Caloric restriction extends lifespan in a clonal plant

When subjected to dietary caloric restriction (CR), individual animals often outlive well‐fed conspecifics. Here, we address whether CR also extends lifespan in plants. Whereas caloric intake in animals comes from ingestion, in plants it derives from photosynthesis. Thus, factors that reduce photosynthesis, such as reduced light intensity, can induce CR. In two lab experiments investigating the aquatic macrophyte Lemna minor, we tracked hundreds of individuals longitudinally, with light intensity—and hence, CR—manipulated using neutral‐density filters. In both experiments, CR dramatically increased lifespan through a process of temporal scaling. Moreover, the magnitude of lifespan extension accorded with the assumptions that (a) light intensity positively relates to photosynthesis following Michaelis–Menten kinetics, and (b) photosynthesis negatively relates to lifespan via a power law. Our results emphasize that CR‐mediated lifespan extension applies to autotrophs as well as heterotrophs, and suggest that variation in light intensity has quantitatively predictable effects on plant aging trajectories. When subjected to caloric restriction (CR), individual animals often outlive well‐fed conspecifics, but little is known about the parallel phenomenon in plants. To this end, we investigated the effects of CR on aging in the tiny aquatic macrophyte Lemna minor by reducing light intensity to limit photosynthesis and restrict caloric availability. We found that reduced light intensity dramatically increased lifespan, emphasising that CR‐mediated lifespan extension applies to autotrophs as well as heterotrophs. Moreover, the magnitude and nature of this lifespan extension suggest that variation in light intensity has quantitatively predictable effects on plant aging trajectories.