The involvement of ethylene in programmed cell death and climacteric-like behaviour during the remodelling of lace plant (Aponogeton madagascariensis) leaves

Programmed cell death (PCD) plays an important role in several plant developmental processes. The phytohormone ethylene has been implicated in PCD signalling in many plant systems, but it is also important in developmental processes such as seed germination, flowering, and climacteric fruit ripening. Lace plant (Aponogeton madagascariensis (Mirbel) H. Bruggen) is an aquatic monocot that develops perforated leaves via the deletion of cells through developmentally regulated PCD. The plant is ideal for studying PCD; however, little is known about the regulation of cellular death involved in this system. The current study examines ethylene as a potential signalling molecule in lace plant PCD and investigates climacteric-like behaviour during lace plant leaf development. Whole plants were treated with the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG), the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), or a combination of both. Subsequently, ethylene levels were monitored, and leaf development was analyzed. The results indicate that ethylene is involved in lace plant PCD signalling. AVG-treated plants had significantly lower ethylene outputs and a significant reduction in perforation formation. The inhibitory effect of AVG was recovered when AVG and ACC were applied simultaneously. The data presented here show for the first time, to our knowledge, climacteric-like behaviour during the remodelling of leaves.