In vitro Effects of BAP and Adenine Sulphate on Shoot Proliferation, Histology and Genetic Fidelity of Polyploid Kelampayan (Neolamarckia cadamba) Clones

Nur Binti Noh and Ho Seng

Background and Objective: Kelampayan (Neolamarckia cadamba) is a fast-growing timber species extensively cultivated in Sarawak, Malaysia. However, recent studies on polyploid Kelampayan clones have reported suboptimal shoot proliferation rates under tissue culture conditions. This study aims to enhance shoot proliferation in polyploid Kelampayan using cytokinin-based growth regulators, specifically 6-benzylaminopurine (BAP) and adenine sulphate (AdS), while also evaluating the morphological, histological and genetic fidelity of the regenerated clones. Materials and Methods: Eight polyploid Kelampayan clones (M5, M6, M7, M13, O3, O8, O11 and O20) were cultured on B5 medium supplemented with varying concentrations of BAP (0.8 and 1.0 mg/L) and AdS (0, 20, 40, 60, 80 and 100 mg/L). Morphological parameters, such as shoot number, shoot length and leaf length, were recorded. Histological analysis was conducted on selected leaf and stem tissues using light microscopy to observe cellular structure, while genetic fidelity was assessed using inter-simple sequence repeat (ISSR) markers to detect somaclonal variation among regenerated shoots. The collected data were subjected to a two-way ANOVA (p<0.05) using GraphPad Prism Version 9.0. Results: Mixoploid clones cultured on B5 medium with 0.8 mg/L BAP and 60 mg/L AdS exhibited a significantly higher mean shoot number (6.80±0.75) compared to the control (3.26±0.82). Similarly, octoploid clones under the same treatment recorded a higher mean shoot number (6.66±2.25). The combination of BAP and AdS also promoted significantly larger and more vigorous shoot structures. Histological observations revealed well-organised vascular tissues and increased cellular differentiation in treated shoots. Genetic fidelity analysis showed high similarity indices between regenerated and mother plants, confirming the clonal uniformity of in vitro-derived shoots. Conclusion: Combining BAP and AdS improves shoot proliferation and structural integrity in polyploid Kelampayan clones. The histological and molecular findings further validate the quality and stability of regenerated plantlets. This optimised protocol offers a viable solution for mass propagation, thereby supporting the sustainable expansion of Sarawak’s timber industry.

View Fulltext Back