Dissertation > Environmental science, safety science > The basic theory for the Environment and Science > Environmental Biology > Ecosystems and pollution ecology

Study on the Damage and the Adaptation Strategy of the Vegetation During Sandy Desertification Process

Author ZhuZhiMei
Tutor YangChi
School Inner Mongolia University
Course Ecology
Keywords Desertification Vegetation Total Population Impaired Suitability Physiological mechanism
CLC X171
Type PhD thesis
Year 2004
Downloads 346
Quotes 4
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Desertification is restricting China's arid and semi-arid areas of socio-economic sustainable development of important factors. Research to Duolun due to its unique geographical location and topography, research areas in northern China, especially desertification grassland desertification research plays a very important role. This article from the soil, plant community, population, individual, morphological, physiological point of view, through three consecutive years (2001.2003 years) of field ecology observation, physiological and biochemical analysis combining indoor at different levels and scales the systematic use of eco- systems ecology, community ecology, population, individual ecology, physiological ecology, scientific theories and methods of integrating large-scale study of the interference problem of desertification, explore sandy grassland desertification under natural conditions during the vegetation damaged process and adaptation . The results are as follows: 1. With the intensification of grassland desertification, soil clay content tends to decrease, sand increased. Decreased soil moisture, especially the upper (0-20cm) decreased significantly, and the water content gradually deeper than the surface. Soil bulk density rise. Soil organic matter, C, N content was significantly decreased, and soil N decay faster than C. Soil C / N ratio showed an increasing trend, indicating that insufficient supply of N in plants is more prominent. Soil particles and soil nutrient status a significant positive correlation between the elements, clay and clay than the relationship between N and C, and C, N between closely related, so the process of desertification due to reduced fine particles decay very soil N obvious. 2. With the progress of desertification, community coverage, density, species richness, biomass, and the gradient between two adjacent p diversity index showed a downward trend, aboveground biomass / belowground biomass ratio values ??changed little. Correlation with the soil indicating that the soil C / N ratio and the communities most closely. 3. With the progress of desertification, a total population of plant height, density, plant specific leaf area, leaf area index, thousands of substances to accumulate a number of indicators of reproductive allocation changes. ① height and density changes in general is decreasing. Where the difference between the gradient chinensis Obviously, Cleistogenes and A.frigida potential, respectively, moderate and potential desertification, desertification stage mild increase in both the stage and the population in which the relevant dominance, and its resistance , adaptability enhanced, whereas the flat alfalfa beans in moderately elevated before desertification, growth is becoming strong, severe desertification is decreased, the growth morphology with other shared stocks subject to the same restrictions, rather than changes in aboveground biomass is consistent. Flat alfalfa beans difference between the density gradient with only manifested in the increase of desertification gradient, rather Cleistogenes only expressed in differences with desertification gradient decreased with increasing aspect A.frigida difference is reflected in the decline in both areas Also reflected in the increased respect. Different populations of the differences between the different desertification gradient and height, density changes in different plants in the deterioration of the environment indicate that the extent of damage and adaptability differences chinensis heavier damage, poor adaptability squarrosa and A.frigida subject to a certain degree of damage, but resistance, adaptability, flat alfalfa beans on desertification than the slow, moderate desertification but beneficial to the growth, but also lead to desertification excessive performance consistent with other population growth adversely. ② Most of the surveyed plants leaf area is decreasing, morphological growth was inhibited, only the cold tarragon and flat alfalfa beans upward trend, but the increase of the degree A.frigida less flat alfalfa beans: bean leaf area and flat alfalfa height, density, long-term adaptation to the environment phenotypic characteristics. ③ leaf area index overall downward trend, flat hunting beans changed little, moderate desertification stages before a slight increase, but declined to severe desertification stages. Total population leaf area index of soil physical and chemical properties are subject to the impact which the cold pole and flat Kai beans less affected. ④ Dry matter accumulation and leaf area index changes similar. Chinensis and C. squarrosa ground dry matter accumulation of soil physicochemical properties with significantly reduced attenuation; flat ground beans protracted dry matter accumulation with soil clay, C reduction with children was significantly increased with soil moisture, total N content and soil C into than irrelevant: Cold pole on the ground with soil physical and chemical properties of dry matter accumulation, while also reducing the attenuation, but not significant. ⑤ population decreased reproductive allocation process, the largest decline chinensis, cold bean pole and flat protracted smaller decline; governed by soil properties affected. Aboveground part of the C content, and C were increased Gabi, N levels were reduced. Chinensis and C. squarrosa C desertification early earth elements increased significantly and the cold pole beans with flat-kai in desertification, the late prime ground C was increased significantly. Therefore, squarrosa L. chinensis and may be greater than the sensitivity and flat protracted cold pole beans, on the other hand the cold pole beans with flat Kai resistance may be larger than L. chinensis and C. squarrosa. 4 grassland desertification process is accompanied by a total population of leaf water content, chlorophyll content decreased, the relative membrane permeability, proline content increased, MDA content increased, SOD, CAT activity increased, while POD activity decreased performance the desertification process in plant physiology damaged commonality. Different plants in different stages of desertification different responses, showing the different levels of plant damage and resistance against desertification, adaptive differences. Flat protracted beans, Cleistogenes and cold poles of chlorophyll indeed showed an upward trend, and the difference between the cold high gradient gt; flat Kai-beans gt; Cleistogenes gt; chinensis, so cold pole chlorophyll levels of resistance than strong, weak resistance chinensis. Binding membrane permeability, proline and MDA accumulation t look flat box damaged beans at least. Chinensis proline and ABA accumulation of injury symptoms, while Cleistogenes and cold pole proline and ABA accumulation has adaptability tendency flat Kai beans proline and ABA accumulation expressed as the environment is not on desertification sensitive. ① chinensis membrane permeability and proline, MDA, ABA content, SOD activity was significantly positively correlated with CAT activity was significantly negatively correlated, indicating that SOD activity, CAT activity decreased, proline, MDA, ABA content increases, leading to an increase in membrane permeability, and finally to membrane damage. The proline and ABA content, SOD activity was significantly positively correlated with POD, CAT activity showed a significant negative correlation, indicating that ABA-induced proline accumulation, SOD activity enhancement, POD, CAf activity reduced, but also lead proline accumulation causes. MDA content and SOD, POD activity was significantly positively correlated, indicating that the desertification process, with chinensis SOD, POD activity increased ROS scavenging capacity has not increased, thus causing a significant accumulation of MDA. POD, CAT activity and ABA content was significantly negatively correlated with POD and CAI, was significantly?

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