Plant Somatic Embryogenesis: Modulatory Role of Oxidative Stress

Plant somatic embryogenesis (PSE) provides several advantages when compared to other in vitro propagation methods of tissue culture. All factors affecting PSE are not known. Some prominent stress factors in tissue culture are serious injuries in explants, subcultures, unbalanced mineral composition of the culture medium and growth regulators, etc. The present review would focus on induction Reactive Oxygen Species (ROS), which lies fairly downstream of the cascade of various stress processes outlined above. The central question the present authors ask is—whether ROS generation is all for toxic or there is some amount of benefit to the somatic embryogenesis. The increasing interest in the functional meaning of ROS and the antioxidant response concomitant to growth, development and cell differentiation in plants suggest a link between ROS production and morphogenetic processes of plants. The authors in this review article consider hydrogen peroxide (H 2 O 2 ) as a model ROS which is omnipresent and naturally generated in a variety of normal cell types, either constitutively or in response to various stimuli. A review of the concerned literature suggests that endogenous H 2 O 2 acts as a cellular ‘messenger’ capable of inducing gene expression and protein synthesis, thus leading to somatic embryogenesis in some plant species.