Cloning and analysis of telomere-associated sequences of <Emphasis Type="Italic">Ginkgo biloba</Emphasis> L.

Total genomic DNA was extracted from leaves of Ginkgo biloba L. by the method of hot CTAB. After determining quantification of DNA sample by microclorimetric spectrophotography, Arabidopsis-type telomere primer and Sau3A I cassette primer were used to isolate telomere-associated sequences from G. biloba L. by the method of cassette-ligation-mediated polymerase chain reaction (PCR). Using this method, two telomere-associated sequences, TAS1 and TAS2, were isolated. The authors preformed Southern hybridization ofEcoR I-treated G. biloba genomic DNA with each clone. The hybridization pattern showed that the clones obtained were derived from G. biloba genomic DNA. There are the Arabidopsis-type TTTAGG tandem repeats in telomeres of G.biloba.     

Restriction map and polymorphisms of nuclear ribosomal genes of Populus balsamifera

Balsam poplar (Populus balsamifera) clones from five populations, which were collected along a transect from northern Wisconsin to the northern tree line, were evaluated for polymorphisms in nuclear ribosomal DNA. For this purpose, a restriction map was constructed using four six-cutter enzymes in single and double digests of genomic DNA. After electrophoretic separation on agarose gels and Southern transfer, blots were hybridized to non-radioactively labeled heterologous rDNA probes of soybean. Among populations, variation was detected in the length of the intergenic spacer between the tandem repeats of the coding regions and in the degree of methylation of one restriction enzyme recognition site. Based on a comparison of the derived restriction map of balsam poplar and other poplars, high homology was evident in the rDNA coding regions among species, whereas the intergenic spacer varied slightly in both length and number of restriction sites.     

油桐尺蛾核型多角体病毒广西株全基因组序列

油桐尺蛾核型多角体病毒广西株基因组序列由Sanger测序的方法得到。拼接后获得了121 268 bp序列,GC含量为36.76%。以长度不小于50 aa的序列认定为功能基因,共预测到131个开放阅读框,通过Blast比对,其中87个能注释到功能基因。对基因组序列进重复序列分析,共发现SSR位点174个,同源重复序列1个。在SSR位点中,包含6种长度的重复基序,且以富含AT的重复基序为主。同源重复序列两端为一59 bp片段或其一部分组成的重复序列,两端分别重复12次和7次,中间则为一段与重复片段无关的236 bp片段。与武汉株相比,广西株病毒在37个核心基因中有4个存在蛋白序列长度上的差异,而在其他非核心基因中有6个基因仅存在于一个病毒株中,另有13个基因存在蛋白序列长度上的差异。     

Analysis and characterization of the <Emphasis Type="Italic">Salix suchowensis</Emphasis> chloroplast genome

By screening sequence reads from the Salix suchowensis chloroplast (cp) genome that were generated by next-generation sequencing platforms, we assembled a complete circular pseudomolecule for the cp genome. This pseudomolecule is 155,508 bp long and has a typical quadripartite structure that contains two single copy regions, a large single copy region (LSC, 84,385 bp), and a small single copy region (SSC, 16,209 bp) separated by inverted repeat regions (IRs, 27,457 bp). Gene annotation revealed that the S. suchowensis cp genome encoded 119 unique genes, including four ribosome RNA genes, 30 transfer RNA genes, 82 protein-coding genes, and three pseudogenes. Analysis of the repetitive sequences revealed 31 tandem repeats, 16 forward repeats, and five palindromic repeats. In addition, a total of 148 perfect microsatellites, which were characterized as A/T dominant in nucleotide composition, were detected. Significant shifting of the IR/SSC boundaries was revealed by comparing this cp genome with those of other rosid plants. We also constructed phylogenetic trees to demonstrate the phylogenetic position of S. suchowensis in Rosidae based on 66 orthologous protein-coding genes present in the cp genomes of 32 species. Sequencing 30 amplicons based on the pseudomolecule for experimental verification revealed 99.88% accuracy for the S. suchowensis cp genome assembly. Therefore, we assembled a high-quality pseudomolecule of the S. suchowensis cp genome, which is a useful resource for facilitating development of this shrub willow into a more productive bioenergy crop.     

Abscisic acid and the regulation of embryo dormancy in the genus Acer

Germination of Acer pseudoplatanus L. and Acer platanoides L. seeds was increased by moist storage of the intact fruits (seed + pericarp) at 5 degrees C, but not at 17 degrees C. In both species, germinative capacity of isolated embryos (seeds with testa removed) was increased by moist storage of fruits at either 5 or 17 degrees C. Thus dormancy loss by intact seeds and excised embryos was not necessarily correlated. Loss of dormancy in isolated embryos was associated with a reduction in free abscisic acid (ABA) content. Embryos from freshly harvested fruits of A. pseudoplatanus had a higher germinative capacity and a lower free ABA content than embryos from freshly harvested fruits of A. platanoides. Morever, germinative capacity increased, and free ABA content decreased, more rapidly with length of fruit storage in A. platanoides embryos than in A. pseudoplatanus embryos.     

云南红豆杉种子贮藏过程中胚的变化

采用显微测量、石蜡切片和离体培养法研究了云南红豆杉种子在贮藏过程中胚的长度、结构和萌发率的变化,结果显示:新鲜种子胚的长度差异明显,在种子贮藏过程中胚的长度变化不明显;多数情况下,成熟种子的胚分化完全,在种子贮藏过程中胚的结构没有发生明显变化;在离体培养中,新鲜种子胚在2周左右萌发,萌发率为70%,随着贮藏时间的延长,胚的萌发率会逐渐降低.因此推测种子休眠不是由胚的生物学特性引起的;胚在种子中能较长时间的保持活力,这是长期适应的结果,但却是以损失萌发率为代价的.     

High-efficiency somatic embryogenesis and morphohistology and histochemistry of somatic embryo development in Larix leptolepis Gordon

A high-efficiency somatic embryogenesis protocol of Japanese larch (Larix leptolepis Gordon) has been established in our investigation. Calli were induced from immature zygotic embryos of female cones of L. leptolepis and then subcultured regularly on to a modified Gupta and Durzan (DCR) basal medium for 5 years. Embryogenic tissues showed distinct morphological changes dur-ing somatic embryo development when they were transferred to a maturation medium supplemented with abscisic acid (ABA) com-pared with the morphology in a medium lacking ABA. Histological observations indicated that polyembryony was a characteristic feature during early embryogeny and somatic embryos at later stages showed normal histodifferentiation. In addition, histochemical analysis revealed that abundant starch granules and proteins accumulated in mature embryos, indicating that they played important roles in the development and regeneration of normal plantlets from somatic embryos on hormone-free germination media     

嘉陵江中上游码头景观资源旅游开发价值与对策初探

通过文献调查法和调研法,对嘉陵江中上游的码头景观资源进行研究与调查,发现在嘉陵江中上游码头景观资源的开发利用中,存在码头功能丧失、码头景观单一、码头文化在城市形象建设中占比较低、古城镇旅游区尚未将老码头纳入重点景区等问题。针对以上问题,从自然和人文区位优势的角度进行分析,提出以下促进嘉陵江中上游码头文化特色旅游资源开发的途径:(1)恢复和重建码头景观;(2)将码头文化融合于城镇形象建设中;(3)恢复码头功能,重现码头活力。通过以上措施,能充分开发并提升嘉陵江中上游码头景观的旅游资源价值。     

Storage lipid dynamics in somatic embryos of Norway spruce (Picea abies): histochemical and quantitative analyses

Adequate storage compounds are a prerequisite for successful development during the later stages of somatic embryogenesis; however, the critical amount of reserves below which somatic embryos fail to mature and germinate has not been determined. We analyzed storage lipids during Norway spruce (Picea abies (L.) Karst.) somatic embryogenesis. As maturation progressed, lipids, which were stored as lipid bodies in the cytoplasm, were localized first in suspensor cells of the early embryos, and later in the embryonic root pole, superficial layers of the hypocotyl and in cotyledons. The concentration of total lipids exhibited marked variation, with values peaking during cotyledon development and then decreasing during maturation. Linoleic (18:2), oleic (18:1), palmitic (16:0) and 5,9-octadecenic (5,9-18:2) acids were the most abundant fatty acids in embryos. As embryos developed, linoleic acid concentration increased slightly, whereas oleic acid concentration decreased. Oleic acid was the most prominent component of the fatty acid spectrum in isolated dormant zygotic embryos and megagametophytes. Addition of 5% polyethylene glycol to the medium during somatic embryo maturation caused a shift in the fatty acid spectrum toward that of zygotic embryos. During maturation, changes in the exogenous carbohydrate supply had no significant effect on total lipid concentration in mature embryos. A marked decrease in lipid concentration was detected during desiccation, indicating the importance of adequate lipid reserves during this developmental stage. The lipid content of zygotic embryos differed considerably with harvest year and location, suggesting that zygotic embryo data cannot be an indicator of somatic embryo quality.     

Analysis and characterization of the Salix suchowensis chloroplast genome

By screening sequence reads from the Salix suchowensis chloroplast(cp) genome that were generated by next-generation sequencing platforms, we assembled a complete circular pseudomolecule for the cp genome.This pseudomolecule is 155,508 bp long and has a typical quadripartite structure that contains two single copy regions, a large single copy region(LSC, 84,385 bp), and a small single copy region(SSC, 16,209 bp) separated by inverted repeat regions(IRs, 27,457 bp).Gene annotation revealed that the S.suchowensis cp genome encoded 119 unique genes, including four ribosome RNA genes, 30 transfer RNA genes, 82 protein-coding genes, and three pseudogenes.Analysis of the repetitive sequences revealed31 tandem repeats, 16 forward repeats, and five palindromic repeats.In addition, a total of 148 perfect microsatellites, which were characterized as A/T dominant in nucleotide composition, were detected.Significant shifting of the IR/SSC boundaries was revealed by comparing this cp genome with those of other rosid plants.We also constructed phylogenetic trees to demonstrate the phylogenetic position of S.suchowensis in Rosidae based on 66 orthologous protein-coding genes present in the cp genomes of 32 species.Sequencing 30 amplicons based on the pseudomolecule for experimental verification revealed99.88% accuracy for the S.suchowensis cp genome assembly.Therefore, we assembled a high-quality pseudomolecule of the S.suchowensis cp genome, which is a useful resource for facilitating development of this shrub willow into a more productive bioenergy crop.     

Radial variations of wood properties in <Emphasis Type="Italic">Casuarina equisetifolia</Emphasis> growing in Bangladesh

Radial variations of wood properties (basic density, fiber length, vessel element length, and compression strength) in plantation-grown Casuarina equisetifolia in Bangladesh were investigated for effective utilization of the wood. Samples disks at breast height were randomly collected from trees in a 10-year-old plantation in Cox’s Bazar Forest Division, Bangladesh. The basic density showed a near-constant value up to 30 mm from the pith and then rapidly increased up to 60 mm from the pith. The fiber length and vessel element length gradually increased from the pith to bark. When radial variation of wood properties was determined according to relative distance from the pith, similar radial patterns were observed among the sample trees, indicating that the wood properties in C. equisetifolia may be related to the growth rate. The compression strength parallel to the grain (CS) increased from the pith to bark. A significant positive correlation was found between the air-dried density and the CS. The results obtained indicated that wood around the pith has a relatively low density, and wood outside the pith area has a relatively high density, suggesting that it could be used as structural lumber. Part of this report was presented at the 58th Annual Meeting of Japan Wood Research Society, Tsukuba, March 2008     

An assessment of heterozygosity and fitness in Chir pine (<Emphasis Type="Italic">Pinus roxburghii</Emphasis> Sarg.) using isozymes

A correlation between heterozygosity of genotypes and survival (fitness) was studied in eight natural populations of Pinus roxburghii through isozyme analysis using horizontal starch gel electrophoresis. Under each population, 20 mother trees of different ages (30 to more than 100 years) were selected which were at least 50 m apart. From each tree, eight seeds were assayed for eleven enzyme systems viz., Aconitase, Aspertate aminotransferase, Glutamate dehydrogenase, Isocitrate dehydrogenase, Leucine-amino peptidase, Malate dehydrogenase, Menadione reductase, Phosphoglucose isomerase, Phosphoglucomutase, 6-Phosphogluconate dehydrogenase and Shikimic acid dehdrogenase which were found to be encoded by 18 polymorphic loci. Genetic constitution of the mother trees was determined by analysing endosperms and embryos separately. The number of alleles in the progeny (embryos) and the mother trees varied from 38 to 42 and 34 to 37, respectively, in all the populations. Distribution of degree of heterozygosity and fixation index for the progeny and the mother trees were calculated. The mother trees showed a substantial shift towards higher degree of heterozygosity as compared to the progeny. Fixation index values were significantly higher and negative for the mother trees as compared to the progeny, which revealed that heterozygosity was positively correlated with survival in P. roxburghii. Application: Heterozygous geneotypes in tree species are shown to have better survival over homozygotes under diverse environmental conditions. Every year, millions of Pinus roxburghii saplings are planted in India. However, the fact that survival is very low might possibly be due to inbred/homozygous plants that suffer from fitness disadvantage. Our study indicates that heterozygotes have a better chance of survival under environmental conditions. The use of heterozygotes should lead to effective establishments of Pinus roxburghii plantations.     

Forensic DNA profiling of tropical timber species in Peninsular Malaysia

Illegal logging poses a significant threat to the sustainability of tropical forest ecosystems. By using Neobalanocarpus heimii (Dipterocarpaceae) as an example, the study assessed the feasibility of using short tandem repeats (STRs) as a tool to identify the source of illegally logged timber. Thirty natural populations of N. heimii were profiled using 12 STRs to develop the DNA profiling databases. As the cluster analysis divided the 30 populations into three genetic clusters, corresponding to three subregions within Peninsular Malaysia. The DNA databases were characterised at the levels of population, subregion and Peninsular Malaysia. Independence tests within and among loci were violated in all the databases due to significant levels of population differentiation and inbreeding. Thus, the effects of population substructure and inbreeding should be incorporated into the calculation of random match probability. The random match probabilities estimated using subpopulation and subpopulation-cum-inbreeding models were biased in favour of the defendant, whereas the random match probabilities estimated using product rule were biased in favour of the prosecutor. The conservativeness tests showed that the subregion and Peninsular Malaysia databases were conservative, and these databases should be able to provide legal evidence for court proceedings against illegal loggers in Peninsular Malaysia.     

The dependance of root growth potential on light level,photosynthetic rate,and root starch content in jack pine seedlings

Number of new roots (root growth potential or RGP), new root length, photosynthesis, total nonstructural carbohydrate content of needles and roots, terminal bud condition, and shoot elongation were measured on jack pine container seedlings for 4 weeks at weekly intervals under greenhouse conditions of 100%, 20%, and 10% sunlight to simulate competition-induced, lower light levels in the field. Both lower light levels significantly reduced photosynthetic rate, RGP, new root length, total nonstructural carbohydrate (especially starch) content of needles and roots, speed of terminal bud flush, and shoot growth. Both light level and photosynthetic rate were positively correlated with RGP and new root length, indicating that jack pine seedlings may use current photosynthate as an energy source to support new root growth. RGP and new root length were also both negatively correlated with root starch content suggesting that jack pine seedlings may also use stored carbohydrates as a potential carbon source for root initiation and initial root growth.     

Some reactions of<Emphasis Type="Italic"> Ips typographus</Emphasis> (L.) (Col.: Scolytidae) to changing breeding conditions in a forest decline area in the Sudeten Mountains,Poland

Investigations on I. typographus populations were conducted in 1992–1994 in the Sudeten (south-western Poland), in Norway spruce stands that were devastated previously by insect outbreaks and that exhibited severe forest decline. Crown defoliation and the volume of infested trees per hectare were used as indices of stand health and breeding conditions; variability in the infestation density, gallery length, and body length of beetles were parameters that were used to estimate the response of I. typographus populations to changing stand conditions. In stands located in the zone above 800 m a.s.l. where both the level defoliation and tree mortality were higher, the infestation density and body length of I. typographus were higher than in the zone below 800 m a.s.l., where stands were less damaged. Contrarily, the gallery length was higher in lower montane zone, where lower infestation densities and body length values were found. A proposed mechanism for this interaction, which is attributed mainly to better breeding conditions for I. typographus populations in weakened stands, is presented and discussed.     

Effect of growth conditions on wood quality characteristics of black pine (Pinus nigra Arn.)

Summary Geographical location (north/south latitude), social position of trees in a forst stand (dominant, codominant, suppressed) and site quality were investigated as to their effect on tracheid length, proportion of latewood and wood density of black pine indigenous to Greece. Tracheid length was fund greater in the northern location, in dominant trees and at intermediate site qualities. Proportion of latewood was higher in the southern location, in suppressed trees and at intermediate site qualities. Density was higher in the southern location, in codominant trees and at good or intermediate site qualities. Statistically, however, many differences at P = 95 % and all differences at P = 99% are not significant.The present study is based on the sampling of 331 trees, 55 years old and older; the probes were taken only from the 10 outer rings, at breast height. The findings from 6 trees, sampled from pith to bark, present disagreement with the above results.Presented at the Conference of IUFRO, Division 5, Oxford, U.K., April 1980     

木荷地理遗传变异和优良种源初选

在2005年底,对福建建瓯、浙江淳安和庆元的3年生37个产地的木荷种源试验林进行了全面调查,系统研究了幼林生长和分枝性状的种源差异、种源与环境互作及地理变异模式.结果表明:木荷树高、当年抽梢长度、地径、冠幅及侧枝总数、侧枝长和侧枝粗等分枝性状都存在显著的种源效应,木荷地理种源分化明显.造林区立地生境和造林地立地条件对木荷种源生长影响显著,如福建建瓯点3年生种源平均树高较北缘区浙江淳安点和高海拔山地浙江庆元点分别提高了24.1%和18.0%.木荷树高、当年抽梢长度、冠幅、侧枝总数等存在显著的种源×地点和种源×重复/地点互作,不同种源在各区试点上的生长相对表现差异显著.相关分析表明,木荷生长和分枝性状的地理变异模式因区试点环境条件差异而迥异.在中心分布区的福建建瓯点,种源生长和分枝性状与产地纬度相关性显著,呈典型的纬向地理变异模式,速生种源主要来源于分布区的中南部;在北缘区的浙江淳安点,种源高径生长与产地经纬度相关性较小,仅发现侧枝总数和树冠浓密度与产地纬度呈一定程度的负相关,速生种源主要来源于分布区的中部;而在较高海拔区的浙江庆元点,由于环境相对恶劣,木荷种源生长和分枝性状与产地纬度呈显著的正相关,偏北部种源的早期生长表现较好.基于种源幼林测定结果,分别从中心分布区和北缘区初选了一批速生用材和生物防火优良种源.     

Effects of exogenous gibberellin and auxin on shoot elongation and vegetative bud development in seedlings of Pinus sylvestris and Picea glauca

The hormonal control of stem unit (foliar appendage and axillary structure, if present, plus subtending internode) number and length was investigated in shoots of Scots pine (Pinus sylvestris L.) and white spruce (Picea glauca (Moench) Voss). Seedlings were treated with six gibberellins (GA1, GA3, GA4, GA5, GA9 and GA20) and two auxins (indole-3-acetic acid (IAA) and naphthaleneacetic acid (NAA)) when either neoformed growth was occurring or the terminal vegetative bud was developing. Hormones were applied by drenching the shoot tip, injecting the stem or spraying the foliage. Combined results for all three application methods indicated that shoot elongation in first-year seedlings (i.e., neoformed growth) was promoted in both species by GA1, GA3, GA4 and, less obviously, by GA9. This promotion was attributable to an increase in length, rather than number, of stem units. However, the number of stem units formed during terminal bud development, as reflected in the number of needles (white spruce) or cataphylls (Scots pine) present on the shoot resulting from the terminal bud, was stimulated by GA1, GA3 and GA4 in both species and by GA9 in Scots pine. The GA-induced increase in the number of preformed stem units was associated with increased bud width in white spruce and increased bud length and resulting shoot length in Scots pine. In contrast, application of IAA or NAA either did not affect or inhibited both neoformed growth and terminal bud stem unit number, depending on the application method and concentration. We conclude that, in the Pinaceae, (1) GA stimulates the activity of both the subapical meristem during neoformed growth and the apical meristem during vegetative bud development, and (2) the early non-hydroxylation pathway, via GA9, is the major route of GA biosynthesis. The role of auxin in the control of stem unit number and length remains to be resolved.