Biomedical subjects

Silong Wang

Publications and source records attributed to Silong Wang.

12 recordsLinked to original sources

PubMed2006

Phytogeographical analysis of seed plant genera in China.

BACKGROUND AND AIMS: A central goal of biogeography and ecology is to uncover and understand distributional patterns of organisms. China has long been a focus of attention because of its rich biota, especially with respect to plants. Using 290 floras from across China, this paper quantitatively characterizes the composition of floristic elements at multiple scales (i.e. national, provincial and local), and explores the extent to which climatic and geographical factors associated with each flora can jointly and independently explain the variation in floristic elements in local floras. METHODS: A study was made of 261 local floras, 28 province-level floras and one national-level flora across China. Genera of seed plants in each flora were assigned to 14 floristic elements according to their worldwide geographical distributions. The composition of floristic elements was related to climatic and geographical factors. KEY RESULTS AND CONCLUSIONS: Variations in percentages of cosmopolitan, tropical and temperate genera among local floras tend to be greater at higher latitudes than at lower latitudes. Latitude is strongly correlated with the proportions of 13 of the 14 floristic elements. Correlations of the proportions of floristic elements with longitude are much weaker than those with latitude. Climate represented by the first principal component of a principal component analysis was strongly correlated with the proportions of floristic elements in local floras (|r| = 0.75 +/- 0.18). Geographical coordinates independently explained about four times as much variation in floristic elements as did climate. Further research is necessary to examine the roles of water-energy dynamics, geology, soils, biotic interactions, and historical factors such as land connections between continents in the past and at present in creating observed floristic patterns.

China↗

PubMed2005

[Dynamics of soil active organic matter in Chinese fir plantations].

Soil active organic matter is the main source of soil nutrients, and plays an important role in the formation and stabilization of soil aggregate. Chinese fir (Cunninghamia lanceolata) is the most important fast-growing timber tree species in southern China, but its continuous plantation has caused soil deterioration. The study on the active fractions of soil organic matter under the first and second generation plantations of Chinese fir and the native broad-leaved forest at Huitong Experimental Station of Forest Ecology, Chinese Academy of Sciences, in Hunan Province showed that their contents were higher under native broad-leaved forest than under Chinese fir plantations, and higher under the first than under the second generation plantation. The content of soil active organic carbon (SAOC), microbial biomass carbon (MBC), water-soluble organic carbon (WSOC) and water-soluble carbohydrate (WSC) was 18.79 g x kg(-1), 421.7 mg x kg(-1), 252.2 mg x kg(-1) and 136.3 mg x kg(-1) under the first generation plantation of Chinese fir, and 22.31 g x kg(-1), 800.5 mg x kg(-1), 361.1 mg x kg(-1) and 220.1 mg x kg(-1) under the native broad-leaved forest, respectively. The corresponding values under the second generation plantation of Chinese fir were 73.6%, 87.9%, 66.3% and 53.2% of those under the first generation plantation of Chinese fir. The results also indicated that there existed some extent correlations among the active fractions of soil organic matter, and higher correlations between soil microbial biomass carbon and other active fractions of soil organic matter.

Carbon↗

PubMed2005

[Microbial diversity in continuously planted Chinese fir soil].

The study on the microbial diversity of 1st, 2nd, 3rd and 4th generation Chinese fir soil at Huitong Forest Experimental Station showed that with the increase of generation, the numbers of bacteria and actinomyces decreased markedly, while that of fungi increased evidently. It was found by PCR and DGGE that the bacterial diversity changed slightly and its genetic similarity among different generations reached 87 %, but the fungal diversity reduced and its genetic similarity was only 45%. The numbers of pathogenic and deleterious fungi increased markedly with increasing Chinese fir generations.

Actinomyces↗

PubMed2005

[Effects of replacing natural secondary broad-leaved forest with Cunninghamia lanceolata plantation on soil biological activities].

This paper studied the effects of replacing natural secondary broad-leaved forest with Cunninghamia lanceolata plantation in the south, central and upstate areas of subtropical China on the changes of soil chemical and biological properties. The results showed that after replacing with Cunninghamia lanceolata plantation, the total organic carbon (TOC) content in surface soil decreased by 31.51% - 58.24%, and the contents of soil total N and P, pH value, C/N and C/P also decreased to different degree. Soil microbial amount was less than that under natural secondary broad-leaved forest, soil urease, invertase, catalase and dehydrogenase activities decreased, while soil polyphenol oxidase activity increased by 8% - 40%. The respiration rate of Cunninghamia lanceolata soil was 51.15% - 54.48% lower than that of natural secondary broad-leaved forest soil. The correlation between soil TOC and polyphenol oxidase activity was negative (R = - 0.723, n = 18), while those between soil TOC, N, P and other enzyme activities were positive. It could be concluded that replacing natural secondary broad-leaved forest with Cunninghamia lanceolata plantation worsened soil quality, and the loss of soil organic matter in Cunninghamia lanceolata plantation ecosystem might be one of the important factors resulted in the decrease of soil nutrients and enzyme activities.

Carbon↗

PubMed2004

[A comparative study on soil fauna in native secondary evergreen broad-leaved forest and Chinese fir plantation forests in subtropics].

In this study, we investigated the response of soil animal communities to the replacement of native secondary forest by Chinese fir plantation forest and successive rotation of Chinese fir in subtropics. Three adjacent forest stands, i.e., native secondary evergreen broad-leaved forest stand (control) and Chinese fir plantation stands of first (20 yr) and second (20 yr) rotations were selected for the comparison of soil fauna. All animals were extracted from the floor litter and 0-15 cm soil layer of the stands in Summer, 2003 by using Tullgren method, wet funnel method and hand-sorting method. Compared to two Chinese fir plantation forests, the native secondary evergreen broad-leaved forest had a higher abundance and a higher taxonomic diversity of animals in soil and litter, but there were no significant differences in the biomass and productivity of soil fauna between all study stands. The abundance or diversity did not differ significantly between the first rotation and second rotation stands, too. The results supported that vegetation cover might be one of the main forces driving the development of soil animal communities, and the effect of successive rotation of Chinese fir on the development of soil fauna was a slow-running process.

Animals↗

PubMed2004

[Function and application of soil microorganisms in forest ecosystem].

Soil microorganism is an important part of forest ecosystem, and plays an important role in sustainable development of forestry. In this paper, we summarized the main functions of soil microorganisms in forest sustainable development from the aspects of 1) the role of soil microorganism and microbiomass; 2) the function of mycorrhizal fungi; 3) the impact of pathogen; and 4) the effect of PGPR. Finally, we also discussed the research trends of forest soil microorganism and its application. Some study areas which should be further studied were also proposed.

Azospirillum↗

PubMed2004

[An overview on studies of soil organic matter in Chinese fir plantation].

Soil organic matter (SOM) is an important component of soil and an important carbon pool of terrestrial ecosystems, which plays an important role in soil nutrient cycling and in the balance of global carbon cycle. This paper discussed the SOM quality in Chinese fir plantation, the influence of rotation on SOM content, the change of SOM during Chinese fir growth, and the effect of human activities such as burning, site preparations and fertilization on SOM. Human activities changed soil environment including soil moisture, temperature, total porosity and nutrient contents, and hence, made the turnover of SOM slower or quicker. The content and quality of SOM in mixed forests were higher than those in pure Chinese fir plantations, and decreased with rotation. In the last part of this paper, some issues to be further researched were put forward, including the turnover model of SOM, its components, and its relationship with global carbon cycle.

Carbon↗

PubMed2004

[Degradation mechanism of Chinese fir plantation].

Chinese fir (Cunninghanzia lanceolata) is a fast-growing species native to China, and has a very important status in production of commercial timber. In response to the growing need for timber, pure Chinese fir plantations have been extensively replanted on the same site in successive rotations, which has resulted in serious problems of soil fertility degradation and productivity decline, and these problems have caused considerable attention from foresters, microbiologists, soil scientists and ecologists. They have also done a lot of work on these problems and studied the mechanism of productivity decline of replanted Chinese fir plantation. In this article, the author described the characteristics of productivity decline and soil degradation, and summed up the factors caused lower productivity, and analyzed the degradation mechanism of replanted Chinese fir plantation. In sum, productivity decline and soil physical and chemical characteristics deterioration were the main properties of replanted Chinese fir plantation. The factors summarized primarily as two kinds of reasons. One was the unreasonable management that was the edogenic factor, and another was the biotic self-characteristics of Chinese fir that was the intrinsic factor of poor establishment of replanted Chinese fir plantation. The combination of the edogenic and intrinsic factors reduced the productivity decline and soil degradation of the replanted Chinese fir plantation.

Biomass↗

PubMed2004

[Soil quality assessment of forest stand in different plantation esosystems].

After a clear-cutting of the first generation Cunninghamia lanceolata plantation in 1982, three plantation ecosystems, pure Michelia macclurei stand (PMS), pure Chinese-fir stand (PCS) and their mixed stand, were established in spring 1983, and their effects on soil characteristics were evaluated by measuring some soil physical, chemical, microbiological and biochemical parameters. After 20 years' plantation, all test indices showed differences among different forest management models. Both PMS and MCM had a favorable effect on soil fertility maintenance. Soil quality assessment showed that some soil functions, e.g., water availability, nutrient availability, root suitability and soil quality index were all in a moderate level under the mixed and pure PMS stands, whereas in a relatively lower level under successive PCS stand. The results also showed that there existed close correlations between soil total organic C (TOC), cation exchange capacity (CEC), microbial biomass-C (Cmic) and other soil physical, chemical and biological indices. Therefore, TOC, CEC and Cmic could be used as the indicators in assessing soil quality in this study area. In addition, there were also positive correlations between soil microbial biomass-C and TOC, soil microbial biomass-N and total N, and soil microbial biomass-P and total P in the present study.

Cunninghamia↗

PubMed2004

[Ecosystem approach: a new concept for ecosystem management].

Ecosystem approach (EA) was firstly proposed by ecologists in developed countries and then supported by a number of international institutions and NGOs, among which, CBD, IUCN and WWF played important roles. Ecosystem approach is an integrated strategy for the management of land, soil and bio-resources. The application of EA will help to reach a balance between conservation, sustainable use, and fair and equitable sharing of the benefits arising out of the utilization of biological resources. Ecosystem approach is a methodology of ecosystem management, focusing on the biological organisms and recognising that human beings, with their cultural diversity, are an integral component of many ecosystems. The decision V/6 adopted by the Conference of the Parties to the CBD at its fifth meeting in 2000 concretized the EA in the form of twelve principles and five operational guidelines. Our government has recently made a lot of efforts in ecosystem management at large scale with many important measures and obtained significant achievements, but the potential role of local governments, institutions and individuals has not been fully played. In the attempts of managing a specific ecosystem, there are many successful cases done by our ecologists, for example, the ecological management of Chinese fir plantation forest in central subtropical China. However, the whole ecosystem at national or regional level is confronted with a lot of serious problems, mainly because there is a lack of complete understanding of the significance of ecosystem management and a lack of guidelines or principles from an integrated scientific theory. The introduction and implementation of ecosystem approach will play an important role in improving the ecosystem management in China.

China↗

PubMed2002

[Effects of plant foliar litter diversity on the growth of Chinese fir seedling and the absorption of (15NH4)2SO4].

Effects of plant foliar litter species composition on the growth of the potted Chinese fir seedling and the absorption of (15NH4)2SO4 was studied. The result showed that there were significant growth responses to foliar litter treatments. A very noticeable trend was that as the tree species of foliar litter placed on pots increases, the growth of Chinese fir seedlings increases steadily. Seedling growth in four-species mixed foliar litter were the largest and that in Cunninghamia lanceolata + Michelia macclurei + Kalooanax septemlobus foliar litter mixture were the second. The others were in order of seedlings in C. lanceolata + M. macclurei + Castanopsis carlesii foliar litter mixture > C. lanceolata + K. septemlobus foliar litter mixture > C. lanceolata + C. carlesii > control (no foliar litter) > C. lanceolata + M. macclurei foliar litter mixture > Chinese fir foliar litter treatment. The recovery of (15NH4)2SO4 by Chinese fir seedlings in no foliar litter treatment was maximum, and seedlings grown in four foliar litter mixture was the second, then it was in order of C. lanceolata + C. carlesii + K. septemlobus = C. lanceolata + C. carlesii + M. macclurei > C. lanceolata + K. septemlobus > C. lanceolata + C. carlesii > C. lanceolata + M. macclurei > C. lanceolata foliar litter treatment. In addition, the residue of (15NH4)2SO4 was greater in soil with foliar litter treatment than in no foliar litter soil. Both of the residual amount of (15NH4)2SO4 in soil and the total recovery of (15NH4)2SO4 increased with the increasing tree species of applied foliar litter.

Absorption↗

PubMed2002

[Effect of vanillin and P-hydroxybenzoic acid on physiological characteristics of Chinese fir seedlings].

Effects of vanillin and P-hydroxybenzoic acid at different concentrations on physiological characteristic of Chinese fir seedlings were studied by potted experiment. The results showed that 10 mmol.L-1 and 1 mmol.L-1 of two kinds of phenolics significantly reduced the content of chlorophyll, rate of photosynthesis and root activity, and that the higher the concentration of vanillin and P-hydroxybenzoic acid, the more the physiological activities was inhibited. By treatment with 1 and 10 mmol.L-1 vanillin, Chinese fir seedlings reduced its photosynthesis rate 25.1% and 37.0%, transpiration rate 20.3% and 37.0%, stomata conductance 33.7% and 46.8% and root activity 51.6% and 78.8%, respectively. The results suggested that vanillin and P-hydroxybenzoic acid accumulated in the soil by continuous cropping of Chinese fir may have some allelopathic effect on the seedlings of Chinese fir and the effect is one of the factors leading to the low productivity of continuously cropped Chinese fir forest.

Antioxidants↗