| Water deficit stress is one of the most important abiotic stresses and limiting factors for plant production. The occurrence of water deficit stress during germination can greatly reduce the germination percentage and ultimately the establishment of the plant, and in some cases, it can completely prevent the plant from germinating. One of the important solutions to prevent moisture and chemical fertilizer losses is the use of zeolite. Zeolites are porous materials with a crystalline structure that, due to the open pores in their structure, allow the passage of certain ions while preventing the passage of others. To investigate the effect of zeolite on radish plant tolerance to water deficit stress, a factorial experiment was conducted as a completely randomized design with three replications in 2024 in the research greenhouse of Gonbad Kavous University. The experimental factors included water deficit stress at three levels, involving irrigation after permissible moisture depletion at 20%, 40%, and 60% (by weight), and zeolite at four levels of 0%, 3%, 6%, and 9% (by weight). The analysis of variance results showed that the effect of zeolite on fresh and dry root weight, fresh and dry shoot weight, and fresh and dry plant weight was significant at the 1% level, and on dry root weight at the 5% level. The mean comparison results showed that with increasing drought stress, fresh and dry weights of roots, shoots, and plants decreased. Application of zeolite led to an increase in fresh and dry weights of roots, shoots, and plants, so that the highest fresh and dry weights of roots, shoots, and plants, respectively, were 13 g, 2.454 g, 11.64 g, 2.5 g, 24.63 g, and 4.953 g, observed in the treatment with 9% zeolite. The lowest values belonged to the treatment without zeolite application. According to the obtained results, zeolite has a good capability to enhance radish plant tolerance to water deficit stress. |