Ecophysiology of anaerobiosis stress due to flood and waterlogging in rice

Abstract

Purpose: Significant research on yield improvement of wetland rice provided a greater understanding of stress physiology, but less on ecophysiology of anaerobiosis stress. This paper explores soil conditions that exist because of waterlogging and submergence, reviews the current research of the effect of the ecophysiology of abiotic stress, and the plant's adaptability through its various biochemical pathways and physiological processes. Findings: Rice has morphologically avoided anoxia due to flooding and submergence ecosystems through its aerenchyma tissues that facilitate oxygen diffusion from shoot to root-tips. The plant hormone system plays a central role in the initiation and regulation of most of these adaptive responses. The biochemical responses of submerged rice are mainly mechanisms of avoiding internal anoxia as the oxygen deficit shift the energy metabolism to anaerobic, with greater activity of glycolytic pathway, fermentation enzymes, and involvement of antioxidant defense mechanisms to cope with the post hypoxia/anoxia oxidative stress. Physiological processes including aerobic respiration, photosynthesis, and phytochrome photo-equilibrium of the submerged rice shoots have evolved to adapt to waterlogging stress. Most of the post-anoxic injury is due to the generation of reactive oxygen and toxic oxidative products as acetaldehyde, hydrogen peroxide and hydroxyl radical. Limitations: This was minimal due to accessibility to the literature. Directions for future research: Future research should be directed towards rice tolerance to waterlogging as well as low water availability and salinity.

Keywords

• anaerobiosis
• anoxia
• ecophysiology
• oryza sativa
• waterlogging