Differences and similarities in radial growth of Betula species to climate change

Betula platyphylla and Betula costata are important species in mixed broadleaved-Korean pine(Pinus koraiensis)forests.However,the specific ways in which their growth is affected by warm temperatures and drought remain unclear.To address this issue,60 and 62 tree-ring cores of B.platyphylla and B.costata were collected in Yichun,China.Using dendrochronological methods,the response and adaptation of these species to climate change were examined.A“hysteresis effect”was found in the rings of both species,linked to May–September moisture conditions of the previous year.Radial growth of B.costata was positively correlated with the standardized precipitation-evapotranspiration index(SPEI),the precipitation from September to October of the previous year,and the relative humidity in October of the previous year.Growth of B.costata is primarily restricted by moisture conditions from September to October.In contrast,B.platyphylla growth is mainly limited by minimum temperatures in May–June of both the previous and current years.After droughts,B.platyphylla had a faster recovery rate compared to B.costata.In the context of rising temperatures since 1980,the correlation between B.platyphylla growth and monthly SPEI became positive and strengthened over time,while the growth of B.costata showed no conspicuous change.Our findings suggest that the growth of B.platyphylla is already affected by warming temperatures,whereas B.costata may become limited if warming continues or intensifies.Climate change could disrupt the succession of these species,possibly accelerating the succession of pioneer species.The results of this research are of great significance for understanding how the growth changes of birch species under warming and drying conditions,and contribute to understanding the structural adaptation of mixed broadleaved-Korean pine(Pinus koraiensis)forests under climate change.

Expression of BpPIN is associated with IAA levels and the formation of lobed leaves in Betula pendula ’Dalecartica’

Auxin polar transport genes PIN(PINFORMED)determine the concentration gradient of auxin in plants.To understand the relationship between the development of different tissues in Betula pendula‘Dalecartica’,BpPIN gene expression and indole-3-acetic acid(IAA)content were analyzed using qRT-PCR,ELISA,and GUS staining.Gene expression of BpPIN genes and IAA levels in the leaves,buds,stems,xylem,and roots of B.pendula‘Dalecartica’and B.pendula as a control were measured.BpPIN1,BpPIN5 and BpPIN6 were upregulated during development in both species,suggesting a dominant role in the development of B.pendula‘Dalecartica’leaves.Moreover,BpPIN1 gene expression was positively associated with IAA levels during leaf,vein and petiole development in B.pendula‘Dalecartica’only.The correlation coefficient of the first three leaves was 0.69(P=0.04),while that of the first three petioles was 0.85(P=0.001).In addition,GUS staining of the pro-DR5::GUS transgenic line of cultivar was correlated with the results of BpPIN1 expression.Overall,these findings suggest that BpPIN1 is associated with the formation of lobed leaves in B.pendula‘Dalecartica’.

Analysis of EST-SSRs in silver birch(Betula pendula Roth.)

Simple sequence repeats（SSRs） defined as sequence repeat units between 1 and 6 bp occur abundantly in both coding and non-coding regions in eukaryotic genomes and these repeats can affect gene expression. In this study, ESTs（expressed sequence tags） of Betula pendula（silver birch） were analyzed for in silico mining of ESTSSRs, protein annotation, open reading frames（ORFs）,designing primers, and identifying codon repetitions. In B.pendula, the frequency of ESTs containing SSRs was 7.8 %with an average of 1SSR/4. 78 kb of EST sequences. A total of 188 SSRs was identified by using MISA software and dinucleotide SSR motifs（65.9 %） were found to be the most abundant type of repeat motif followed by tri-（27.1 %）,tetra-（4.8 %）, and penta-（2.2 %） motifs. Based on ORF analysis, 175 of 178 sequences were predicted as ORFs and the most frequent SSRs were detected in 50 UTR（58.43 %）,followed by in ORF（31.46 %） and in 30UTR（8.43 %）. 102 of 178 ESTs were annotated as ribosomal protein, transport protein, membrane protein, carrier protein, binding protein,and transferase protein. For a total of 102 SSRs（57.3 %）with significant matches, a set of 102 primers（100 %） with forward and reverse strands was designed by using Primer 3 software. Serine（Ser, 19.6 %） was predominant in putative encoded amino acids and most of amino acids showed nonpolar（35.3 %） nature. Our data provide resources for B.pendula and can be useful for in silico comparative analyses of Betulaceae species, including SSR mining.

长白山白桦(Betula platyphlla)纯林和白桦山杨(Populus davidiana)混交林凋落物的分解

采用交互分解实验,研究长白山白桦叶片和白桦、山杨与水曲柳混合叶片在白桦纯林和白桦山杨混交林内的分解过程。两年的分解实验结果表明,两种类型叶片均存在一个快速分解阶段和一个慢速分解阶段,森林类型和凋落物类型对凋落物分解率的影响在快速分解阶段不显著而在慢速分解阶段显著;混交林内的环境促进了凋落物分解和养分元素释放;在同一林型内,底物质量高的混合叶片其分解率和养分元素释放率均大于底物质量低的白桦叶片;凋落物的底物质量在一定程度上可以抵消森林类型对凋落物分解的影响;白桦山杨混交林混合叶片分解速率和养分元素释放率要显著大于白桦纯林内的白桦叶片,说明白桦山杨混交林的物质循环速度和养分元素供应能力要显著大于白桦纯林。

盐桦(Betula halophila)愈伤组织的高效诱导和不定芽的分化

设计不同激素、不同水平的单因子试验和正交试验,统计盐桦出愈率、分化率,筛选出诱导盐桦愈伤组织的最适外植体和最适培养基。盐桦愈伤组织高效诱导和不定芽分化的最适外植体为茎段;诱导愈伤组织的最适培养基为:LS+BA 0.5 mg/L+NAA 0.4;愈伤组织分化抽枝的最适培养基为:LS+BA 0.5 mg/L+NAA0.02 mg/L;高效诱导愈伤组织和不定芽分化的最适培养基为:LS+BA 0.5 mg/L+NAA 0.2 mg/L。琼脂7%,蔗糖浓度20 g/L。愈伤组织诱导率和不定芽分化率分别达到82%和93.6%以上。

干旱胁迫下白桦(Betula platyphylla)实生苗叶片的水分代谢与部分渗透调节物质的变化

在土壤干旱胁迫进程中 ,白桦实生苗叶片的自然含水量呈下降趋势 ;相对含水量总的变化趋势与自然含水量相同 ;束缚水含量及束缚水 /自由水比值显著升高 ,复水后 ,三者又重新恢复至正常水平。随着土壤水分逐渐减少 ,可溶性蛋白质的含量呈现减少趋势 ,复水后 ,可溶性蛋白质含量又可恢复至正常水平。白桦实生苗叶片可溶性糖含量增加 。

浙东中新世Betula mioluminifera Hu et Chaney的发现及古气候重建

随着古气候和古环境研究的日渐深入,"特有种气候分析法"成为新生代定量重建古气候研究的重要方法之一。使用这一方法分析了浙江东部天台中新统下南山组的古亮叶桦(Betula mi-oluminifera Hu et Chaney)压型化石,研究了其叶结构特征及表皮微细构造,定量推论浙江天台中新世时年平均温度为12.5～22.1℃,春季平均温度为13.0～23.1℃,较现在温暖。我国内蒙、吉林、山东、云南等地的新近系发现过古亮叶桦,分布的北界为42°N。其现存最近亲缘种亮叶桦(Betula luminifera)生活在101～119°E,23～34°N之间,海拔500～1800m的山区,是我国特有树种。亮叶桦分布范围的缩小显示中新世一段时期我国气候逐渐变冷的趋势。

Growth and nutrient dynamics of Betula alnoides seedlings under exponential fertilization

Betula alnoides is a fast-growing hardwood species grown in large plantations in Southeast Asia and South China.Nitrogen requirements for producing robus seedlings,growth and nutrient dynamics were investigated using exponential fertilization treatments.Root collar diameter,height,dry mass and nutrient contents of seedlings increased exponentially in all fertilization treatments as time progressed.Moreover,with water soluble fertilizer（Plant Products plus microelements N–P2O5–K2O：20–20–20）,300 mg N seedling-1was adequate.Vector analysis revealed that P was the most responsive nutrient element followed by N and K.Dilutions of N and K were evident in the plants without N addition,which induced initial P sufficiency and then luxury consumption probably due to the antagonistic interaction between N and P.However deficiencies of N,P and K were mostly observed in al exponential regimes during the experiment because seedling growth rate exceeded nutrient uptake rate,inferring that further study on improving the nutrient uptake efficiency is needed.Analysis of relationships among nutrient supply,dry mass,N content and N concentration demonstrated that 100–400 mg N seedling-1induced sufficiency to luxury consumption of nitrogen without significant change in dry mass,and 400 mg N seedling-1is recommended to apply for nutrient loading of seedlings before outplanting.The findings will help improve seedling quality and enhance the production of robust seedlings for plantation forestry of this species.

Construction and analysis of a subtracted cDNA library of Betula platyphylla female inflorescence

Female inflorescence of Betula platyphylla was sampled at an interval of eachtwo days to analyze the background of gene expression in floral phase. On the basis of SMARTstrategy, the driver cDNA was obtained from total RNA of the last sample and the tester cDNA wasfrom that of the others by RT-PCR which were subsequently used to construct a subtracted cDNAlibrary. The result of the ESTs (expression sequence tags) blastX showed that the genes in thesubtracted cDNA library could be mainly clustered into 5 groups related to metabolism,transportation and signal transduction, cell cycle, stress response, and regulation. Therelationship between gene expression and development was also discussed.

新疆桦木属(Betula L.)新分类群

为与中国植物志21卷桦木属的分组等级保持一致,将新疆桦木属(BetulaLinn.)分为1组(Sect.),4亚组(Subsect.);8种,5变种。其中包括1新亚组,4新变种和1新纪录种。

Analysis of three types of triterpenoids in tetraploid white birches(Betula platyphylla Suk.) and selection of plus trees

Betulin, oleanolic acid, and betulinic acid are naturally occurring pentacyclic triterpenoids that have significant medicinal value. Considerable amounts of these triterpenoids are available in the outer bark of white birch. In this study, we used ultrasound-assisted extraction （UAE） to extract triterpenoids from birch bark rapidly and with high efficiency. Using high performance liquid chro- matography （HPLC）, three types of triterpenoids were separated and detected. We examined the differences among triterpenoids extracted from diploid versus tetra- ploid white birch. Then, we used factor analysis to screen out tetraploid white birches with comprehensively excel- lent performance. The results indicate that the optimum conditions for extraction include the use of ethanol as an extraction solvent, a solid-to-liquid ratio of 0.1 g/10 ml, ultrasonic power set at 100 W, a temperature of 60 ℃ and an extraction time of 15 min. A reversed-phase C18 col- umn （4.6 mm × 250 mm × 5 μm） with a column tem- perature of 30 ℃ and the mobile phase composed of A （acetonitrile） and B （0.1% aqueous phosphoric acid, v/v） at a flow rate of 0.5 ml/min were used, and the detection wavelength was 195 nm. No significant difference wasobserved between diploid and tetraploid white birch in terms of the content of three types of triterpenoids （at a confidence level of 0.05）. As triterpenoid content, height, and DBH （diameter at breast height） are strongly interre- lated, we used factor analysis to evaluate all individuals, and we screened out six plus trees with excellent com- prehensive characters.

Progeny test of tetraploid Betula platyphylla and preliminary selection of hybrid parents

Estimating genetic parameters of parental lines through progeny testing and choosing good hybrid parents are important for genetically improving seed orchard trees.In this study, 24 tetraploid progeny seedlings were used as experimental materials, which came from test cross design：six tetraploid Betula platyphylla lines（Q33, Q13, Q103,Q19, Q83 and Q14） as female parents and four individual B. platyphylla diploid lines（F3, F4, F9 and F11） as male parents were crossed. Variance analysis of height, diameter, height-to-diameter ratio, and internodal distance showed that the differences between hybrid combinations reached highly significant levels. Using multi-objective decisionmaking, we performed a comprehensive assessment of the various hybrid combinations. Using a selection rate of 20 % of the standard, five hybrids were selected;their genetic gains in average height, diameter, height-todiameter ratio, and internodal distance were 20.95, 6.07,13.07 and 8.96 %, respectively. We also analyzed the combining ability and genetic parameter effect values of parents and hybrid combinations. The combined analysis revealed that Q13, Q103, Q33 and Q83 were superior females; F3, F4, and F9 were superior males; and F3 × Q13, F4 × Q83 and F9 × Q33 were superior hybrid combinations. The heights and diameters of these progenies were 22.49 and 11.48 % greater than average,respectively.

中国东北林区桦木属(Betula)分类探讨(英文)

许多学者先后对东北林区桦木属的分类进行了深入研究,对种及种下分类等级意见至今不一致,给综合开发利用桦木类群资源造成了混乱。笔者经多年深入林区实践、调查、采集标本,结合种群特征、地理分布、生境特点综合分类,不以蜡叶标本作为唯一依据,鉴定了桦木属种及种下等级,基本上同意傅沛云(1995)对东北林区桦木属的分类。但笔者认为东北白桦(B.mandshurica(Regel) Nakai)应视为独立种,取消栓皮白桦(Betula platyphylla Suk.var. phellodendroides Tung)名称及英吉里岳桦(ermanii Cham.var.yingkiliensis liou et Wang)名称,卵叶桦(Betula ovalifolia Rupr )不应该降为柴桦变种(Betula fruticosa Pall.),仍为独立种。图1表4参10。

Effects of environmental factors on seedling growth and anthocyanin content in Betula ‘Royal Frost’ leaves

Determining the influences of environmental factors on seedling growth and leaf color may improve our understanding of the chromogenic mechanisms in leaves and the biosynthesis of anthocyanin. To determine the optimum conditions for Betula 'Royal Frost' seedling cultivation, we assessed seedling growth and anthocyanin content under natural conditions. The temperature had a significant influence on height but not on radial growth. Between June and September, the anthocyanin content was significantly positively correlated with light intensity and air moisture and significantly negatively correlated with temperature. In single-factor experiments to determine the variation in anthocyanin content in the greenhouse, anthocyanin content increased with increasing soil water content and at first increased, then decreased with increasing pH of the irrigation water and temperature, but decreased with increasing light intensity. K2SO4 can increase the anthocyanin content. So to maintain leaf color, seedlings should be cultivated with < 200 mu mol m(-2) s(-1) light intensity at 20 A degrees C and soil moisture content between 60 and 90%, and the irrigation water should be neutral or alkaline. Additionally, spraying with K2SO4 can be beneficial.

Identification of SSR loci in Betula luminifera using birch EST data

Expressed sequence tags（ESTs） are generated from single-pass sequencing of randomly picked cDNA clones and can be used for development of simple sequence repeat（SSR） markers or microsatellites.However,EST databases have been developed for only a small number of species.This paper provides a case study of the utility of freely available birch EST resources for the development of markers necessary for the genetic analysis of Betula luminifera.Based on birch EST data,primers for 80 EST-SSR candidate loci were developed and tested in birch.Of these,59 EST-SSR loci yielded single,stable and clear PCR products.We then tested the utility of those 59 markers in B.luminifera.The results showed 28（47.6%） yielded stable and clear PCR products for at least one B.luminifera genotype.In addition,this study describes a rapid and inexpensive alternative for the development of SSRs in species with scarce available sequence data.

A New Caffeoylquiniclactone, Neochlorgeniclatone from the Leaves of Betula platyphylla Suk.

A new caffeoylquiniclactone, named neochlorgeniclatone, was isolated from the leaves of Betula platyphylla Suk. The Structure was established by spectroscopic data.

A New Monoterpene Glucoside from the Leaves of Betula platyphylla Suk.

A new monoterpene glucoside. (2E,67.)-2.6-dimethyl-8-beta -D-glucosyloxy-2,6-octadienoic acid, was isolated from the leaves of Betula platyphylla Suk. The structure was established by spectroscopic data.

ANALYSIS OF BIOLOGICAL GEOCHEMISTRY OFCHEMICAL ELEMENTS IN Betula ermanii FORESTIN CHANGBAI MOUNTAINS,CHINA

ABSTRACT: Based on catalogue of biology and geochemistry of chemical elements, content characteristics and variation law of the large nutrient elements, the needful trace elements, the uncertain needful elements, the non-needful elements and the toxic elements in Betula ermanii trees are analyzed. The result shows that the content of the large nutrient elements in Betula ermanii trees is higher than that of other kinds of element; the contents of all kinds of elements in foliage with vigorous metabolism are higher than those in other parts; the content variations of the large nutrient elements and the needful trace elements with similar chemical property, geochemical property and biological function in different parts of Betula ermanii trees show the similar laws; but the other three kinds of elements variations are without laws. It is indicated that the variation of the needful elements in the plant follows a certain law, they are in relative equilibrium under undisturbed condition.

Plant hormone treatments to alleviate the effects of salt stress on germination of Betula platyphylla seeds

We analyzed the germination traits (germination rate, germination potential, and germination index) of seeds from 23 half-sib families of birch (Betula platyphylla). The germination rates of the 23 families ranged from 38.57 to 76.50%. Seeds from the eight families germinating at the highest rates were then used for germination experiments under salt stress. Germination rate, germination potential, and germination index of these eight half-sib families decreased with increasing salt concentrations. The effects of four different hormones (6-benzylaminopurine, 6BA;gibberellin, GA3;naphthalene acetic acid, NAA;and melatonin) at various concentrations on the germination of seeds from the eight half-sib birch families under salt stress were investigated. Treatments with 6BA and GA3 alleviated the effects of salt stress on seed germination, whereas treatments with NAA and melatonin aggravated the effects of salt stress. The most effective treatments for alleviating the effects of salt stress on birch seed germination were 10 mg/L 6BA and 300 mg/L GA3. This study provides practical information for screening birch families for salt tolerance at the seed germination stage, and for cultivation of birch in saline environments.

Dynamics of Betula ermanni population in subalpine vegetation in Changbai Mountain, Northeast China

Betula ermanni population was divided into three groups: the upper population (2 000–2 200 m), the middle population (1 700–2 000 m), and the down population (1 400–1 700 m) in Changbai Mountain. The dynamics ofBetula ermanni populations in subalpine vegetation are studied and the population life table, fecundity schedule, survival curves, age structure, and fecundity curves were established. The results showed that the, middle population is obviously, the transition from the upper population to the down population.