薄姜木扦插育苗试验研究

针对薄姜木播种育苗存在种子资源少、来源不稳定、发芽率低等问题,对薄姜木开展扦插试验,探讨扦插穗条、基质配置、激素处理3个关键因素对薄姜木扦插生根的影响。结果表明,扦插基质以红心土+火烧土(3∶1)或红心土+河沙(3∶1)或红心土+腐殖质土(3∶1)为佳,插穗以半木质化、粗度为0.3~0.5 cm的枝条最为理想,生长激素以350~450×10~(-6)ABT 1号生根粉浸蘸20 s的处理效果为最好,生根率可达60%以上。     

引种植物蓝鲸花扦插试验研究

以蓝鲸花作为研究对象,采用黄沙、泥炭、黄心土分别组合,配比成不同培养基质,进行了蓝鲸花扦插繁殖试验。结果表明:最适蓝鲸花扦插繁殖的基质为(黄沙∶泥炭∶黄心土=1∶1∶2),生根率为80%,加入生根粉的纯沙生根率为93%,说明生根粉可大大提高蓝鲸花的扦插生根率。     

不同处理对白果蒲桃扦插成活率的影响

通过不同轻基质、不同遮光度和不同生根剂对白果蒲桃扦插成活的研究,结果表明:不同轻基质、不同遮光度和不同生根剂对白果蒲桃扦插成活率均存在极显著性差异。不同处理中,轻基质A(4泥碳土:3珍珠岩:3红心土)的白果蒲桃扦插成活率最高,为68.31%;3针遮光网的白果蒲桃扦插成活率最高,为78.67%;生根粉ABT浓度500 mg/kg处理白果蒲桃扦插成活率最高,为89.92%。生产上,白果蒲桃扦插繁殖推荐如下处理方法:穗条生根粉ABT浓度500 mg/kg处理+轻基质A(4泥碳土:3珍珠岩:3红心土)+3针遮光网。     

蒜香藤的扦插育苗试验

对蒜香藤进行GGR6号不同浓度(300、500、700、1 000mg/L)处理及不同基质(纯黄心土、50%黄心土+50%细沙、细沙)的扦插试验,结果显示以细沙作为扦插基质,用浓度为300mg/L的GGR6号生根粉速蘸后扦插,生根率可达90%。     

巨尾桉组培苗嫩梢扦插育苗技术探讨

采用巨尾桉组培生根移植苗嫩梢进行扦插育苗试验,结果表明巨尾桉嫩梢扦插育苗可全年进行,以10月至翌年4月扦插效果最好。7~9月高温天气育苗,应采用黑纱网大棚下覆盖黑纱网,以提高生根率。育苗基质宜采用红心土+砂包心土,用ABT生根粉1号1 000×10-6或IBA 1000×10-6处理插穗,均可以取得较好效果,生根率可达95%以上。     

黄花倒水莲扦插育苗技术试验初报

以吲哚丁酸IBA和ABT生根粉两种溶液的不同浓度处理及不同土壤基质处理分别对黄花倒水莲(Polygala fallax Hemsl.)扦插生根的影响进行试验研究。结果表明：吲哚丁酸IBA和ABT生根粉两种溶液的不同浓度处理对黄花倒水莲扦插根数、根长、稍长和生根率的影响均达到极显著水平,最佳浓度均为0.1g/L,生根率分别达到95%与90.4%,均极显著高于对照组;田园土+细河沙与黄心土+细河沙两种不同土壤基质处理对黄花倒水莲根数、根长、稍长及生根率的影响均达到极显著水平,效果最好的是黄心土+细河沙处理组,生根率达到91.6%,田园土+细河沙处理组效果次之,生根率为79.4%,均极显著高于对照组。     

巴戟天扦插及林下栽培试验

选取巴戟天当年生半木质化藤蔓和2年生木质化藤蔓作插穗;插穗经50、100、150 mg·L^-1的NAA、IBA、ABT生根粉浸泡4 h后,扦插于黄心土、1份黄心土+1份河沙(等体积配比,下同)、1份黄心土+1份泥炭土+1份河沙的基质中,扦插60 d后统计生根率。以1年生扦插苗进行林下栽培试验,并连续4年调查其生长量。结果表明：以黄心土、1份黄心土+1份河沙、1份黄心土+1份泥炭土+1份河沙为基质扦插巴戟天,其扦插生根率分别为65.51%、72.62%、74.35%。以1份黄心土+1份河沙、1份黄心土+1份泥炭土+1份河沙为基质,其扦插生根率均显著高于(P<0.05)以黄心土为基质的。以不同浓度的3种植物生长调节剂处理的扦穗,其生根率比对照(清水)的均有显著提高(P<0.05)。3种植物生长调节剂中,以ABT处理的插穗生根效果最好;以IBA处理的插穗生根效果次之,但优于以NAA处理的。插穗的木质化程度对巴戟天扦插生根率有极显著影响(P<0.01),木质化插穗的扦插生根率极显著高于半木质化插穗的。以50 mg·L^-1的ABT生根...     

红千层扦插育苗试验

应用正交试验方法,探讨了红千层不同扦插季节、不同基质、生根剂不同浓度和浸泡时间对扦插成活率的影响。结果表明:在秋季选用混合基质(黄心土∶粗河沙∶草木灰=1∶1∶1),采用ABT1号生根粉200 mg·kg-1浸泡2 h,扦插生根率最高。     

山茶花品种六角红在不同配比基质上的扦插试验

对山茶花品种六角红在不同配比基质上进行扦插试验,发现插穗在不同配比基质上的成活率、生根数和根长均存在极显著差异。方差分析结果表明:1)插穗在2/3黄心土+1/3腐熟松针土配比基质上的成活率最高,达92%;生根数最多,为7.20;根长最长,达10.13 cm;2/3黄心土+1/3腐熟松最适宜用于山茶花扦插。2)1/3黄心土+1/3河沙+1/3腐熟松针土也可以作为扦插基质,插穗的成活率达到84.33%。3)插穗在1/2黄心土+1/2河沙上的成活率也达80%,但生根数较少,根系不长。4)插穗在1/2黄心土+1/2草木灰和1/3黄心土+1/3草木灰+1/3河沙这2种配比基质上成活率都很低,并且生根数少,根系生长慢,不适合用作扦插基质。       

印度橡胶榕嫩枝扦插育苗试验

用不同基质(腐殖质土、河沙、黄心土)、ABT2号生根粉的不同浓度(100mg/L、300mg/L、500mg/L)以及不同浸泡时间(30min、60min、90min)对印度橡胶榕做扦插试验，结果表明ABT2号生根粉药液浸泡能明显促进印度橡胶榕生根、生长。以300mg/L的ABT2号生根粉浸泡60min、腐殖质土为基质的处理最佳，平均生根率可高达86％。     

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.