Salicylic acid and boric acid improve flower growth, yield, and cold tolerance in French marigold (Tagetes patula)

A decrease in air temperature harms many ornamental plants, especially flowers grown in green space. to prevent cold stress, various elicitors are used that reduce the harmful effects of low temperature. therefore, in this study, we investigated the impact of two elicitors, viz. salicylic acid (sa) and boric acid (ba), on the growth and yield parameters of french marigold (tagetes patula). plants were exposed to cold stress, and their physiological and morphological traits were studied. results showed that the application of elicitors, especially at higher concentrations, had a positive effect on morphological and physiological traits. interaction of sa×ba with a concentration of 2 mm, increased flower diameter (20%), stem height (19%), stem and root fresh weights (27% and 35% respectively), stem and root dry weight (31% and 39% respectively), and flower quality (26%). also, the interaction of these two elicitors led to a decrease in ion leakage (22%), malondialdehyde (28%), and proline (24%) content, and an increase in chlorophyll fluorescence (28%), catalase (20%), and ascorbate peroxidase (33%) activity. in general, combined treatment with2 mm salicylic acid and boric acid improved growth and yield characteristics as well as cold stress tolerance in french marigold.