木质素过氧化物酶和锰过氧化物酶高产菌株的诱变育种

利用低能N+注入,对产木质素过氧化物酶(Mnp)和锰过氧化物酶(Lip)活力均较高的菌株N1023进行诱变,研究了不同能量和不同剂量N+离子诱变后菌株的存活率与突变率、突变菌株的产酶活力及遗传稳定性.结果表明:不同能量和不同N+离子剂量注入对菌株有显著影响,诱变菌株N1023j产Mnp和Lip双酶活力分别提高了27.29%和22.58%,同时诱变菌株N1023j有很好的遗传稳定性.     

高产脂肪酶酵母菌株的分离筛选及紫外诱变

利用定向分离法从市场购得的苹果、梨、葡萄、面粉、酒糟、啤酒花等6个样品中分离出7株产脂肪酶菌株:曲霉1株,酵母6株.其中从面粉中分离出来的菌株MF具有较高的酶活力,粗酶活力达29.17 U·mL-1,经初步鉴定为假丝酵母(Candida sp.).对该菌株产酶条件进行优化可知:该菌的最佳碳源是1%的10: 1(m/V)的酵母膏+乳化液;最佳氮源为2%的3:1(m/m)玉米粉+蛋白胨;培养的最适初始pH值为8.0,最佳培养时间为72 h,最适反应温度为40℃,最佳反应时间为30 min.优化后的酶活力达41 U·mL-1,比优化前提高了40.5%.对MF菌株进行初步紫外诱变处理,突变菌株酶活力70.83 U·mL-1,比未处理的菌株的脂肪酶活力提高了105%.     

复合诱变选育恶臭假单胞菌高产菌株的研究

以恶臭假单胞菌Pseudomonas putida野生株Ps-FLAG01为出发菌株,经超声波(US)-硫酸二乙酯(DES)复合诱变后,筛选出一高产菌株Ps-FLAG05,其总酶活力为0.325 3 u/mL,比出发菌株提高25.89%;对其发酵培养基配方进行了优化,最佳配方为:玉米浆1.0%,葡萄糖3.5%,氯化钠0.15%,诱导剂4.5%,与原配方相比,发酵水平提高了13.03%.     

制备生物柴油用脂肪酶产生菌的诱变和筛选

以提高全细胞生物催化制备生物柴油的效率为目的,采用紫外诱变的方法对产脂肪酶的米根霉菌株进行诱变和筛选。筛选得到的诱变株命名为LY6,脂肪酶水解酶活(4.33 U/mL)是原始菌株的4.33倍,合成酶活(0.28 U/mL)是原始菌株的1.12倍,脂肪酶水解酶最适反应pH值为7.0。将筛选得到的菌株制备成固定化全细胞生物催化剂催化大豆油转酯化制备生物柴油,在醇油比为3∶1(物质的量之比,下同)时,脂肪酸甲酯得率比原始菌株提高了41.0%,达到87.3%;在醇油比为4∶1时,最终生物柴油的甲酯得率比原始菌株提高了16.8%,达到96.1%,故经筛选得到的菌株能作为全细胞生物催化制备生物柴油的优良菌株。     

土壤中产淀粉酶菌株的分离、鉴定及提高产酶能力的研究

利用形态分析结合18S rDNA序列分析鉴定菌株,采用物理诱变、化学诱变及复合诱变等方法诱变菌株,进一步筛选获得了具有更高产淀粉酶能力的菌株。研究表明：通过筛选获得具有高产淀粉酶能力的真菌菌株fu-1,鉴定为黑曲霉,命名为黑曲霉An。An进一步经紫外诱变、化学诱变筛、复合诱变筛选出产酶活力最大的菌株。成功得到了高产淀粉酶活力的菌株An-7c-2u。     

N~+注入诱变黑曲霉选育单宁酶生产菌株

以黑曲霉为出发菌株,经多次N+注入诱变,得到突变高产单宁酶菌株黑曲霉ANO2。该突变菌株其产单宁酶酶活为670.2 U/mL,较出发菌株的单宁酶酶活442.3 U/mL提高51.4%以上,突变菌株经传10代培养,产酶特性稳定,是一株比较理想的单宁酶生产菌株。     

高产漆酶真菌菌株的筛选及酶学性质研究

从6株野生真菌和5株食用真菌中筛选出高产漆酶菌株,并对筛选出的野生菌株漆酶酶学性质进行初步探究。使用G-PDA确定菌株的产漆酶能力,然后通过液体发酵对产生的粗酶液进行酶活力测定,确定高产漆酶菌株,最后分别在不同pH和温度下进行酶学性质探究。初步筛选结果:第7天时,05号菌丝直径最大89.1mm,08号显色圈直径最大76.8mm,04号的显色圈颜色最深,09号显色反应最不明显。对于漆酶活力:04号活力最高262.7U/mL,其次是08号和05号分别为255.3U/mL、203.9U/mL。01和06号酶活力达到最大所需时间最短。酶学性质方面,08号的最适pH是3.2、最适温度是40℃;在不同pH、温度下分别保温2h,pH=4.0酶活力残余率为94.20%;温度在20~40℃内,酶活力残余率在99.00%以上。结果表明,0.04%G-PDA最适作为产漆酶真菌的初筛培养基;高产漆酶能力的菌株有04、05和08号菌株,且08号菌株漆酶的最适应用条件是pH=4.0、温度为40℃。     

思茅松毛虫肠道脂肪酶高产菌株的筛选及其酶特性研究

从思茅松毛虫幼虫肠道中分离出3属7株产脂肪酶菌,以思茅松松节油为底物,筛选高产脂肪酶菌株,测定脂肪酶活性,确定酶解特性,生长量和产酶特性。结果表明:以思茅松松节油和橄榄油为底物时,7株产脂肪酶菌均表现出不同的产脂肪酶活性,其中以菌株D12的产脂肪酶活性最高。以思茅松松节油为底物时,菌株D12的脂肪酶活力高达4.06 U·mL-1;菌株D12为中温型产碱性脂肪酶菌株,最适作用温度40℃,最适pH值为8.0;菌株D12经发酵至60 h时,OD600值高达0.68,说明其生长量达到最大,在48 h左右时酶活力达到最高,为6.6 U·mL-1。     

低能离子注入法诱变选育纤维素酶产生菌的研究

以纤维素酶产生菌里氏木霉(Trichoderma reesei)为实验菌株,研究了低能N+注入对T.reesei存活率、菌体总抗氧化能力(T-AOC)、蛋白质含量以及产酶能力的影响.结果表明,T.reesei经N+注入后存活率曲线呈现“双马鞍型”,这与离子注入典型的“马鞍型”曲线不同.菌体总抗氧化能力与注量之间的关系曲线同样在1.50×1016和2.50×1016 cm-2注量处呈现两个峰,与存活率曲线的变化趋势一致.由此推测,离子注入微生物所诱导的总抗氧化能力的强弱变化很有可能决定微生物的存活情况.实验通过诱变筛选得到3株纤维素酶高产菌株150-1,150-2和250-6,高产菌株纤维素酶的平均活力比出发菌株提高24.3％,均表现出很强的发酵积累纤维素酶的能力,尤其在发酵后期更为突出.     

美国白蛾高毒力白僵菌菌株的紫外线诱变选育

【目的】对分离自美国白蛾幼虫虫尸的1株白僵菌菌株BH01进行紫外线诱变,以获得高毒力突变株,为美国白蛾的生物防治提供新的工程菌株。【方法】将白僵菌的孢子悬浮液置于紫外灯下进行诱变处理,诱变处理后获得的菌株进行培养后以产孢量超过原始菌株2倍以上作为依据筛选正向突变菌株,测定其对美国白蛾5龄幼虫的致病力,筛选高毒力突变株进行继代培养,研究其产孢量和致病力的稳定性。【结果】对原始菌株BH01经紫外线诱变处理后获得28个菌落,孢子校正死亡率为85.5%,将获得的菌落重新接种于PDA平板上得到产孢量高于原始菌株2倍以上的正突变株BH01-5、BH01-12、BH01-25。其中诱变菌株BH01-5对美国白蛾5龄幼虫的校正死亡率明显低于原始菌株,BH01-25与原始菌株相当,而BH01-12的校正死亡率和LT50值分别为原始菌株的1.30和0.68倍,具有显著差异。将突变株BH01-25和BH01-12继代培养6次,发现诱变菌株BH01-25菌株在继代过程中产孢量和致病力明显降低,表现出与原始菌株类似的趋势,但其产孢量始终高于原始菌株,另外,原始菌株培养第4代时即开始降低,BH01-25至第6代时才出现明显的降低,表现出了更好的稳定性。诱变菌株BH01-12在试验的6代继代培养过程中,无论产孢量还是对美国白蛾幼虫的致病力方面均未出现下降,且均明显优于原始菌株。【结论】经过对分离自美国白蛾幼虫的1株球孢白僵菌BH01进行紫外诱变,得到了产孢量和致病力均高于原始菌株的突变株BH01-12,该菌株经过继代培养后,其产孢量和致病力均未出现降低,表现出一定的遗传稳定性,具有很好的生产和应用前景。     

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.