Biomedical subjects

Lanzhu Ji

Publications and source records attributed to Lanzhu Ji.

14 recordsLinked to original sources

PubMed2006

[Potential effects of elevated carbon dioxide on forest leaf-feeding insects].

Elevated atmospheric CO2 concentration may result in a decline of leaf nutritional quality (especially N) and an increase in some kinds of defensive secondary components such as phenolic compounds. The changes in tree phytochemistry, combined with the effects of elevated CO2 per se, have a potential impact on leaf-feeding insects. This paper reviewed the effects of elevated CO2 on the performance of leaf-feeding forest insects at individual level and community level. The elevated CO2 per se had very little influence on the metabolism of insect. Over half of the tree-insect experimental system showed that under high CO2, the performance of individual insect became poorer, while the others showed that insect had little or no response to the treatments. The direction and magnitude of the changes in insect performance could be affected by various factors, and the effects of treatments were strongly species-dependant. The magnitude of the changes in phytochemistry, the sensitivity and adaptive capacity of insect to poorer leaf quality, the differences in plant growth conditions and experimental methods, and the mediated effects of other environment factors, e. g., soil NO3-, light, temperature, and O3, were all closely related to the final performance of insect. But, the larvae's consumption usually increased under enriched CO2 treatment, which was widely thought to be a compensatory response for poorer plant quality. The experiments on forest community level found identically a reduction in herbivory, which was contrary to the results from small-scale experiments. The change of insect population and the true response of consumption by leaf-feeding forest insects under CO2 enrichment environment remain unclear, and more field-based experiments need to be conducted.

Animals↗

PubMed2005

[Stem respiration of Pinus koraiensis in Changbai Mountains].

In this paper, soil respiration chamber, a simple and precise method, was used to measure the stem respiration of trees. LI-6400-09 respiration chamber serving as a system is usually used in soil respiration, but we made polyvinyl chloride (PVC) collar and fixed it on the stem surface to measure the stem respiration. From May to October 2003, the stem respiration of Pinus koraiensis, the dominant tree species in Changbai Mountain, was measured in different time and different places using this technique. Meanwhile, the temperatures in the stems and in the forests were measured. The results showed that the stem respiration rate had a remarkably seasonal tendency with a single peak, the maximum was in August and the minimum was in February. The stem respiration rate had an exponential relationship with stem temperature, and the curve exponential regressions for stem respiration rate and temperature factor of trees with big DBH were better than those with small DBH. The stem respiration in different DBH trees was higher in the south stem face than that in the north stem face, and the variance of respiration rate between south and north decreased with a decrease of DBH trees. During the growing season from May to October, the average maintenance respiration accounted for 63.63% in different DBH trees, and the maintenance respiration contribution to total respiratory consumption increased with increasing DBH, which was 66.76, 73.29% and 50.84%, respectively. The stem respiration Q10 values ranged from 2.56-3.32 in different DBH of trees, and the seasonal tendency for stem R, and Rm in different DBH of trees was obtained by using respiration Q10. Therefore, the differences between different parts of stem and different DBH of trees should be considered in estimating the respiration model in ecosystem.

Air↗

PubMed2005

[Effects of simulated water stress on photosynthesis rate and WUE of Fraxinus mandshurica].

This paper studied the photosynthesis characteristics and water use efficiency (WUE) of Fraxinus mandshurica under three years simulated water stresses 85%-100% (CK), 65%-85% (MW) and 45%-65% (LW) of field water-holding capacity. The results showed that in comparing with CK, the photosynthesis rate and WUE were higher in treatment MW, but decreased by 7.26% and 1.13%, respectively in treatment LW, indicating that Fraxinus mandshurica could fully exert its photosynthesis potentiality under long-term medium water stress, and was more resistant to moderate than to critical water stress. In treatment CK, the diurnal change of Pn and WUE was a single and a double peak curve, respectively, while in treatments MW and LW, the diurnal change of Pn was a double peak curve, but that of WUE had no significant peak, which correlated not only to the physiological characteristics of Fraxinus mandshurica under different water stress, but also to the diurnal change of environmental factors.

Ecosystem↗

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

[Nitric oxide, a signaling component of ABA-induced stomatal closure].

The present study provided the evidence that exogenous NO and ABA regulated the stomatal movement in poplar leaves. It showed that different levels of SNP and ABA induced the stomatal closure in detached leaves. NO enhanced stomatal closure that induced by ABA. The effect of NO and ABA on stomatal closure was suppressed by c-PTIO, a specific NO scavenger. It was confirmed that NO involved in ABA-mediated stomatal movement. The activities of POD were dramatically inhibited, but those of SOD hardly decreased in different levels of SNP and ABA treatment. However, in vitro experiments indicated that the activities of POD were dramatically inhibited by NO, but not ABA. The results demonstrated that NO mediated ABA-induced stomatal closure of trees, and was a signaling component of ABA-induced stomatal closure.

Abscisic Acid↗

PubMed2004

[Soil N2O and CH4 fluxes in broad-leaved Korean pine forest of Changbai Mountains].

The soil N2O and CH4 fluxes in the broad-leaved Korean pine forest of Changbai Mountains under two treatments were measured by static chamber-gas chromatograph. The results showed that litter significantly influenced N2O emission and CH4 uptake, and the effect efficiency was 36.9% and 23.4%, respectively. The N2O emission fluxes of the two treatments showed similar seasonal variations, with the highest in spring, higher in summer, and lower in autumn and winter. Furthermore, their diurnal variations were the same, the maxima both occurred at 18 o'clock, and the minima appeared at 12 o'clock and 14 o'clock. As for CH4 uptake fluxes, their seasonal variations were similar. The CH4 uptake fluxes were significantly higher in summer and autumn than in spring and autumn, and their diurnal variations were also the same, both went up from 14 o'clock to 18 o'clock and then started to go down until 6 o'clock. The results also indicated that soil N2O emission fluxes were negatively linear-correlated to CH4 uptake fluxes in the broad-leaved Korean pine forest.

China↗

PubMed2004

[Insect species diversity in Korean pine broad-leaved mixed forest in Changbai Mountains].

The study on the insect species diversity in Changbai Mountains showed that there were 1960 insect species belonging to 26 orders, 131 families and 1162 genera, among which, 881 species were pests belonging to 11 orders and 105 families, and 638 were serious ones. In forest insect communities, defoliator insect community was more divers than natural enemy community, and predatory insects were more divers than other natural enemies. The indices of annual species evenness of defoliator insect community, parasitic insect community and predatory insect community were 0.884, 0.830, and 0.806, respectively, and the diversity changed with season was in the order of predatory insects > parasitic insects > defoliator insects.

Animals↗

PubMed2003

[Effects of soil temperature and moisture on soil respiration in different forest types in Changbai Mountain].

The effects of soil temperature (0, 5, 15, 25, 35 degrees C) and water content on soil respiration in three forest types in Changbai Mountain were evaluated in laboratory condition. The results indicated that the soil respiration rate was positively correlated to soil temperature from 0 to 35 degrees C and it increased with soil water content from 0.21 to 0.37 kg.kg-1. The soil respiration rate decreased with soil water content when water content was over the range. The result suggested the interactive effects of temperature and water content on soil respiration. There were significant differences in soil respiration among the various forest types and the highest was in broad leaf Korean pine forest, then in erman's birch forest, and it was the lowest in dark coniferous forest. The optimal condition for soil respiration in broad-leaved Korean pine forest was at 35 degrees C under 0.37 kg.kg-1 water content, and it was at 25 degrees C under 0.21 kg.kg-1 in dark coniferous forest and at 35 degrees C under 0.37 kg.kg-1 water content in erman's birch forest. Because the forests of broad leaf Korean pine, dark coniferous and erman's birch are located at various altitudes, the soil temperatures had 4-5 degrees C variation in different forest types during the same period. The soil respiration rates measured in brown pine mountain soil were lower than those in dark brown forest and they were higher in mountain grass forest soil than those in brown pine mountain soil.

Carbon Dioxide↗

PubMed2002

[CCA of water beetles' distribution and environmental factors in lentic samples of north Changbai Mountain].

The relationship between 28 species water beetles in 12 lentic samples and environmental factors of North Chang-bai Mountain was studied by Cononical Correspondence Analysis (CCA). The results showed that degree of underwater humus and altitude are the major factors correlated with beetles distribution, and the correlation coefficients of environmental factors and axes of CCA were 0.8371 and 0.7206 respectively, while water temperature and plant density also had certain effects. Under the influence of environmental factors, the water beetles' populations were different in different habitat. Coelambus impressopunctatus, Colymbetes magnus, Helophorus browni, Haliplus spp. distributed in deep water pool. Water temperature was not important for those beetles. Ilybius sp. and Limnebius glabriventris correlated with altitude and humus.

Animals↗

PubMed2002

[Effect of drought stress on apparent resource utilization efficiency of Quercus mongolica].

To study the effect of drought stress on the physiological characteristics and resource utilization efficiency of Quercus mongolica, a dominant species in the Korean pine broad-leaved forest in Changbai Mountain, a comparative experiment was carried out under three soil moisture gradients as 85%-100% (high water, CK), 65%-85% (Medium water, MW), and 45%-65% (low water, LW) of field water-bolding capacity. The results showed that net photosynthetic rate, stomatal conduction, transpiration rate, water utilization efficiency, apparent CO2 utilization efficiency and apparent light utilization efficiency of the seedlings of Quercus mongolica were all significantly influenced by simulated drought stress. Stomatal conduction, water utilization efficiency and net photosynthetic rate of large tress of Quercus mongolica were affected by the soil drought stress, while transpiration rate, apparent CO2 utilization efficiency, and apparent light utilization efficiency were not influenced. Moderate soil water condition could greatly increase gas exchange and water utilization efficiency. These results indicated that the responses of gas exchange and resource utilization efficiency to various water stresses were different. Quercus mongolica was a species with variable resistance to drought stress, and the resistance would be improved by drought stress, especially moderate water stress.

Carbon Dioxide↗

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

[Ecological forecasting: a frontier in ecology].

An evolving science of ecological forecasting is beginning to emerge, and could have an increasingly important role in policy-making and management of natural resources and environment. The progress in computer science, quantitative analysis and ecological theory, together with the application of new high technology, will increase our ability to forecast ecosystem change. The authors introduced the connotation of ecological forecasting, relevant research advances, and some typical examples. Ecological forecasting is an important frontier in ecology, and also, would be an important direction for future ecological study.

Decision Making↗