Biomedical subjects

Zhanqing Hao

Publications and source records attributed to Zhanqing Hao.

15 recordsLinked to original sources

PubMed2006

[Effects of bryophytes in dark coniferous forest of Changbai Mountains on three conifers seed germination and seedling growth].

This paper studied the effects of Hylocomium splendens and Rhytidiadelphus triquetrus, the main bryophytes in dark coniferous forests of Changbai Mountains, on the seed germination and seedling growth of Pinus koraiensis, Picea koraiensis and Larix olgensis. The results indicated that at definite concentrations, the water extract of H. splendens inhibited Picea koraiensis seed germination, while that of R. triquetrus promoted it. Although the water extracts of the two bryophytes had no obvious effects on the seed germination of Picea koraiensis and Larix olgensis, they expedited the occurrence of the tree species' daily germination peak. The water extracts of test bryophytes inhibited the seedling growth of P. koraiensis and Picea koraiensis, but promoted that of Larix olgensis. The living shoots of the two bryophytes had no obvious effects on the seed germination of Picea koraiensis and Larix olgensis, but delayed the daily germination peak of Picea koraiensis while promoted that of Larix olgensis, andthe killed shoots inhibited the seed germination of all test tree species. Living shoots in larger amounts promoted the seedling growth of Picea koraiensis and Larix olgensis, but killed shoots were inadverse.

Bryophyta↗

PubMed2006

[Respiration rate of broadleaved Korean pine forest ecosystem in Changbai Mountains].

In this paper, the respiration rates of soil, foliage, and stem and branch in the broadleaved Korean pine forest ecosystem of Changbai Mountains were measured by Li-6400 CO2 analysis system in 2003, with the microclimate factors determined synchronously. The correlation models of ecosystem respiration with environmental factors were established, and the respiration rate of each component of the ecosystem was estimated based on the vegetation characteristics of the broadleaved Korean pine forest. The results showed that the annual total respiration rate of the ecosystem was 1602. 8 g C x m(-2), with a mean of (4. 37+/-2. 98) micromol x m(-2) x s(-1) , and the respiration of soil, foliage, and stem and branch contributed about 63% , 21% , and 16% of the total, respectively. There was a significant correlation between system respiration and daily mean air and soil temperature, and about 87% and 95% of the ecosystem respiration could be explained by the air and soil temperature, respectively.

China↗

PubMed2005

[Assessing forest ecosystem health II. A case study].

On the bases of samples investment and related data collected by others, and with the method of health distance assessment and the ecosystem health index system of Korean pine and broad-leaved mixed forest established in prior paper, this paper attempted to assess the ecosystem health of Korean pine and broad-leaved mixed forest under various human disturbances. The results showed that the health degree was in the order of 20% intensity selective cutting stand (0.21) < 50% intensity selective cutting stand (0.44) < middle and mature birch stand (0.67) < youth birch stand (0.72) < Korean pine plantation (0.74) < larch plantation (0.77).

Biomass↗

PubMed2005

[Roles of bryophyte in nutrient cycling in dark coniferous forest of Changbai Mountains].

This paper measured the nutrient contents of five main bryophytes in the dark coniferous forest of Changbai Mountains, and estimated their values per unit area. The results showed that bryophyte had a nitrogen content 54.371 kg x hm(-2), being 12.22% of total nitrogen content of arbor, shrub and herb, and its potassium and phosphorous content was 12.042 kg x hm(-2) and 31.679 kg x hm(-2), occupying 5.63% and 70.57% of the total, respectively. The phosphorous content of bryophyte was higher than that of arbor, and 2.4 and 792 times as much as that of herb and shrub, respectively, indicating that bryophyte was an important phosphorous pool. Soil nitrogen and potassium content under different coverage of bryophyte had little difference, while soil phosphorous content was significantly different. The soil with no bryophyte coverage had the highest phosphorous content (0.419 +/- 0.023 g x kg(-1)), while that with 80%-100% bryophyte coverage had the lowest one (0.346 +/- 0.017 g x kg(-1)), suggesting that soil phosphorous content was decreased with increasing bryophyte coverage.

Bryophyta↗

PubMed2004

[Bryophyte biomass in dark coniferous forest of Changbai Mountain].

In this paper, the floor and epiphytic bryophyte biomass was sampled from the dark coniferous forest on the north slope of Changbai Mountain, with an altitude from 1100 m to 1700 m. The floor bryophyte biomass was measured by the method of transect sampling, and epiphytic bryophyte biomass was measured by McCune method. The results showed that bryophytes distributed unevenly, and their biomass changed greatly with increasing altitude. The biomass was the least (543 kg x hm(-2)) at 1100 m, but the greatest (5097 kg x hm(-2)) at 1250 m. The changes of bryophytes biomass could indicate different environmental situations. The biomass change of Hylocomium splendens and Rhytidiadelphus triquetrus with ascending altitude had some relativity with the community character of forest ecosystem. The biomass of Hylocomium splendens increased, but that of Rhytidiadelphus triquetrus decreased with altitude ascending from 1100 m to 1700 m. Moreover, the biomass changes could also show the needed physiological conditions of different bryophytes.

Altitude↗

PubMed2004

[Effect of cone-picking on natural regeneration of Korean pine in Changbai Mountain Nature Reserve].

The storage and distribution of Korean pine seeds on Korean pine forest floor in Changbai Mountain Nature Reserve were investigated, and the data were compared with those in 1970s when the forest was little disturbed. Based on the dependence of natural regeneration of Korean pine on seed predating animals, the effect of commercial cone-picking on natural regeneration of Korean pine was discussed. The results showed that Korean pine seeds were generally berried under litter layer, and most of them were dropped during cone-picking. The density of Korean pine seeds was 1582-2640 x hm(-2), accounted for 0.3%-0.5% of that in 1970s. Furthermore, over 67.8% of these seeds were rotten. Unlike the seeds distributed by squirrel, many (46.7%-77.1%) of them distributed singly. Animals that pick seeds from cone and thus are important for natural regeneration of Korean pine have reduced their population or even disappeared in recent years because most Korean pine cone were collected by people. Therefore, cone-picking was one of the obstacles for natural regeneration of Korean pine in Changbai Mountain Nature Reserve.

Conservation of Natural Resources↗

PubMed2004

[Assessing forest ecosystem health I. Model, method, and index system].

Ecosystem health assessment is one of the main researches and urgent tasks of ecosystem science in 21st century. An operational definition on ecosystem health and an all-sided, simple, easy operational and standard index system, which are the foundation of assessment on ecosystem health, are necessary in obtaining a simple and applicable assessment theory and method of ecosystem health. Taking the Korean pine and broadleaved mixed forest ecosystem as an example, an originally creative idea on ecosystem health was put forward in this paper based on the idea of mode ecosystem set and the idea of forest ecosystem health, together with its assessment. This creative idea can help understand what ecosystem health is. Finally, a formula was deduced based on a new effective health assessment method--health distance (HD), which is the first time to be brought forward in China. At the same time, aiming at it's characteristics by status understanding and material health questions, a health index system of Korean pine and broadleaved mixed forest ecosystem was put forward in this paper, which is a compound ecosystem based on the compound properties of nature, economy and society. It is concrete enough to measure sub-index, so it is the foundation to assess ecosystem health of Korean pine and broadleaved mixed forest in next researches.

Ecosystem↗

PubMed2004

[Structure characteristics and health distance assessment of various disturbed communities of Korean pine and broadleaved mixed forest in Changbai Mountains].

Through samples investigation, this paper analyzed and classified the community structures of overcutting original forests, secondary birch forests and larch plantation forest under different disturbances. At the same time, some indexes which can reflect the integrity and stability of stand structure were selected. Health Distance (HD) method, a new idea, was attempted to assess ecosystem health of Korean pine and broadleaved mixed forest in Changbai Mountains. The results showed that the health degree was in order of original broadleaved stand (0.14) < structure switched stand (0.23) < structure reserved stand (0.32) < structure destroyed stand (0.33) < heavy disturbed stand (0. 44) < secondary birch stand (0.53) < larch plantations (0.68). Hopefully, it will be a helpful reference on the restoration of Korean pine and broadleaved mixed forest and on the regional forestry sustainable development.

China↗

PubMed2004

[Utilization suitability of forest resources in typical forest zone of Changbai Mountains].

Conservation of natural forest does not simply equal to no logging. The Northeast China Forest Region has a logging quota of mature forest as part of natural forest conservation project. How to determine the logging spots rationally and scientifically is very important. Recent scientific theories of forest resources management advocate that the utilization of forest resources should stick to the principle of sustaining use, and pay attention to the ecological function of forest resources. According to the logging standards, RS and GIS techniques can be used to detect the precise location of forest resources and obtain information of forest areas and types, and thus, provide more rational and scientific support for space choice about future utilization of forest resources. In this paper, the Lushuihe Forest Bureau was selected as a typical case in Changbai Mountains Forest Region to assess the utilization conditions of forest resources, and some advices on spatial choice for future management of forest resources in the study area were offered.

China↗

PubMed2004

[Effects of soil water regimes on the growth of Quercus mongolica seedlings in Changbai Mountains].

This paper studied the response of the seedlings of Quercus mongolica, one of the dominant tree species in Changbai Mountains, to the artificially controlled three soil water gradients, including their morphology, biomass and photosynthetic characteristics. The results indicated that various water regimes significantly affected the biomass and its distribution pattern in the leaves, branches and roots, as well as the leaf gas exchange. Under soil water stress, the crown structure changed, and the tree height, groundline diameter, single leaf area, and aboveground and belowground biomass were inhibited. As soil water content decreased, the ratio of belowground and aboveground biomass dry weight significantly increased. Water stress had a negative effect on net photosynthetic rate, CO2 use efficiency and carbon use efficiency. The responses of stomatal conductance, transpiration rate and water use efficiency to water stress were complicated. Only at low soil water content, the stomatal conductance and transpiration rate significantly decreased, while water use efficiency increased. It was demonstrated that Quercus mongolica was the tree species with variable resistance to drought, and the resistance could be improved by long-term soil water stress.

Biomass↗

PubMed2004

[Landscape pattern variation of forest resources in typical forest zone of Changbai Mountains].

Based on GIS and RS data of 1985 and 1999 and the ground information from Lushuihe Forest Bureau, this paper studied the forest landscape pattern and its changes in typical forest zone of Changbai Mountains. According to the standard variance of patch areas in 1985 and 1999, the patch area distribution of mature conifer forest, mature broad-leaved forest, middle-aged conifer forest, and middle-aged broad-leaved forest was less symmetrical, showing that these land covers had landscape diversity and species diversity. According to landscape similarity index, the mature conifer forest, mature broad-leaved forest, middle-aged conifer forest and middle-aged broad-leaved forest, which were relatively stable than other land covers, made the majority of the landscape in the study area. According to patch density, the porosity of wetland was high in 1985 and 1999, indicating that wetland had little homogenization and formed more mosaics. The fragmentation extent of farming land, due to multiple cultivating types, azimuths and shapes, was high in both phases. Attributing greatly to anthropogenic factors, the fragmentation extent of wetland was high all along. In brief, the forest landscape pattern was changed greatly in the studied phases, and human activities affected heavily on it.

Biodiversity↗

PubMed2004

[Research advances in bryophyte ecological function].

Though the body of bryophyte is small, its species is abundant (about 23,000), being an important part of biodiversity. The previous studies were focused on its taxology, while its ecological functions in ecosystem were ignored. Bryophyte can adapt to various environments, distribute in many extreme surroundings, and has rebuilding ability to environments. It has a very strong ability of holding and absorbing water, especially the epiphytic bryophyte can intercept a great deal of rain, and its function in water circulation is very obvious. Bryophyte can absorb a lot of nutrient elements by body surface, but its function in nutrient cycling was usually ignored. In some extreme environments, bryophyte is the important primary producer. Sphagnum biomass is more enormous, and maybe, is the important C pool. Bryophyte can sensitively response to the air and heavy metal pollution, and is a kind of bio-indicators. In order to promote the further studies on bryophyte ecological function, the related research advances were reviewed in this paper.

Biodiversity↗

PubMed2003

[Approaches for assessing forest ecosystem health].

Assessment and indicator system become the key issues in the research on ecosystem health in 21st century. Assessing forest ecosystem health gradually attach much attention because it is an important component of terrestrial ecosystem. The definition, measurement, evaluation and its management had been discussed broadly, and some theories, assessing methods and frameworks had been proposed, which provides a new concept and a serial research approaches for dealing with the crisis of terrestrial ecosystems, even the environment problems in the world. Now, the common operational models for assessing forest ecosystem health do not exist owing to the manifold limitations. This paper discussed forest ecosystem health problem, and brought forward three preconditions for assessing forest ecosystem health: 1) a clear conceptual framework; 2) adequate data sets; 3) proper research and analysis techniques. The issues of three preconditions were discussed, and the possible approaches for the assessing research on forest ecosystem health, e.g., long-term studies and environment monitoring, space-for-time substation studies, e.g., history approaches, economics valuation and others were expariated.

Ecosystem↗

PubMed2002

[Effect of elevated atmospheric CO2 concentrations on photosynthesis light response characteristics of three coniferous tree species seedlings].

Potted seedlings of Pinus koraiensis, Picea koraiensis, and Larix olgensis, the dominant coniferous tree species in Changbai Mountain, were grown under elevated CO2 concentration (700 mumol.mol-1) and ambient CO2 concentration (400 mumol.mol-1) for two year, and their photosynthesis light response curves were determined with CI-301PS CO2 gas analysis system under a series of light intensity from 0 to 2500 mumol.quanta.m-2.s-1. The comparison of dark respiration rate (DRR), maximum net photosynthetic rate (Amax), quantum use efficiency (QUE), light compensation point (LCP), light saturation point (LSP) and photo inhibition point (PP) for the seedlings of these coniferous tree species under different CO2 concentration showed that Larix olgensis, which had better adaptation of photosynthesis to elevated CO2 concentration, was heliophilous species. The shade-tolerant species Picea koraiensis showed the least adaptation of photosynthesis to elevated CO2 concentration. Furthermore, the relationship between photosynthetic physiological character of tree species and their succession status was also discussed in this paper.

Carbon Dioxide↗

PubMed2002

[Alpha diversity of communities and their variety along altitude gradient on northern slope of Changbai Mountain].

From 700 to 2600 m on northern slope of Changbai Mountain, twenty plots were investigated with an interval of 100 m in altitude, and alpha diversity of communities and their variety along altitude gradient were studied. The results showed that in different successional layers of trees, or shrub and herb layers, richness and diversity decreased linearly with the increase of altitude. Tree species decreased from 19 species at 700 m to only 1 species at timberline. Shrub and herb species decreased from 20 and 61 species at 700 m to 2 and 15 species at 2600 m respectively. The peak values of richness of trees and herbs along altitude gradient were appeared just in the ecotones between different types of vegetation, and it reflected the characteristics of high species richness in ecotones.

Altitude↗