Benefits of soil phylolith content on the resistance to a combine temperature elevation and water stress of a high silicon accumulating plant (Oryza Sativa L.) growing in silicon depleted soil

Abstract

Global climate change is expected to increase the intensity and the frequency of concurrent stresses. Among them, the sum of the elevation in temperature and the lack of water may have a catastrophic impact on anthropised and natural ecosystems. Silicon (Si) has recently shown some interesting prospects for its effect on the ability of plants to overcome this type of stress. All plants accumulate this element, which is the second most present in the earth's crust, and return it in the form of amorphous crystals called phytoliths (PhSi). This return helps to supply the dissolved Si pool in the soil and contributes to the subsequent intake, especially in highly weathered soils. A pot experiment involving two culture chambers was set up to simulate the impact of the return of PhSi on the growth of rice plants (Oryza sativa) under optimal and stress conditions. The stress involves a constant rise in temperature of 4 degrees to be consistent with the Representative Concentration Pathway (RCP) 8.5 scenario of the IPCC (2013) and a period of withholding of water of 10 days. The addition of PhSi significantly increased the amount of Si dissolved in the pots and the amount absorbed by plants. Plants subjected to stress conditions have generally achieved to reverse the adverse effects by increasing the number of secondary roots and decreasing their specific leaf area. These two traits were amplified by the addition of Si. The results of this study show that silicon could have a beneficial impact on the ability of plants to overcome the adverse effects of climate change.