The study deals with the role 2,4-D and Kin and their interaction in callus induction , growth and differentiation from Nigella sativa L. ,which were used in (10-3, 10-5 ,10-7, l0-9, l0-11 ) molar for each and by their interaction with each other. The results showed the best enhancement media are that contain 10-5 M of 2,4-D with 10-7 M of the Kin in which the fresh weight of the growing callus 12.49 g ,by the age that lasts 75 days , followed by the medium containing 10-5 M of 2,4-D alone in which the fresh weight of the callus reached to 10.96 g in 75 days.
The results showed also the best differentiation of the shoots happened in the media supplemented with 10-11 for each 2,4-D and Kin,While addition of 10-11, 10-9 of both 2,4-D and Kin had achieved the best growth for the roots.
The study induced knowing the role of ( Sulphanilamide ) a chemical compound in initiation, growth and differentiation of Nigella sativa. It was clear that the best enhancement media for callus initiation and growth are that containing suphanilamide by 75 micromollar with 10-5 , 10-9 M for 2,4-D and Kin, also the media fortified by 100 micromollar of sulphanilamide alterating with 10-5, 10-7 M for 2,4-D and Kin, as for shoots enhancement the best results were obtained after using the media containing 100 micromollar of sulphanilamide with l0-9, l0-11 Mr of Kin .
Results also showed variation of the callus content of thymol comparing them by the thymol extract (control sample). The variation depended on the type and concentration of the growth regulators used.