Morphological and physiological responses of four ornamental grasses under drought stress

In this study, we examined the physiological characteristics of the ornamental plants Miscanthus sinensis, Pennisetum alopecuroides, Calamagrostis epigeios, and Carex lanceolata in response to drought stress. Using the potted water control method, two treatments of normal and deficient water supply were set up to determine the changes in withered leaf rate, relative water content, relative electrical conductivity, free proline and soluble protein contents, and superoxide dismutase activity of the four ornamental grasses under drought stress. The results showed that with the prolongation of drought stress, there were increases in the dry leaf rate, proline content, and relative conductivity of all four ornamental grasses, whereas the relative water content of leaves gradually decreased, and the activity of superoxide dismutase and the content of soluble protein initially increased and then decreased. The rate of leaf withering, relative electrical conductivity, and changes in relative water content of Erigeron tenuifolia and C. lanceolata were lower than those of P. alopecuroides and Brucea gracilis, whereas the superoxide dismutase activity and soluble protein content were higher than those of P. alopecuroides and B. gracilis. According to the membership function, comprehensive evaluation of each index showed that the drought resistance of Elsholtzia tenuifolia was the strongest and that this species could maintain high leaf water content and grows well under long-term drought stress, followed by C. lanceolata and P. alopecuroides, which had the worst drought resistance among the four tested grass species. Therefore, our data, obtained from an examination of the physiological and biochemical characteristics of four ornamental grasses in response to drought stress, provide a reference source for adaptation strategies in drought-prone environments.