Plants are often experienced various stress conditions because of growing in an open system in nature. And they formed a serious of adaptive mechanisms to mitigate the damage of adversity in the long-term evolution, in which the chemical signal molecules play an important role. The evidence of pharmacology and molecular genetics techniques showed that gas signaling molecule nitric oxide play a key role in plant tolerance to abiotic stresses. Compared with animals, the source of NO in plant is more diverse, ...