Effects of ROS and caspase-3-like protein on the growth and aerenchyma formation of Potamogeton perfoliatus stem.

Aerenchyma formation plays an important role in the survival of Potamogeton perfoliatus in submerged environment. To understand the regulatory role of reactive oxygen species (ROS) and caspase 3-like protein signaling molecules in aerenchyma formation, we investigated the effects of exogenous NADPH oxidase inhibitor (diphenyleneiodonium chloride, DPI), catalase inhibitor (3-amino-1,2,4-triazole, AT), and caspase-3-like protein inhibitor (AC-DEVD-CHO, DEVD) on morphological and physiological characteristics and aerenchyma formation in P. perfoliatus. The results showed that after DPI treatment, caspase-3-like protein activity decreased, ROS-related enzyme activities increased, and H2O2 content decreased, thereby inhibiting aerenchyma formation. When the concentration of DPI was approximately 1 μmol/L, the inhibitory effect was the most obvious. On the contrary, after the AT treatment, caspase-3-like protein activity increased, ROS-related enzyme activities decreased, and the H2O2 content increased, ultimately promoting aerenchyma formation, and the promotion was the most obvious under treatment with approximately 500 μmol/L AT. After DEVD treatment, the inhibition of vegetative growth caused by DPI or AT treatment was alleviated, significantly reducing caspase-3-like activity and inhibiting aerenchyma development. The results of this study show that ROS has a positive regulatory effect on aerenchyma formation, and caspase-3-like protein is activated to promote ROS-mediated aerenchyma formation. This experiment provides a new theoretical basis for further exploration of the signal transduction effects of ROS and caspase-3-like protein in plant cells and their roles in plant development.