Research Projects

Plants absorb silicon as silicic acid from soil and deposit its polymerized form silica at various locations throughout their bodies. In Poaceae family plants, silica cells fill almost their entire cell volume with silica deposited on a proteinaceous template. Silica cells secrete a protein called Siliplant1 (Slp1) that interacts with supersaturated silicic acid in the apoplast, precipitating silica between the cell wall and the cell membrane. The growing silica displaces the cytoplasm, shrinking it to accommodate silica, leading to silicification. After silicification, silica cells undergo programmed cell death, leaving behind micrometric voids with potential debris. This process involves rapid changes in cellular architecture, with organelles and cytoskeleton re-organizing and possibly disintegrating during silicification. The ultrastructural details of silica cells during development and the fate of cell organelles after cell death are not well understood. The current proposal aims to follow the ultrastructural changes in rice silica cells using confocal fluorescent light (CFLM) and scanning electron microscopes (SEM). Leaf pieces representing different silicification zones will be fixed, freeze-fractured, dehydrated, coated, and observed in an SEM to see the 3-D architecture of cell organelles at nano-metric precision. Fluorescent stains will be used to track the cytoskeleton and cell organelles at micrometric resolution during silicification and even after cell death. These two microscopic techniques will help decipher the ultrastructural details of developing silica cells and test the hypothesis of whether carbon trapped within plant silica can alleviate the effects of global warming due to excessive carbon emissions.