Measuring the response of terrestrial ecosystems to elevated CO2 concentrations is very important for understanding the effects of global change. In this study,OTC (open top chambers) were used to simulate elevated CO2 concentrations in the Songnen Grass-land. As well,phytoliths in Leymus chinensis were extracted to study the relationships between phytoliths and CO2 concentration. The results show the rondel is abundant in Leymus chinensis,while the trapeziform polylobate is rare. When phytolith production is increased,the rondel phytoliths grow bigger and the proportions of the different phytolith types changes under high CO2 concentration. These types include elongate hollow,acicular hair cell,square and laminate and are only observed in samples grown under high CO2 concentrations. All this evidence demonstrates that phytoliths in Leymus chinensis are sensitive to CO2 concentration,and indicate that phytolith analysis may have potential use in the study of global change,identifying different ecotypes of Leymus chinensis and for the reconstruction of paleoatmospheric CO2 concentrations.
GE YongJIE DongMeiGUO JiXunLIU HongMeiSHI LianXuan
The characteristics of phytoliths in Leymus chinensis leaves from five different pH-value habitats from Songnen Plain in China were analyzed to reveal their environmental implications and possible use for quantitative reconstruction of the paleoenvironment. The phytoliths in leaves of L. chinensis from the five habitats showed a non-linear correlation with soil pH. The main types of phytoliths from the different habitats were exactly the same, including silicified stomata, hat-shaped, lanceolate, elongated, multilateral-plate, and tooth-shaped. However, there were significant differences in the contents of each shape of phytoliths among the five habitats. The amount and the volume of weakly tooth-shaped, lanceolate phytoliths and silicified stomata increased with increased pH, while the total amount of phytoliths was reduced. In addition, there were different types of phytoliths in the L. chinensis leaves from the five habitats of different pH, suggesting that the types of phytoliths were controlled, at least in part, by soil pH. The changes of size and percentage of phytoliths were most remarkable at pH 10.15–10.18, indicating that this is the highest pH value that L. chinensis can tolerate.
JIE DongMeiLIU ZhaoYangSHI LianXuanLIU HongMeiGE Yong
