Effects of trampling and ethephon on leaf morphology in trampling-tolerant Plantago asiatica and Eleusine indica

Summary The effects of simulated human trampling on leaf morphology and ethylene production as well as the effect of an ethylene releaser ethephon on leaf morphology were investigated for trampling-tolerant species, Plantago asiatica and Eleusine indica , and trampling-susceptible species, Gnaphalium affine and Panicum bisulcatum . In Pl. asiatica , trampling decreased the leaf length and increased the leaf blade length to width ratio and the leaf blade length to leaf (leaf blade + petiole) length ratio. In E. indica , trampling only decreased the leaf blade length to width ratio. Trampling increased ethylene production in intact seedlings of Pl. asiatica , E. indica and G. affine . The ethephon (1 mM) treatment increased the leaf blade length to width ratio in seedlings of Pl. asiatica , but decreased that in seedlings of E. indica in a manner similar to the morphological changes induced by trampling. In contrast, no significant differences in leaf morphology were observed between the ethephon-treated and control seedlings of trampling-susceptible species. These results suggest that trampling-tolerant species have higher responsiveness to ethylene than trampling-susceptible species and change their leaf morphology in response to ethylene induced by trampling.