Jun 2007, Volume 2 Issue 2
    

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  • Origin and differentiation of endemism in the flora of China
    WU Zhengyi, SUN Hang, ZHOU Zhekun, PENG Hua, LI Dezhu
    2007, 2(2): 125-143. https://doi.org/10.1007/s11515-007-0020-8
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    The present paper analyzed 239 endemic genera in 67 families in the flora of seed plants in China. The results showed that there are five families containing more than ten endemic genera, namely, Gesneriaceae (27), which hereafter refers to the number of endemic genera in China, Composite (20), Labiatae (12), Cruciferae (11), and Umbelliferae (10), 15 families with two endemic genera, and another 30 families with only one endemic genus. Four monotypic families (Ginkgoaceae, Davidiaceae, Eucommiaceae and Acanthochlamydaceae) are the most ancient, relict and characteristic in the flora of seed plants in China. Based on integrative data of systematics, fossil history, and morphological and molecular evidence of these genera, their origin, evolution and relationships were discussed. In gymnosperms, all endemic genera are relicts of the Arctic-Tertiary flora, having earlier evolutionary history, and can be traced back to the Cretaceous or to the Jurassic and even earlier. In angiosperms, the endemic genera are mostly relicts, and are represented in all lineages in the Eight-Class System of Classification of Angiosperms , and endemism can be found in almost every evolutionary stage of extant angiosperms. The relict genera once occupied huge areas in the northern hemisphere in the Tertiary or the late Cretaceous, while neo-endemism mostly originated in the late Tertiary. They came from Arctic-Tertiary, Paleo-tropical-Tertiary and Tethys-Tertiary florisitic elements, and the blend of the three elements with many genera of autochthonous origin. The endemism was formed when some dispersal routes such as the North Atlantic Land Bridge, and the Bering Bridge became discontinuous during the Tertiary, as well as the climate change and glaciations in the late Tertiary and the Quaternary. Therefore, the late Tertiary is the starting point of extant endemism of the flora in China.
  • Breeding and application of Jiafuzhan, a new elite early indica rice cultivar in China
    WANG Houcong, QIU Simi, FANG Yashun, HUANG Yumin, CHEN Ruming, ZHONG Xinbin, HUANG Huakang, ZHANG Shi, ZHENG Xuan, CHEN Shuanglong, CHI Xiaowen, ZHANG Weiqing, CAI Jinlei, LIAO Xinying, SUN Chuanzhi
    2007, 2(2): 144-150. https://doi.org/10.1007/s11515-007-0021-7
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    After 20 years of dedicated research, Jiafuzhan has been successfully developed under the new technologies in breeding high-quality early indica rice cultivars. Its rice quality has almost reached the A-level Editable Rice of Agriculture Department of China, and its average production reaches 400 500 kg/(666.7 m2). This new cultivar also has other characteristics such as enhanced resistance of blast and fallen, steady productivity, and strong adaptability. Jiafuzhan has been put into production of over 11.4?104 hm2 in Fujian Province and has been introduced and extended in other Provinces like Jiangxi, Guangdong, and Guangxi, China. The successes of breeding Jiafuzhan is a solution to the existing perennial problems in the rice industry, such as poor grain quality of big-grain rice and early indica rice, low productivity, and poor blast resistance of elite rice.
  • Phylogenetic relationships of Galeaspids (Agnatha)
    ZHU Min, GAI Zhikun
    2007, 2(2): 151-169. https://doi.org/10.1007/s11515-007-0022-6
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    We present the first parsimony analysis of the agnathan subclass Galeaspida based on the analysis of 53 morph ological characters. Three most parsimonious cladograms (126 steps in length; CI = 0.508; RI = 0.801) were discovered. An amended classification of the Galeaspida is proposed corresponding to the present analysis. Our results suggest that hanyangaspids, xiushuiaspids and dayongaspids from the Llandovery-Wenlock of Silurian are basal galeaspids. Within the remaining galeaspids, three major mono phyletic groups (the Eugaleaspidiformes, the Polybranchiaspidiformes and the Huananaspidiformes) are well supported. It is shown that the dorsal fenestrae of the headshield evolved twice within the Galeaspida, one in the polybranchiaspidiform lineage, and the other in the huananaspidiform lineage (nested within the Huananaspidae). The chronological distribution of galeaspids highlights two radiations of the group, one for basal galeaspids and eugaleaspids in the Telychian (Llandovery) of Silurian, and the other for polybranchiaspidiforms and huananaspidiforms in the Lochkovian of Early Devonian.
  • Cloning and expressing a recombinant human tissue inhibitor of metalloproteinase-2 (TIMP-2) in methylotrophic yeast Pichia pastoris and its characterizations
    YAN Xunyou, ZHAO Hongliang, XUE Chong, LIU Zhimin, ZHANG Weiguang
    2007, 2(2): 170-175. https://doi.org/10.1007/s11515-007-0023-5
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    To obtain human tissue inhibitor of metalloproteinase-2 (TIMP-2) cDNA and the secretory expression of TIMP-2 gene in Pichia pastoris, we designed and synthesized a 618 base pairs artificial gene coding for the TIMP-2 with a computer-aided design method using a standard chemical synthesis technique, which was composed of frequently used codons in the highly expressed Pichia pastoris genes. Then the synthetic gene encoding TIMP-2 was checked by means of dideoxynucleotide sequencing. The verified gene of TIMP-2 was cloned to the Escherichia coli-yeast shuttle vector of pPIC9 to construct a recombinant plasmid pPIC9-T2. The plasmid was transformed into GS115 cells of the methylotrophic yeast, Pichia pastoris by electroporation, and we got the expression cell through phenotype selection and induction with methanol. Separation, purification, and bioactivity analysis of the expressed products were performed.
  • Correlation between the distribution pattern of virulence genes and virulence of Aeromonas hydrophila strains
    ZHU Daling, LI Aihua, WANG Jianguo, LI Ming, CAI Taozhen, HU Jing
    2007, 2(2): 176-179. https://doi.org/10.1007/s11515-007-0024-4
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    Nine strains of Aeromonas hydrophila isolated from diseased fish or soft-shelled tortoise were tested for the presence of three virulence genes including the genes encoding aerolysin, hemolysin, and extracellular serine protease (i.e., aerA, hlyA, and ahpA, respectively). These genes were investigated using polymerase chain reaction (PCR) with specific primers for each gene. And the pathogenicities to Carrassius auratus ibebio of these strains were also assayed. PCR results demonstrated that the distribution patterns of aerA, hlyA, and ahpA were different in these strains. 6/9 of A. hydrophila strains were aerA positive, 8/9 of strains hlyA positive, 7/9 of strains ahpA positive, respectively. However, the assay for pathogenesis showed that two strains (A. hydrophila XS91-4-1 and C2) were strong virulent, two strains (A. hydrophila ST78-3-3 and 58-20-9) avirulent and the rest middle virulent was to the fish. In conclusion, there are significant correlation between the distribution pattern of the three virulence genes and the pathogenicity to Carrassius auratus ibebio. All strong virulent A. hydrophila strains were aerA+hlyA+ahpA+ genotype, and all aerA+hlyA+ahpA+ strains were virulent. Strains with the genotype of aerA-hlyA-ahpA+ have middle pathogenicity. In the present study, we found for the first time that all A. hydrophila isolated from the ahpA positive were virulent to Carrassius auratus ibebio. Additionally, there was a positive correlation between the virulence of A. hydrophila and the presence of aerA and ahpA.
  • Computational simulations on the fish-type-II antifreeze protein-ice-solvent system
    LIU Kai, WANG Yan, TAN Hongwei, CHEN Guangju, TONG Zhenhe
    2007, 2(2): 180-183. https://doi.org/10.1007/s11515-007-0025-3
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    Based on the computational simulation with the vacuum environment for the fish-type-II antifreeze protein-ice-solvent (water) system, the multi-complex system of the antifreeze protein-ice-water has been constructed and calculated. We have studied the interaction of such protein-ice system with water solvent through the dynamics simulation with 350 ps. By employing the Molecular Dynamics simulation and semi-empirical method calculation, we have further investigated the interface properties of the antifreeze protein and ice crystal combined system. Consequently, a water solvent affects significantly the properties of this combined system.
  • Biological effects of low-energy C ion implantation on sesame (Sesamum indicum L.)
    ZHANG Lan, JIA Hanchao, FANG Tian, ZHOU Yunlong, SU Ying
    2007, 2(2): 184-186. https://doi.org/10.1007/s11515-007-0026-2
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    Field cultivation experiments on white sesame (Sesamum indicum L.) seeds implanted with low-energy C ion showed that different dosages of C ion implantation produce different biological effects. Sesame plants in 6 different dosage
  • Subpopulation genetic structure of a plant panmictic population of Castanea sequinii as revealed by microsatellite markers
    WANG Ying, KANG Ming, HUANG Hongwen
    2007, 2(2): 187-195. https://doi.org/10.1007/s11515-007-0027-1
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    Castanea squinii Dode, an endemic tree widely distributed in China, plays an important role both in chestnut breeding and forest ecosystem function. The spatial genetic structure within and among populations is an important part of the evolutionary and ecological genetic dynamics of natural populations, and can provide insights into effective conservation of genetic resources. In the present study, the spatial genetic structure of a panmictic natural population of C. sequinii in the Dabie Mountain region was investigated using microsatellite markers. Nine prescreened microsatellite loci generated 29 33 alleles each, and were used for spatial autocorrelation analysis. Based on Moran s I coefficient, a panmictic population of C. sequinii in the Dabie Mountain region was found to be lacking a spatial genetic structure. These results suggest that a high pollen-mediated gene flow among subpopulations counteract genetic drift and/or genetic differentiation and plays an important role in maintaining a random and panmictic population structure in C. sequini populations. Further, a spatial genetic structure was detected in each subpopulation s scale (0.228 km), with all three subpopulations showing significant fine-scale structure. The genetic variation was found to be nonrandomly distributed within 61 m in each subpopulation (Moran s I positive values). Although Moran s I values varied among the different subpopulations, Moran s I in all the three subpopulations reached the expected values with an increase in distances, suggesting a generally patchy distribution in the subpopulations. The fine-scale structure seems to reflect restricted seed dispersal and microenvironment selection in C. sequinii. These results have important implications for understanding the evolutionary history and ecological process of the natural population of C. sequinii and provide baseline data for formulating a conservation strategy of Castanea species.
  • Reproductive biology in an invasive plant Solidago canadensis
    HUANG Hua, CHEN Guoqi, GUO Shuiliang
    2007, 2(2): 196-204. https://doi.org/10.1007/s11515-007-0030-6
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    Solidago canadensis, a perennial Compositae plant originating from North America, was introduced into China as a horticultural plant in 1935. Under natural conditions, Solidago canadensis allocates large amounts
  • Two-dimensional pattern analysis on dominant species and community in subalpine meadow of Luya Mountain, Shanxi Province, China
    ZHANG Jintun
    2007, 2(2): 205-209. https://doi.org/10.1007/s11515-007-0031-5
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    The spatial pattern analysis of population and community is important to understand community structure and has become one key topic in modern plant ecology. There are many techniques for analyzing one-dimensional pattern in ecological literature. Two-dimensional pattern analysis is better than one-dimensional analysis in the study on community spatial characteristics and structure. However, it is hard to analyze these two-dimensional patterns due to poor effective methodology. The two-dimensional sampling using two transects that meet at right angles was applied to get quadrat data in this work. And then the data from the two transects were analyzed separately by one-dimensional pattern analysis method, two-term local quadrat variance. The length, width, and area of patches at different scales of pattern for populations were obtained from the analysis. For community pattern, detrended correspondence analysis (DCA) was employed to summarize the species information firstly, and then the first DCA axis scores were analyzed to check its pattern. The application of this method to the pattern analysis on dominant populations and community for subalpine meadow (Comm. Polygonum viviparum + Carex rigescens + Kobresia bellardii) in the Luya mountains showed that it could release the characteristics of spatial pattern clearly and was a very effective technique. The method is easy to use and saves time with obvious advantages, compared with the two-dimensional pattern analysis methods presented in the literatures. In the study meadow, the patterns of the main dominant species, Polygonum viviparum, Carex rigescens, and Kobresia bellardii, were apparent and comparatively regular in shape with large areas of patches at the same scale compared with other species such as Festuca sp. and Thalictrum petaloideum. There were two or three scales of patterns for each plant population studied. This was related to population features, the interaction with environmental factors, and their dominant position in the community. The two scales of patterns for the meadow community were clear. The pattern of community was closely correlated with that of the main dominant species. The patches of dominant species were inter-distributed and overlapped, and formed the community pattern together. This is beneficial for utilization of resources, and keeping the community stable.
  • Exclusion effects on vegetation characteristics and their correlation to soil factors in the semi-arid rangeland of Mu Us Sandland, China
    YANG Xiaohui, CI Longjun, ZHANG Kebin, HOU Ruiping
    2007, 2(2): 210-217. https://doi.org/10.1007/s11515-007-0032-4
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    Exclusion has been applied as a main measure for re-vegetation all over the world. This paper, by comparing the results of year-round exclusion, seasonal exclusion, and non-exclusion, quantified the vegetation variations under three different exclusion measures and their correlation to soil factors. The analysis results for community species component and plant diversity using multi-response permutation procedures (MRPPs) showed that exclusion did change the species com ponent and increase plant diversity remarkably, while the period of exclusion had no significant influence on these two community features. The indicator species analysis and calculation of similarity indices indicated that community for year-round exclusion were becoming xerophytization and unpalatability, and showed highly spatial heterogeneity of plant species distribution, whereas community for seasonal exclusion was under stable non-equilibrium condition. Detrended correspondence analysis (DCA) and detrend canonical correspondence analysis (DCCA) results of relationship between plant species and soil variables demonstrated that soil moisture was a controlling factor for plant species component, microbiotic soil crust cover, soil organic matter, and soil bulk density had significant effects on soil moisture, among which microbiotic soil crust was a leading factor owing to its limitation to rainfall infiltration on the one hand, and its constraints to entrance of herbaceous seeds into soil or to germination of soil seeds on the other hand. As a result of long-term removal of animal grazing, crust kept intact in year-round exclusion community, which was a main reason of community xerophytization. It was also obvious from ordination results that some important environmental factors, such as tempo-spatial change of rainfall and corresponding tempo-spatial change of soil moisture, were neglected during direct gradient analysis. In addition, biodiversity was close related to soil nutrients as well as to soil moisture condition (soil water content and crust cover), and it had positive relation to available N, and negative relation to available P. Higher soil N had advantage to non-leguminous plants growth on nutrition-poor sand land definitely. The impact of P to community component was unclear and should be studied from plant physiology. Further researches on non-equilibrium theory in semi-arid rangeland will provide a scientific and flexible animal development paradigm for being implementing livestock fen-raising and grazing-forbidden policies in China.
  • Genetic diversity of six populations of Atractomorpha sinensis and Atractomorpha peregrina in Shanxi Province, China
    LU Fuping, LI Cuilan, GUO Yaping, MA Enbo, DUAN Yihao
    2007, 2(2): 235-241. https://doi.org/10.1007/s11515-007-0028-0
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    Ten enzymes (AAT, CK, G3PDH, HEX, IDH, LDH, MDH, ME, PGI, PGM) were examined using horizontal starch gel electrophoresis to estimate the levels of genetic variation within and among six natural populations of two grasshopper species Atractomorpha sinensis and A. peregrina from Shanxi, China. The collecting sites were geographically distant from each other from south to north: Quwo district, Linfen city; Xiangyuan county, Changzhi; Jinyuan district, Taiyuan city; Yuanping county, Xinzhou city and Fanshi county of Xinzhou. A.sinensis showed 43 alleles at 16 loci but A. peregrine showed 39 alleles at 15 loci (Idh-1 was deficient). The zymograms showed that some common alleles were shared at several loci in these two species (Aat-1-b, Aat-2-b, G3pdh-a, Ck-1-b and Ldh-b). However, Hex-1-a, Hex-2-a, Hex-3-a, Idh-2-b, Mdh-2-b, Mdh-1-f, Pgi-b, Pgm-b had common alleles in A. sinensis and Hex-1-b, Hex-2-b, Hex-3-b, Idh-2-a, Mdh-2-a, Mdh-1-d, Pgi-a, Pgm-c were of high frequency in A. peregrine instead. Most of the observed genotype frequencies were found to significantly deviate from the Hardy-Weinberg expectations in both species. A tendency of clinal distribution of allele frequency was observed at three loci. The frequency of the moderately migrating allele Me-c (0.318-0.740) in A. peregrina, Hex-1-a (0.800-1.000) and Ldh-b (0.487-0.750) in A. sinensis demonstrated increased frequency from north to south. Such tendency suggests that the allele frequency in these three loci may be correlated with the species  geographic distributions. A. sinensis showed higher genetic diversity than A. peregrina as indicated by higher mean number of alleles per locus (A = 1.9-2.3 in A. sinensis and 1.7-2.2 in A. peregrina), percentage of polymorphic loci (56.3%-68.8% in A. sinensis and 43.8%-56.3% in A. peregrina), and the observed heterozygosities (Ho = 0.072-0.096 in A. sinensis and 0.070-0.107 in A. peregrina). The observed heterozygosities of the six populations were all noticeably lower than the Hardy-Weinberg expectations, mostly due to heterozygote deficiency in the populations of both species. The overall mean FST were small (FST = 0.045, P>0.05 in A. sinensis populations and 0.087, P>0.05 in A. peregrina populations). Nei s genetic identity (I) estimates indicate low intraspecific (>0.95) but higher interspecific (0.377-0.447) genetic diversity. The cluster analysis based on modified Roger s genetic distance (D) showed that the two species were divided into two branches. Both species are of limited dispersal capacity and a moderate geographical barrier might significantly restrict the gene exchange among populations, resulting in accumulation of local genetic differentiations. The A. sinensis populations used in this study were separated from each other by 155.2 to 271.4 km and the A. peregrina populations were separated from each other by 78.8 to 174.9 km with observable physical barriers. The allozyme data showed only minimal genetic differentiation at population level, most likely as a result of gene exchange. It is reasoned that natural factors and human agricultural activities might have facilitated migration and dispersal for the two species.
  • Population dynamics of Dremomys pernyi and Callosciurus erythraeus in protective and non-protective pine forests at different ages
    MEN Xingyuan, GUO Xianguo, DONG Wenge, QIAN Tijun
    2007, 2(2): 242-246. https://doi.org/10.1007/s11515-007-0029-z
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    Four pine forests (6 10, 11 15, 16 20, and 31 40 year-old) located in the Cangshan Mountain and Erhai Lake National Reserve and 7 pine forests (1 5, 6 10, 11 15, 16 20, 21 30, 31 40, and more than 50 year-old) located in the non-protective area near the national reserve were selected. Three replications of each forest was set and a total of 33 sites were investigated. At each site, we quantified 6 habitat variables (species richness, abundance, and percentage of grasses and shrubs coverage respectively at the bottom layer of forests) within randomly determined 5 m ? 5 m areas. One hundred cages were set in five lines at each site to trap small mammals, whose species and numbers were recorded. Dominance of Dremomys pernyi and Callosciurus erythraeus in small mammal communities, time niche breadth, and time niche overlap between the two small mammals were calculated, respectively. Step-wise regression was used to analyze the relationship between small mammals and habitat factors. Our results indicated that D. pernyi occurred earlier than C. erythraeus in protective pine forests. D. pernyi was captured in 6 10 year-old forest initially, and C. erythraeus was captured in 16 20 year-old forest initially. D. pernyi and C. erythraeus were captured in the 31 40 and 21 30 year-old forests initially in the non-protective area, respectively. Populations of D. pernyi and C. erythraeus in the 31 40 year-old protective forests were 3 and 3.75 times of those in the sameaged non-protective forests, respectively. Shrubs significantly influenced the populations of the two small mammals. The population of D. pernyi was positively correlated with the density of shrubs; the population of C. allosciurus erythraeus was positively correlated with the coverage of shrubs, and negatively correlated with the coverage of grasses. D. remomys pernyi and C. allosciurus erythraeus were important for pine forests to scatter pine seeds. Human activities in the non-protective pine forests decreased the vegetation heterogeneity at the bottom layer of pine forests, postponed the occurrence of D. pernyi and C. erythraeus, and decreased the populations of the two small mammals.