Reduce the Adverse Effects of Dodder on Sweet Basil by Seed Priming with Salicylic Acid (SA) and Sown in Residues of Syrian Bean-Caper

Seed priming can improve plant capacity in response to different stresses. This study investigated the effectiveness of seed priming with salicylic acid (SA) and Syrian bean-caper (Zygophyllum fabago L.) shoot residues in promoting the germination and growth of sweet basil (Ocimum basilicum L.) infested by field dodder (Cuscuta campestris Yunck.). Basil seeds were pre-treated with 0.5 mM of SA for 12 h at 25 degrees C. In the allelopathic plant treatments, 10 g of the Syrian bean-caper powder was mixed into the top 5 cm of pot soil. Among the studied varieties, the Iranian variety had the highest susceptibility to infestation with dodder and application of the Syrian bean-caper residues. Dodder infestation reduced plant biomass, relative water content, leaf area index, soluble proteins, and pigments content, especially in the Iranian variety of basil. By contrast, dodder infestation stress increased proline, soluble sugars, malondialdehyde, superoxide dismutase, peroxidase, and catalase. Application of the Syrian bean-caper residues via reducing the seed emergence of dodder increased the basil plant's height, dry weight of shoots, leaf area index, relative water content, soluble proteins, and chlorophyll a and b. The positive effects of the Syrian bean-caper residues were higher in the Italian variety of basil than in the Iranian variety. Despite these inhibitory effects of the Syrian bean-caper residues on the dodder infestation, it decreased the basil plant's height, dry weight of roots, relative water content, soluble proteins, and chlorophyll a and b in the vegetative growth stage. However, the application of SA reduced these inhibitory effects and alleviated the negative impact of the Syrian bean-caper residues on basil plants.