The study looked at how drought and UV-B radiation affect the photosynthesis and leaf structure of Rosa roxburghii plants. The researchers found that both stress factors reduced chlorophyll content but increased the ratio of chlorophyll a to chlorophyll b. Photosynthesis efficiency decreased significantly. The leaves' stomata and chloroplast membranes were damaged, with more osmiophilic globules in chloroplasts and enlarged thylakoid stacks. Drought worsened the negative effects of UV-B radiation and improved water use efficiency in the leaves.