Study on phytochemical traits and improving seed germination methods of Iranian endemic populations of caper (Capparis spinosa L.) medicinal plant

Caper, Capparis spinosa, has medicinal, edible, and industrial uses and has been used since ancient times to treat kidney, spleen, liver, paralysis, gout, and rheumatism diseases. Dormancy caused by hard seed shell is one of the problems of seed germination in this plant, In order to study on improving seed germination methods and biochemical characteristics, a factorial experiment on the basis of completely randomized design was conducted with three replications. To improve seed germination, four caper populations (Tehran, Torbat-e-Jam, Firuzabad, and Barazjan) were treated with six seed treatments (control, ultrasonic, potassium nitrate, gibberellic acid, chilling, and scarification). Phytochemical characteristics of the populations were also compared. The results of phytochemical traits showed that the Torbat-e-Jam population had the highest antioxidant activity with an IC50 equal to 26.4. The highest amount of total phenol equal to 227.03 mg of gallic acid per gram of dry extract, and total flavonoid equal to 71.54 mg of quercetin per gram of dry extract was obtained from Tehran population. The results showed that the highest percentage of germination with 62% and the highest germination rate with 3.5% per day was identified in the treatment of Firozabad population under scratching conditions. Also, the results of this study showed that in Tehran, Torbat-e-Jam, Firozabad, and Barazjan, the percentage of germination increased by 6.55, 7.25, 3.44, and 11.25 times, respectively compared to the controls. According to the results of the current study, seed scarification is recommended to increase the germination rate of a caper valuable medicinal plant.