Responses of phytolith in guinea grass (Leymus chinensis) leaves to simulated warming, nitrogen deposition and elevated CO2 concentration in Songnen grassland, Northeast China

Deposited in plant cells and their intercellular space, phytoliths, a special form of silica, could be used to determine information on plant structure and physiology especially their size and content. With the hypothesis that phytolith in plant would change under variable climate and environment, the dominant plant species in Songnen grassland, guinea grass (Leymus chinensis), was treated by an open-top chamber (OTC) to elevate CO2 concentration, infrared heaters, and artificial nitrogen (N) addition for three years from 2006-2008. Phytoliths were extracted by wet-ashing method and analyzed by variance analysis and so on. We found that the responses to elevated CO2 are complicated, and warming is positive while N addition is negative to the deposition of phytoliths in L. chinensis leaves. Especially, warming could reduce the negative impact of N addition on phytolith in L. chinensis. The short cell's taxonomic in graminea is significant because of no disappearance with simulated environmental changes. The phytolith originated in the long cell and plant intercellular space are more sensitive to elevated CO2 concentration, warming, and N addition, and could become some new indicators for environmental changes. In conclusion, different phytolith types have various responses to simulated warming, N addition and elevated CO2 concentration.