Qianqian Fan & David Jespersen
Abstract
Lower doses of UV-C radiation have been found to enhance plant performance in seashore paspalum (Paspalum vaginatum) in previous literature with a concomitant decrease in leaf growth. Whether altered growth patterns could be elicited in different turfgrass species and the physiological reasons behind the responses required further investigation. This study sought to investigate growth inhibition by UV-C radiation at a low dose in seashore paspalum and bermudagrass [Cynodon spp. (L.) Pers.] in terms of photosynthesis as well as changes in phytohormones. Treatment with UV-C inhibited growth in both species but with more damaging effects seen in bermudagrass. The reduced growth was attributed to changes in phytohormone profiles associated with regulation of shoot growth and defense pathways, including increased contents of jasmonic acid for bermudagrass, decreased contents of salicylic acid for seashore paspalum, and increased contents of abscisic acid for both species. The accumulation of other phytohormones involved in oxidative stress defense could also contribute to the growth inhibition in both species. Additionally, for bermudagrass, the decline in its photosynthesis rate might be another major reason for reduced leaf growth under UV-C treatment. This study provides deeper insight into UV-C elicited growth inhibition and offers a new perspective on utilizing non-lethal UV-C as a potential tool for turfgrass management.
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