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Inner Mongolia University (2021)

Plant Phytolith Carbon Sequestration Potential and Its Relationships with Climate in Inner Mongolia Grassland

孙婷宇

Titre : Plant Phytolith Carbon Sequestration Potential and Its Relationships with Climate in Inner Mongolia Grassland

Auteur : 孙婷宇

Grade : Master 2021

Université : Inner Mongolia University

Résumé partiel
Phytolith is amorphous silicon(SiO2·nH2O)deposited in plant cell wall,cell cavity or intercellular space.As a component of biological silicon,phytolith plays an important role in the geochemical life cycle of silicon.Phytolith is fixed with a certain amount of organic carbon(0.1%-6.0%)during its formation,which is called phyt OC.Phytolith has stable structure,high temperature resistance,corrosion resistance and other characteristics,and can exist in soil for a long time.Therefore,phytolith carbon is an important part of the global carbon sink that can exist stably for a long time,and it is of great significance to slow down the increase of atmospheric CO2concentration.Due to the large area of grassland,the dominant grasses have high carbon content in phytolith and phyt OC,which has become the focus of research on phyt OC sink in recent years.However,there is still a lack of systematic research on the relationship between phytolith and phyt OC accumulation and environmental factors in grassland.We sampled grassland plants and determined their phytolith and phyt OC contents in the temperate zone of Inner Mongolia along a climate gradient,and calculated their its reserves,and analyzes their changes in relation with climate and soil factors.We aimed at understanding the mechnisms of plant phytolith formation,and to provide more basis for accurately estimating phyt OC sequestration potential.The main research conclusions are as follows:1.With the increase of climate humidity(decrease of aridity),the phytolith content of Leymus chinensis,the dominant plant widely distributed in the steppe grassland,increased significantly.That is,its phytolith content was positively correlated with precipitation(P<0.05),negatively correlated with annual mean temperature(P<0.05),but not correlated with soil property indicators.There was no significant correlation between phytolith content and climatic factors in mixture of 4 Stipa plants(Stipa kelmenzii,S.krylovii,S.gandis and S.baicalensis,which were substituted with each other on the climatic gradient.Significant correlations between phytolith and phyt OC contents and climatic factors were neither detected in two species of Cleistogenes(C.songolica and C.squarrosa).2.On the climate gradient,plant community aboveground productivity increased with the increase of precipitation,but plant water use efficiency(PUE)decreased.

Mots clés : grassland ;climate gradient ;water use efficiency ;soil properties ;phytolith;phytoc ;

Présentation (CNKI)

Page publiée le 27 octobre 2021