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Table of Content
    Volume 11 Issue 2
    20 March 2003
      
    论文
    Allozyme variation in Sophora moorcroftiana , an endemic species of Tibet, China
    ZHAO A-Man, LIU Zhi-Min, KANG Xiang-Yang, ZHOU Shi-Liang
    Biodiv Sci. 2003, 11 (2):  91-99.  doi:10.17520/biods.2003013
    Abstract ( 3166 )   PDF (480KB) ( 2696 )   Save
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    The genetic diversity of ten populations of Sophora moorcroftiana in the middle reaches of the Yarlung Zangbo River, Tibet, China was assessed using allozyme analysis by horizontal sliceable starch gel electrophoresis. Twenty four loci (46 alleles) of 13 enzyme systems demonstrate low levels of genetic variation within populations, with the value of Pp=25.0%~37.5%,Ap=1.3~1.7 and Hep=0.112~0.169. At the species level, the genetic diversity of S. moocroftiana (Ps=37.5%, As=1.9, Hes=0.171) was lower than the mean value of angiosperms of long lived woody species (Ps=59.5%,As=2.10,Hes=0.183). Wright′s F statistics analysis indicated that FIS, a measure of the deviation from random mating within the 10 populations, was -0.0071, suggesting deviation from Hardy-Weinberg equilibrium and a slight heteroygote excess in some populations. The higher level of differentiation (FST=0.1748) among populations than those of other long lived woody plants may result from habitat fragmentation and low levels of gene flow (Nm=1.1802) caused by environmental deterioration and human disturbance, including over felling and over-grazing. It was worth noting that populations H2 (Xietongmen), H31 (Jiangdang1), H32 (Jiangdang2), and H5 (Langsailing) harbored the majority of alleles and had high levels of genetic diversity, suggesting that these populations in particular should be conserved in situ.
    Genetic diversity of the relict plant Metasequoia glyptostroboides
    LI Xiao-Dong, HUANG Hong-Wen, LI Jian-Qiang
    Biodiv Sci. 2003, 11 (2):  100-108.  doi:10.17520/biods.2003014
    Abstract ( 2908 )   PDF (356KB) ( 2970 )   Save
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    Forty-eight individuals of eight populations of Metasequoia glyptostroboides (Dawn Redwood), including six relict populations and two cultivated, were analyzed by random amplified polymorphic DNA (RAPD) markers to determine the genetic variations among and within the populations. A total of 57 loci (including 22 polymorphic loci) were amplified using 16 random primers. The average percentage of polymorphic loci (PPL) was 38.6% in the relict populations. The difference of the percentage of polymorphic loci among all the populations was evident (10.53%~33.33%). Of the eight populations, Xiaohe and Guihua populations in Lichuan City, Hubei had high PPL(33.33% and 31.58%), while the population in Longshan Luota, Hunan had relatively low PPL (10.53%), and the two cultivated populations also had low PPL (10.53% and 8.77%). As analyzed by POPGENE version 1.31, the data from the relict populations has an average Nei's gene diversity of 0.1305, and Shannon's genetic diversity of 0.1921. Correlation coefficient between genetic distance and geographic distance was 0.23466 (P=73.27%). Among the relict populations,Gst was 0.1082, indicating that there was some differentiation among the populations. The two cultivated populations and the two Lichuan relict populations clustered together. In view of the damage and fragmentation of original habitats, the low genetic diversity and the dispersed distribution of wild Metasequoia glyptostroboides , we suggest establishing a conservation spot in the optimal habitat of Xiaohe and Guihua in Lichuan, where we can breed and plant seeds from the remaining 250 wild trees. By this means, the remaining genetic diversity resources of the species can be preserved to the greatest extent.
    Conservation genetics of the endemic species Myricaria laxiflora (Tamaricaceae) in the Three Gorges Reservoir area, Hubei
    LI Zuo-Zhou, WANG Chuan-Hua, XU Tian-Quan, WU Jin-Qing, HUANG Hong-Wen
    Biodiv Sci. 2003, 11 (2):  109-117.  doi:10.17520/biods.2003015
    Abstract ( 2953 )   PDF (374KB) ( 2385 )   Save
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    Allozymic variation of 13 natural populations and one ex situ population of Myricaria laxiflora were analyzed using isoelectric focusing in thin-layer polyacrylamide slab gels. Thirteen loci of five enzyme systems were examined and used for the analysis of population genetic diversity and structure. A high genetic diversity was observed in this species, with mean number of alleles per locus ofA=1.8, mean percentage of polymorphic lociP=78.7% and average expected heterozygosityHe=0.317, which were higher than the average value of Chinese endemic plant species. An excess of heterozygous genotypes was found both in natural and ex situ populations, suggesting a slight deviation from the Hardy-Weinberg equilibrium in the populations. The total genetic diversity (Ht) is 0.3733 within the species, while the genetic diversity within and among populations (Hs vs Dst) were 0.3168 and 0.0565, respectively, indicating that 84.86% of the genetic variation occured within populations and only 15.14% among natural populations. The mean gene flow among populations (Nm) was 1.401 and genetic distances among populations ranges from 0.002 to 0.176. Cluster analysis using UPGMA on Rogers' genetic distance revealed that populations of M. laxiflora growing along riversides in the Three-Gorges Reservior area were separated into upstream and downstream groups at Baishui River, Xietan region in Hubei Province. A level of genetic diversity similar to that of natural populations was observed in the ex situ population at Wuhan Botanical Garden, so the ex situ conservation program was considered to be successful in preserving genetic diversity. Combining analysis of the genetic diversity with available information on breeding system, status of natural habitat, and evolutionary history, the causes for the endangerment of M. laxiflora are discussed. It is likely that the species gradually evolved as a relict species after the Quaternary Glaciation. Based on evaluation of the current ex situ conservation program, we suggest that similar habitats upstream and downstream of the Three-Gorges Reservoir or on nearby tributaries should be selected as ex situ conservation spots for M. laxiflora populations with high genetic diversity before their original habitats are submerged by the Three-Gorges Reservoir.
    RAPD variation within and among five populations of Tegillarca granosa
    LI Tai-Wu, LI Cheng-Hua, SONG Lin-Sheng, SU Xiu-Rong
    Biodiv Sci. 2003, 11 (2):  118-124.  doi:10.17520/biods.2003016
    Abstract ( 2807 )   PDF (297KB) ( 2505 )   Save
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    The Randomly Amplified Polymorphic DNA(RAPD)technique was applied to assess the genetic variation among five populations of Tegillarca granosa. Under predetermined optimal reaction conditions, 154 RAPD sites were detected ranging from 300 bp to 2300 bp with 20 primers. The number of amplified bands ranged from 1 to 11 in every individual. The experimental data were analyzed with the Popgen 3.2 and PHILIP software. The results showed that: (1)no evident differentiation existed among the five populations, and they all belong to one community; (2) the nearest phylogenetic relationship occurs between the Korean population and Zhejiang populations, then between the Shandong and Fujian groups in turn; (3) the high level of mean heterozygosities suggests that the resource of Tegillarca granosa was in good condition with high genetic variation, and (4)the heterozygosities and proportion of polymorphic loci of the hatchery populations were lower than that of the wild population, which could be attributed to artificial or other factors. We suggest that it is important to take measures soon to maintain the germ plasm resource of Tegillarca granosa, so as to promote sustainable development of its aquaculture.
    An analysis of interspecific associations of Pinus squamata with other dominant woody species in community succession
    ZHANG Zhi-Yong, TAO De-Ding, LI De-Zhu
    Biodiv Sci. 2003, 11 (2):  125-131.  doi:10.17520/biods.2003017
    Abstract ( 3052 )   PDF (306KB) ( 2570 )   Save
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    Pinus squamata is an extremely endangered pine from northeast Yunnan Province of China, which was reported from only one locality where there are 32 individuals in the field. In order to analyze its ecological relationships with other trees and shrubs, a series of techniques, including analysis of variance, χ2 test and percentage of co occurrence, were used to analyze interspecific associations of dominant woody species in communities with P. squamata. The results indicated significantly positive correlation of the association of overall woody species in the two communities with P. squamata. There is also significantly positive correlation in the community on the north facing slope, but only a positive correlation in the community on the south-west facing slope. Considering that the community on the south-west facing slope is mixed coniferous and broad leaved forest and that on the north facing slope is evergreen broad-leaved forest, the results imply that the communities with P. squamata may be in succession from mixed coniferous and broad leaved forest to evergreen broad-leaved forest. Combined with the data of χ 2 test and percentage of co-occurrence, we conclude that P. squamata has no significant correlation with other woody species, and its co occurrence with other trees may be by chance. Finally, its requirements for survival may be threatened by evergreen broad leaved woody species.
    The relationship between modular growth of Kingdonia uniflora and the environment
    ZHANG Wen-Hui, WANG Yan-Ping, LIU Guo-Bin
    Biodiv Sci. 2003, 11 (2):  132-140.  doi:10.17520/biods.2003018
    Abstract ( 2924 )   PDF (365KB) ( 2081 )   Save
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    Kingdonia uniflora is a perennial herb, a typical clonal plant that is an endemic and endangered plant in China. It is distributed in the middle and high mountains at altitudes of 2500-3900 m in Shaanxi, Gansu, Sichuan, and Yunnan Provinces. Its open dichotomously-veined leaves, as well as other primitive characters, have attracted the interest of botanist. In order to explore the conservation strategy and counter measures to threats, the growth course of every module, including root, rhizome and leaf, of K.uniflora in Taibai Mountain were studied systematically, and the environmental factors that influence populations were analyzed. The growth patterns of modules of different K. uniflora populations had a similar tendency, which could be expressed by the equation:y=A+B1x+B2x2+B3x3,where y is modular growth parameters,xis age, and A and B are constants. The modular growth parameters (root, rhizome and leaf) of K.uniflora populations in different communities were significantly different (P< 0.05).The number and the architectural index of root, rhizome and leaf developmental growth of K.uniflora populations in Abies fargesii communities at altitudes of 2700~2900m was better than that of populations in Betula utilis communities at altitudes of 2500~2700 m and in Larix potaninii var. chinensis communities at altitudes of 2900~3100 m. The habitat in Abies fargesii community was most favorable for K. uniflora populations, whereas the L. potaninii var. chinensis community was moderately favourable, and Betula utilis community was marginal. From principal component analysis (PCA) of the nine main environmental factors that influenced the modular growth of K. uniflora populations, human disturbance, climate (illumination, air temperature and humidity), and soil condition (pH and moisture), were shown to be the most important factors. In addition, the thickness of humus and the organic content of soil, and the coverage of the community also played important roles. Reflecting the importance of asexual propagation in the life of K. uniflora and the special range of dependent environmental variables, more attention should be paid on protecting and building favorable environmental conditions. Disturbance by human beings should be stopped. The habitat of communities of Abies fargesii, Betula utilis, and L. potaninii var. chinensis, where K. uniflora populations live should be conserved. The action of blindly transferring individuals of K. uniflora from the wild to the garden should not be promoted.
    Species diversity of the fungal genus Lachnum (Hyaloscyphaceae, Ascomycotina) from tropical China
    YU Zhi-He, ZHUANG Wen-Ying
    Biodiv Sci. 2003, 11 (2):  141-146.  doi:10.17520/biods.2003019
    Abstract ( 2840 )   PDF (229KB) ( 2034 )   Save
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    Species diversity of Lachnum from tropical China was investigated. Four hundred and fifty one specimens of the genus were involved and they belong to 35 taxa. Of them, Lachnum abnorme var. abnorme , L. brasiliense , L. flavidulum , L. pteridophyllum , L. sclerotii and L. virgineum account for 73.4% of the specimens examined and are the most common species occurring in tropical China. The results indicate that species richness ( S =22) and diversity index ( H ′=2.6696) are highest in Hainan, and that species richness in Yunnan is the same as that in Guangxi. The coefficient of community ( cc ) was used to compare the floristic similarity of different areas. Impact of elevation, habitat, and substrate on species composition was also discussed. Within the 100~2000 m asl zone where the genus is found, three distribution patterns of Lachnum were identified: cosmopolitan, disjunct, and endemic.
    Low -density species and the mechanism of their formation and maintenance in tropical forests
    ZHUO Yuan-Wu, AN Shu-Qing, XIANG Hua-Jun, QIN Feng-Fei, ZHENG Jian-Wei, WANG Zhong-Sheng
    Biodiv Sci. 2003, 11 (2):  147-154.  doi:10.17520/biods.2003020
    Abstract ( 2778 )   PDF (303KB) ( 1830 )   Save
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    Low -density species are species that occur with a low density of mature individuals. They are the most common species in tropical forests. Knowledge and protection of low density species are key tobiodiversity conservation in tropical forests. The meanings of low density species is broader than that of rare species. Low density species also include species that have low density, wide distribution range and a huge number of mature individuals. Low survivorship of seeds and seedlings near the parent individual is an important mechanism of creation of low density species. Low density species probably arise from intraspecific density dependent effects and limited population recruitment. The possible mechanisms of maintenance of low density species lie in both external factors, such as capacities of insect pollinating, and inner factors, including flower number and flowering duration of tropical plants. Some tropical species are self fertilized, compensating for the decline in opportunity for cross breeding due to extreme low density. Up to now, few studies have been carried out in this field. We should design more detailed research in combination with research on the properties of tropical forests, so that we can provide a theoretical basis and practical advice for biodiversity conservation in tropical forests of our country.
    Sampling strategy for genetic diversity
    JIN Yan, LU Bao-Ron
    Biodiv Sci. 2003, 11 (2):  155-161.  doi:10.17520/biods.2003021
    Abstract ( 3535 )   PDF (246KB) ( 3184 )   Save
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    An appropriate sampling method not only serves as a prerequisite for conservation and utilization of biodiversity occurring in nature, but also affects the results of population genetic research. A strategic sampling method for genetic diversity can be defined as the optimum sampling method to achieve representation of the full genetic variation represented in a species or a population within a manageable number of samples. Therefore, strategic sampling must consider two factors: 1) the number of samples (including number of populations in a given area and number of individuals within a given population), and 2) the methods of sampling in relation to the genetic structure of the populations under consideration. The well known Hardy Weinberg Equilibrium and other principles of population genetics provide the theoretical bases of sampling strategy design. The theoretical models of sampling based on the Hardy Weinberg Equilibrium offer a general guideline for the number of individuals to be sampled within a population and the number of populations to be sampled in a given region if there is no detailed genetic and environmental information available. Based on this, approximately 30 individuals from a population could be considered as a recommended size for collection under such conditions. When designing a sampling strategy, the biotic and abiotic factors that can influence the genetic diversity captured in the organisms under study should also be considered. The taxonomic status, life cycle, geographical distribution, breeding system, and environmental heterogeneity of a target species will significantly affect the pattern of genetic variation and consequently the design of sampling strategy. In general, the optimum sampling strategy should be designed on the basis of the biological features of the target species, environmental conditions, and objectives for conservation, utilization, or research.
    Biodiversity of endophytic fungi Pestalotiopsis
    WEI Ji-Guang, XU Tong
    Biodiv Sci. 2003, 11 (2):  162-168.  doi:10.17520/biods.2003022
    Abstract ( 2888 )   PDF (274KB) ( 2286 )   Save
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    Pestalotiopsis species is an important group of endophytic fungi. Endophytic Pestalotiopsis distributed in roots, stems, leaves and reproductive parts of its host plants. Twenty three endophytic Pestalotiopsis species have been identified. The colonization rates of endophytic Pestalotiopsis in observed plants were greatly different. Endophytic Pestalotiopsis was a dominant group in the tissues of Rhizophora apiculata ,Cocos nucifer ,Taxus yunnanensis,Camellia sasanqua ,Fragraea bodeniiand Cordemoya integrifolia . Most of endophytic Pestalotiopsis colonized more than one host plant, however, a few of them colonized only one. The distributions of endophytic Pestalotiopsis are related to ecological and environmental conditions and location of host plants. Some endophytic Pestalotiopsis act either as parasites or as saprophytes due to the different stage of host plants and (or) environmental conditions. Endophytic Pestalotiopsis produced a variety of secondary metabolites including antitumor components (taxol and torreyanic acid), antifungal and antibacterial components (cyclohexenone, torreyanic acid and pestaloside) showing a bright future of application.
    Indicators for monitoring biodiversity in urban and suburban parks
    CHEN Bo, BAO Zhi-Yi
    Biodiv Sci. 2003, 11 (2):  169-176.  doi:10.17520/biods.2003023
    Abstract ( 2543 )   PDF (247KB) ( 2243 )   Save
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    Urban and suburban parks are rich in habitats, plants and animals. With the rapid development of urbanization, biodiversity in cities and suburbs will decrease inevitably, so it is important to protect the biodiversity in parks. To achieve this goal, monitoring biodiversity is basic. Up to now, most studies on biodiversity conservation in China focus on species diversity, but few on habitat diversity. Actually, it has been proven that habitat conservation is more important than species conservation. Therefore, we introduce a method for the general monitoring of the biodiversity in urban and suburban parks developed by Hermy and Cornelis, two Belgian scholars. The method partitions diversity along two axes, habitat diversity and species diversity. At the habitat level, the diversity in so-called “habitat units” is measured. These units are divided into planar, linear and punctual elements. For each category they calculated a Shannon-Wiener diversity index and a saturation index. The latter is the ratio of the actual diversity index to the theoretical maximum diversity index in the region. At the species level, species richness and biodiversity indices of vascular plants, butterflies, amphibians and breeding birds were calculated. These values were compared with the total number of species in Flanders, resulting in a saturation index for each park for plants and animals. In this way, 20 biodiversity indicators were obtained. This method was applied to measure the biodiversity in the municipal park of Loppem (West Flanders, Belgium). We discuss the advantages and disadvantages of this method, and suggest that it should be utilized, based on specific situations.

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