马尾松家系的叶绿素含量和气孔形态的研究

对马尾松（Pinus massoniana）10个家系的叶绿素含量和气孔形态进行了测定、分析和比较。结果表明：闽北种源比闽西南种源叶绿素含量高，叶绿素a/b值低；气孔密度和孔径呈负相关，10个家系气孔多呈凹状，少数呈突起状。     

光照强度对卡亚生长和光合特性的影响

为探究卡亚（Cnidoscolus aconitifolius）生长最适宜的光照强度，以卡亚半年生容器苗为材料，测定其在4种（100%、65%、45%和15%）光照强度下的生长和光合生理指标。结果表明，光照强度对卡亚生长和光合生理指标均影响显著。随光照强度减弱，卡亚的苗高、地径、叶片数、叶面积、叶生物量、地上部分生物量和总生物量均呈先升后降的趋势，均在A2处理（45%自然光照）下最大；根生物量和根冠比呈逐渐下降趋势；净光合速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）和水分利用率（WUE）均呈先升后降的趋势，均在A2处理下最大；胞间二氧化碳浓度（Ci）呈先降后升的趋势；叶绿素相对含量呈先升后降的趋势，在A2处理下最大。随光照时间增加，叶绿素相对含量逐渐增加，90天与180天光照时间下的叶绿素相对含量差异极显著。隶属函数分析表明，A2处理的平均隶属函数值最大，综合排名第1，表明45%自然光照为卡亚生长最适宜的光照强度。     

镉胁迫对刺槐幼苗生长与光合生理特性的影响

目的 探究镉胁迫对刺槐生长与光合生理特性的影响。 方法 以刺槐幼苗为研究对象,测定不同浓度镉处理下刺槐生长、叶绿素含量、叶绿素荧光参数、呼吸速率和气孔特性等。 结果 在镉胁迫下,刺槐幼苗地径、株高受到明显抑制;高浓度处理植株的鲜质量、干质量下降,低浓度处理植株则略微上升,但均与对照差异不显著。随着镉浓度增加,刺槐叶绿素a、叶绿素总量呈下降趋势,而叶绿素b、类胡萝卜素变化无规则,但与对照差异不显著;初始荧光（F0）与最大荧光产量（Fm）先升后降,最大光化学效率（Fv/Fm）逐步下降,非光化学淬灭系数（qN）逐步上升,实际光化学量子效率(ΦPSII)均低于对照值,但差异不显著;胁迫植株气孔宽度、气孔面积降低,气孔逐步闭合,呼吸效率受到显著抑制;通过相关分析显示,多数指标之间显著性相关;经随机森林回归分析,初始荧光（F0）、根系镉含量、气孔宽度和叶绿素a的重要性分别在叶绿素荧光参数、植株富集镉含量、气孔特性、光合色素中最强,成为影响刺槐光合功能的最关键因子。 结论 刺槐幼苗生长与光合生理受到一定影响,但仍表现出较强的镉胁迫耐受性,可为镉污染地区的园林应用提供参考。     

落羽杉属种源研究∶生长和生物量变异

对落羽杉属不同种源、家系和树种苗期、幼林期生长量（高、胸径、冠幅）、保存率和生物量及其分配（总生物量，干、枝、叶、根生物量及其比值）进行了５年研究。发现落羽杉不同种源、家系间、内均存在显著的性状变异。变异系数以种源、家系间最大，个体间其次。生物量的变异系数大于生长量。未发现不同种源、家系在不同地点存在明显互作。采用多性状综合选择法评选出７个优良种源、家系或树种（１６００、４０１、中山杉、３０４、５０２、鸡公山落羽杉和７０１），它们的生长量、生物量大，叶生物量较大，地上部分生物量／根生物量比值大。其综合选择指数值比平均值大１３．９７％～３５．３３％，树高比平均值大１１．２２％～２４．４９％，比本地近似树种（江宁池杉）大３４．５４％～４６．１８％；胸径比平均值大１２．８１％～４８．２８％，比江宁池杉大３８．７９％～８２．４２％；总生物量比平均值大５４．５９％～１１０．６７％；保存率一般也高于平均值及本省江宁池杉。这些优良种源、家系或树种可以在江苏全省及国内类似地区作用材、防护和观赏树种推广应用。     

水涝对银杏生长及生理的影响

山东农业大学王华田等人，5月中旬对2年生盆栽银杏水涝处理，处理后第5天株高生长和叶片数量增加与对照差异不大，但处理后第10天处理株大幅度降低。水涝对植株生物量积累，尤其对叶片的生物量积累影响很大，水涝对银杏光合作用有明显抑制作用。短期水涝对蒸腾强度和气孔导度影响不大，持续水涝引起气孔关闭。水涝对根系的伤害表现为根系活力大幅度降低。水涝对叶片的伤害表现为叶片变小、发黄、叶绿素含量降低。水涝对银杏生长及生理的影响     

落羽杉属种源研究：生长和生物量变异

对落羽杉属不同种源,家系和树种苗期,幼林期生长量（高,胸径,冠幅）,保存率和生物量及其分配（总生物量、干,枝,根生物量及其比值）进行了５年研究,发现落羽杉不同种源,家系间、内均存在显著的性状变异,变异系数以种源,家系间最大,个体间其次。     

风吹楠与大叶风吹楠的叶绿素含量比较研究

以从云南省西双版纳州、德宏州和临沧市的5个县收集保存的风吹楠和大叶风吹楠为材料,采用便携式叶绿素仪(SPAD-502)和分光光度计测定风吹楠和大叶风吹楠叶片SPAD值与叶绿素含量并进行比较分析。结果表明,风吹楠6个家系90株1 350片叶的SPAD值变幅为51.00~82.00,总叶绿素含量在6个家系间的变幅为2.11~3.75 mg/g,家系间差异达到极显著水平(P0.01);大叶风吹楠4个家系60株900片叶的SPAD值变幅为48.00~72.00,总叶绿素含量在4个家系间的变幅为1.79~2.59 mg/g,家系间差异达到极显著水平(P0.01)。共10个家系150株的SPAD值与叶绿素a、叶绿素b和总叶绿素含量的相关性达到显著正相关(P0.05)或极显著正相关(P0.01),可用便携式叶绿素仪(SPAD-502)来估测叶绿素含量。风吹楠与大叶风吹楠的SPAD值和叶绿素含量存在明显的种间差异。     

湿地松家系生长和材性遗传变异分析*

对广西南宁地区林科所引自津巴布韦１０年生的１０个湿地松家系的材性和生长因子进行了遗传变异分析。结果如下：（１）湿地松材性和生长因子都具有中等以上的家系遗传力，各因子家系间差异显著，特别是管胞长度、树高和材积指数家系间差异极显著，具有较大的遗传改良潜力。（２）基本密度与晚材率间具有中等程度的正向表型和遗传相关关系，与管胞长度为弱的负向表型相关和遗传相关；晚材率与管胞长度为弱的负向表型和遗传相关。生长性状间存在着极显著的正向表型和遗传型相关关系。基本密度和晚材率与生长因子间为弱的正向遗传相关；管胞长度与生长因子间具有弱的负向表型相关和极显著的负向遗传相关关系。（３）树高对湿地松材性具有较高的间接选择效应。     

马尾松和红锥叶片解剖和光合对穿透雨减少的响应

目的 探究8 a干旱胁迫条件下树木叶片光合生理特征与叶片解剖结构的响应及二者之间的关系。 方法 在南亚热带选取2种典型人工林（马尾松和红锥）设置林内穿透雨减少的模拟干旱实验,在穿透雨减少8 a后测定叶片气体交换参数、叶绿素荧光参数、叶片解剖特征以及叶片养分（N、P）含量。 结果 （1）穿透雨减少后,马尾松针叶上、下表皮、叶片厚度以及气孔密度显著增加,而红锥仅叶片上表皮厚度显著增加,海绵组织厚度显著降低。（2）马尾松和红锥的气体交换参数（净光合速率Pn、气孔导度Gs、蒸腾速率Tr）、叶绿素荧光参数（光系统Ⅱ最大光化学效率Fv/Fm、实际光化学效率 ΦPSII,表观电子传递速率ETR）以及叶氮、磷含量在穿透雨减少8 a后均未发生显著变化。（3）与马尾松相比,红锥受到的气孔限制（Ls）更大,水分利用效率（WUE）更高,尤其在干季更明显。 结论 马尾松和红锥应对干旱胁迫的策略存在差异,马尾松通过调节叶片解剖结构产生更具耐旱的针叶来应对干旱,红锥则更倾向通过调节气孔（Ls）、提高水分利用效率（WUE）来适应干旱。     

樟子松含碳量家系变异与高碳汇家系选择

以黑龙江省林口县青山实验林场34年生樟子松自由授粉家系子代测定林为试验材料,筛选含碳率高、碳储量大的优良家系。测定其主要生长性状以及树枝、树叶、树干的含碳率,根据生长量模型估算各部分的生长量及碳储量,运用SPSS18分析软件估算各性状的变异系数、相关系数。结果表明,树干材积、树干生物量、树干碳储量、地上部分生物量及地上部分碳储量性状家系间存在丰富的遗传变异,变异系数分别为19.181%、20.955%、20.923%、19.894%和19.901%。木材基本密度、含碳率、木质素含量和综纤维素含量家系间遗传变异较小,变异系数分别为4.011%、1.158%、1.616%和6.566%。相关分析结果表明,林木树干含碳率仅与树高、树叶含碳率呈正相关关系,相关系数较小。树干碳储量与树高、胸径、材积、树干生物量呈极显著正相关。利用方差分析及Ducan多重比较,综合选出地上部分碳储量最高,生物量最大的优良家系77-19和77-16,两个家系的平均地上部分碳储量为39.154 kg,比家系平均地上部分碳储量高出19.29%。     

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.