Abstract

Sheikh Abdul Shakoor

Plants have a unique capability to deposit Silicon (Si) within and between the cells as silica and thus creating casts of the cells commonly known as Silica bodies or Phytoliths (Plant stones). Silicon is present in plants in amounts equivalent to calcium, magnesium and phosphorus and is the second most abundant element after oxygen in soil. In Poaceae (Grass family) Si often is present in higher quantity than any other inorganic constituent. Yet except for certain algae, including prominently the diatoms and the Equisetaceae (horsetails or scouring rushes), it is not considered an essential element for plants. As a result it is being routinely omitted from formulations of culture solutions and considered a nonentity in much of plant nutrition research, which ultimately has lead to negative impacts on the proper growth and development of the plants. Silicon-deprived plants grown in conventional nutrient solutions to which silicon has not been added are in many ways experimental artifacts. They are often structurally weaker than silicon enriched plants, abnormal in growth, development, viability and reproduction. Furthermore, such plants are susceptible to biotic and abiotic stresses such as metal toxicities and prey easily to disease organisms and to herbivores ranging from phytophagous insects to mammals. Hence, the above mentioned points necessitate reviewing the background of silica in plants, its essentiality, cycling and potential roles in plant life.