利用多菌种共培养降解橡宛单宁制备鞣花酸

以橡宛单宁为原料，通过培养、分离筛选出14种菌株。研究了单一菌株培养和混合菌株共培养对橡宛单宁生物降解的影响，证实了用降解速率快但耐单宁性较差的菌株与耐单宁性好但降解速率较慢菌株共培养，可以显著提高橡宛单宁的生物转化率和鞣花酸的产率，两者分别达到68％和23％。所建立的生物降解的方法可用于由橡宛单宁制备鞣花酸。     

利用多菌种共培养降解橡椀单宁制备鞣花酸

以橡单宁为原料 ,通过培养、分离筛选出了 14种菌株。研究了单一菌株培养和混合菌株共培养对橡单宁生物降解的影响 ,证实了用降解速率快但耐单宁性较差的菌株与耐单宁性好但降解速率较慢菌株共培养 ,可以显著提高橡单宁的生物转化率和鞣花酸的产率 ,两者分别达到 6 8%和 2 3%。所建立的生物降解的方法可用于由橡单宁制备鞣花酸     

黑荆树单宁与金属离子络合性质的研究

采用pH电位滴定法测定了不同温度下,离子强度(I)0.1 mol/L的NaCl溶液中单宁酸、橡椀单宁、黑荆树单宁的加质子常数和若干金属络合物稳定常数,考察了单宁结构单元对Fe3 、Cu2 、Zn2 、Ni2 的离子络合选择性的影响,讨论了影响加质子常数和稳定常数的因素。研究结果表明,实验温度下单宁对Fe3 、Cu2 的络合稳定常数大小为:黑荆树单宁>橡椀单宁>单宁酸,对Zn2 、Ni2 的络合稳定常数大小为:橡椀单宁>黑荆树单宁>单宁酸。升高温度有利于酚羟基的解离但不利于单宁-金属络合物的形成。用柱层析提纯的黑荆树单宁对其金属络合物的稳定常数的影响不大。     

微生物降解葡萄皮单宁研究

为降低葡萄皮单宁的分子量和聚合度,选取青霉(Penicillium sp.)和米曲霉(Aspergillus oryzae)为微生物菌株对葡萄皮单宁进行生物降解。以儿茶素的生成量和转化率为指标,分析碳源、氮源、时间、温度、pH和诱导培养基中单宁质量浓度对降解效果的影响。结果表明:外加碳源和氮源有利于青霉和米曲霉菌株的生长;时间为葡萄皮单宁降解得到不同中间产物的关键参数;温度、pH和葡萄皮单宁的质量浓度对菌株活性和降解能力均有不同程度影响;青霉对葡萄皮单宁的降解效果好于米曲霉。青霉最佳降解条件:培养时间24 h,温度28℃,pH6.5,单宁质量浓度12.5 g/L,儿茶素最大生成质量浓度0.32 mg/mL,转化率52.3%;米曲霉最佳降解条件:培养时间36 h,温度28℃,pH 6.5,单宁质量浓度10.0 g/L,儿茶素最大生成质量浓度0.16 mg/mL,转化率32.2%。因此,可通过生物降解法调控葡萄皮单宁的化学组成,适当降低单宁的分子量和聚合度。     

白橡锯材热压干燥特性与工艺研究

以白橡锯材为研究对象,采用热压机对其进行热压干燥处理,系统研究了热压温度、热压压力和试件宽度等因素对白橡木材干燥特性、颜色、吸湿性和尺寸稳定性的影响规律,获得了优化的热压干燥工艺。研究结果表明:采用热压干燥法可以实现白橡木的快速高效干燥,随着热压温度的升高,木材干燥速度显著加快,颜色逐渐加深,热压压力和试件宽度对干燥速率和颜色的影响不明显;热压干燥可以显著减小白橡木材的平衡含水率(EMC)和湿胀率,提高其尺寸稳定性,且随着热压温度的升高,白橡木材EMC和湿胀率降低,热压压力和试件宽度对木材EMC和湿胀率无明显影响;与对照材相比,热压干燥白橡木材的EMC降低9.97%~33.67%,径向和弦向湿胀率分别降低8.54%~33.96%、11.26%~30.02%;白橡木材的优化热压干燥条件为:热压温度为140~150℃热压压力为0.1 MPa,板材宽度为自然宽。     

橡椀栲胶锅炉水质处理

一、栲胶水质处理原理栲胶是由植物鞣料制成的,主要成份是单宁(见表1)。单宁是一种高分子无定型的有机酸,能成胶态溶解于水中,pH在3—4之间。橡椀栲胶的单宁是没食子酸的衍生物,很容易在温和条件下水解生成没食子酸由于羟基和羧基的存在,橡梳栲胶在炉水中有如下作用: 1.与水中的阳离子生成单宁酸盐沉淀。 2.以代负电荷的栲胶分子为核心,与炉     

稀土微肥对桃叶片光合生理特性的影响

本试验以二年生桃树为试材，研究了稀土微肥为叶绿素、蛋白质含量和光合速率的影响。结果表明，低浓度稀土可显著提高桃功能叶叶绿素和蛋白质的含量，延缓桃衰老叶叶绿素的降解，从而提高桃叶片的光合效率；高浓度的稀土对桃叶片叶绿素、蛋白质含量和光合效率的提高具有不利的影响；稀土对叶绿素、蛋白质含量以及光合作用的影响效应存在明显的滞后期。     

栓皮栎栲胶品质与生态因子的相关分析

研究秦岭南坡、秦岭北坡和黄土高原3个分布区6个地点的栓皮栎橡、树皮、叶片、枝条、根和主干木材的单宁含量及其差异,并采用灰色关联度分析其与生态因子的关系,结果表明：3个分布区栓皮栎各器官单宁含量存在显著差异,各器官单宁含量由高到低为秦岭南坡＞秦岭北坡＞黄土高原,秦岭南坡栓皮栎是生产栲胶的最适林地。各地区均为橡单宁含量最高,其次是树皮、叶片、枝条,根和主干木材单宁含量最低。土壤速效磷、速效氮和速效钾是影响栓皮栎各器官单宁含量的主导土壤因子,土壤有机质是影响栓皮栎各器官单宁含量的重要土壤因子,且均与栓皮栎各器官单宁含量呈正相关。无霜期、年日照时数、年均降水量是影响栓皮栎各个器官单宁含量的主导气候因子,其中无霜期和年均降水量与栓皮栎各器官单宁含量呈正相关,年日照时数与其呈负相关。无霜期较长,降水量较高,日照时数较低,土壤速效磷、速效氮和速效钾和有机质含量较高的地区是栓皮栎栲胶生产的优先区域。     

用橡椀栲胶作陶瓷粘土解胶剂(电解质)的生产试验初报

栲胶是多元酚组成的有机物,它是由富含单宁的林产品——果壳、树皮提制出来.我区栲胶资源极为丰富,尤其橡椀资源在百色、河池两地区储量更大,年产橡椀栲胶可达二至三千吨.栲胶主要用于制革工业.但橡椀栲胶属于水解类单宁,目前在制革工业用量不大.为了寻找它的新用途,我们于1976年5～6月间,在北流瓷厂进行了用橡椀栲胶代替单宁酸、纯碱作泥料球磨粉碎及注浆成型试验,在厂党委直接领导和全体职工大力支持下,经过25次生产条件大型试验结果,球磨泥料粉碎细度合格,注浆成型及旋坯成型也好,对产品白度无影响,质量稳定,符     

小陇山林区橡树资源及其开发利用研究

甘肃省小陇山林区橡树种类较多，分布广，资源丰富，是本林区的主要建群树种。橡仁富含淀粉，橡碗富含单宁，可多层次深度开发，其废弃物还可综合利用。通过对小陇山壳斗科栎属植物资源详细的调查，摸清了资源现状及橡树叶、籽、壳、碗产量，提出了橡树资源开发利用对策。     

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.