银杏花粉研究进展

银杏是最古老的孑遗植物,银杏花粉是银杏重要的雄性细胞,是最精深的物质所在。从银杏花粉的形态及系统学地位、花粉的萌发生长、花粉产量、贮藏和生活力、花粉中的活性成分和银杏花粉制品开发研究等方面对银杏花粉的相关研究进行综述,提出银杏花粉形态的研究要多学科结合进一步深入,银杏花粉的萌发生长过程需要更深入探究,银杏花粉的贮藏与生活力的测定技术要探索更可行的方法,银杏花粉制品的开发需要进一步加强,为如何加快银杏花粉的研究步伐提供参考。     

银杏栽培与管理技术

银杏是现存种子植物中最古老的种类,在神农架有野生状态林木分布.首先介绍了银杏的形态特征,其次,阐明了银杏的适生环境及分布,分析了银杏的经济价值,重点阐述了银杏的造林技术,最后介绍了银杏的早果丰产栽培技术.     

郑州市银杏产业开发现状及前景分析

通过对郑州市银杏产业开发现状进行调查 ,结合当前国内、国际银杏开发存在的有利条件和不利因素 ,对郑州市银杏产业开发前景进行了科学分析。由分析可知 ,银杏产业开发者只有通过建立合理栽植模式 ,提高栽培管理技术水平、提高深加工技术、开发银杏新产品等途径来提高银杏综合效益和产品附加值 ,从而把银杏产业开发引向一个良性循环轨道 ,使银杏产业创造良好的经济效益和社会效益     

我国银杏生产现状与发展建议

根据对我国银杏主产省，区银杏生产情况，银杏的价值情况分析以及国内有关银杏方面的研究报告，分析了目前我国的银杏生产和市场供求现状，将我国主要银杏产地划分为5个自然区，分别指出了各栽培区银杏生产的利弊，并提出我国银杏生产实现持续，快速发展建议。     

银杏栽培与管理技术

银杏是现存种子植物中最古老的种类,在神农架有野生状态林木分布。首先介绍了银杏的形态特征,其次,阐明了银杏的适生环境及分布,分析了银杏的经济价值,重点阐述了银杏的造林技术,最后介绍了银杏的早果丰产栽培技术。     

依托资源优势 发展银杏产业

银杏生产已成为山东邳州市农村经济支柱型产业,目前全市银杏成片园26万亩,其中银杏采叶园10万亩,四旁栽植650万株,银杏栽植总株数1414万株,银杏年产量1060吨,占全国总产量10%以上;年产银杏干青叶12000吨,成立了全国首家省级银杏集团公司,拥有银杏叶提取物生产线13条、银杏叶烘干厂3家,年产银杏酮能力250吨,在圃各类银杏苗木2.5亿株,年产各类银杏保健品300吨,2003年全市银杏系列产值逾10亿元,银杏重点产区的富铁、港上等银杏基地镇农民收入中有70%以上是来源于银杏产业。一、抢抓发展机遇,夯实产业基础邳州种植银杏有悠久的历史,1986年就被林…     

银杏大树夏季移植养护技术分析

银杏是一个著'的园林观赏树。根据银杏生物学特性和北方城市的生态环境,结合银杏大树移植和现代种植技术经验,总结了银杏夏季移植方法和后期管理技术,以降低银杏移植风险。     

银杏花粉研究进展

银杏是最古老的孑遗植物,银杏花粉是银杏重要的雄性细胞,是最精深的物质所在。从银杏花粉的形态及系统学地位、花粉的萌发生长、花粉产量、贮藏和生活力、花粉中的活性成分和银杏花粉制品开发研究等方面对银杏花粉的相关研究进行综述,提出银杏花粉形态的研究要多学科结合进一步深入,银杏花粉的萌发生长过程需要更深入探究,银杏花粉的贮藏与生活力的测定技术要探索更可行的方法,银杏花粉制品的开发需要进一步加强,为如何加快银杏花粉的研究步伐提供参考。     

浮梁县银杏培育技术

指出了银杏具有重要的生态价值和药用价值，浮梁县有栽培银杏450年历史，有银杏（古树）188株，有优良品种2个，分析了浮梁县发展银杏的有利条件及经营情况，详细地探讨了银杏栽培技术。     

浮梁县银杏培育技术

指出了银杏具有重要的生态价值和药用价值,浮梁县有栽培银杏450年历史,有银杏(古树)188株,有优良品种2个,分析了浮梁县发展银杏的有利条件及经营情况,详细地探讨了银杏栽培技术.     

Comparative Study in Chemical Character and Fatty acid Compositions of Masked Civet''''s Fat and Nutria''''s Oil

IntroductionMaskedciVet(Paguma18vata),Mammalia,Viverridae,ismainlydiStributedinShanxi,Sichuan,Tibet,Yunnanprovinces,etc..Itsmeatisdeliciousandhasspecialflavor.Itiseasytoberaisedartificially,withhighproduCtivity.Nutria(MyocasterCOypus),Rodentia,Capromyidae,originatedinArgentina,Chili,etc.insouthAmerica.Itisakindofherbivoresfur-bearer.itsartificialraisinghassuchmeritsasdurablefurandlowcostandhighproduCtivity.MaskedcivetandnutriahavehigheconomicvalueandwideprospeCtofutilization.Atpresen…     

Chemical composition of wood and its connection with wood anatomy in Betula pubescens

ABSTRACT

The connection between chemical composition and anatomy of wood is poorly studied. Abiotic and biotic growth conditions affect the synthesis of structural compounds and the anatomy of wood at the same time as they affect growth. In this study, the wood chemical composition, and connections between wood chemistry and anatomy were studied in downy birch (Betula pubescens Ehrh.) grown on four growth sites possessing mineral and peat soils. Lignin, holocellulose, extractive and ash contents, and effective heating value were analysed and compared with libriform fibre double wall thickness and lumen diameter, vessel size and number, and ray and axial parenchyma numbers. Measured lignin and extractive contents were exceptionally high and holocellulose content low. Correlations between wood anatomy and effective heating value were partly different on different soils. Correlations between holocellulose and anatomy were the opposite of the correlations between other chemical compounds and anatomy. The significant correlations between chemical composition and anatomy were commonly opposite in trees grown on peat than in trees grown on mineral soil. Particularly, vessel characteristics and fibre wall thickness correlated significantly with wood chemistry in trees grown on mineral soil. The connections between wood anatomy and chemistry proved to be soil-dependent.     

Cytotaxonomy and Cytogeography of Vicia sect. Vicilla in Northeast of China

Intr0ducti0nKupicllal1asll1adearevisiol1ofFlciaL.i11tI1ettorldsincel976.Sect.Hcillai11cludcsaboutfiftcensPCcics.Tllel1losttaxaintl1issectionbelOI1gtoAsiansPCcics,wllichdistfibuteinSibcriainRussia,N0rtl1east,NortI1andWestofChina,Mongolia,Japa11andKorca,sucI1asVamoena,VamurensisandV.laI,onicaetc..Tl1rcetaxaal110ngtl1en1,VpiSghrlnis,V'hIm0It)ruInal1dVmpIicamainIydistributeinEuroPe.Vsyh,aIic0aIsodistributesintI1eNortl1ofAsia.Climmosol11enul11bersandkaryotyPes0fAsial1scct.Vicilla…     

采伐作业对长白山阔叶红松林林下植被影响的研究(英文)

森林采伐是森林经营中的一个关键环节。采伐对树木天然更新的影响直接关系到森林的结构、组成及森林的可持续经营。本文以长白山阔叶红松林为研究对象,对择伐5 年后不同作业迹地(集材道、楞场和采伐后林窗)的幼苗更新及灌木、草本的多样性进行研究,并以没有进行采伐干扰的林地作为对照。共设计样地23 块,在各个小样地内调查幼树的种类、树木、高度;灌木和草本植物的种类、树木、高度和盖度,应用SPSS 软件进行一元方差分析。结果表明,择伐作业影响幼苗的更新,灌木和草本的多样性在作业迹地增加,尤其在林隙处的多样性最高。适当采伐能促进幼苗的更新,特别是阔叶树种的更新。集材道对幼苗密度的影响比对幼苗高度的影响大,幼苗密度在集材道上密度最高;采伐作业对针叶树种有严重的影响,在三种作业迹地上针叶树种的密度都比对照低。为了维持森林的结构和组成,在森林收获和楞场的建立时,必须采取科学措施保护针叶树种。此外,采伐林窗和楞场的面积都应该减小。为了确保采伐迹地建群树种的更新,经营中应该在保护生物多样性的前提下,适当控制过于旺盛的灌木和草本层的生长。本研究结果将为采伐后作业迹地的恢复和森林的可持续经营提供科学的依据。图1 表4 参14。     

Effects of thinning on growth of six tree species in north-temperate forests of Lithuania

This paper summarises the results from 35 years-observed thinning experiments on 256 permanent sample plots in 10–60 year-old stands of ash, aspen, birch, oak, pine and spruce in Lithuania. Thinning enhanced crown projection area increment of residual trees. The largest effect was observed in stands of aspen and birch (growth increase by 200%), followed by ash and oak (over 100%), and spruce and pine (about 80%). Thinning also promoted dbh increment, especially in younger stands, and the increase of dbh increment was positively correlated with the thinning intensity. The strongest reaction was exhibited by oak and aspen, while ash, birch and conifers reacted to a lower extent. Low and moderate intensities of thinning stimulated volume production in younger stands while the opposite was observed in older stands with increasing removals. Spruce stands exhibited relatively strongest increase of volume increment and pine, –the weakest, while the effect on deciduous species was intermediate. The results demonstrate that significant increase in volume increment is achievable with thinning of only young forest stands, e.g. 10–20 year-old pine, birch and ash, or 10–30 year-old oak, aspen and spruce.     

Early development of three planted indigenous tree species and natural understorey vegetation in artificial gaps in an Acacia mangium stand on an Imperata cylindrica grassland site in South Kalimantan,Indonesia

Early performance of two dipterocarp species Anisoptera marginata and Shorea parvifolia, and a long-living pioneer species Peronema canescens (Verbenaceae) planted in artificial gaps (size 260 m²) and surrounding untreated stands was studied in a fast-growing plantation of Acacia mangium on an Imperata cylindrica grassland site in South Kalimantan, Indonesia. Forty seedlings of each species were planted at one-meter intervals in lines across each of the five gaps, starting and ending under closed stand. Survival, height and diameter (d_0.05) increments were measured, and the effect of gap opening on the composition and abundance of understorey vegetation (grass, shrub and native tree seedlings and saplings) was studied. 19 months after planting, average survival rates were 97% for A. marginata, 94% for P. canescens and 71% for S. parvifolia, with no statistical differences between gap and closed stand. Substantial mortality and damage of dipterocarps were caused by wild boars; minor damage by dieback (for S. parvifolia) and insect pests (for A. marginata). Early growth was clearly influenced by distance from gap centre and light conditions; the growth of seedlings was greater the nearer the seedlings were situated to centre and the higher the level of daily photosynthetic photon flux density (PPFD) was. Gap opening increased the growth of shrub species Chromolaena odorata, but not that of Imperata grass. It also increased the density and height growth of saplings of native pioneer and secondary tree species. Seedling density increased both in closed stand and actual gaps, but was higher inside gaps.Results indicate good prospects for diversifying the composition of fast-growing forest plantations on severely degraded former forest lands and integrating slow-growing valuable species in plantation programs. Both in-depth ecophysiological studies on species-specific growth requirements, and practical oriented research on silvicultural options and economics need further studies.     

Repair and strengthening of timber cantilever beams

This research aims to study the feasibility of repair and strengthening of timber cantilever beams used in historic buildings. It is conducted to investigate the feasibility of using different valid materials and techniques to repair and strengthen timber cantilever beams in new and historic timber buildings. The study is performed in terms of structural performance as well as historic and architectural values. An experimental program of several different materials and techniques is executed. The results are driven in terms of initial cracking load, crack propagation for the tested samples at different loading stages, deflection values, and failure load for each repaired or strengthened material and technique. The main variables are timber types (new and historic), repair and strengthening materials (steel plates, Glass Fiber Reinforced Polymer wrap, and Carbon Fiber Reinforced Polymer laminates), repair or strengthening techniques (near surface mounted and externally bonded system), and cantilever length (1000 and 1250?mm). Test results indicated that using steel plates, glass fiber wrap, and carbon fiber laminates increases the value of failure loads and decreases the deflection at both; repaired and strengthened timber cantilever beams compared to control beams.     

耐寒桉树永州引种栽培技术研究

通过引种栽培试验表明：永州是桉树的适宜引种区，可大量发展桉树。以栽培邓恩桉、边沁桉表现最佳，它们不仅生长快、材质好，而且抗逆性强，既耐严寒又耐高温耐瘠薄。柳桉也可发展，史密斯桉、多枝桉在土层深厚、气候温和的地方可少量发展。赤桉在前1～2年表现较佳，生长快，但到以后几年生长趋缓，必须选出优良家系，才能大量种植。     

Cloning and RNAi Construction of a LEAFY Homologous Gene from Populus tomentosa and Preliminary Study in Tobacco

PtLFY, a LEAFY （LFY） gene, was cloned from Populus tomentosa （LM50） by PCR. Sequencing analysis indicated that PtLFY was 2629 bp long, composed of three exons and two introns and encoded 378 amino acids. The splice donor sites and the splice acceptor sites were in identical positions to the LFY and its homologues. The amino acid sequence inferred was 68%-99% homologous to those of LFY and its homologues by blast analysis in GenBank. The Southern blot analysis indicated that there was a single copy of the PtLFY gene in genomic DNA of male and female P. tomentosa （LM50 and 5082）. The pBI121-Ptalfy （reverse）-intron-Ptlfy-GUS-nos was constructed using RNA interference （RNAi） technique and verified by PCR and digestion identification and transformed into tobacco. Some transgenic tobacco plants were obtained by PCR and PCR-Southern identification. The growth was generally repressed in transgenic tobacco plants compared with wild-type ones and some phenotypic differences were observed.     

Comparison of tree growth and undergrowth development in aerially seeded and planted Pinus tabulaeformis forests

Direct seeding is a less expensive practice than planting and has the potential to become a viable alternative to transplanting for afforestation and regeneration purposes. As an effective and a less costly regeneration method, aerial seeding has been applied with several tree species. As early as 1956, Chinese people engaged in aerial seeding and stands with a total of 2.97×10⁷ hm² have been developed up to 2004. Our study tested whether the growth of planted Chinese pine (Pinus tabulaeformis Carr.) seedlings and its undergrowth development in northwest aspects differ from that of aerially sown seedlings on the northern and northwestern aspects of slopes. In 2007, we collected data such as height, diameter at breast height (DBH), clear bole height and canopy widths of trees, abundance, coverage, and frequency of shrubs and herbs from 21-year-old planted Chinese pine stands on a northwestern aspect (PNW), aerially sown stands in a northwest aspect (ANW) and aerially sown stands in a northern aspect (AN). Results showed that the relation of crown area and mean DBH was best fitted by a double inverse model for the ANW and AN forests and by a quadratic model for the PNW forest. There was no difference in the growth between ANW and AN forests, while growth was significantly higher in the PNW forest than in the ANW and AN forests. That was consistent with the Sorenson diversity indices in the shrub and herb layers, indicating that there was a large number of the same species in both aerially seeded stands, although their locations were different. Both the number of species in the undergrowth and the Shannon-Wiener index in the shrub layer were higher in the PNW stands than in the ANW and AN stands. Dominant families for all three stands were Rosaceae and Compositae in the shrub and herb layer, respectively. The dominant species for all three stands was Spiraea pubescens in the shrub layer, while the dominant species was different from each other in the three stands. The discrepancy in diversity and composition of species in the herb layer show that herbs are sensitive to shrubs in the three forests. High mortality and skewed diameter distributions reflect severe competition and too high a density in the aerially seeded forests. Thus, aerial seeding is a viable and effective regeneration technique, but management practices, such as thinning, should be applied to these forests.