EFFECT OF MEDIUM COMPONENTS AND EXPLANT ON BELLADONNA CALLUS INDUCTION IN VITRO

Abstract

An experiment was conducted at the tissue culture lab., Dept of Hort., College of Agriculture ,University of Baghdad during 2009-2010 . Explants (shoot tip – cotyledon – hypocotyls) were cultured on a modified Murashige and Skoog (MS) or Gamborge (B5) medium .Tow kinds of auxins at four levels of either 2,4-dichloro phenoxy acetic acid (2,4-D) or naphthalene acetic acid (NAA) ,were added to medium . Concentration of each auxin were 0 , 1.5 , 3.0 and 4.5 mg / l . The study included effect of each medium components or explants or auxin on callus initiation. Results indicuted that no sign of contamination after sterilization belladonna seeds by using sodium hypo chloride at 4.5% for 15 minutes.MS medium ,complemented with 1.5 mg/l of 2,4-D was superior in giving higher fresh and dry weight, of callus that induced from shoot tip to be 177.7 and 18.9 mg , respectively .In comparison with the same 2,4-D concentration in B5 medium that gave only 110.0 and 12.3 mg of fresh and dry weight, respectively .The MS medium supplied with 4.5 mg/l 2,4-D gave the lowest fresh and dry weight of 23.4 and 2.0 mg callus which is formed the cotyledon, respectively. The callus which induced when cotyledons were explanted on MS medium supplement with 3.0 mg / l 2,4-D gave the highest values 44.3 ,5.0 mg for both fresh and dry weight callus respectively , while MS medium supplemented with 3.0 mg/l NAA gave 18.9 and 2.5 mg for both fresh and dry weight callus, respectively .Shoot tip was superior than cotyledons and hypocotyls in inducing callus initiation 45.74 ,5.00 mg 38.98, 3.78 mg and 17.84 ,2.04 mg for both fresh and dry weight callus inducted from shoot tip , cotyledons and hypocotyls, respectively. We found the best medium for callus induction from belladonna explants is MS medium and the best hormone is 2,4-D compared with NAA and the best explants is shoot tip compared with cotyledon and hypocotyls.