Hydrogen peroxide is involved in drought stress long-distance signaling controlling early stomatal closure in tomato plants

O peróxido de hidrogênio está envolvido na sinalização de longa distância do déficit hídrico controlando o fechamento estomático precoce em plantas de tomate

Abstract

It has long been hypothesized that hydrogen peroxide (H₂O₂) may play an essential role in root-to-shoot long-distance signaling during drought conditions. Thus, to better understand the involvement of H₂O₂ in drought signaling, two experiments were carried out using tomato plants. In the first experiment, a split-root scheme was used, while in the second experiment, the tomato plants were grown in a single pot and subjected to drought stress. In both experiments, H₂O₂ and catalase were applied together with irrigation. Control plants continued to be irrigated according to the water loss. In the split-root experiment, it was verified that the application of H₂O₂ to roots induced a clear reduction in plant transpiration compared to untreated or catalase-treated plants. In the second experiment, we observed that H₂O₂-treated plants exhibited similar transpiration when compared to untreated and catalase-treated plants under drought stress. Similarly, no difference in water use efficiency was observed. Thus, we conclude that the increase in H₂O₂ in the root system can act as a long-distance signal leading to reduced transpiration even when there is no water limitation in the shoot. But it has little effect when there is a reduction in the shoot water potential.

Keywords:
reactive oxygen species; root-to-shoot communication; split-root; water loss; water relations