ABSTRACT
Abiotic stress limits the crop growth and productivity of plants. Indeed, abiotic stress decreases the growth of plants by inhibiting the process of photosynthesis. Among the elements, silicon (Si) ranks second in abundance on earth crust. Unfortunately, so far, it is not found to be essential in higher plant growth processes (Epstein 1999). However, the application of Si has enhanced the tolerance of plants to various abiotic and biotic stresses. Si is also known to improve the process of photosynthesis in plants under different abiotic stresses, such as drought, salinity, heavy metal toxicity, and ultraviolet B (UV-B), and provide tolerance to plants under these conditions. There were several works on the role of Si on plant growth by defense mechanisms, but they did not specifically address the effect of Si on photosynthetic machinery. Therefore, in this chapter we discuss the tolerance mechanism of plants with special reference to the photosynthetic machinery subjected to different abiotic stresses.
