Abiotic stresses such as extreme temperatures, low water availability, high salt levels and mineral deficiency and toxicity are frequently encountered by plants in both natural and agricultural systems. In many cases, several classes of abiotic stress challenge plants in combination. For example, high temperatures and scarcity of water are commonly encountered in periods of drought, and can be exacerbated by mineral toxicities that constrain root growth.
Higher plants have evolved multiple, interconnected strategies that enable them to survive abiotic stress. However, these strategies are not well developed in most agricultural crops. Across a range of cropping systems around the world, abiotic stresses are estimated to reduce yields to less than half of that possible under ideal growing conditions.