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*Corresponding Author: Hongze Liao,
Screening drought-resistant alfalfa cultivars is crucial for sustainable forage production in semi-arid and arid regions. To investigate the effects of drought stress on the physiological characteristics of alfalfa (M. sativa L.) seedlings and to screen drought-resistant alfalfa varieties, this experiment used five alfalfa cultivars as materials and conducted germination tests under four polyethylene glycol (PEG)-6000 concentrations (0%, 5%, 10% and 20%).
The physiological indicators of the seedlings treated with PEG-6000, including free proline (Pro), soluble protein (SP), soluble sugar (SS), malondialdehyde (MDA), superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), were measured and analyzed.
The results showed that drought stress significantly affected the physiological characteristics of the five alfalfa cultivars. As the drought stress intensified, except for Pro and SP content, the five physiological indicators of WL363HQ showed an increasing trend; the changes in physiological indicators of WL168HQ, WL440HQ, Baimu 202 and Kehan under different stress concentrations exhibited significant variability. The comprehensive evaluation using the membership function method indicated that WL363HQ possessed superior drought resistance compared to the other cultivars. The findings of this study will provide theoretical basis for research on the drought resistance mechanisms of alfalfa, the breeding of new drought-resistant varieties and the cultivation of alfalfa cultivars in semi-arid and arid regions.
Alfalfa, Antioxidant enzymes, Drought stress, Membership function, Osmotic stress, Physiological indicators