植物DNA甲基化研究进展

植物经常暴露在各种生物和非生物的胁迫之下,这些胁迫会影响植物的生长发育和繁殖并最终导致植物死亡。为了抵御不利的环境条件,植物已经进化出复杂而精细的网络来感知胁迫并激活防御系统。为此,植物激活许多信号转导通路,这些信号转导通路可以改变一些胁迫响应基因的表达,从而引起植物形态、生理和生化的改变以适应逆境。DNA胞嘧啶甲基化是高等真核生物的主要表观遗传机制之一,在维持基因组稳定性和调节基因表达方面起着关键作用。表观遗传变异比遗传变异更为灵活。一旦环境条件发生变化,为了适应新的环境植物都会发生表观遗传的改变。许多研究表明DNA甲基化参与植物的发育和应激反应。基于相关研究对DNA甲基化进行了综述,对植物逆境胁迫有重要意义。     

Armillaria ostoyae in managed coniferous forests in Kastamonu in Turkey

Although several Armillaria species have been reported in Turkey, there is little information about their ecology in Turkish forests. In this study, we investigated five forest stands, approximately 5–74 ha in size, in Kastamonu province in the Black Sea Region of Turkey for the presence of Armillaria species in stumps and logs. The stands were mixed Abies nordmanniana ssp. bornmülleriana and Pinus sylvestris forests managed using a selective cuttings system; the proportion of fir in the total number of stems and stumps ranged from 36 to 98%. Based on sequence analysis of the internal transcribed spacer and intergenic spacer regions of the rDNA, all rhizomorphs sampled from the stumps and logs were of Armillaria ostoyae. The size of the genets was estimated with random amplified microsatellites analysis of the isolates and ranged from single stumps to approximately 450 m². One to seven genets were found in each stand. These results indicate that the genets had arisen from spores and vegetative spread was limited on most sites.     

林木远缘杂交育种现状及研究进展

远缘杂交是拓宽种内遗传资源、扩大基因库和弥补近源杂交局限性的重要手段, 目前在林业生产上已取得了重要成果。然而, 由于生殖隔离的存在, 远缘杂交往往具有一定的不亲和性, 对育种进程造成了较大的阻碍。文中对远缘杂交育种的发展历史、原理、育种策略及在林业上的研究成果进行了综述, 并对远缘杂交育种过程中存在的困难及解决办法进行了分析, 以期为远缘杂交育种在林业上的应用提供参考。     

Influence of site in the wood quality of Eucalyptus in plantations in Brazil

Genetic materials interact with the environment in specific ways, therefore their responses in wood need to be better understood. The present study sought to evaluate the influence of different climatic conditions in Minas Gerais, Brazil on Eucalyptus grandis × Eucalyptus urophylla wood. Two six-year-old clones were cultivated in Belo Oriente, Ferros, Santa Bárbara, Itabira and Peçanha. Five trees from each clone were sampled from the base to top direction. Wood density, heartwood/sapwood ratio, vessels, fibres, and extractive and lignin contents were determined, as well as their correlation with environmental variables. Vessel diameters, heartwood/sapwood ratio, and extractive and lignin contents all increased due to higher water availability in Santa Bárbara and Itabira. In both genetic materials, the variables linked to growth and wood quality were related to environmental factors.     

唐山市采煤塌陷区湿地生物多样性调查及评价

湿地生物多样性评价是生物多样性保护和实现可持续发展的基础性工作,本研究采用全面调查、样地设置等多种方法对物种进行调查,运用物种多样性和生态系统多样性的指标体系对唐山市采煤塌陷区湿地生物多样性进行较全面的评价。       

Structure of aquatic insect communities in tank-bromeliads in a East-Amazonian rainforest in French Guiana

Tank-bromeliads are discrete habitats which contain distinct aquatic communities, and which commonly occur in the neotropics. Because they span a broad range of ecological gradients in terms of habitat structure and amount of resources, researchers study the associations between the biodiversity of communities and these gradients in rainforests, where the very high species richness and densities within other continuous habitats makes it difficult to quantify animal communities. We analysed the diversity of aquatic insect communities in relation to different tank-bromeliad species in a primary rainforest (French Guiana) using artificial intelligence and complex optimization techniques to classify communities and model their determinants. First, the self-organizing map (neural network) was used to classify 158 bromeliads according to the quantitative structure of the insect communities. Catopsis berteroniana and Guzmania lingulata formed separate clusters of plants on the virtual map, while Vriesea splendens, Vriesea pleiosticha and Aechmea melinonii were grouped together in the remaining clusters. Some insect taxa occurred in all bromeliads, while other taxa were specific to a given species. Second, general linear modelling allowed us to specify the influence of the bromeliad species; water volume and volume of fine particulate organic matter inside of the tank; elevation above the ground; and sampling site on taxonomic richness and insect abundance. The number of taxa and individuals per plant increased with greater water volume, but the slope of the relationships depended on the bromeliad species. The significant influence of bromeliad species suggested that at similar water volumes different plant species had different taxon richness and insect abundance. Greater amounts of fine particulate organic matter were detrimental to community diversity in the tanks, probably because they decreased available space by clogging it and/or affected oxygen concentrations. The influence of tank-bromeliad species on the aquatic insect community was primarily related to their physical (and probably chemical) features rather than to species-specific associations sensu stricto. The classification of bromeliads with respect to animal species is likely to provide referential schemes for those biodiversity patterns to be expected under certain conditions, and may help to target model communities for subsequent experimental research.     

Research advance in wood composites in China

Inthe21stcentury,thewoodsupplyinChinawillcontinLJetobelessthanthedemand,soChinawillneedtousewoodasetfectivelyasPossible.Theuseotwoodcompositesisaveryefficientwaytosavewood.ChinalackssLJfficientforeststomeetitsdemandforwood,especiallyinfinequalitywoods.BecauseofChina'spopulationandfiberdemand,efficientuseofwoocJismoreimportanttoChinathanthattosomeothercoLJntries.However,Chinawasneitherconvincedofthisandnordiditpayattentiontothestudyofwoodcompositesbeforethe1970's.FacingthewoodcrisisChinaf…     

Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha^?1), and 36% were at least satisfactory (≥1300 ha^?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.     

影响森林细根分解的机理研究进展

细根是森林地下生态系统的重要组成部分,其生产、周转和分解构成土壤与生物间的物质循环,是陆地生态系统C和养分循环的重要环节。细根分解的影响因素总体来讲包括植物本身和环境因素,每个影响因子各自独立成体系,又彼此紧密联系。以往的研究基本上都是各因素相互独立的研究。本文根据国内外近几十年来树木细根分解的研究现状,对细根分解所受的影响因子进行了综述,旨在进行纵向比较,得出细根分解目前的研究进展和动态,探讨影响细根分解因素的作用机理;总结当前存在的问题,并对细根分解研究方向进行了展望,为我国细根分解研究的深入开展提供良好借鉴。     

科尔沁沙地盐碱地造林技术研究

通过多年对科尔沁沙地西部盐碱地提高造林成活率技术措施的研究，结果表明：采用开沟造林技术是适合当地特点的成功造林措施：造林成活率达到85％以上，林木生长量比一般整地造林方式高一倍。在地下水位浅、土壤盐渍化程度严重的地区，采用筑台地造林，其成活率可高达90％，造林5年后即可郁闭成林，林木生长量为一般造林地的2倍：采用上述2种整地造林技术，可有效改善土壤中养分和水分状况，同时土壤含盐量和pH值均明显下降，在沙地盐渍化轻度地区可采用穿透碱隔深穴造林措施。     

Biomass harvesting in Eucalyptus plantations in Western Australia

Australia is at an early stage of exploring the use of forest biomass to generate energy. This study evaluated the biomass yield and the productivity rates of equipment for harvesting biomass in a poor-quality eucalypt plantation. The operation consisted of a tracked feller-buncher, grapple skidder and mobile chipper. Time study methods were used to measure the harvesting operation. A multiple regression model was constructed to predict skidding productivity. Biomass production was 63.9 t ha^?1 based on the recorded load weight of eight trucks. Delays were documented and analysed. The average delay for all equipment was about 30% of working time. The study results will help guide biomass harvesting managers to estimate productivity and cost of similar operation sites.     

浅谈鹤北林业局伐区生产工艺的复杂化和对应措施

鹤北林业局由于多年的大量采伐，带来了伐区生产的艰难性和复杂性，针对这种情况，为了确保伐区木材生产的安全，本文作者提出了具体的措施。     

巴彦淖尔市临河区林木、花卉寄生真菌多样性调查

对巴彦淖尔市临河区林木、花卉腐烂发霉及病斑、病害的植物组织的寄生真菌进行分离鉴定,经显微形态观察鉴定,分别为半知菌亚门2属8种,子囊菌亚门1属1种,表明巴彦淖尔市真菌有着丰富的多样性,并为植物保护提供有力依据.     

21世纪我国林业生产初探

论述了21世纪我国林业生产将面临的机遇和挑战,以及如何在知识经济环境中、调整观念,创立林业发展新体系,推动我国林业生产的发展.     

上海中央公园特大银杏树白蚁防治探讨

通过对上海松江中央公园内65株特大银杏树白蚁为害情况的调查,发现该公园银杏受害率为100%,其中存在活白蚁的银杏占总量的56.9%,采用毒土处理、粉剂疗法、建立白蚁监测点等措施,经过两次灭杀,活白蚁的灭杀率达到92.3%和93.3%,从而使存在活白蚁银杏树的比例从56.9%下降到2.7%,白蚁发生情况明显降低。       

Carbon pools in tree biomass and the soil in improved fallows in eastern Zambia

This study quantified tree and soil C stocks and their response to different tree species and clay contents in improved fallows in eastern Zambia. From 2002 to 2003, soil, and destructively harvested two-year old tree, samples were analysed for C. There were significant differences (P < 0.05) in aboveground tree C stocks, and in net organic C (NOC) intake rates across coppicing tree species at Msekera and Kalunga. Aboveground C stocks ranged from 2.9 to 9.8 t ha^-1, equivalent to NOC intakes of 0.8–4.9 t ha^-1 year^-1. SOC stocks in non-coppiced fallows at Kalichero and Msekera significantly differed (P < 0.05) across treatments. SOC stocks to 200 cm depth ranged from 64.7 t C ha^-1 under non-coppicing fallows at Kalunga to 184.0 t ha^-1 in 10-year-old coppicing fallows at Msekera. Therefore, tree and soil C stocks in improved fallows can be increased by planting selected tree species on soils with high clay content.     

2006年特大干旱中森林植被对农作物的防护作用

2006年四川发生了百年一遇的特大干旱。按照自然地理条件相近、森林覆盖率有较大差异的原则;同时,在同一行政区内按森林覆盖率的高低分成对照组。在县层面上,共3对对比县,在乡层面上共7对对比乡。对比县中,森林覆盖率高的一组森森覆盖率为34.20%～52.29%,平均为43.16%,森林覆盖率低的一组为16.60%～27.28%,平均为20.84%;对比乡镇中,森林覆盖率高的一组森林覆盖率为28.50%～56.23%,平均为41.29%,森林覆盖率低的一组为10.70%～19.12%,平均为14.61%。在干旱后期,调查了四川盆地丘陵区9个县14个乡镇主要农作物(水稻、玉米和红薯)的受灾率、成灾率和绝收率。调研结果表明,森林对农业的旱情具有一定的缓解作用。在县层次上,与森林覆盖率低的相比,森林覆盖率高的主要农作物(水稻、玉米和红薯)的平均受灾率、成灾率、绝收率分别降低16.6%、16.2%、4.0%;在乡镇层次上,与森林覆盖率低的相比,森林覆盖率高的主要农作物(水稻、玉米和红薯)的平均受灾率、成灾率、绝收率分别降低20.3%、19.7%、12.7%;与无农田防护林网相比,有农田防护林网的水稻平均受灾率、成灾率分别降低5.8%、22.8%,没有绝收现象,而无防护林的水稻平均绝收率为6.5%。     

Recent trends in nursery practice in New Zealand

The plantation resource in New Zealand is now 1.73 million hectares, of which 90% is Pinus radiataD. Don (radiata pine). The resource has been expanding at over 50,000 ha per year since 1992, although new planting is currently declining. In 1998, new planting and restocking of previously clear-felled areas was 81,100 ha. Initial stocking rates vary, but are typically in the range of 800–1000 plants per hectare, requiring around 80 million nursery plants to be raised per year.Sufficient open-pollinated seed is produced for New Zealand requirements. An increasing proportion of more expensive control-pollinated seed is being used to increase genetic gain. This has led to increased use of vegetative propagation by cuttings and tissue culture, providing more than 25% of current planting stock. These propagules, especially cuttings, often have better early performance compared with seedlings, perhaps because of their larger size. Clonal forestry options are also now being evaluated.Seedling quality specifications have been well defined for bare-root radiata pine, but not well quantified for more recent plant types such as vegetative propagules or container-grown plants. Both root system quality and physiological age can be important for vegetative propagules. These propagules, especially cuttings with a physiological age of less than 4 years, have performed as well as seedlings for growth, and have been better than seedlings for stem form and early stability. Container-growing of planting stock is being introduced with this more valuable genetic material, and issues of plant quality are being raised, as it is expensive to grow large stock in containers. More research should be done to determine what plant quality standards are required to ensure successful establishment with these stock types.     

我国固沙植物资源化利用研究进展

我国干旱、半干旱沙区广泛采用种植植物的措施固定流沙,因其可以更持久地、可持续地发挥防护效能。固沙植物以多年生灌木、半灌木和草本植物为主,不仅可以良好地适应当地的自然条件,而且具有较高的生态经济价值。研究优良固沙植物的饲用价值、绿化价值以及药用价值,对合理开发利用沙区植物资源具有非常重要的意义。文中回顾了我国不同优良固沙植物的资源分布情况,综述了沙区植物资源利用概况,包括沙质地区固沙植物的饲料资源、绿化资源以及药用资源利用,探讨了我国固沙植物资源利用过程中的不合理现象及存在问题,提出固沙植物资源的可行性保护措施,为充分发挥沙区植物资源防风固沙、水土保持的生态效益以及最大限度地提高当地的经济效益提供参考。     

Variations in soil chemical properties and microbial biomass in artificial gaps in silver fir stands

Changes in soil chemical and microbiological parameters in small (185 m²) and medium (410 m²) gaps, created in mature silver fir (Abies alba Mill) stands (mean height 30 m) in the Calabrian Apennines (Southern Italy), were studied over 2 years. Medium gaps had high soil temperature and photosynthetically active radiation (PAR) transmittance and low soil moisture. Within small gaps we detected a greater amount of organic matter, with respect to under canopy cover sites and medium gaps. Moreover, a different trend of the organic matter between small and medium gaps was observed. In the medium gaps, with respect to under canopy cover sites and small gaps, we found a relatively low content of organic matter, associated to a lower amount of humic acid, which suggested that the organic substrate undergoes a mineralization rather than a humification process. An opposite trend was observed in small gaps, where the increase of organic matter content, associated to an increase of humic acid and microbial biomass, suggested a better humification process. Moreover, in small gaps the highest level of urease and the greatest fluorescein diacetate (FDA) hydrolysis were observed. The different trend of organic matter observed in small and medium gaps may be related to changes in the environmental conditions. PAR transmittance, significantly higher in medium gaps, contributed to increase soil temperature and decrease soil moisture, affecting soil microbial populations and organic matter trend. These results suggest that the creation of small gaps represents the silvicultural practice with minor environmental impact.