The role of ethylene in photosynthate partitioning and source-sink modulation in crops

The regulation of photosynthesis by the volatile plant hormone ethylene was first described in the work of Kays and Pallas from 1980, who showed that ethylene inhibits photosynthesis in peanut plants. Ever since, the negative effect of ethylene on this crucial process has been receiving more and more attention, especially in terms of yield loss in many important crops. More recent molecular genetics and physiological experiments have shown that ethylene is part of a vast and complex network, which involves many other phytohormones as well as diverse environmental cues, regulating almost every aspect of plant photosynthesis. In this book chapter, we describe the influence of ethylene on photosynthesis, from the uptake of CO2 through stomata to the incorporation of carbon atoms in complex sugars, and finally the fate of newly synthetized photosynthates. We finalize the chapter by discussing how stress conditions impact plant photosynthesis through ethylene.