SPECIFIC PHOTOREGULATION BY PHYTOCHROME OF EPINASTY and LIGHT-INDUCED ETHYLENE PRODUCTION IN MARCHANTIA POLYMORPHA*

Abstract— A study is made of the influence of phytochrome on light-induced ethylene production and epinasty in green Marchantia polymorpha thalli. Ethylene production of thalli irradiated with terminal far-red is not substantially affected by the presence or absence of CO₂, in contrast with the controls which show a clearcut CO₂ dependency. Photoreversibility and fiuence response data indicate the involvement of the low energy red'far-red reversible type of phytochrome action for both the light-induced ethylene production and the control of epinasty. The far-red effect is further characterized by a difference in escape from reversibility between light-induced ethylene production and the elimination of epinasty.