An investigation of tissue culture and co-cultures of different explants in Calendula officinalis

Abstract Two experiments were conducted separately to investigate the effects of the medium and explant types on the callus induction and regeneration of Calendula officinalisas a medicinal plant. In the first experiment, explants were placed on a ¼ MS medium on three levels of NAA (1-Naphthaleneacetic acid) and KIN (Kinetin) in sterile conditions. The parameters, time to callus initiation, callus volume, and the percentage of callus induction were measured to evaluate the callus condition in this experiment. Variance analysis of the results on the first experiment showed that there was no considerable difference in terms of callus induction in mediums with a combination of hormones, while the effect of explant source on these traits was significant. In the second experiment (co-culturing of different explants), main effects of cotyledon, hypocotyl and meristem explants as single cultures, and also effects of cotyledon and meristem, hypocotyl and meristem explants as co-cultures in the two mediums, KIN + NAA and TDZ (Thidiazuron) + IBA (Indole-3-butyric acid), were studied. The results of the second experiment showed that co-cultured explants have a better regeneration. It also indicated a better condition for traits related to the root of the co-culture system. Moreover, the impact of the two explants, hypocotyland meristem, together onrootingandregenerationwas remarkable.