A mitochondrial DNA minisatellite reveals the postglacial history of jack pine (Pinus banksiana), a broad-range North American conifer

Jack pine (Pinus banksiana Lamb.) is a broadly distributed North American conifer and its current range was covered by the Laurentian ice sheet during the last glacial maximum. To infer about the history and postglacial colonization of this boreal species, range-wide genetic variation was assessed using a new and highly variable minisatellite-like marker of the mitochondrial genome. Among the 543 trees analysed, 14 distinct haplotypes were detected, which corresponded to different repeat numbers of the 32-nucleotide minisatellite-like motif. Several haplotypes were rare with limited distribution, suggesting recent mutation events during the Holocene. At the population level, an average of 2.6 haplotypes and a mean haplotype diversity (H) of 0.328 were estimated. Population subdivision of genetic diversity was quite high with G(ST) and R(ST) values of 0.569 and 0.472, respectively. Spatial analyses identified three relatively homogeneous groups of populations presumably representative of genetically distinct glacial populations, one west and one east of the Appalachian Mountains in the United States and a third one presumably on the unglaciated northeastern coastal area in Canada. These results indicate the significant role of the northern part of the US Appalachian Mountains as a factor of vicariance during the ice age. A fourth distinct group of populations was observed in central Québec where the continental glacier retreated last. It included populations harbouring haplotypes present into the three previous groups, and it had higher level of haplotype diversity per population (H = 0.548) and lower population differentiation (G(ST) = 0.265), which indicates a zone of suture or secondary contact between the migration fronts of the three glacial populations. Introgression from Pinus contorta Dougl. var. latifolia Engelm. was apparent in one western population from Alberta. Altogether, these results indicate that the mitochondrial DNA variation of jack pine is geographically highly structured and it correlates well with large-scale patterns emerging from recent phylogeographical studies of other tree boreal species in North America.     

Genes induced by WDS are differentially expressed in two populations of aleppo pine (<Emphasis Type="Italic">Pinus halepensis</Emphasis>)

Gene expression in response to water-deficit stress (WDS) is a critical factor determining the survival and growth of pine seedlings. To understand how gene expression varies with different water stress levels, we differentially screened a cDNA library from roots of aleppo pine (Pinus halepensis) seedlings subjected to WDS. We found 156 clones of genes up-regulated and 56 down-regulated in response to WDS. Of the 14 clones selected for further characterization, 8 resemble WDS-responsive genes previously identified in angiosperms. The genes showing similarities to known proteins included an aldehyde dehydrogenase, a late embryogenesis abundant (LEA) protein, a chitinase, a cyclophilin, an MYB factor, an inorganic pyrophosphatase, a sucrose synthase, and a 4-coumarate ligase. Six of the clones did not have any similarity to previously identified proteins of known function. Quantitative polymerase chain reaction (qPCR) was used to compare the differential expression of these genes during control (no stress), moderate, and severe WDS treatments of seedling progeny from two different geographic origins within Israel, Yirka, and Beit Jann. The difference in expression between the treatments for various genes ranged from 1.9 to 8.0 cycle threshold. Most of the genes were expressed at similar levels in trees from the two populations or at higher levels in trees from Beit Jann, Israel. Northern blot analyses done for four highly expressed genes verify the results of the qPCR.     

Pinaceae show elevated rates of gene turnover that are robust to incomplete gene annotation

Gene duplications and gene losses are major determinants of genome evolution and phenotypic diversity. The frequency of gene turnover (gene gains and gene losses combined) is known to vary between organisms. Comparative genomic analyses of gene families can highlight such variation; however, estimates of gene turnover may be biased when using highly fragmented genome assemblies resulting in poor gene annotations. Here, we address potential biases introduced by gene annotation errors in estimates of gene turnover frequencies in a dataset including both well‐annotated angiosperm genomes and the incomplete gene sets of four Pinaceae, including two pine species, Norway spruce and Douglas‐fir. We show that Pinaceae experienced higher gene turnover rates than angiosperm lineages lacking recent whole‐genome duplications. This finding is robust to both known major issues in Pinaceae gene sets: missing gene models and erroneous annotation of pseudogenes. A separate analysis limited to the four Pinaceae gene sets pointed to an accelerated gene turnover rate in pines compared with Norway spruce and Douglas‐fir. Our results indicate that gene turnover significantly contributes to genome variation and possibly to speciation in Pinaceae, particularly in pines. Moreover, these findings indicate that reliable estimates of gene turnover frequencies can be discerned in incomplete and potentially inaccurate gene sets. Because gymnosperms are known to exhibit low overall substitution rates compared with angiosperms, our results suggest that the rate of single‐base pair mutations is uncoupled from the rate of large DNA duplications and deletions associated with gene turnover in Pinaceae.     

阔叶红松林生态化学计量学特征及其对纬度梯度的响应

为研究红松叶片的养分及生态化学计量学特征的空间分布及其影响因素,依据我国温带阔叶红松林的分布特点,沿纬度梯度,选取长白山(42°27'N)、张广才岭(44°16'N)和小兴安岭(48°05'N)等3个地区的典型阔叶红松老龄林,测定红松叶片碳(C)、氮(N)、磷(P)含量,及表层土壤(0—15 cm)、中层土壤(15—30 cm)的有机碳(SOC)、全氮(TN)和全磷(TP)含量,分析了其分布特征及其相互关系。结果表明:1)红松叶片C、N、P含量显著高于土壤。表层土壤C、N、P含量变化范围分别为27.6—87.4,2.0—7.2 mg/g和0.26—0.92 mg/g;中层土壤为8.1—59.7,0.7—4.6 mg/g和0.2—0.82 mg/g;而叶片为495.5—507.4,12.7—172.5 mg/g和1.1—2.1 mg/g。2)土壤中的SOC、C/N、C/P均随纬度升高极显著增加,而叶片各元素计量特征随纬度的变化不显著。3)叶片N、P含量分别与土壤N、P含量显著正相关,同时,叶片N与土壤C/N、P与土壤N/P显著相关。相比较而言,红松叶片N、P含量较低,这可能说明阔叶红松林土壤N、P供应不足,而叶片N/P仅为9.9,说明东北阔叶红松林N限制更加明显。本研究为阐明东北温带阔叶红松林的养分供应状况和限制因素,为阔叶红松林区提高红松生产力的管理措施的提出奠定了基础。     

松树受害后一些化学物质含量的变化及其对马尾松毛虫种群参数的影响

通过探讨松树受害后松针的一些化学物质变化与马尾松毛虫Dendrolimus punctatus 种群参数的相互作用关系。结果表明：松针被马尾松毛虫为害后,针叶的氨基酸含量减少、单宁和总酚含量增加;马尾松毛虫取食被害松针后,体内的2种解毒酶(过氧化氢酶、羧酸酯酶)活性增加,其种群参数表现出发育历期延长、体重减轻、死亡率增加、生殖力下降的变 化。     

红松林不同演替阶段夏季鸟类群落研究

红松林不同演替阶段夏季鸟类群落研究常家传鲁长虎刘伯文许青（东北林业大学,哈尔滨１５００４０）ＳｔｕｄｙｏｆｔｈｅＢｉｒｄｓＣｏｍｍｕｎｉｔｙＳｔｒｕｃｔｕｒｅｉｎＤｉｆｅｒｅｎｔＳｕｃｃｅｓｉｏｎＰｅｒｉｏｄｏｆＫｏｒｅａｎＰｉｎｅＦｏｒｅｓｔ．Ｃｈ...     

长白山北坡椴树阔叶红松林群落主要树种分布格局的研究

应用方差 /均值比检验、波松分布的X2 检验及负二项分布的X2 检验 3种方法 ,对比不同的取样样方 ,研究了椴树阔叶红松林群落主要树种的分布格局 ,并根据 1hm2 样地的定位图进行检验 .研究结果表明 ,乔木树种的合适取样样方为 5m× 5m ,其中红松、椴树、水曲柳、山槐、白牛子属于聚集型分布 ,蒙古栎、春榆属于随机分布 .     

长白山红松阔叶林林冠空隙特征的研究

将林冠空隙干扰作为红松阔叶林动态维持的重要因素,对长白山红松阔叶林林 冠空隙的形成方式、出现频度、分布格局、结构及林冠空隙内形成本的数量、年龄分布、种 群特征等进行了系统分析．结果表明．长白山阔叶红松林多数林冠空隙由双形成本形成, 每个林冠空隙拥有的形成木为２．４４株;林冠空隙形成的速率为０．９２个ｈｍ２·ａ－１,林冠空 隙干扰的间隔期（周转期）为７５１ａ;扩展林冠空隙面积大多在１００～６００ ｍ２之间,其中以 ４００～５００ ｍ２所占比例最大．冠空隙在５０～３５０ ｍ２之间,其中以２００～２５０ ｍ２所占比例最 大;每个形成本所形成的扩展林冠空隙平均面积为 １４１ ８２ ｍ２,形成的冠空隙面积平均为 ６７．６３ ｍ２．     

闽北马尾松人工林密度控制模型研究

本文以闽北地区196块常规马尾松人工林标准地资料为基础,应用离散阶段连续状态的动态规划方法,建立可变间隔期的马尾松人工林密度控制模型,并研究马尾松人工林林分密度效应.表明该模型效果较理想,可用于指导林业生产.     

Effect of different nitrogen nutrients on the viability, protein synthesis and tannin production of Scots pine callus

The effect of two different media on the growth, metabolism and viability of Scots pine ( Pinus sylvestris ) callus cultures was studied. Inorganic nitrogen in the culture media (modified MS) was in the form of either KNO₃ or NH₄NO₃. The cultures were started from buds of mature Scots pine. Growth was poor on the medium with KNO₃, but this compound had a noticeable effect on the metabolism of the callus, which was reflected in alterations in protein and polyphenol synthesis and the pH of the culture medium. Although the fresh mass, water content and viability of the callus decreased when KNO₃ was the exclusive inorganic nitrogen nutrient, protein synthesis was more abundant. Electrophoretic analyses indicated alterations in the patterns of soluble proteins and purified glycoproteins. Phenylalanine ammonia-lyase (EC 4.3.1.5) activities were high in all the calluses, and concentrations of condensed tannins and their precursors, catechins, were higher than in intact buds. The role of inorganic nitrogen nutrition in the deterioration of tissues is discussed on the basis of the effect of ammonium on the metabolism of pine callus.