作为红叶榆叶梅茎段的灭菌处理方式,选择6-BA1.0mg/L+NAA0.15mg/L+ZT0.15mg/L作为诱导培养的激素浓度。     

‘Y-1’苹果矮化砧木初代培养

为建立苹果矮化砧木‘Y-1’初代培养体系,以大田‘Y-1’当年生幼嫩枝条茎段为外植体,对消毒剂的选择、外植体采集时间和初代培养中植物生长调节剂的应用进行了研究。结果表明:先用75%酒精处理30s,再用0.1%HgCl_2处理5 min是苹果矮化砧木‘Y-1’茎段灭菌的最佳方法,其外植体成活率高达66.46%;外植体最佳取材时间是5月初,接种后外植体的污染率明显低于它取材时间,而芽的成活率、萌发率则显著提高。MS+1.0 mg/L 6-BA+0.5 mg/L IBA是苹果矮化砧木‘Y-1’茎段腋芽萌发的最适宜培养基,萌发率高达79.15%;     

红锥优树外植体褐化抑制方法研究

植物组织培养技术是红锥(Castanopsis hystrix)优树无性化推广的重要途径,但外植体诱导培养过程中的褐化现象严重影响了其高效组织培养再生体系的建立。文章通过对红锥外植体取材季节、木质化程度、灭菌处理、光照等技术要素以及防褐化剂种类等进行生长对比试验,结果表明:外植体取材季节对褐化率无显著影响;外植体木质化程度对褐化率有极显著影响(P0.01);采用75%酒精进行外植体灭菌与未采用酒精的外植体相比,褐化率增加15.0个百分点,褐化程度加剧,其中采用2 min的新吉尔灭(1%)+2.5 min升汞(0.1%)两者结合进行灭菌效果较好;低温预处理外植体及暗培养均未达到抑制褐化的效果;添加防褐化剂PVP 80 mg·L~(-1)、V_C1.0 g·L~(-1)均能有效抑制褐化,褐化率分别为33.3%、12.2%,且腋芽长势好。     

悬铃木组培快繁技术研究

选用悬铃木带腋芽(裸露)的半木质化茎段为外植体,进行组织培养技术研究。结果表明:6月中旬接种外植体较好,适宜消毒处理为75%酒精表面消毒10s后用0.1%HgCl2灭菌3、6min;最佳增殖培养基为MS+6-BA0.1+IBA0.5;20～25d增殖系数为5.92;试管苗根诱导以1/2MS+IBA0.5为宜,生根率为80%。     

云南樱桃Cerasus yunnanensis优株组培无菌材料获得方法的研究

以云南樱桃优良单株的嫩枝为外植体,研究了不同的预处理方式、取材时间、取材部位和消毒方法对其无菌材料获得的影响。结果表明:外植体宜随采随处理,且枝条带叶冷藏时间不宜超过5 d;外植体最佳采集时间为春季4月,最佳的取材部位为顶芽下第4～5个茎节;最佳表面消毒灭菌方法为1%新洁尔灭5 min+0.1%升汞溶液2～8 min。     

油茶不同外植体灭菌条件研究

以油茶种子、茎段为外植体,采用酒精、升汞、高锰酸钾3种灭菌剂,探讨不同处理对外植体污染和种子萌发的影响。结果表明,油茶茎段较好的灭菌方法:毛刷刷洗+75%酒精10~15 s+0.1%HgCl 10~15min,污染率最低为24.5%;新萌条较好的灭菌方法:75%酒精4~7 s+0.1%HgCl 5~6 min,污染率最低为14.3%;种子灭菌的条件:0.5%KMnO40~24 h+75%酒精3~15 min+0.1%HgCl 20~40 min(不剥壳去皮),75%酒精30 s+0.1%HgCl 8 min(剥壳去皮),这2种处理污染率均较低,种子发芽率相差不大。该结果为油茶再生体系的建立奠定基础。     

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.