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PubMed2006

Studies on cultivated ephedra plants in inner mongolia autonomous region and ningxia hui autonomous region.

Progression of the desertification in northern China has been causing damage to wild Ephedra plants on which we depend for most of supply of the traditional herbal medicine, "Ma huang." The Chinese government encourages the cultivation of Ephedra plants, and Ephedra fields have been reclaimed in the original Ephedra habitats in recent years. We surveyed 7 Ephedra fields that have been recently developed in the Inner Mongolia Autonomous Region and Ningxia Hui Autonomous Region to collect information on Ephedra plant cultivation, especially pertaining to crop species. Specimens taken from those Ephedra fields were genetically and morphologically analyzed, and their ephedrine alkaloid content was examined. DNA analyses of Ephedra specimens, including DNA sequencing of ITS (internal transcribing sequence of nuclear ribosomal DNA) and trn L/F (intron of trnL and intergenic spacer between the trnL and trnF of chloroplast DNA) region and species-specific amplification of trn L/F were conducted to identify Ephedra species. Based on the results of DNA sequencing and morphological determination, the crops grown in 6 fields ware identified as Ephedra sinica, while co-planting of E. sinica and E. intermedia was found in one field where a higher appearance rate of plants with varied morphology from wild Ephedra plants was observed. Furthermore, direct sequencing of the PCR product of the trn L/F region of some specimens from the field and their species-specific PCR showed ambivalent result. Cloning and sequencing of the PCR product of the trn L/F region of those specimens DNA suggested their heteroplasmy, containing both E. sinica- and E. intermedia-type chloroplasts. On the other hand, the profile of the ephedrine alkaloid content was clearly correlated with the result of direct sequencing of the trn L/F region; the specimens showing the E. sinica-type sequence contained more ephedrine than pseudoephedrine, and the specimens of the E. intermedia-type more pseudoephedrine.

China↗
PubMed2005

Evolutionary process of stress response systems controlled by abscisic acid in photosynthetic organisms.

There are many serious problems causing a food crisis such as desertification, population explosion, and environmental destruction, suggesting that a severe food crisis will become reality across the globe. Therefore, the transgenic plants, which have tolerance to environmental stresses, may take on greater and greater importance in attempts to increase food production. Aquatic photosynthetic organisms, such as prokaryotic cyanobacteria and eukaryotic green algae, are considered as an evolutionary origin of higher plants and their basic metabolisms including photosynthesis are similar to higher plants. Thereby, stress responsive genes or reactions from these organisms may be exceedingly advantageous sources for creation of stress-tolerant transgenic plants. In this study, the physiological roles and biosynthesis of abscisic acid (ABA), well known as a signal molecule in the adaptation to environmental stresses, in microalgae were investigated from the point of the view of its functional evolution in the response to environmental stresses. Chlamydomonas reinhardtii, a green alga, and Synechocystis sp. PCC 6803, a cyanobacterium, were employed in this study as model organisms. It is expected that this comparative analysis will provide basic information for the creation of stress-tolerant transgenic plants. ABA may act in C. reinhardtii as a signal molecule to induce antioxidant reactions for elimination of reactive oxygen species, but not to induce specific response reactions to mitigate water stresses. In Synechocystis, on the other hand, exogenously added ABA did not influence the growth and gene expression. Moreover, ABA did not relieve growth suppression caused by water and oxidative stresses. From the carotenoid composition and bioinformatic analysis, it can be suggested that the ABA biosynthetic pathway generally found in higher plants exists completely in C. reinhardtii, but incompletely in Synechocystis.

Abscisic Acid↗
PubMed2005

Ecological dynamic model of grassland and its practical verification.

Based on the physico-biophysical considerations, mathematical analysis and some approximate formulations generally adopted in meteorology and ecology, an ecological dynamic model of grassland is developed. The model consists of three interactive variables, i.e. the biomass of living grass, the biomass of wilted grass, and the soil wetness. The major biophysical processes are represented in parameterization formulas, and the model parameters can be determined inversely by using the observational climatological and ecological data. Some major parameters are adjusted by this method to fit the data (although incomplete) in the Inner Mongolia grassland, and other secondary parameters are estimated through sensitivity studies. The model results are well agreed with reality, e.g., (i) the maintenance of grassland requires a minimum amount of annual precipitation (approximately 300 mm); (ii) there is a significant relationship between the annual precipitation and the biomass of living grass; and (iii) the overgrazing will eventually result in desertification. A specific emphasis is put on the shading effect of the wilted grass accumulated on the soil surface. It effectively reduces the soil surface temperature and the evaporation, hence benefits the maintenance of grassland and the reduction of water loss in the soil.

Biomass↗
PubMed2002

Soil carbon sequestration in degraded semiarid agro-ecosystems--perils and potentials.

The Kyoto Protocol opens new possibilities for using the biosphere as a carbon sink. Using agro-ecosystems as carbon sinks may be the most appropriate practice from both environmental and socioeconomic points of view. Degraded agro-ecosystems in Africa might benefit significantly from the improved land management that would be part of a carbon sequestration program. There are vast areas of these agro-ecosystems in Africa and their rehabilitation is an urgent matter. We agree with UNEP that there are potentially important synergies to be made between the Convention on Climate Change, the UN Convention to Combat Desertification and the UN Convention on Biodiversity. In this paper, we have investigated the potential for increasing soil carbon content in semiarid agro-ecosystems in the Sudan and found that increasing fallow periods will result in increased soil carbon content and converting marginal agricultural areas to rangeland will restore the carbon levels to 80% of the natural savannah carbon levels in 100 years. The economic gain from a future carbon sequestration program has the potential of a significant contribution to the household economy in these agro-ecosystems.

Africa↗
PubMed2004

Is rangeland agriculture sustainable?

The objective of this paper is to examine the sustainability of rangeland agriculture (i.e., managed grazing) on a world-wide basis, with a focus on North America. Sustainability is addressed on three fronts: 1) ecological, 2) economic, and 3) social acceptance. Based on previous and on-going research, we suggest that employment of science-based rangeland grazing management strategies and tactics can ensure ecological sustainability. The formidable challenge in employing such technology centers around the need to balance efficiency of solar energy capture and subsequent harvest efficiencies across an array of highly spatially and temporally variable vegetation growing conditions using animals that graze selectively. Failure to meet this fundamental challenge often accelerates rangeland desertification processes, and in some instances, enhances rate and extent of the invasion of noxious weeds. We also suggest that the fundamental reason that ecologically sound grazing management technologies are often not employed in the management of grazed ecological systems is because social values drive management decisions more so than ecological science issues. This is true in both well-developed societies with substantial economic resources and in less-developed societies with few economic resources. However, the social issues driving management are often entirely different, ranging from multiple-use issues in developed countries to human day-to-day survival issues in poorly developed countries. We conclude that the long-term sustainability of rangeland agriculture in 1) developed societies depends on the ability of rangeland agriculturalists to continually respond in a dynamic, positive, proactive manner to ever-changing social values and 2) less-developed societies on their ability to address the ecological and social consequences arising from unsustainable human populations before the adoption of science-based sustainable rangeland management technologies.

Agriculture↗
PubMed2006

[Sustainable utilization of Radix Glycyrrhizae for protection of ecology environment and herbal resources].

Radix Glycyrrhizae is a commonly used herbal drug for traditional Chinese medicine in China, and it is also an important material for drug, food, chemical industry, and dye industry. Furthermore, in Northwest China, Radix Glycyrrhizae acts as a key plant for preventing desertification, which currently is the most serious environmental problem in China. This report concentrated on discussing the great potential value of Glycyrrhiza on ecosystem, introducing the principles of protection and sustainable utilization of Glycyrrhiza resource, offering the suitable methods of utilization, and suggesting how to carry out the research on the substitute drugs. To protect the ecosystem and herbal resource of Radix Glycyrrhizae, we should use this herb in a more reasonable way.

China↗
PubMed2004

Preliminary survey of ticks (Acari: Ixodidae) on cattle in northern Sudan.

In a cross sectional survey conducted during the period June 2001 to July 2002, the geographical distribution of ticks on cattle in the Sudan was determined. Seventeen locations were surveyed from Northern, Central, Eastern, Western, Blue Nile and White Nile Provinces. Total body collections of ticks were made from 20 cattle at each location. Four tick genera and 11 species were identified. The tick species collected included Amblyomma lepidum, Amblyomma variegatum, Boophilus decoloratus, Hyalomma anatolicum anatolicum, Hyalomma dromedarii, Hyalomma impeltatum, Hyalomma marginatum rufipes, Hyalomma truncatum, Rhipicephalus evertsi evertsi, Rhipicephalus sanguineus group and Rhipicephalus simus simus. Major ecological changes have occurred due to extensive animal movement, deforestation, desertification and establishment of large mechanized agricultural schemes. These factors have certainly affected the distribution of ticks and tick-borne diseases in the Sudan. The absence of A. variegatum and A. lepidum in northern Sudan was not surprising, since these tick species are known to survive in humid areas and not in the desert and semi-desert areas of northern Sudan. The absence of B. annulatus in northern and central Sudan is in accordance with the finding that this tick species is restricted to the southern parts of the central Sudan. The presence of H. anatolicum anatolicum in Um Benin in relatively high abundance is an interesting finding. The present finding may indicate that the southern limit of this species has changed and moved southwards to latitude 13 degrees N. It is concluded that major changes in tick distribution have taken place in the Sudan.

Animal Husbandry↗
PubMedDate not supplied

Current extent of disasters in Africa.

The people oFf Africa are exposed to a wide range of disasters that seriously have aggravated the Continent's economic situation. Economic losses and human sufferings from drought, desertification, locust infestation, infectious diseases, epidemics, and armed conflicts are the dominant disasters that the people in the African countries face, and they have rendered the population utterly vulnerable. Disasters have aggravated Africa's economic situation. The cumulative effect of disasters include loss of property, injury, death, mounting food import bills, health hazards, environmental degradation, backward economic development, displaced people, refugees, and nutritional deficiency. Today, 175 million Africans out of a total population of 744 million people (23.5%) are suffering from chronic hunger; this is an increase of 50% from 25 years ago. In many African countries, up to half of the population suffers from absolute poverty. It is projected that Africa will be the only Continent to continue with the current level of poverty for another decade.

Africa↗
PubMed2001

Shifting-sand control in central Tibet.

The middle reaches of the Yarlung Zangbo, the Lhasa, and the Nianchu rivers form the center of politics, economy, and culture in the Tibetan Autonomous Region. Due to the fragility of the natural environment and overexploitation of land by the local people, desertification is becoming a serious problem in the valleys. Shifting sands cover an area of 578 km2 and have caused problems such as damage to farmland and grassland, traffic blockage and burying of water projects. This paper discusses strategies and techniques for combating shifting sands, including reformation of the agricultural structure, exploitation of new sources of energy, and combinations of mechanical and biotic measures. Using mechanical measures, straw barriers, and gravel layer covers, artificial vegetation can be established on the mobile sand dune by sowing and planting introduced species.

Agriculture↗
PubMed2002

An approach to the fluctuation mechanism of ecotone.

In this paper, the relationship among land productivity, population pressure and the fluctuation mechanism of ecotone is analyzed, taking counties and banners of southeast Inner Mongolia plateau as an example, which is the most fragile part in the farming and husbandry interleaving belt of north China due to its severe desertification degree and low level of economic development. The Cv for the total output value of agriculture decreases from southeast to northwest, with the same rule as which the overloading population cumulated distributes, and both indicators have close relation with the high linear coefficient of 0.83. These reveal the fluctuation mechanism for ecotone: fluctuation of the level of economic development is a scientific and practical measure both to weakness degree and to instability of ecotone, because it is a synthesized response to the variation of climate as well as irrational land uses, which reinforce and magnify the fluctuation. In detail, the heavier the population overloading, the severer the grassland reclamation, the stronger the dependence of regional productivity on rainfall, the lower the level of economic development, the rougher the fluctuation of ecotone, but the weaker the PRED system.

Agriculture↗
PubMed1990

"Ghana faces ecological disaster".

The rate of deforestation in Ghana is alarming and urgent steps need to be taken to reverse the trend, Robert D. Mann, a British tropical agriculturist, has warned. He says, "There will be further disintegration of the local climate, deterioration of soil fertility and reduced food-crop production, if the present trend of denudation by felling trees and uncontrolled bush fires is not halted and reversed." Mann, who has conducted research on "deforestation, drought and famine in Africa" was in Ghana recently to speak on the "role of the Church in West Africa in stimulating action to combat desertification". Representatives of protestant churches in Ghana, Togo, Liberia, Gambia, Nigeria, Cote d'Ivoire and Sierra Leone attended the 3-day conference which was organized by the Overseas Department of the British Methodist Church. It was to enable participants to share perspectives on the nature, scale and seriousness of the deforestation problem. Participants also exchanged experiences on village-based projects for promoting tree planting and agro-forestry, and developed strategies for the rural development programs. Robert Mann noted that Ghana was not only affected by its proximity to the Sahel, but also by its own deforestation. The situation in Ghana, once renowned for her extensive forests and woodland, has now drastically changed. By 1980/81 the area of closed forest had been reduced to 17,000 sq km from 47,9000 sq km in 1937/38. He said in 1939 the volume of wood exported from Ghana was 42,450 cubic meters but it rose to 1,471,600 cubic meters by 1987. Such activities, Mann said, put severe strain on the environment and affected both the economy and sociocultural basis of the country.

Africa↗
PubMed2002

[Influencing mechanism of several shrubs and subshrubs on soil fertility in Keerqin sandy land].

Keerqin sandy land is one of serious desertification areas in the semiarid zone of north China, and shrubs are the dominant plant life form and play an important role in the region. The effects of "fertile island" and rhizosphere of several shrubs and subshrubs were studied. The results showed that the concentrations of organic C, total N and total P, and values of electrical conductivity (EC) in the soils under the canopy of shrubs increased by 56%, 51%, 37%, and 51%, respectively, compared with those of the soils in open spaces, but there was no significant difference in pH value between the soils under shrub canopies and in open spaces. Shrub rhizosphere soils had significant higher contents of organic C, total N, and values of EC as well as lower pH value compared to the bulk soils, but there was no significant difference in total P between rhizosphere and bulk soils. There were close relationships between the properties in soils under shrub canopies and the rhizosphere soils, indicating that the development of "fertile island" were favorable to root growth and induced greater amount of rhizodeposition, and vice versa. Soils under Artemisia frigida and Caragada microphylla canopies and rhizospheres had significant higher organic C and total N contents than those of Artemisia halodendron and Salix gordejvii. This results suggested that shrubs were of vital importance for accumulation of nutrients and maintenance of soil fertility in Keerqin sandy land ecosystem.

Carbon↗
PubMed2002

Characteristics of regional climate change and pattern analysis on Ordos Plateau.

The characteristics of precipitation, temperature and their combination determine the special ecological environment pattern of Ordos Plateau. Analyzing its evolutionary trend attributes to understanding the succession process of the ecological environment of Ordos Plateau and has crucial instructional significance on the ecological restoration research being conducted in this region. Four time scales, arranging from ten days, one month, one season growing season contrasting to non-growing season) to one year were adopted to analyze the climate data which included nearly 30 years and were collected by eight weather stations on Ordos Plateau. The results indicated that the mean annual temperature and the mean monthly temperature of February, September and December, had increased significantly during the late 30 years. The annual precipitation did not show significant changes but its distribution pattern had changed obviously. The ratio of precipitation of major growing season (May-October) to annual precipitation had increased distinctively, and five counties' precipitation reached statistically significant level. And the ratio of precipitation of latter growing season (September) to one year decreased significantly while the ratio of non-growing season (November-next April) to one year changed insignificantly. The results showed that maybe the interaction of increased mean temperature and insignificant change of precipitation in non-growing season was one of the reasons why the desertification of the region was deteriorating in recent years. Using some factors closely relating to vegetation succession such as mean annual temperature, mean annual precipitation, distributive pattern of precipitation, mean temperature of the coldest month, mean temperature of the warmest month, precipitation of the warmest month, mean temperature of growing season, precipitation of growing season, potential evapotranspiration(PET) and radiative dryness index(RDI), to synthetically analyze the climate characteristics of Ordos Plateau. The regionalized Ordos Plateau to three synthetical climate types were recognized as follows: Type I, semi-humid and low evaporation(including Jungar Banner, Dongsheng City and Ejin Horo Banner), Type II, semi-arid, semi-humid and moderate evaporation(including Uxin Banner and Dalad Banner), Type III, arid and high evaporation(including Hanggin Banner, Otog Banner and Otog Qian Banner).

China↗
PubMed2002

[Preliminary research on environmental characteristics of oasis-desert ecotone].

Taking Minqin Oasis in the downstream of Shiyanghe Rivers as example, the shrub characteristics of sand dune, which was closely related to the vegetation of the interface between the outside of oasis and desert, was studied in this paper. The change of vegetation coverage and dune density indicated that the vegetation coverage in the ecotone was obviously higher than that in the outside of oasis and in drift desert. There existed an area outside oasis that was obviously affected by human activies and 0-600 m away from the outside of oasis. Meanwhile, the appearing position of area outside oasis was different in different place. The naked area ratio of dune in the area outside oasis was the biggest, so that the area outside oasis was the main resource of drift sand resulting in desertification of oasis. Over extracting ground water in oasis district resulted in a forming of dropping funnel of ground water there, and resulted in a fluid of ground water from desert to oasis. Ultimately, human activites aggravated those processes to some extent.

Agriculture↗
PubMed2003

[Advances of several selected topics in landscape ecological studies of grasslands].

China's grassland is confronted with a mass degradation, desertification, dramatic declining of productivity, environmental deterioration, and rapid loss of biodiversity, which directly threaten the sustainable development of pasture areas. This situation implies that proper management of grassland is essential in China. Based on abundant literatures in landscape ecological research of grassland, this paper summarizes and analyzes the latest progresses in this field in both China and abroad. Studies on landscape pattern, biodiversity, landscape degradation and restoration, and landscape aesthetic value as well as the advances in research methods are focused, aimed at providing references to research in this field in China. Some management strategies from abroad are also summarized to offer references to the Chinese counterparts.

Ecology↗
PubMedDate not supplied

Agriculture and environment.

Agriculture came into existence about 15,000 years ago and passed through different stages of gathering, hunting, hoe culture, and sedentary agriculture, followed by modern agriculture. It began simultaneously in five world centers concentrating on different crops, most suited to the respective areas, and it was affected by changes in climate which determined the distribution of populations and their occupations. With the increase in population, the need for food progressively increased, necessitating introduction of modern agriculture to enhance production. The indiscriminate and faulty use of advanced technology to meet the food demand of fast-increasing populations added to its share to the destruction of the environment. The two approaches that contributed to this were horizontal expansion and vertical expansion. The former resulted in deforestation, desertification, soil erosion, land salting, and water logging, as well as the frequent occurrence of droughts and famines; the latter destroyed the soil structure and fertility through decreased microbial populations, fish culture, wildlife and bird sanctuaries, in addition to producing water and soil pollution and serious health hazards in human beings and fauna. The real culprit of this geobiologic devastation is the population growth rate, which needs to be contained at safer levels.

Agriculture↗
PubMed2003

[Soil organic carbon pool and its spatial distribution pattern in the Circum Bohai Region].

The research and management of soil carbon pool and the effect of land-use on it are the key project of study on global change. In this paper, the data of 1,374 soil profiles in the Circum Bohai Region were used to estimate the soil organic carbon (SOC) pool of this region. The results showed that in this region, the total soil organic carbon pool in 1 m depth was 2.1 Pg C, and the biggest SOC pool was brown soil, occupying 55.6% of the total SOC. The second one was moisture soil, accounted for 26.9%. The SOC pools of aeolian sandy soil and dark brown soil were very small, only about 0.1% of the total. However, the soil organic carbon density (OCD) of boggy soil was the biggest (22.90 kg C.m-2), the second was dark brown soil (16.04 kg C.m2), and the lowest were aeolian sandy soil (2.88 kg C.m-2) and solonchak (6.0 kg C.m-2), implying that desertification and salinalization could reduce soil organic carbon. Moreover, the results also suggested that the topsoil held 673.30 Tg C. It meant that there was about one-third of the total SOC could be easy to be disturbed. According to the OCD at its level distribution gradient, it could be divided into four regions, i.e., coastal region, plain region, northwestern region, and hilly region. The order of OCD from high to low was hilly region, northwestern region, plain region, and coastal region. This regulation reflected not only the role of climate and landform, but also the effect of human activity intensification on SOC. Therefore, it was very important to protect and manage the land in this region well for the SOC maintenance and the sustainable land use.

Carbon↗
PubMed2003

Microvascular assessment in Behçet disease: videocapillaroscopic study.

The aim of this study was to evaluate microvascular assessment in patients with Behcet disease (BD) by means of an intravital videocapillaroscopic study. Sixteen BD patients were compared with an equivalent group of healthy subjects matched for age and sex. Videocapillaroscopy (VCP) was performed in peripheral areas and in conjunctiva, and morphological and quantitative parameters were assessed. In both areas VCP showed several morphological alterations (microaneurysms, megacapillaries, desertification areas) detectable in a high percentage of patients; quantitatively we found significant changes of incisuring and sludging score, of capillary loop intermediate branch length (in peripheral areas) and of arteriole/venule diameter (in conjunctiva). Therefore, vessel involvement included both the number and the whole vessel structure and was seen both in peripheral and conjunctival areas when the two different vascular beds of micro- and paramicrocirculation were examined. We conclude that an important rearrangement of microcirculation is detectable in BD and that VCP may have diagnostic and prognostic value, providing qualitative and quantitative information able to define the systemic extension of vascular damage and the degree of vessel wall alteration.

Adult↗