Direct and indirect method of plant regeneration from root explants of Caesalpinia bonduc (L.) Roxb.— A threatened medicinal plant of Western Ghats.

An in vitro regeneration protocol has been standardized via direct and indirect methods from excised root explants of C. bonduc, a threatened woody legume used for the treatment of contagious diseases, inflammation, leprosy, antiperiodic, febrifuge, anthelmenthic, urinary disorders, leucorrhoea, piles and to heal wounds. MS medium supplemented with 17.75 µmol BAP and 2.46 µmol IBA, induced a mean of 3.40 ± 1.07 shoots directly from the surface of excised root explant. Subsequently, the shoots rooted readily on MS half strength medium with out growth regulators. In indirect organogenesis, callogenic frequency was optimized (96.66%) at the concentration of 9.04 µmol 2, 4-D and 0.88 µmol BAP. An average, 15.30 ± 5.25 shoots were differentiated from the root callus at the concentration of 17.57 µmol BAP and 2.85 µmol IAA. Shoots regenerated through callus were rooted well on MS half strength medium with growth regulators at 2.95 µmol IBA. Rooted plantlets were transferred to the pots containing sterilized soil and were successfully hardened at greenhouse condition for three weeks then exposed to the natural environment. Survival rate was more (95%) in plantlets derived through direct organogenesis than (60%) the plantlets regenerated through root calli.

Regeneration of plantlets from mature embryo calli of Western Ghats land race cultivar of rice, Oryza sativa L.

The Malnad region located in the Western Ghats of Karnataka is known for the cultivation of indigenous rain fed land race cultivar of rice. The present study was to investigate the callogenic and caulogenic potentialities of the two indigenous rice cultivar namely Karimundaga and Kanadatumba using dehusked mature embryo explants. For callus and shoot bud differentiation, the explants were cultured on Murashige and Skoog (MS) medium supplemented with 2,4-D (1–3 mg/L), IAA (1–2 mg/L), Kn (1–4 mg/L) and BAP (1–4 mg/L). The morphogenic potentialities of the two rice cultivar differed in texture of callus. In both the cultivar callogenic frequency was optimized at 1 mg/L 2,4-D concentration, it was 94% in Karimundaga and 58% in Kanadatumba. Supplementation of IAA either alone (1–2 mg/L) or in combination with Kn or BAP at 1 to 4 mg/L concentration of each induces shoot bud differentiation from the calli. In the cultivar Karimundaga caulogenic frequency was highest (10.60±2.55) at 1.0 mg/L IAA and 4.0 mg/L BAP concentration. While in the cultivar Kanadatumba highest number of shoot buds (7.90±2.69) was differentiated at 1.0 mg/L IAA and 4.0 mg/L Kn concentration. The calli derived regenerants were successfully acclimatized in the greenhouse and agro-morphological variations were evaluated. The growth characteristics and yield related parameters exhibited by in vitro plants were lower than the in vivo plants.