Eleven polymorphic microsatellite loci in Lindera benzoin,Lauraceae

Microsatellite markers were developed for studies of the genetic diversity and population substructure of Lindera benzoin, Lauraceae (spicebush). Nuclear microsatellite sequences were obtained from DNA libraries that were enriched for (CA), (GA), (AAG) and (ATG) repeat motifs. From 69 microsatellite sequences, 20 primer sets were developed. Of these, 11 primer pairs resulted in amplified polymorphic loci. In 29 samples of eastern Pennsylvania spicebush plants, the number of microsatellite alleles ranged from two to 16 per locus with observed heterozygosity values ranging from 0.10 to 0.82.     

Photosynthetic and genetic differentiation in sun and shade populations of Holcus mollis L.

Three Holcus mollis L. populations, one with 2n = 28 chromosomes living in a forest and two with 2n = 35 chromosomes, the first living in a forest, the second in open land, are compared for photosynthesis.Simultaneous measurements of oxygen and carbon dioxide, either in high light, low light, or dark experiments indicate that the 2n = 28 chromosomes population is photosynthetically well adapted to shade, while 2n = 35 chromosomes forest population, is not.The 2n = 35 chromosomes plants growing in the forest does not automatically acquire the photosynthetic character of a shade plant, the genome must show an evolution for this. In our study, only the plants with 2n = 28 chromosomes demonstrated the shade adaptation.     

Differential induced response to generalist and specialist herbivores by Lindera benzoin (Lauraceae) in sun and shade

Theoretically, induced defenses should be prevalent within low resource environments like the forest understory where constitutive defenses would be costly. Also, the induced response should be stronger when the herbivore is a generalist rather than a specialist, which often have mechanisms to avoid or overcome plant defenses. These ideas have been previously tested for herbaceous species, and we examined these predictions in Lindera benzoin (spicebush), a common woody shrub of the eastern deciduous forest. Lindera benzoin plants in contrasting light environments served as control plants or were subjected to one of four treatments: application of jasmonic acid, clipping, herbivory by the specialist Epimecis hortaria (tulip tree beauty) and herbivory by the generalist Spodoptera exigua (beet armyworm). Following treatment, we assessed induced responses by measuring leaf chemistry (C/N ratio, protein content, and peroxidase activity), and by using insect bioassays with E. hortaria larvae. We found no difference in peroxidase activity between light environments in controls, plants treated with clipping or jasmonic acid. In plants subject to insect herbivory, peroxidase activity was greater in shade plants than in sun plants. The magnitude of this increase in the shade varied between the herbivores, with a 32 fold increase in plants exposed to the generalist S. exigua and a 9 fold increase in plants exposed to the specialist E. hortaria . Leaves from shade plants had more protein and lower C/N ratios than leaves from sun plants, regardless of induction treatment. In control plants, E. hortaria larvae consumed more leaf biomass and achieved greater final weights in the sun than in the shade, but these differences disappeared with induction treatments were applied. These results are among the first to show rapid induction in a woody plant, and different levels of induction with light environments and with specialist versus generalist herbivores.     

Genetic differentiation of submerged plant populations and taxa between habitats

Ceratophyllum spp., Callitriche spp., Zannichellia spp. and Potamogeton pectinatus L. are widespread submerged macrophyte species, often occurring at high abundance and forming an integral part of the vegetation of many types of shallow aquatic systems. Several species occur in both freshwater and brackish water habitats. Most have a mixed reproduction system and can reproduce sexually by seeds and propagate asexually by rhizomes, turions, root tubers or axillary tubers. It is hypothesized that sexual propagules are more important than vegetative fragments to ensure long-distance-dispersal, which in case of frequent bird or water flow-mediated dispersal should lead to lowered genetic differentiation. At a regional level, we used dominant ISSR markers in a multi-species approach and observed the largest clonal differentiation between brackish water and freshwater populations of the western European lowland (Belgium). Differentiation was pronounced at taxon level (e.g. Zannichellia), as a salinity gradient (P. pectinatus) or as a coastal-to-inland conductivity gradient (Callitriche obtusangula). These differences and trends suggested a very limited dispersal at regional level across both habitats and regions. To test the hypothesis whether vegetative reproduction and dispersal may have an important function in maintenance of the species at local scale, we investigated the microsatellite diversity and clonal distribution within and between populations of P. pectinatus from a single catchment, representing upstream forest ponds and downstream river sites along the Woluwe (Brussels, Belgium). Clonal diversity was low on average, however, with a higher number of multilocus genotypes in upstream forest ponds than in downstream river sites. A few but abundant clones were present along various stretches of the river indicating clonal spread and establishment over larger distances within the river. Clonal dispersal at a local scale was more pronounced in river than in pond habitats, indicating a higher relative importance of water flow than bird-mediated dispersal for establishment of P. pectinatus in river sites. Dispersal of seeds and establishment of seedlings were assumed more effective within ponds than in river habitats. Upstream forest ponds can be regarded as source populations and refuges of clonal diversity for recolonization of the more stressful downstream river habitat.     

浙江省境内乌药种群遗传多样性研究

利用ISSR分子标记方法对浙江省境内的8个乌药自然种群的遗传多样性和遗传分化进行了研究。从100个引物中筛选出12个用于正式扩增的ISSR引物,在8个种群160个个体中共检测到125个位点,其中多态位点100个,多态位点百分率(P)为80%,各种群P平均为60.5%。乌药总的Shannon信息指数(I)为0.3762,Nei指数(h)为0.246 4,各种群I平均为0.317 3,h平均为0.213 1。AMOVA分析表明在总的遗传变异中,11.44%的变异发生在种群间,88.56%的变异发生于种群内,种群间的遗传分化系数(Gst)为0.134 9,乌药种群间的基因流(Nm)为3.205 2。8个种群间的平均遗传距离为0.049 4,利用算术加权平均数法(UPGMA)对乌药8个种群进行聚类,结果可分为2大类群,台州市的水磨坑、上泮、苍山等3个种群聚为一类,其余5个种群聚为另一类。     

Pigment analysis of sun and shade populations of Cladonia verticillaris

The natural occurrence of the lichen Cladonia verticillaris as sunny and shaded populations implies changes in the pigment content. Shade specimens contain more chlorophyll a and b as well as more - and β-carotene than those found in unshaded lichens. However, lichens growing in sunny locations contain more methyl β-orcinol carboxylate, orcinol and fumarprotocetraric acid than those found in lichens growing under low light intensities. No structural differences in the chloroplasts of the two species bave been detected.     

Genetic differentiation within and between two habitats.

We investigate the usefulness of analyses of population differentiation between different ecological types, such as host races of parasites or sources and sink habitats. To that aim, we formulate a model of population structure involving two classes of subpopulations found in sympatry. Extensions of previous results for Wright''s F-statistics in island and isolation-by-distance models of dispersal are given. It is then shown that source and sinks cannot in general be distinguished by F-statistics nor by their gene diversities. The excess differentiation between two partially isolated classes with respect to differentiation within classes is shown to decrease with distance, and for a wide range of parameter values it should be difficult to detect. In the same circumstances little differentiation will be observed in "hierarchical" analyses between pools of samples from each habitat, and differences between levels of differentiation within each habitat will only reflect differences between levels of gene diversity within each habitat. Exceptions will indicate strong isolation between the different classes or habitat-related divergent selection.     

Developmental process of sun and shade leaves in Chenopodium album L.

The authors’ previous study of Chenopodium album L. revealed that the light signal for anatomical differentiation of sun and shade leaves is sensed by mature leaves, not by developing leaves. They suggested that the two‐cell‐layered palisade tissue of the sun leaves would be formed without a change in the total palisade tissue cell number. To verify that suggestion, a detailed study was made of the developmental processes of the sun and shade leaves of C. album with respect to the division of palisade tissue cells (PCs) and the data was expressed against developmental time (leaf plastochron index, LPI). The total number of PCs per leaf did not differ between the sun and shade leaves throughout leaf development (from LPI ?1 to 10). In both sun and shade leaves, anticlinal cell division of PCs occurred most frequently from LPI ?1 to 2. In sun leaves, periclinal division of PCs occurred synchronously with anticlinal division. The constancy of the total number of PCs indicates that periclinal divisions occur at the expense of anticlinal divisions. These results support the above suggestion that two‐cell‐layered palisade tissue is formed by a change of cell division direction without a change in the total number of PCs. PCs would be able to recognize the polarity or axis that is perpendicular to the leaf plane and thereby change the direction of their cell divisions in response to the light signal from mature leaves.     

Genetic and epigenetic differentiation between natural Betula ermanii (Betulaceae) populations inhabiting contrasting habitats

Disentangling the molecular mechanisms of adaptation in natural plant populations in response to different environmental conditions is a central topic in evolutionary biology. In the present study, we investigated a wind-pollinated woody species of Changbai Mountain of northeastern China, namely, Betula ermanii Cham. This woody species B. ermanii is not only a dominant species in subalpine forest (SF), but it also occurs in the alpine tundra (AT) regions. This attribute indicates that it may play important roles in the two contrast habitats. In order to evaluate the influences of different habitats on differentiation in B. ermanii, we assessed the genetic and epigenetic population structure in selected populations from two contrasting habitats by using amplified fragment length polymorphism (AFLP) and methylation-sensitive AFLP techniques. According to our results, the AT group not only exhibits higher genetic and epigenetic diversity than the SF group but also shows greater population genetic and epigenetic differentiation. In addition, the analysis of cytosine methylation levels also revealed that the AT group exhibits higher degrees of genome methylation than the SF group. Taken together, our results indicate that populations from two contrasting habitats show significantly different genetic and epigenetic population structures. Along with other potential explanations, these findings suggest that environmental conditions could play an important role in facilitating adaptive evolution in B. ermanii.     

Genetic survey of Rhodiola rosea L. populations from the Swiss Alps based on SSR markers

Rhodiola rosea is a perennial adaptogenic medicinal plant found in the cool climates of the northern hemisphere. This species is highly variable both in morphological and phytochemical traits. The genetic diversity of five populations located in the Swiss Alps was studied with twelve SSR markers. However, only eight markers turned out to be informative in this study. The primer pairs for these eight SSR markers produced 37 fragments. The number of alleles per locus ranged from two to eight. The observed heterozygosity was between 0.09 and 1.0, whereas the expected heterozygosity was between 0.13 and 0.72. The genetic diversity was in the same range for all five populations. Principal coordinate analysis revealed that individuals from different populations did not cluster together, which confirmed that diversity within and among the populations were almost equivalent. The genetic fragmentation of this alpine species despite of its fragmented and isolated habitats, did not happened yet. The results of the present study on the genetic diversity were consistent with an earlier study on the chemical diversity with the same individuals.     

Photomorphogenesis of leaves: shade-avoidance and differentiation of sun and shade leaves.

Leaf shape is an important factor in optimal plant growth, because leaves are the main photosynthetic organs. Plants exhibit plasticity in leaf shape and structure, allowing them to optimize photosynthetic efficiency. In Arabidopsis thaliana(L.) Heynh., several types of leaves develop differentially, according to light intensity and quality. When shaded, the expansion of leaf lamina is inhibited, while the petiole elongation is enhanced. This phenomenon is part of the so-called shade-avoidance syndrome. Under low light, A. thaliana develops shade leaves with only one layer of palisade tissue, whereas under high light, it develops sun leaves that have nearly two complete layers of palisade tissue. Although the molecular mechanisms of these photomorphogenic phenomena in leaves are not well understood, recent studies of A. thaliana have provided some insight. For example, some cytochrome P450s may be involved in the specific control of the petiole length during photomorphogenesis. On the other hand, switching between sun and shade leaves is regulated by long-distance signaling from mature leaves in Chenopodium album. Here we provide an overview of the mechanisms of photomorphogenesis in leaves based on recent findings.     

Morphological variation in Plantago lanceolata L.: effects of light quality and growth regulators on sun and shade populations

The effects of different ratios of red to far-red light (R/FR-ratio) and of exogenously applied growth regulators on the morphology of plants from sun and shade populations were studied. Large differences in growth form were found between populations adapted to either sun or shaded habitats. Low R/FR-ratios, simulating vegetation shade, induced a growth form similar to that of plants from the shade population. High R/FR-ratios, simulating sunlight, had the opposite effect. Most morphological differences between shade and sun populations and effects of low R/FR-ratios on growth form could be mimicked by exogenously applied gibberellin (GA₃). In contrast, application of a gibberellin inhibitor (CCC) induced a growth form similar to that of the sun population and of plants grown under a high R/FR-ratio. Interactions between genetic background, the R/FR-ratio, and hormone treatment, were small and the factors exerted their action independently. The results are discussed in relation to the influence of developmental constraints on the evolvability of optimal phenotypes and the plastic responses therein.     

Photosynthetic adaptation of Solanum dulcamara L. to sun and shade environments

Summary The photosynthetic response properties of individuals of Solanum dulcamara L. collected from sun and shade habitats were compared in controlled environments. Light-saturated photosynthetic rates and seven additional parameters associated with photosynthetic and growth performance were measured over a range of 12 environmental conditions that simulated natural habitat differences in light intensity, moisture availability and daily temperature amplitude. In contrast to previous studies, the results suggest there is no ecotypic differentiation with respect to the sun and shade environments from which the individuals were collected. It appears that all but one of the field-collected individuals are capable of successfully inhabiting the full range of light environments from which the species was collected.     

Genetic differentiation between close eastern Mediterranean Dicentrarchus labrax (L.) populations

Differentiation at nine microsatellite loci revealed that a Levantine Basin sea bass Dicentrarchus labrax population probably represents a further subdivision of this species in the eastern Mediterranean.     

燃油植物香叶树的开发利用与栽培

我国木本油脂植物种类很多,特别是在我国亚热带地区分布很广,但分布零散.香叶树在云南腾冲县有比较集中的资源,其果实含油率很高,是加工生物柴油的良好原料.分析了香叶树油用于生物柴油的有利条件,并介绍了香叶树栽培技术要点,供有条件的地区发展香叶树资源与生产时参考.     

Variations in leaf morpho‐anatomy and photosynthetic traits between sun and shade populations of Eurya japonica (Pentaphylacaceae) whose seeds are dispersed by birds across habitats

Eurya japonica occurs in diverse light environments through seed dispersal by birds. As the seed size is extremely small, we hypothesized that newly germinated seedlings with restricted depth of roots and length of the hypocotyl would suffer high mortality due to increased transpiration in sunny habitats and low light in shady habitats. We also expected that surviving seedlings would differ in leaf traits between habitats as a result of selection. We aimed to determine how photosynthetic traits differ between habitats and how leaf structure is related to this difference. We examined photosynthesis and leaf morpho‐anatomy for plants cloned from cuttings collected from the forest understory (shade population) and neighboring roadsides and cut‐over areas (sun population) and then grown under two irradiances (18.5% and 100% sunlight) in an experimental garden. Under growth in 100% sunlight, cloned plants from the sun population exhibited significantly greater area‐based photosynthetic capacity compared to cloned plants from the shade population at a comparable stomatal conductance, which was attributable to a higher area‐based leaf nitrogen concentration. On the other hand, mean values of photosynthetic capacity did not significantly differ between the two populations. Cloned plants from the sun population had significantly thicker leaf laminas and spongy tissue and lower stomatal density compared to cloned plants from the shade population. Thickened leaf lamina might have increased leaf tolerance to physical stresses in open habitats. The variation in leaf morpho‐anatomy between the two populations can be explained in terms of the economy of leaf photosynthetic tissue.     

观赏灌木小枝和叶性状在林下庇荫环境中的权衡关系

小枝与叶片间的关系能够很好地反映植物对环境的适应策略。目前,从枝叶间权衡关系的角度研究树木对庇荫环境适应性的报道尚少,其中主要包括"生长-生长"权衡和"生长-生存"权衡两种假说。因此,为了探讨灌木在庇荫环境中,是否会在小枝和叶性状间采取权衡策略,来提高光照资源的利用能力或增强生存和防御能力,在城市绿地的林隙和林冠下两种光环境中,选择了没有人工修枝、整形等经营措施的金银木(Lonicera maackii)、小花溲疏(Deutzia parviflora)和连翘(Forsythia suspensa)等11种、79株观赏灌木作为研究对象,采集其当年生小枝,观测并计算了每棵灌木所处环境的有效光合辐射(PAR)相对累积光量和红光/远红光(R/FR),以及灌木的小枝干重(TDW)、单位小枝叶干重(LDW)、出叶强度(LN/TDW)、叶面积支持效率(LA/TDW)、比枝长(TL/TDW)和单叶面积(ILA) 6个性状。对数据进行标准化和数据转换后,运用Pearson相关检验分析光环境指标和灌木枝叶性状间的相关性;采用标准化主轴估计法进行异速生长方程的参数估计;使用多元回归分析不同光强下各性状的相互关系。结果表明:(1) PAR相对累积光量和R/FR与TDW和LDW呈极显著(P0.01或P0.001)正相关,与TL/TDW、LA/TDW、LN/TDW呈极显著(P0.001)负相关,与ILA相关性不显著(P 0.05)。整体上,R/FR与各灌木性状的相关性大于PAR相对累积光量;(2) TDW和LDW存在极显著(P0.001)的异速生长正相关关系。随着光强的减小,灌木当年生小枝和叶片的生物量都趋于减小,但是表现出相对偏向于叶片生物量的投资偏好;(3) LA/TDW和TL/TDW存在极显著(P0.001)的等速生长正相关关系。但随着光强的减小,比枝长随叶面积支持效率增加而增加的速率却减小,说明灌木在庇荫条件下,更倾向于采取忍耐型的光资源利用策略;(4) ILA和LN/TDW呈极显著(P0.001)异速生长负相关关系。随着光强的减小,灌木趋向于表现出单位小枝上着生大量小叶的现象。所以总体上,庇荫环境下的观赏灌木存在投资偏好和权衡,倾向于通过枝叶生长提高光截获能力来适应弱光环境,与"生长-生长"的权衡假说相符,但整体上,观赏灌木的耐阴性较差,故不建议种植在庇荫环境中。     

A Review of Current Theories and Methods in Cladistics and a Cladistic Study of Twelve Lindera Species in Eastern China

Cladistics has become a widely used method for phylogenetic reconstruction．Because of rapid improvement Of cladistic theories and methodologies,and application of new data,especially,molecular data,it is becoming realistic to reconstruct phylogenies of organisms,and to establish natural classifications based on these phylogenies．This paper reviews some current cladistic theories and methods in a practical way,such as choosing characters,defining character states,polarizing characters,analyzing data matrices, calculating consensus cladograms,choosing among multiple equally most parsimonious cladograms,estimating reliability of cladograms,and applying cladograms to classification, character evolution,and biogeography． Based on 36 morphological characters．a parsimony analysis of 12 species representing six sections in subgenus Lindera and an outgroup species from subgenus lteodaphne of the genus Lindera(Lauraceae)was conducted．The results suggest a close relationship between section Lindera and section Sphaerocarpae,which is different from the previous phylogenetic hypothesis within the genus．In the strict consensus cladogram,two species,L．megaphylla and L.chienii,from section Cupuliformes are in the most primitive and the most advanced clades respectively,indicating that the section is polyphyletic．The cladogram also suggests that section Lindera be a polyphyletic group．     

Genetic differentiation between parapatric 'nearshore' and 'offshore' populations of the bottlenose dolphin.

The existence of nearshore and offshore populations of the bottlenose dolphin has been documented throughout its range. In several cases the two regional forms have been shown to be morphologically distinct, although there is considerable overlap for most characters. The populations off the eastern coast of North America have been the subject of a long-term programme of research on their distribution and movements. In this study, we compare mitochondrial and nuclear genetic markers between dolphins classified as either nearshore or offshore type. These putative populations were found to be distinct at both nuclear and mitochondrial genetic markers. Further, the level of variation among the nearshore dolphins was reduced compared with the offshore population. A broader geographical comparison suggests a shared lineage between offshore dolphins from the western North Atlantic and both offshore and nearshore dolphins from the eastern Atlantic. These results are consistent with local differentiation based on habitat or resource specialization in the western North Atlantic, and suggest differences in the character of the nearshore/offshore distinction in different parts of the world.