During the last ten years, knowledge about the multitude of adaptive responses of plants to low oxygen stress has grown immensely. The oxygen sensor mechanism has been discovered, the knowledge about the interaction network of gene expression is expanding and metabolic adaptations have been described in detail. Furthermore, morphological changes were investigated and the regulative mechanisms triggered by plant hormones or reactive oxygen species have been revealed. This book provides a broad overview of all these aspects of low oxygen stress in plants. It integrates knowledge from different disciplines such as molecular biology, biochemistry, ecophysiology and agricultural / horticultural sciences to comprehensively describe how plants cope with low oxygen stress and discuss its ecological and agronomical consequences. This book is written for plant scientists, biochemists and scientists in agriculture and ecophysiology.