Biomedical subjects

Guobin Liu

Publications and source records attributed to Guobin Liu.

9 recordsLinked to original sources

PubMed2025

Environmental Stresses Constrain Soil Microbial Community Functions by Regulating Deterministic Assembly and Niche Width.

Increasing evidence indicates that the loss of soil microbial α-diversity triggered by environmental stress negatively impacts microbial functions; however, the effects of microbial α-diversity on community functions under environmental stress are poorly understood. Here, we investigated the changes in bacterial and fungal α- diversity along gradients of five natural stressors (temperature, precipitation, plant diversity, soil organic C and pH) across 45 grasslands in China and evaluated their connection with microbial functional traits. By quantifying the five environmental stresses into an integrated stress index, we found that the bacterial and fungal α-diversity declined under high environmental stress across three soil layers (0-20 cm, 20-40 cm and 40-60 cm). Metagenomic-based analyses showed that the diversity of functional genes decreased along the stress gradients. High stress enhanced the abundance of genes associated with broad functional categories (e.g., glycolysis/gluconeogenesis, TCA cycle, DNA replication/repair and cell growth/death) but reduced the abundance of genes linked to specialised functional categories (e.g., C, N, S and methane metabolism). Phylogenetic null models and niche analyses indicated that stochastic assembly processes predominated in high-diversity communities, in which bacterial and fungal taxa had a narrow ecological niche. However, in low-diversity communities, deterministic assembly processes were dominant, and taxa had wide niches, correlating with the reduction in gene abundance observed for broad and specialised functional categories. Given the essential role of the microbiome in regulating ecosystem functions, our findings suggest that low-diversity-induced deterministic community assembly processes and a wide niche under high environmental stress may regulate microbial functions. These findings emphasise the ecological mechanisms through which microbial biodiversity regulates terrestrial ecosystem functioning.

Soil Microbiology↗

PubMed2006

[Dynamics of Sophora davidii population in a hilly region closed for thirty years in Loess Plateau].

Taking wild grass ground as the reference, this paper studied the dynamics of Sophora davidii population on the sunny, semi-sunny and semi-shady slopes of hilly region in Loess Plateau after 30 years closed for reforestation, and analyzed the age structure, spatial distribution pattern, life table, and survival curve of the population. The results showed that S. dvidii population in the region belonged to progressive type, with more young and less old individuals. Among the three habits, semi-sunny slope had the highest population density. The survival curve of S. dvidii population was approached to Deevey 11 type. The population pattern was of clustered distribution, with the aggregating intensity increased with age. Water and light were the main environmental factors affecting the recovery and development of S. davidii community. The better recovery of S. davidii population suggested that the measures of closing the land for reforestation were efficient.

China↗

PubMed2005

[Effects of artificial seabuckthorn forest on soil and water conservation in loess hilly region].

Seabuckthorn is regarded as a main eco-economical tree species, and plays an increasing important role in eco-environmental construction in Northwest, Northeast and North China. Our study on artificial seabuckthorn forest in loess hilly region showed that the average rainfall interception rate of 7-10 ages seabuckthorn canopy was 8.5%, and the litter layer of 5-10 ages seabuckthorn forest could intercept 0.89 mm rainfall. Seabuckthorn forest could improve soil infiltration and anti-strike ability through improving soil physical and chemical properties, and the numbers of its hair roots and the depth of its litter layer were the main indices of soil anti-strike ability. The effects of seabuckthorn forest on soil and water conservation increased with its increasing age. In 2-3 ages stage, the effects were weak, and the runoff and sediment were mainly affected by the characters of rainfall. In 4-5 ages stage when the forest became maturing, the annual runoff depth and annual erosion modulus were 1.8-3.2 mm and 24.64 t x km(-2), respectively. In 6-12 ages stage when the forest matured, the runoff and sediment on seabuckthorn woodland changed slowly, the annual runoff depth and annual erosion modulus being 0.3 -3.4 mm and 0-6.75 t x km(-2), respectively, and the characters of rainfall had much less effect on them. In the stage from young (2-5 ages) to mature forest, the sediment charge in runoff changed sharply, ranged from 77. 31 kg x m(-3) to 9.12 kg x m(-3), but in 6-12 ages stage, the sediment content in runoff changed very slowly, and the range was 0-5.09 kg x m(-3).

Conservation of Natural Resources↗

PubMed2005

[Assessment indicators of soil quality in hilly Loess plateau].

By the methods of sensitivity analysis, main component analsis and discriminant analysis, this paper screened the sensitive indicators from 32 soil attributes to assess the productivity and erosion-resistance ability of the soils in hilly Loess Plateau. The results showed that soil available phosphorus content, anti-scouring ability, infiltration coefficient, labile organic carbon content, organic matter content and urease activity were the most sensitive indicators for soil quality assessment and the main targets for soil quality management and improvement, while soil biological indicators were with high and medium sensitivity. Five soil quality factors were summed up from 29 soil chemical, physical and biological attributes, i. e., organic matter, texture, phosphorus, porosity and microstructure. Except the factor porosity, the other four factors were significantly different between different land use types. Eight indicators including soil organic matter content, infiltration coefficient, anti-scouring ability, CEC, invertase activity, mean weight diameter (MWD) of aggregates, available phosphorus, and MWD of microaggregate were identified as the assessment indicators of the soil quality in hilly Loess Plateau, with the organic matter content, infiltration coefficient and anti-scouring ability as the key indicators.

Carbon↗

PubMed2004

[Root growth dynamics of Adenophora potaninii populations and its relation with environmental factors in northwest Sichuan Province].

In this paper, the dynamics of the root biomass and form development of Adenophora potaninii populations in different natural habitats in Northwest Sichuan were studied, and the factors influencing the root growth and form development were analyzed. The root biomass accumulation process of the mean individuals of the whole A. potaninii population in its life could be expressed by Logistic equation. From 1-3 years, the root length grew fast, but the root biomass accumulated slowly. From 4 years old, the root system developed in high speed, and the fast growth period of the root system could maintain until 15 year old. The basic patterns of root biomass accumulation process of different A. potaninii populations at different altitudes were similar to that of the whole population. However, the root system accumulation and root development was related closely with habitant conditions, and the root forms of different populations at different altitudes were significantly different (P < 0.05). At middle altitude (2800-3300 m), the biomass and form of root system could achieve a higher level, and the good harvest of root biomass could be obtained because of the favorable soil and climate conditions, and the less external disturbance of human beings. Therefore, this area could be an important base for A. potaninii population to grow. Whereas at the lower altitude (2600-2800 m), the biomass accumulation and the form development of root system were confined and maintained at a lower level because of the drought climate and the external disturbance of human beings. At the higher altitude (3300-3500 m) area with the harsh habitats, especially with lower temperature and lower pH, the root biomass of the mean individuals was significantly lower, and the individual form of root system was smaller, compared with that at middle altitude area. In order to use natural A. potaninii resource sustainablely, all the area should be planned, and the reasonable rotational prohibition of grazing and digging should be carried out.

Altitude↗

PubMed2004

[Concept and methodology on up-scaling issue of small watershed prototypes for reconstructing ecological economies in Loess Plateau].

The general ecological situation of Loess Plateau is kept deteriorating, despite great efforts have been made and some achievements were gained after 50 years' endeavor to control soil erosion and renovate ecological landscape. Investigations on the past 20 years results from 11 experimental sites showed that the extension of prototypes and models derived from these sites, which were all based on one scale of small watershed, were unsatisfactory. The possible reasons for such a situation could be attributed to the too coarse scale of map, on which, the regional planning were set up and the locations of these experiment sites were decided, the too fine scale of the small watershed which were usually 3-10 km2 in size, the shortage of studies on various scales particularly on the meso-scale, and the lack of methods of scaling on up-scaling. Based on the analysis of restraints in management of small watershed, the specific concept and relevant proposed methods of resemblance-scaling and multi-scale complementarity were put forward and tested.

Biodiversity↗

PubMed2003

[Individual and modular biomass dynamics of Kingdonia uninflora population in Qinling Mountain].

The individual and modular biomass dynamics of Kingdonia uninflora populations in Qinling Mountain were studied systematically. They could be expressed by Logistic equation. The ratio of leaf to bud biomass of population decreased with its increasing age, whereas the ratio of the root system to the subterranean stem biomass increased. The individual and each modular biomass of different populations at different altitudes were significant different (P < 0.05), which were larger at altitude 2700-2900 m than at the lower and higher altitudes. The rate of leaf biomass decreased as altitude rose, whereas that of the subterranean stem increased. In the favorable area, the rate of root system biomass was less, whereas the bud biomass was bigger compared with other habitats. The individual growth and modular biomass accumulation were closely related to habitat condition.

Altitude↗

PubMed2003

[Population dynamics of Quercus variabilis on northern slope of Qinling mountains].

Studies on the population dynamics, age structure, spatial distribution pattern, life table, and survival curve of Quercus variabilis showed that the Q. variabilis population on the northern slope of Qinling mountains was increasing. The number of young-aged individuals was larger, and that of middle-aged and old individuals was smaller. The life tables for different age classes showed that the mortality at age classes I and II was the highest, and the mortality rate was decreased with increasing age. However, at age classes VII and VIII, the mortality rose again for their decrepitude. The expected life span of age classes III, IV and V was higher, and decreased gradually with increasing age. The survival curves were the type of Deevey III, and the distribution pattern of population was aggregative as a whole. As the age increased, the intensity of aggregation decreased, and tended to a random distribution at higher elevations. A wise management should accelerate the recovery of Q. variabilis population and the enhancement of its productivity. The altitude 800-1,100 m was the favorable habitat for Q. variabilis population. As for the Q. variabilis at lower altitude, its protection should be reinforced, and the disturbance from human beings should be reduced. Forest thinning and other fostering management at middle altitude should be given in time. The target trees at higher altitude should be fostered.

Altitude↗

PubMed2002

[Ecological benefits of artificial seabuckthorn stands in semi-arid hilly region of Loess plateauion soil- and water conservation and soil moisture].

There is a remarkable function on decreasing runoff and sediment in seabuckthorn and its mixed stands, but the effects on soil- and water conservation are different due to different structure and patterns of seabuckthorn and its mixed stands. The intensity of soil water use by seabuckthorn forest was different along with the month in growing season. In growing season, soil moisture in 0-500 cm layer was 5.1%, the lowest in the end of May and 8.8%, the highest in the end of October. This intensity was also different with forest age. 8 ages seabuckthorn forest consumed 231.2 mm of soil stored water in 0-500 cm layer annually, and soil moisture was 5.6%. Therefore, it should be cut for increasing soil moisture. In end of the third year after cutting, soil moisture in 0-160 cm layer could recover, and the value would be 10.3%-14.6%. Seabuckthorn forest could reduce the effect of slope location on soil moisture. Seabuckthorn and its mixed stands have similar intensity of soil water use, and there was a soil dry layer phenomenon in their stands.

China↗