Drought and flooding are complex stress which impairs plant and microorganism growth/development. Drought causes water loss from the cell, increasing the cytoplasm's molecular crowding. This water loss alters the cell's physiology since the increase in macromolecular crowding produces alterations to proteins. It affects metabolic networks, processes related to replication of DNA, transcription and translation, the integrity of the membranes, etc. Some of the most critical effects of flooding include a reduction in water and nutrient uptake and a decrease in metabolism. The severe constraint is the starvation of oxygen and carbon dioxide caused by prolonged water diffusion rates compared to air. The limitation of oxygen availability in flooded soil causes hypoxic and anoxia conditions in the root. Furthermore, flooding leads to changes in soil chemical characteristics, including soil acidification and redox potential, which limits the availability of soil nutrients and causes the accumulation of phytotoxins. These results indicate that plant growth is suppressed under flooding stress through decreasing energy/nutrients supply and accumulating toxic metabolites.