An experiment was performed to establish a suitable regeneration protocol for the rapid propagation of Piper nigrum L. using nodal segments and leaf tissues as explants through direct and indirect organogenesis. After surface sterilization, several types of explant were inoculated onto gelled MS medium containing various concentrations and combinations of growth regulators for callus and direct shoot induction. The highest callus induction frequency was 92% and 84% in the case of leaf tissues and nodal segments, respectively, in gelled MS medium containing 2.0 mg/l 2,4-D. Multiple shoots (6.43±0.35 shoots per unit callus) were obtained when the calli from both explant types were cultured on MS medium containing 1.0 mg/l BAP. Nodal segments showed the best result (85%) in terms of direct shoot induction in MS medium supplemented with 1.5 mg/l BAP, where the highest number of shoots per explant was 5.03±0.69. The directly induced shoots were multiplied and elongated on MS medium containing 1.0 mg/l BAP and 0.5 mg/l IBA, the number and length of regenerated shoots per culture being 6.07±0.39 and 5.84±0.65 cm, respectively. The best response to root induction (86.67%) was observed when shoots were transferred to ½ strength of gelled MS medium supplemented with 1.5 mg/l IBA within 16-24 days, with 13.60±1.76 roots per shoot unit. The well-rooted shoots were successfully acclimated in a mixture of soil, sand, and compost (1:1:1) with a survival rate of 88%. Jahangirnagar University J. Biol. Sci. 11(1 & 2): 31-40, 2022 (June & December)

An experiment was conducted to develop a suitable in vitro plant regeneration technique for Rosa hybrida L. cv. ‘Double Delight’ using nodal segments and leaf tissues as explants through direct and indirect organogenesis. Aseptic explants were inoculated onto gelled MS medium contained various strengths of plant growth regulators alone and in combinations for callus and direct shoot induction. MS medium containing 2.0 mg/l BAP was found to be the most effective for direct shoot induction from nodal explants (87.5%) as it produced the maximum number of shoots per explant. The highest callus induction frequency was found to be 80% in leaf tissue, 72% in nodal segments and 96% in leaf and intermodal segments of in vitro raised plantlets in MS medium containing 2.5 mg/l 2, 4-D. The best percentage of indirect shoot organogenesis (93.33%) with maximum number and length of shoot were found when the different explant-derived callus was transferred in 3.0 mg/l BAP supplemented medium. The direct and indirectly induced shoots were multiplied on MS medium containing 3.0 mg/l BAP, where the average number and length of shoots per culture were 7.20 ± 0.80 and 5.22 ± 0.47 cm, respectively. Maximum rooting (80%) was observed in ½-strength of gelled MS medium containing 15.0 g/l sucrose with 1.0 mg/l IBA. Plantlets with the proper root system were then placed in a polybag with a 1:1:1 ratio of sand, garden soil, and compost, and they had a survival rate of about 76%. Plant Tissue Cult. & Biotech. 33(1): 25-36, 2023 (June)

The present experiment was conducted to establish an efficient protocol for mass propagation of Dendrocalamus giganteus Wall. ex Munro through in vitro culture using nodal segments as explants. The highest percentage of shoot induction (86.67 %) was obtained in the liquid MS medium supplemented with 1.5 mg/l BAP and 1.0 mg/l TDZ with maximum number of shoots (3.91 ± 0.87) per explant. The highest number and length of shoots were 22.83 ± 1.30 shoots/culture and 7.71 ± 0.96 cm, respectively induced on agitated liquid MS medium supplemented with 2.0 mg/l BAP and 1.0 mg/l TDZ. Incorporation of 8 % coconut water in the above mentioned medium resulted satisfactory shoot growth and development. The best response towards root induction (90 %) was observed when 3-4 shoots clump were transferred onto halfstrength of gelled MS medium fortified with 4.0 mg/l IBA with 9.31 ± 1.45 roots per unit shoot. Successful acclimatization of well-rooted clumps of 4-5 shoots was achieved in a mixture of soil, sand, and compost (1 : 1 : 1) with 90% survival rate. Bangladesh J. Bot. 52(2): 337-343, 2023 (June)