The effect of a non-circadian photoperiod on the growth, physiology, and production of a romaine lettuce cultivar

Abstract

The circadian rhythm serves to match plant physiology and behavior with the environmental cycles caused by the rotation of the planet. The circadian rhythm contributes towards the structure and function of plants and their overall performance which is an important consideration in agriculture. Arabidopsis has served as a model plant for understanding circadian function, but it is important to establish if these lessons can be extrapolated to other species. This study investigated the effect of a non-circadian light cycle on Lactuca sativa (lettuce) plants reared from germination in those conditions. Canopy size, gas exchange, and carbohydrate storage and use were investigated, and it was found through repeated measures ANOVA analyses that non-circadian light cycles are indeed associated with decreases in many metrics commonly associated with plant performance such as stomatal conductance, carbon dioxide exchange, leaf-level sugar storage, and canopy area, but not with total canopy volume or total biomass. This opens up the possibility of further analysis into the feasibility of using non-circadian light cycles in controlled environment agricultural settings and indicates some cross species agreement with the effects these light cycles are found to have with the model species Arabidopsis