Impact of Low Light on Photosynthetic Characteristics, Antioxidant Activity, and Yield of Brassica napus L.

Low light is an abiotic stress that has a significant impact on crop growth. However, the impact of low light on rapeseed yield has not been well documented. Our study aims to examine the potential effects of low light on the photosynthesis antioxidant capacity and yield composition of leaves by simulating low light environments. According to the study results, low light reduces key photosynthetic enzymes and sucrose synthase activity in rapeseed leaves, leading to a decrease in leaf carbohydrate accumulation. The reduced number of pods per plant and the number of pods per grain are the direct factors leading to the decrease in rapeseed grain yield, while the increase in grain weight compensates for some of the yield loss. In addition, low light increased the content of malondialdehyde in leaves and altered the activities of catalase (CAT) and superoxide dismutase (SOD). Low light inhibits photosynthesis in leaves, reduces leaf productivity, and leads to a decrease in yield. High-yielding varieties have stronger antioxidant capacity and lower production of malondialdehyde. By revealing the effects of low light on the photosynthesis and antioxidant capacity of rapeseed leaves, this studyprovide new insights into the composition of low light affecting rapeseed grain yield and explain significant guidance for the planting and management of different rapeseed varieties in low light areas.