Successful plant regeneration system via de novo organogenesis in Syzygium cumini (L.) Skeels: an important medicinal tree

Abstract

Syzygium cumini L. (Myrtaceae) is an evergreen medicinal tree confined to tropical and subtropical regions of the world and is mainly recognized for healing of type, two diabetes. An efficient indirect regeneration system has been standardized for this tree using cotyledonary node, inter-node, nodal and leaf segment explants excised from 10 days old aseptic seedling. For callus induction explants were incubated on Murashige and Skoog (1962) medium supplemented with different concentrations of 2, 4-Dichlorophenoxy acetic acid (2, 4-D) or 2, 4, 5-Trichloro phenoxy acetic acid (2, 4, 5-T). All the tested concentrations facilitated callus initiation with different types and varying regeneration potentialities. The regenerated callus on different treatments showed variation in color and texture and best callogenesis (75%) was observed on (7.5 µM) 2, 4-D after 4 weeks. Different morphogenic response was observed when callus was transferred to a secondary organogenic medium fortified with (5.0 µM) benzyl adenine or Kinetin. The yellow white friable (YWF) callus obtained from CN explants exhibited appearance of small leafy structures on secondary medium. Not all types of calli originating from various types of explant were organogenic. Best shoot induction (93%) were observed in (YWF) type of callus obtained from CN explants on MS medium enriched with 5.0 µM BA + 0.25 µM NAA + 10 mg/l AgNO3 with maximum mean shoot number (10.19 ± 0.05) and mean length (4.12 ± 0.32 cm) per clump after 4 weeks of transfer. However the shoot number got increased up to 48 shoots/clump on subsequent subculturing after 12 weeks. For ex vitro rooting shoot lets (4 cm) were excised and pulse treated in full or half strength MS medium augmented with varied concentrations of IBA. Best rhizogenesis (80%) was achieved on 200 µM IBA treated shootlets after 4 weeks of transfer to sterilized soilrite. The regenerants were successfully acclimatized and established in earthen pots with 90% survival.