黑孢块菌的苗木菌根化合成效果研究

黑孢块菌菌根化幼苗是该菌在树木上完成半人工模拟栽培的基础。采用黑孢块菌的液体纯菌种1－4mL对4个树种幼苗进行接种，90d后都能形成菌根，其感染率达94．4％－100％；菌根形态主要有4种类型，以珊瑚关居多，其次为棒状及二叉状，但不同树种上其各类型所占比例各不相同，黑孢块菌不同接种量的云南松幼苗，平均高比对照增加76．67％－131．74％，而生物量则增加1.62-2.17倍，以每株接种4mL菌液的效果为佳；不同pH值的基质试验结果表明，pH值为6.5-7.0时其菌根感染率高，生物量增加明显，苗木长势也较好。     

西澳粘滑菇在尾叶桉上的菌根合成*

利用经特殊培养的西澳粘滑菇菌种，人工接种在尾叶桉幼苗根部，３５ｄ后有６０％的幼苗根部都长出１～２个子实体，经鉴定，该子实体为原接种菌。菌根感染率检查结果表明，有８０％幼苗形成菌根。生长８个月的幼苗其平均树高比未接种苗增加５２．２％，地径增加２９．４％，地上及地下部分生物量（干重）分别比对照增加２６８％及２１４．３％。西澳粘滑菇不仅在华南地区桉树上可以完成菌根合成，而且对幼树生长的增产效果十分明显，是华南地区桉树的优良菌根菌。     

外生菌根对桉树青枯病的防治效应

应用８种外生菌根菌对青枯病进行测定的结果表明,８个菌株对青枯病菌均有不同程度的抑菌;对桉树菌根生苗木进行截根接种的试验结果表明,菌根化苗木可降低发病率４０－７２．７８％;菌根化苗在重病区造林,发病率比妆种降低２０－３８．９％;在新造林地上造林,发病率仅是８．３％,比未接种苗降低１１．８－２４．５％。因此,利用菌根技术,实行桉树苗木菌根化,是目前桉树青枯病的有效且可行的方法之一。     

尾叶桉菌根化苗木造林试验

尾叶桉幼苗接种菌粮菌后，成为带菌根的菌根化苗木。使用菌根化苗木造林结果表明，其增效明显。经测定，造林１１．５个月的幼树平均高达４．４８～４．８１ｍ，比对照区增加６．４％～１４．３％，胸径达３．９６～４．２０ｃｍ，比对照区增加６．１６％～１３．６７％，幼林蓄积达１７．９５ｍ３／ｈｍ２，比对照区增加３９．９％。     

松茸菌株对6种松树幼苗的感染及其菌根解剖学研究

利用我国滇产松茸9924菌株及日产松茸99606菌株，分别对云南松、华山松、马尾松、火炬松、湿地松及加勒比松6种松树幼苗实施人工菌根接种。研究结果表明，接种后90d的云南松和湿地松分别有75％和78．1％的幼苗受感染并形成菌根；接种后180d,6种松树幼苗分部都可形成菌根，菌根感染率分别达90．63％－100％，感染指数达50．00－84．68；菌根形态主要有棒状、二叉分枝状及多叉分枝状3种；随树种的不同，各类菌根形态所占比例也不同；不同树种根系上形成菌根的长度也有差异，以马尾松根系上的菌根最长，华山松的菌根最短；此外，各种组合之间在菌套厚度，哈蒂氏网结构上也略有差别。     

根瘤菌、菌根菌对厚荚相思苗期生长的影响

对厚荚相思苗期进行接种根瘤菌、菌根菌、根瘤菌＋菌根菌的比较试验,结果表明：接种菌根菌的促生效果显著。幼苗高生长、地上部分干重、地下部分干重、根瘤个数、根瘤重量平均数比对照分别提高了53．36％。73．30％,89．69％,224．01％和186．96％。接种各菌种对幼苗的促生效果排序为：菌根菌＋根瘤菌〉根瘤菌〉菌根菌〉对照。苗木根部菌根菌感染强度排序为：菌根菌〉菌根菌＋根瘤菌〉对照。     

菌根真菌对树苗根部病害的防治作用

采厚环乳牛肝、血红铆钉菇、彩色豆马勃３种外生菌根菌纯培养接种物,对日本落叶松、油松播种苗进行接种试验,测定其对苗木根部病害的生物防治作用。试验表明,３种外生菌根真菌对苗木猝倒病均有的抑制作用。接种不同菌根真菌的松苗猝倒病发病率双对照降低４．０％～５５．９％,苗高、地径、单株鲜重等生长指标提高２．８％～６２．９％,菌根侵染率达８２．０％～９６．０％。     

松树截根菌根化育苗和造林的研究*

根据苗木根系分泌物能促进菌根真菌萌发和生长的原理，结合我国林业育苗的特点，提出了松树幼苗截根与人工接种菌根真菌结合的育苗方式。结果表明，截根菌根化育苗在促进根系发育和菌根形成，加速苗木生长，提高苗木生物量、苗木质量和产苗量等方面都有显著优势，苗木的侧根数、侧根总长、苗木菌根化率、吸收根菌根化率、苗高、地径、鲜重、干重分别提高２０．０％～９６０．０％、５６．２％～３８９．５％、０．０％～４００．０％、５６．２％～１７９２．０％、２２．３％～１７９．３％、３１．２％～２５３．８％、３３．３％～９１８．２％和２１．８％～７４０．０％，苗木成活率和Ⅰ级苗分别提高９．０％～２２．１％和４９．３％～１５０．０％，Ⅱ、Ⅲ级苗和等外苗分别降低４０．６％～７７．３％、６１．６％～８８．５％和８２．５％～１００．０％。利用截根菌根化苗木造林，提高成活保存率５．５％～４６．０％，并促进幼树生长，树高、地径和材积指数分别增加１３．０％～５６．４％、２５．５％～６１．７％和８７．８％～４５０．０％。效益分析证明，截根菌根化育苗具有明显的经济效益和社会效益，仅苗期可定量计算的增收（节支）总额可达４４６６２元／ｈｍ２。     

棕榈藤的VA菌根接种研究*

利用菌根菌地表球囊霉对黄藤及单叶省藤等幼苗进行人工接种，一年后进行观测，其菌根感染率达４３．３％～８１．２５％；对苗木有促生效果，特别是配合适当施肥措施条件下，效果更明显。无论平均叶片数、叶片长、根长、地上及地下干重，均有不同程度增加，其中以黄藤地上干重增加尤为显著，比对照增加６５．２％，显著性测验表明，差异十分显著；接种处理的苗木，地上及地下部分含磷量增加亦非常明显，特别是地下部分增加较多，为对照的１．１３倍。     

棕榈藤VA菌根研究*

在广东、广西及海南３省区收集不同气候及立地条件下的４个藤种共２２个藤根及土壤样品，经镜检及湿筛分析结果表明，１１个藤根样品中有１０个具ＶＡ菌根，菌根感染率达８．３０％－４３．８％；在１１个土壤样品中全部具ＶＡ菌根菌；其ＶＡ菌根菌种类达１３种之多，分别隶属无柄囊霉属、球囊霉属、硬囊霉属和盾巨孢囊霉属共４个属；其中，粗柄硬囊霉和小果硬囊霉为我国新分布种；此外，还有４个未发表种，分属于球囊霉属和盾巨孢囊     

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.