Mitochondrial DNA variation in Olga Bay larch (Larix olgensis A. Henry) from Primorsky Krai of Russia

Two mitochondrial DNA fragments, nad4(3c-4r) and nad5(1-2r), were sequenced in 58 larch accessions from the range of Larix olgensis A. Henry. Combinations of the nad4 polymorphic sites formed four haplotypes, two of which (H3 and H4) were unique and two (H1, H2) were common. Haplotype H1 was found only in pure L. olgensis from the vicinity of Olga Bay and in a number of accessions from the southern part of the range. Haplotype H2 was detected in the other samples from the range of Olga Bay larch, as well as in hybrid forms. Similarly to the nad4(3c-4r) fragment, the mtDNA fragment UBC460 was able to differentiate larch populations from the range of L. olgensis examined.     

Genetic variability and differentiation in the larch populations within the range of Larix olgensis A. Henry in Primor'e region

The level of within- and among-population variation of larch inhabiting the range of Larix olgensis A. Henry in Primorye was estimated on the basis of 440 RAPD loci identified by means of 12 random primers. In ten population examined, the proportion of polymorphic loci was 35-60%, the average expected heterozygosity varied from 0.1340 to 2169, and the average gene flow estimate was 1.38. According to Fisher's test for heterogeneity, the pairwise differences of the fragment frequencies between the populations were statistically significant. The subdivision index G(ST) = 0.2663 indicated that the interpopulation variation component accounted for approximately 27% of the total variation. Coefficients of Nei's genetic distance between the populations varied from 0.0137 to 0.0934. Most of the samples with high support clustered according to the geographic positions relative to one another within the range. These results suggest that the populations examined are characterized by high genetic variation, like the larch populations of Siberia and the Russian Far East studied earlier, but, in contrast to the latter, exhibit higher among-population variability.     

长白落叶松群体遗传变异及优良家系选择的研究

以黑龙江省林口县青山林场21年生长白落叶松(Larix olgensis Henry)异地保存林为材料,分析白刀山种源优良木和劣等木群体的生长变异情况。结果发现优势木群体和劣等木群体差异不显著。树高、胸径、材积都存在丰富的变异,其中变异系数最大的是材积,其次是胸径,最小的是树高,其变异系数分别为46.24%、19.82%和12.25%;优势木群体树高、胸径、材积的变异系数分别是12.98%、20.77%和49.36%;劣等木群体树高、胸径、材积的变异系数分别是11.47%、18.79%和43.16%。同一性状树高、胸径、材积优势木群体变异高出劣等木群体变异系数分别为1.51%、1.98%和6.2%。方差分析表明家系间差异显著,选择了856、859、563、552、567、864号6个优良家系,优良木与劣等木群体各占3个;6个家系平均值分别超过优势木群体平均值和劣等木群体平均值0.017 7和0.013 6 m3。按照各自群体10%入选率,则遗传增益分别是38.74%和30.04%。     

Exogenous succinic acid mediates responses of Larix olgensis A. Henry to cadmium stress

Abstract

Trace metal contamination of soil is an increasing problem. Organic acid application can restore trace metal elements such as cadmium (Cd) in contaminated soil. Changbai larch (Larix olgensis A. Henry) is an economically important forestry species in northeast China; however, growth is inhibited by severe Cd contamination. We investigated the effects of different concentrations of exogenous succinic acid (SA) on Cd tolerance and physiological and morphological toxicity in L. olgensis seedlings. Seedlings were planted in pots containing Cd-contaminated or uncontaminated Haplic Cambisol. Seedlings in Cd-contaminated soil were treated daily with SA solution at 0, 0.04, 0.2, 1.0, and 2.0?mmol kg^?1 of soil for 10, 20 or 30?days. Cd treatment induced seedling damage and significantly increased the relative conductivity and malondialdehyde content of the leaves, inhibiting soluble protein and proline contents, superoxide dismutase and peroxidase activity, chlorophyl fluorescence and pigment content. Decreases in the length, surface area, volume of roots and leaves, and specific root length were also observed. Effects increased in control plants with time. SA treatment also reduced the Cd content of the fine roots and leaves and Mg, K, and Ca contents. Moreover, plant growth was significantly promoted and damage was reversed, especially at 5.0 and 10.0?mmol?L^?1 SA for 30?days. SA therefore alleviated Cd-induced injury, improving tolerance to Cd stress. SA application combined with afforestation could therefore help restore Cd-contaminated soil in northeast China. Further studies aimed at determining the detoxification mechanism of L. olgensis seedlings are now required.     

Genetic diversity and differentiation of Gmelin larch Larix gmelinii populations from Evenkia (Central Siberia)

Within- and among-population diversity of Gmelin larch Larix gmelinii (Rupr.) Rupr. from Evenkia was inferred from data on 17 genes determining allozyme diversity of ten enzymes. More than 50% of the genes proved to be polymorphic. On average, each tree was heterozygous at 9.2% genes. Heterozygosity expected from the Hardy-Weinberg proportions was higher, 12.5%. A deficit of heterozygous genotypes was observed in all populations under study and attributed to inbreeding. With Wright's F statistics, average individual inbreeding was estimated at 26.6% relative to the population (F(IS)) and at 27.8% relative to the species (F(IT)). The greatest deficit of heterozygosity was observed for the youngest population. Within-population variation accounted for more than 98% of the total variation, while the contribution of among-population variation was 1.66%. Genetic distance between populations varied from 0.0025 to 0.0042, averaging 0.0035.     

Genetic variability and differentiation in the larch populations within the range of <Emphasis Type="Italic">Larix olgensis</Emphasis> A. Henry in Primorye

The level of within-and among-population variation of larch inhabiting the range of Larix olgensis A. Henry in Primorye was estimated on the basis of 440 RAPD loci identified by means of 12 random primers. In ten populations examined, the proportion of polymorphic loci was 35–60%, the average expected heterozygosity varied from 0.1340 to 0.2169, and the average gene flow estimate was 1.38. According to Fisher’s test for heterogeneity, the pairwise differences of the fragment frequencies between the populations were statistically significant. The subdivision index G _ST = 0.2663 indicated that the interpopulation variation component accounted for approximately 27% of the total variation. Coefficients of Nei’s genetic distance between the populations varied from 0.0137 to 0.0934. Most of the samples with high support clustered according to the geographic positions relative to one another within the range. These results suggest that the populations examined are characterized by high genetic variation, like the larch populations of Siberia and the Russian Far East studied earlier, but, in contrast to the latter, exhibit higher among-population variability.     

长白落叶松、日本落叶松和兴安落叶松幼苗光合作用特性比较研究

研究长白落叶松(Larix olgensis Herry.),日本落叶松(Larix kaempferi Carr.) 和兴安落叶松(Larix gmelinii Rupr.)当年生和一年生幼苗的光合作用日变化、季节变化和光响应曲线,结果表明：①三种植物中,长白落叶松、日本落叶松当年生和一年生幼苗和兴安落叶松当年生幼苗光合速率日变化都呈双峰曲线,具有明显的“午休”特征。兴安落叶松一年生幼苗的光合速率日变化呈单峰曲线。②日本落叶松的光饱和点 (LSP) 最高,兴安落叶松光补偿点（LCP）最低。③三种落叶松的一年生幼苗都是在生长中期表现出最大的光合能力。从年龄来看,落叶松当年生幼苗在生长初期和生长中期的光合能力要低于一年生幼苗,但在生长后期高于一年生幼苗。④从种来看,生长初期,当年生和一年生幼苗的最大净光合速率(P_max)均为日本落叶松＞兴安落叶松＞长白落叶松;生长中期,当年生幼苗的P_max规律与生长初期相似,一年生幼苗的P_max为长白落叶松＞日本落叶松＞兴安落叶松;生长后期,当年生幼苗的P_max为长白落叶松＞兴安落叶松＞日本落叶松,一年生幼苗的P_max与生长中期一年生幼苗的规律正好相反。通过分析我们得到结论：三个树种在生长季节相同阶段具有不同的光合特性;每个种不同年龄和生长季节不同阶段也表现出不同的光合特性;三个树种中,长白落叶松幼苗对光抑制引起的光合器官损伤的修复能力最强,日本落叶松次之,兴安落叶松最弱;日本落叶松幼苗较喜光,光合作用能力较强,不易发生光抑制,而兴安落叶松幼苗较耐阴。因此在育苗和造林时应考虑不同树种的光合特性调节最佳的光照条件。     

Demand for Assimilates Determines the Productivity of Intensive and Extensive Rice Crops in Primorskii Krai

Intensive and extensive rice crops (Oryza sativa L.), regionally cultivated in Primorskii krai (maritime territory), were grown under full and 50% attenuated solar radiation. Plants of different varieties were used to examine the supply of newly synthesized and reutilized ¹⁴C-assimilates to caryopses and to estimate the dry weight dynamics of whole plants, vegetative organs, and grains. Cultivar-specific differences were revealed with respect to the sink capacity of caryopses, the export of photosynthates from the upper leaf and their delivery to the panicle, and the contributions of newly produced and reutilized assimilates to grain filling. In rice plants of all varieties grown under full insolation, the amount of photosynthates produced during grain filling was insufficient to satisfy the demand of caryopses; one-fourth or one-fifth of this demand was satisfied at the expense of mobilization of stored metabolites. The mobilization was accelerated by the elevated demand for assimilates and by attenuated insolation. In artificially shaded plants of intensive varieties, the pool of newly produced assimilates was lower and reutilization of previously gained assimilates started earlier than in shaded plants of extensive varieties. It is concluded that the higher grain yield of intensive rice varieties, cultivated in Primorskii krai, is determined by a higher demand for assimilates and by a higher production and accelerated supply of newly formed photosynthates to caryopses during the first half of the grain-filling stage. The potential productivity of these varieties is constrained by the deficit of assimilates during the second half of grain-filling stage. The low grain productivity of extensive varieties is caused by the insufficient number of grains in panicles and by low demand for assimilates throughout the period of grain filling.     

Genetic diversity, population structure, and differentiation of Siberian larch, Gmelin larch, and Cajander larch on SSR-marker data

The genetic diversity of SSR markers was studied in six populations of Siberian larch, two popu-lations of Gmelin larch, and four populations of Cajander larch. Seven pairs of nuclear microsatellite loci were used for this analysis. 103 allelic variants were detected in 365 individuals of three species of larch. According to the AMOVA results, the variability proportion that characterizes the differences between three Larix species was twice as higher (15%) than the proportion that accounts for among-population differences within the species (6%). The differentiation of the populations of three species of larch based on SSR markers exceeded 12% (F _ST = 0.121). A significant correlation of the genetic distances with the geographic distances between populations was found (r = 0.835, P = 0.01).     

长白落叶松半同胞家系生长和木材性状遗传变异与联合选择

长白落叶松（Larix olgensis）是我国东北重要的用材树种,根据生长和木材性状对其进行综合选择至关重要。本研究以吉林省延边自治区汪清林业局32年生的49个长白落叶松半同胞家系为材料,对其9个生长性状（树高、地径、胸径、3 m径、材积、尖削度、冠幅、分枝角和通直度）和4个木材性状（木材基本密度、管胞长度、管胞宽度和管胞长宽比）进行测定与分析。结果表明：不同变异来源间所有性状差异均达极显著水平（P<0.01）;各性状家系遗传力均较高（0.51~0.96）;表型变异系数为3.04%（分枝角）~23.15%（冠幅）;各性状相关系数为-0.367（管胞宽度与管胞长宽比）~0.994（胸径与材积）;主成分分析结果表明,4个主成分的累计贡献率达到78.46%,包含了家系生长性状和木材性状的大部分信息;分别以生长和木材性状对家系进行综合评价,初步筛选出5个生长性状优良家系（S78、S81、S80、S84和S83）和5个木材性状优良家系（S37、S51、S6、S30和S19）,结合生长和木材性状初步筛选出5个优良家系（S89、S74、S76、S82和S83）。本研究初选的材料可以为良种选育提供基础,亲本可以为改良种子园营建提供材料。     

不同地点51个长白落叶松无性系苗期生长变异和遗传稳定性分析

长白落叶松是我国东北林区非常重要的速生用材树种之一。以不同地点51个长白落叶松无性系为材料,对其2年生苗高和地径进行调查分析,探讨其苗期生长变异和遗传稳定性。结果表明:长白落叶松无性系苗高和地径在地点间、无性系间、地点×无性系间差异均达到极显著水平(P<0.01);不同地点苗高和地径的表型变异系数处于23.89%~36.82%,除四平试验点的地径重复力为0.172外,不同地点苗高和地径的重复力均处于0.573~0.891;遗传稳定性分析结果表明,无性系LO 13等28个无性系的遗传稳定性较高;相关分析结果表明苗高与地径呈极显著正相关关系;利用多性状综合评价法,以20%的入选率对无性系进行选择,不同地点均选出10个综合表现较好的无性系,其中无性系LO 10和LO 26在不同地点均被入选优良无性系,且其遗传稳定性较强,可将其初选为优良无性系。     

北京市华北落叶松优树群体遗传多样性分析

利用SSR分子标记对北京市华北落叶松人工林5个群体的220棵优树进行遗传多样性和群体结构分析。20对SSR引物共检测到81个等位基因,每个位点等位基因数2~8个不等,平均4.05个。群体观测和期望杂合度平均值分别为0.429和0.440,Shannon信息指数和多态性信息含量分别为0.756和0.380。5个群体中,百花山和云蒙山遗传多样性水平最高,雾灵山遗传多样性水平最低。AMOVA分析结果显示,2.65%的遗传变异来自于群体间,剩余97.35%的遗传变异来自于群体内。遗传分化系数仅为0.023,表明北京市华北落叶松优树群体遗传分化程度很低。基于Nei's遗传距离可以将5个群体划分为3个类群,四海镇和雾灵山归为第Ⅰ类,松山归为第Ⅱ类,百花山和云蒙山归为第Ⅲ类。STRUCTURE群体结构分析结果与上述聚类分析结果大体一致。以上研究为华北落叶松人工林遗传多样性评价和优良种质资源收集、保护和利用提供理论依据。     

兴安、长白及华北落叶松RAPD 分子标记的物种特异性鉴定

以中国北方地区主要乡土落叶松树种兴安落叶松(Larix gmelini)、长白落叶松(L. olgensis)和华北落叶松(L. principisrupprechtii)的针叶及种子胚乳为研究材料, 采用RAPD分子标记技术对3种落叶松进行不同物种的种间鉴别。结果表明, 通过引物筛选得到了4个可以鉴别3种落叶松的RAPD引物, 其中有2个引物在落叶松针叶和种子胚乳基因组中都扩增出相同的条带。引物OPB-11在兴安和长白落叶松基因组DNA中1 500 bp处扩增出特异条带, 而在华北落叶松中没有; 引物OPX-14在兴安落叶松基因组DNA中1 200 bp处扩增出特异条带, 而在长白落叶松中没有; 还有2个引物可分别作为3种落叶松苗木和种子鉴别的辅助标记。本研究从分子水平上为落叶松的种间鉴别提供了新的鉴定方法。     

兴安、长白及华北落叶松RAPD分子标记的物种特异性鉴定

以中国北方地区主要乡土落叶松树种兴安落叶松（Larix gmelini）、长白落叶松（L.olgensis）和华北落叶松（L．principis—rupprechtii）的针叶及种子胚乳为研究材料,采用RAPD分子标记技术对3种落叶松进行不同物种的种间鉴别。结果表明,通过引物筛选得到了4个可以鉴别3种落叶松的RAPD引物,其中有2个引物在落叶松针叶和种子胚乳基因组中都扩增出相同的条带。引物OPB-11在兴安和长白落叶松基因组DNA中1500bp处扩增出特异条带,而在华北落叶松中没有：引物OPX-14在兴安落叶松基因组DNA中1200bp处扩增出特异条带,而在长白落叶松中没有：还有2个引物可分别作为3种落叶松苗木和种子鉴别的辅助标记。本研究从分子水平上为落叶松的种间鉴别提供了新的鉴定方法。     

长白山落叶松林下笃斯越桔群落生物量的空间分布

以长白山区落叶松林下笃斯越桔群落为研究对象,调查其群落的地上、地下各部分的生物量及其空间分布规律。结果表明:地上部枝条生物量主要分布在50cm高度以下,基径3～5mm粗枝的生物量在地上部分各级别中所占比重最大。笃斯越桔地下部生物量较大,占总生物量的75.2%～92.6%;地下部生物量主要集中在死苔藓层内,占总根量的66.3%～85.0%,而其中<1mm细根所占比重最大,为该层总根量的42.6%～82.7%。在泥炭层内笃斯越桔根系占总根量的12.3～29.7%,比重较小。笃斯越桔的根系生物量占所有植物根系生物量的8.8%～60.7%,笃斯越桔以细根为主。本研究结果为笃斯越桔资源的合理开发与保护利用以及生态系统碳汇功能评估等提供了基础。     

Climate response of radial growth and early selection of Larix olgensis at four trials in northeast China

The objective of this study was to evaluate the age trends of genetic variation in radial growth of different provenances and growth-climate relationship in different locations. Tree-ring cores of 10 L. olgensis provenances were sampled from four representative trials with different climatic conditions in 2019. The results of ANOVA show that significant differences for DBH at different ages were detected among provenances within sites, except for 10, 11, 37, and 38 years at LS. The phenotypic and genetic coefficient of variation in different sites were generally decreased with age. Although there were large fluctuations for provenance repeatability at different ages across sites, they all belonged to high repeatability. Age-age correlations show that the early selection for DBH could be made at the age of 10 years at the semi-arid area in Heilongjiang province and the southeast slope of Xiaoxing'an Mountains, while the ages for early selection at the southeastern slope of Daxing'an Mountains and the western slope of Zhangguangcai Mountain were 13 and 12 years old, respectively. The results of growth-climate relationships showed that temperature and precipitation played key roles in the radial growth of larch at each site. In the semi-arid area in Heilongjiang province, radial growth showed significant correlations with August temperature (positive) of the current year, and with previous May temperature (negative) and November temperature (positive), and previous December precipitation (positive). The current June temperature (negative) and precipitation (positive) were important factors affecting the radial growth at the southeastern slope of Daxing'an Mountains. July temperature of the current year had a negative relationship with larch growth at the southeast slope of Xiaoxing'an Mountains, while there were no significant correlations between radial growth and climatic factors at the western slope of Zhangguangcai Mountain. The results reported in this study provide a valuable insight about early selection for different sites and can serve as a reference for future breeding and improvement research.     

Genetic diversity and connectivity in a brooding reef coral at the limit of its distribution

Remote populations are predicted to be vulnerable owing to their isolation from potential source reefs, and usually low population size and associated increased extinction risk. We investigated genetic diversity, population subdivision and connectivity in the brooding reef coral Seriatopora hystrix at the limits of its Eastern Australian (EA) distribution and three sites in the southern Great Barrier Reef (GBR). Over the approximately 1270 km survey range, high levels of population subdivision were detected (global F_ST = 0.224), with the greatest range in pairwise F_ST values observed among the three southernmost locations: Lord Howe Island, Elizabeth Reef and Middleton Reef. Flinders Reef, located between the GBR and the more southerly offshore reefs, was highly isolated and showed the signature of a recent bottleneck. High pairwise F_ST values and the presence of multiple genetic clusters indicate that EA subtropical coral populations have been historically isolated from each other and the GBR. One putative first-generation migrant was detected from the GBR into the EA subtropics. Occasional long-distance dispersal is supported by changes in species composition at these high-latitude reefs and the occurrence of new species records over the past three decades. While subtropical populations exhibited significantly lower allelic richness than their GBR counterparts, genetic diversity was still moderately high. Furthermore, subtropical populations were not inbred and had a considerable number of private alleles. The results suggest that these high-latitude S. hystrix populations are supplemented by infrequent long-distance migrants from the GBR and may have adequate population sizes to maintain viability and resist severe losses of genetic diversity.     

抚育间伐对长白落叶松人工林土壤碳、氮及其组分的影响

抚育间伐作为重要的森林经营措施之一,能够改变林分结构和稳定性,进而影响森林生态系统的生物地球化学循环.然而,抚育间伐对森林土壤碳、氮循环的影响程度如何尚不明确,尤其缺少长期试验结果报道.本研究以黑龙江省孟家岗林场经过4种不同强度和频度的抚育间伐处理后的60年生长白落叶松人工林为研究对象(4次低强度的间伐,LT4;3次中等强度的间伐,MT3;2次高强度间伐,HT2;不进行间伐的对照,CK),从酸水解法划分土壤碳、氮库(活性碳、氮库Ⅰ,活性碳、氮库Ⅱ和惰性碳、氮库)的角度研究了抚育间伐对长白落叶松人工林土壤总有机碳、全氮的影响机制.结果表明: 抚育间伐显著增加了土壤有机碳和全氮含量,增幅分别高达48.7%～50.3%和28.9%～42.7%.抚育间伐均增加了3种碳、氮组分的含量,而增加的程度因碳、氮组分和抚育间伐措施的不同而异.与活性碳库Ⅰ和活性碳库Ⅱ的增加程度相比,惰性碳库的增加程度最大,LT4、MT3和HT2处理下惰性碳库分别增加71%、69%和75%.此外,抚育间伐也显著增加了惰性碳占土壤总有机碳的比例.LT4显著提高了土壤微生物生物量碳、氮含量和微生物熵,而MT3和HT2对微生物生物量碳、氮和微生物熵却无显著影响.抚育间伐可能通过产生较多的粗木质残体于土体中,增加土壤木栓质和木质素等顽固组分的输入,进而导致土壤惰性碳含量增加,降低有机质的分解,最终导致土壤有机碳增加.