To study the dynamics in crop-field soil biodiversity under long-term fertilization is important for agricultural ecosystem protection. We selected a long-term fertilized paddy field under rice/rape rotation from the Taihu Lake region as a study site, and identified weed seeds in the topsoil (0–15 cm) by microscopic examination. Weed seed number and crop yields were recorded. We analyzed the effect of long-term fertilization on soil weed seed bank diversity and the relationship between weed seed diversity and crop yields. The fertilizer treatments were as follows: non-fertilizer (NF), chemical fertilizer only (CF), chemical fertilizer and pig manure combined (CMF), and chemical fertilizer plus crop stalk (CSF). The results indicated that in the cultivating seasons of both rice and rape, under the treatment of chemical fertilizer plus rice crop stalk, the density of soil weed seed bank was the lowest, whereas the total species number and diversity was the high-est. Furthermore, the crop yields were maximal and the steadiest under this treatment. There was definite correlation among fertilizer treatments, soil weed seed bank diversity and crop yields. It was concluded that balanced fertilizer management helps to maintain soil weed seed bank diversity, increase crop yields, and prevent crop yields from fluctuating. Therefore, among the four fertilizer treatments, chemical fertilizer plus rice crop stalk was the best one to increase the productivity of agricultural ecosystems and simultaneously protect biodiversity.

The nature reserve, as a cornerstone of global ecological conservation, has become the focus for ecological management and design programs. The aim of this study is to describe the differentiation dynamics of vegetation in various functional subzones under relevant protection conditions. Based on remote sensing, GIS and other methods of landscape analysis, the 1987- and 2001- normalized difference vegetation index (NDVI) data of Songshan National Nature Reserve, Beijing were calculated using two-stage Landsat 5 Thematic Mapper images. Vegetation analysis was analyzed for trends, including three tendencies: decrease, stabiliza-tion and increase. Landscape metrics were calculated to portray the change pattern of vegetation, and spatial heterogeneities of vegetation dynamics and change pattern were compared in various functional subzones. The major results were achieved as follows: (1) Vegetation cover remained in general stable or was to some extent improved since the nature reserve had been established. The gradients of vegetation cover had already been constructed, i.e. core zone > buffer zone > experimental zone. (2) Under the strictest protection measures, vegetation in the core zone appeared to be highly stable and had been further improved. The stabi-lization-type vegetation dynamic was found in the central part of the zone and the increase-type dynamic was found on the edge of the zone. The decrease-type vegetation dynamic was consistent with natural vegetation dynamics in a randomly distributed state. (3) As a result of development and exploitation, the stabilization of vegetation in the experimental zone was low and variable, with a strong fluctuation as well as a dynamic of alternating increase and decline. Its vegetation coverage was the lowest and the vegetation tended to degrade gradually. (4) To some extent, a random distribution pattern was observed in the vegetation of the buffer zone.

The Taihu Lake region has a long history of cultivating rice (Oryza sativa L. sub. japonica) and has a high yield of rice. However, the genetic basis of rice varieties is becoming more and more narrow, which may result in potential risk to agricultural production. In order to enlarge the genetic basis of rice varieties by virtue of local varieties, we examined the genetic diversity of 823 varieties of japonica rice landraces from Taihu Lake region. We found that, among the 19 traits studied, the coefficient of variation of 15 quantitative traits ranged from 4.6% (seed setting rate) to 33.7% (yield per plant). There existed 10 phenotypes for husk color, 6 for apiculus color, 5 for awn type, and 4 for grain shape, respectively. For the 19 traits, the phenotypic diversity index (H′) ranged from 0.757 (grain shape) to 1.930 (filled grains per panicle), av-eraging 1.540. Phenotypic variance of accessions headed after 10 September was larger than that of acces-sions headed before 10 September (including this day). Principal component analysis showed that plant height, panicles per plant, spikelets per panicle, filled grains per panicle, spikelet density, 1,000-grain weight, yield per plant, and panicle neck length were important traits in explaining the phenotypic diversity of japon-ica rice landraces from the Taihu Lake region.

Phellodendron amurense is a rare and endangered medicinal plant in China. We assessed the genetic diversity within and among populations of this species using AFLP. A total of 129 individuals from 10 wild populations were detected by eight pairs of AFLP primers. These primers generated a total of 1,704 bands, of which 1,581 were polymorphic. The results revealed a high level of genetic diversity. At species level, the percentage of polymorphic loci (PPL) was 92.77%, the effective number of alleles per locus (N_e) was 1.4636, Nei’s gene diversity (H) was 0.2316, and Shannon’s information index (I) was 0.4275, respectively. At population level, the estimates of PPL =54.20%, N_e=1.2487, H=0.1524 and I=0.2371. The coefficient of genetic differentiation (G_st) was 0.3420. UPGMA cluster analysis showed that there was a possible correlation between genetic variance and habitat differences. As a conclusion, we propose that conservation of P. amurense should be in their natural habitats, including Mts. Changbaishan, Wandashan, Daxing’anling, and Xiaoxing’anling, Qianshan and Yanshan. At the same time, the preservation of germplasm resources in botanical gardens should be carried out by sampling more individuals from multiple sites.

The genotypes of 10 indigenous Chinese cattle breeds and three introduced breeds were investigated using 10 microsatellite DNA markers recommended by the Food and Agriculture Organization of the United Nations (FAO) and the International Society of Animal Genetics (ISAG) through fluorescence-multiplex PCR. The allele frequency, polymorphism information content (PIC), and heterozygosity were computed to estimate the genetic variation of each population. To determine the genetic relationships among the breeds, phylogenetic trees were constructed based on Nei’s genetic distance and Nei’s standard genetic distance using the unweighted pair-group method with arithmetic mean. As a result, 13 breeds were clustered into three groups. The first group belongs to the common cattle breeds including Yanbian, Changbai, Yanjiang, Monggol, Altay White Head, Hazake, Fuzhou, and Tibetan, while the second group contains those with zebu blood including Xigazê Humped and Apeijiaza. The third group consists of foreign breeds including German Yellow, Simmental, and Charolai. The results may provide a scientific basis for the study of characteristics of Chinese indigenous cattle breeds so as to preserve and utilize them.

Based on the maritime data collected from 23°30′–33°00′ N and 118°30′–128°00′ E of the East China Sea in four seasons during 1997–2000, we analyzed the dynamics of medusa diversity and the causes. A total of 103 medusa species were observed, which were mainly distributed in southern and northern offshore of the East China Sea. Higher species diversity indices (H′) of medusa occurred, respectively, in the southern part of the sea, offshore, and in summer and winter. The number of species was closely correlated with H′ value, whereas the abundance was not correlated with it significantly. The lower H′ value nearshore in spring and autumn resulted from the aggregation of Muggiaea atlantica nearshore of Zhejiang Province and Diphyes chamissonis at the Yangtze River estuary. Water temperature, followed by salinity, was main environmental factor influencing the distribution of species diversity. H′ value was related to the water temperature of 10 m layer in winter and spring, while it is associated with surface water temperature in summer and with 10 m-salinity-layer in autumn. The isoline distribution of H′ value reflected the direction of currents and changes in water masses in the East China Sea, the H′ isoline was a good indicator for analyzing the East Sea cold masses.

In order to probe into the dynamics of butterfly species and quantities in different habitats at high elevation, from 1993 to 1997, we surveyed butterfly diversity in four habitat types at the Huzhu Northern Mountain National Forest Park, Qinghai. We selected a plain among valleys, a temperate steppe, a mixed coniferous and broad-leaved forest, and an alpine shrub meadow as our study sites. We trapped 4,745 butterflies, belonging to eight families, 57 genera and 86 species. The genera with the most abundant species included Colias (6 species), Pieris (5 species), Aporia (4 species), Pontia (3 species), and Melitaea (3 species). The most individual number occurred in the families Pieridae and Lycaenidae. In terms of butterfly species composition and quantities, significant differences existed among different habitats. The number of butterfly species was the largest in the mixed coniferous and broad-leaved forest, while the individual number peaked in the plain among valleys. The species diversity of butterflies was highest in the mixed coniferous and broad-leaved forest and the lowest in alpine shrub meadow, while the evenness index was highest in mixed coniferous and broad-leaved forest and lowest in the plain among valleys. Dominance was the highest in the alpine shrub meadow. The mixed coniferous and broad-leaved forest had the most endemic genera/species (20 genera, 24 species), followed by the alpine shrub meadow (8 genera, 8 species), the plain among valleys (6 genera, 7 species), and the temperate steppe (5 genera, 6 species). The similarity coefficients of butterfly species among different habitats ranged from 0 to 0.4259. Using cluster analysis to identify the species composition of butterflies, we discovered that the plain among valleys had the highest similarity with the temper-ate steppe, and secondarily with the mixed coniferous and broad-leaved forest, and third with the alpine shrub meadow. In order to protect the butterfly diversity of this area, we suggest establishing a natural protected zone to better balance tourism and biodiversity protection.

By using living trapping, we studied the characteristics of rodent communities in desert-oasis landscape in the middle reaches of the Heihe River, Gansu. Field study was carried out from April to May, and September in 2005. A total of 4,800 living trappings were set in eight typical habitats, including sand dune, gravel-sandy desert, stabilized sandy desert, desert scrubland, shelter belt, irrigated grassland, irrigated crop field and riverine grassland. In total, 254 individuals representing 9 species, 8 genera, and 3 families were captured. We then calculated characteristic indices of community structure for the eight habitats. The species diversity index (Shannon-Wiener index) ranged from 0.6859 (irrigated grassland) to 1.7036 (stabilized sandy desert), while Pielou evenness index ranged from 0.6531 (sand dune) to 1.0000 (riverine grassland). Using Pearson correlation coefficients and hierarchical clustering, we could roughly classify the 8 ro-dent communities as 2 major types, i.e. desert type and oasis type. Desert-type habitats generally harbored higher species diversity and population density. Dipus sagitta showed a high density and was dominant in desert-type habitats, especially in sand dune. Cricetulus barabensis was common in habitats with relatively high vegetation coverage but also recorded in desert-type habitats (sand dune excluded). Among the four jerboa species, only Allactaga sibirica was found in oasis-type habitats. We did not capture any rodent in core region of shelter belt. However, we did record some individuals in the edge region. No significant rela-tionship was found between Shannon-Wiener diversity index and capture rate(r=0.240, P=0.566). Our results suggest that human disturbance in study area may have been beneficial to maintain rodent diversity.

Study of the distribution and fluctuation of endophytic bacteria in tomato plants is important for screening of specific endophytic bacteria strains to control bacterial wilt of tomato. We isolated 624 endophytic bacteria strains from the roots, stems and leaf tissues of 303 symptomless tomato plants collected from Guangxi. By conventional methods, these strains were identified as Bacillus, Pseudomonas, Xanthomonas, Microbacterium, Corynebacterium, Erwinia, Enterobacter, and Agrobacterium. Among them, Bacillus, Pseudomonas, and Agrobacterium were main genera and Bacillus was the dominant genus. The endophytic bacteria were the most common in the roots of tomato plants, followed by those in stems and leaves. The to-tal amount of endophytic bacteria increased gradually from the seedling stage to flowering stage, and then decreased gradually from fruit setting stage to ripening stage. The amount of most endophytic bacteria genera fluctuated in correspondence with the total amount of endophytic bacteria with the exception of Microbacte-rium, whose number kept decreasing from seedling to ripening stages. More endophytic bacteria were found in tomato plants cultivated in the spring than those cultivated in the autumn.

Expressed sequence tags (EST), which have been increasing rapidly in number recently, provide important resources for the development of molecular markers. Compared with conventional markers derived from genomic DNA, the EST-derived markers are a novel type of molecular tool with remarkable advantages such as being easy to develop, more informative, and highly transferable. EST markers have been used in many research fields. In the present paper, five kinds of recently developed EST markers, including EST-PCR, EST-SSR, EST-SNP, EST-RFLP, and EST-AFLP, as well as their development strategies based on bioinformatics, are introduced. Moreover, the applications of these markers in comparative genomics studies, including comparative mapping, genetic diversity evaluation, and phylogenetics and so on, are also reviewed.