水杨酸诱导油茶抗炭疽病的研究

应用水杨酸溶液喷洒油茶叶片可有效诱导植株产生对炭疽病的局部性和系统性抗性.浓度150 mg·L-1诱导抗性效果最好,其对嫩叶的局部诱导病斑减小率为54.15%,对老叶的病斑减小率为61.55%.该浓度的水杨酸溶液喷洒对油茶炭疽病的系统性诱导抗性可使病斑减小率达46.7%;田间试验防治效果达到45.32%.水杨酸诱导油茶产生的局部性抗性可持续20 d而抗性水平无明显下降.扫描电镜显示在诱导处理的油茶叶片上,分生孢子能够萌发,但是芽管的生长受抑制,甚至异常变形卷曲.     

浙江引种显齿蛇葡萄二氢杨梅素提取工艺优化及含量分析

显齿蛇葡萄Ampelopsis grossedentata叶片中富含二氢杨梅素，其嫩叶可加工成藤茶。本研究建立了显齿蛇葡萄叶中二氢杨梅素的HPLC检测方法，并对浙江引种的3个种源4个种质(广西种源、贵州种源、湖北种源、湖北大叶种源)显齿蛇葡萄老叶和嫩叶中二氢杨梅素的含量进行对比分析。结果表明，显齿蛇葡萄叶片中二氢杨梅素的最佳萃取条件为：液料比20∶1，萃取溶剂75%乙醇，萃取温度40℃，频率20 kHz、功率500 W超声萃取3次，每次25 min，在此条件下二氢杨梅素的提取得率可以达到16.21%；二氢杨梅素HPLC检测方法的标样拟合方程为y=218.74 x,R²=0.999 7，平均加标回收率为98.88%，能较好地满足研究的需求；3个种源普通显齿蛇葡萄，湖北种源叶片(嫩叶)中二氢杨梅素含量最高，达291.87mg·g^-1，但3个种源间并无显著性差异；湖北大叶种源叶片(嫩叶)中二氢杨梅素含量最低，并与其它3个种源均存在极显著性差异(P<0.01)；显齿蛇葡萄嫩叶与老叶中的二氢杨梅素含量差异极显著(P<0.01)，其中贵州种源...     

竹子硝酸还原酶的初步研究

以粉单竹（Lingnania Chungii McClure)为对象，研究了竹亚科植物硝酸还原酶（NR）活力的测定方法，并进行了硝酸盐对NR的诱导研究，研究结果表明：当年生已定型的绿叶NR活力最高，当年生已展开嫩叶次之，上年生的老叶最低，用pH 9.0含PVP（聚烯吡咯烷酮）65mg/mL的磷酸缓冲液作提取液匀浆的叶片NR活力较高，反应底物硝酸钾（KNO3）浓度以50mmol/L为佳，叶片用硝酸盐诱导可提高NR活力，但NR活力经4h诱导出现最稳定，当年生叶NR活力经诱导4h出现最高峰后呈下降趋势。     

葡萄不定芽离体诱导再生植株的研究

进行了紫苑、魏可和砧木 99R几个葡萄品种不定芽离体诱导再生植株的研究。实验通过对其叶片、叶柄、茎段外植体的诱导再分化 ,以器官发生途径实现植株再生。结果表明 :不同品种间存在差异 :(1)紫苑不定芽诱导再生效果最好 ,其中用IBA与TDZ组合诱导最好 ,叶柄在MS +IBA0 .2 0mg/L +TDZ0 .75mg/L培养基中再生率高达 4 2 .9% ;用IBA与BA组合效果也较好 ,叶柄和茎段在MS +IBA0 .0 5mg/L +BA2 .0mg/L中再生率达 30 .8%。 (2 )魏可叶柄不定芽诱导再生在MS +IBA0 .2 0mg/L +BA2 .0mg/L培养基再生率 2 0 .0 %。 (3)砧木品种 99R不定芽诱导再生率较低 ,叶片在MS +IBA0 .0 1mg/L +BA1.5mg/L培养基中再生率 2 0 .8%。(4)栽培品种比砧木易于诱导再生不定芽     

葡萄SSR反应体系的优化

以葡萄新鲜幼嫩叶片为材料,研究了SSR分析过程中的影响因素,包括Taq酶、Mg2 、dNTP、引物、模板DNA浓度、退火温度等,建立了适合葡萄SSR反应的PCR体系,即20μl反应体系中含有Taq酶1.0 U、Mg2 浓度为1.5 mmol/L,dNTP 0.2 mmol/L,引物0.5μmol/L,模板DNA20~30 ng。扩增程序为:95℃预变性4 min;95℃变性50 s、50~60℃退火1 min7、2℃延伸1 min 30 s,30个循环;最后72℃延伸7 min。     

酿酒葡萄霜霉病季节流行动态与爆发成因

通过对生长季酿酒葡萄园空气中霜霉病菌孢子囊进行逐日逐小时捕捉,并对病情进行调查,记载气象资料,对霜霉病菌孢子囊飞散动态及病害爆发成因进行了详细研究,以期对病害爆发进行预测,用于指导该病的防治.结果表明:8月至9月上中旬为整个生长季中孢子囊飞散的高峰;孢子囊的日飞散动态是昼少夜多,8:00之前和18:00之后孢子囊飞散量占全天的87%.全天各小时段孢子囊飞散量与空气相对湿度呈显著正相关(R=0.676 9,P<0.01),而与空气温度呈显著负相关(R=-O.676 7,P<0.01).品种、地势、空气温度、降雨量和菌量等综合因素共同影响葡萄霜霉病的发生与流行.     

外源SA对干旱胁迫下金莲花种子萌发及幼苗生长的影响

为提高金莲花种子萌发和幼苗生长阶段的抗旱性,试验选用采自河北小五台山国家级自然保护区的金莲花种子,利用PEG-6000模拟干旱,探讨了外源SA对干旱胁迫下金莲花种子萌发和幼苗生长的影响,并探索了减轻干旱胁迫危害的最适SA浓度及各个生长指标、生理指标的变化规律。结果表明:通过对不同处理及对照的发芽率、发芽势、发芽指数、根冠比、相对含水量、叶片叶绿素含量以及叶片相对电导率进行测定比较,外源SA的最佳缓解浓度为1.0mmol/L。该结论为促进其规范化栽培和扩大其在干旱半干旱地区的种植范围提供了科学依据。     

NaCl胁迫对辽东丁香种子萌发的影响

为探索辽东丁香种子的耐盐性,在NaCl溶液浓度依次为0mmol/L、25mmol/L、50mmol/L、75mmol/L、100mmol/L、125mmol/L、150mmol/L的条件下进行试验,研究盐胁迫对辽东丁香种子萌发的影响,结果表明:NaCl溶液对辽东丁香种子萌发具有显著的抑制作用,随着NaCl溶液浓度的增加,其发芽率、发芽势和发芽指数均显著降低(最高57%、26%和6.68,最低4%、4%和0.27);同时,NaCl溶液能够明显减缓种子的萌发速度,浓度越高,启动萌发需要的时间越长。     

4个鲜食葡萄品种抗寒研究

该文对爱博欣一号、巨峰、红乳、美人指等4个鲜食葡萄品种的1a生枝条进行了不同低温处理,采用电导法测定电解质渗透率,并对低温处理的枝条进行了恢复性生长试验。结果表明:4个葡萄品种的抗寒性差异极显著,其抗寒性强弱顺序为:爱博欣一号巨峰红乳美人指。     

棕榈小苗抗冷试验研究

为研究外源水杨酸(SA)、没食子酸丙酯(PG)对提高棕榈苗抗寒性的机理以及适宜的处理浓度,该试验利用已驯化并适应当地小气候的棕榈母树上的种子,繁育实生小苗,利用外源水杨酸(SA)、没食子酸丙酯(PG)对小苗进行叶面喷施,然后再低温胁迫,观察生长情况。结果表明:喷施适宜浓度SA、PG,可缓解低温对棕榈小苗叶片的伤害,其中SA 1.5mmol L、PG 1.0mmol/L效果较好。     

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.