Abscisic acid (ABA) helps protect plant photosynthesis from damage caused by light at low temperatures. When ABA was applied to barley seedlings, it increased the amount of protective pigments in the leaves, leading to better photosynthesis. The seedlings treated with ABA had higher levels of carotenoids and xanthophylls, which are important for light protection. The xanthophyll cycle, a process that helps plants deal with excess light, was more active in ABA-treated plants. This resulted in better protection against light damage in the leaves of ABA-treated plants compared to untreated ones.