Chan Lai Keng

Effect of yeast extract and chitosan on shoot proliferation, morphology and antioxidant activity of Curcuma mangga in vitro plantlets

This paper reported the effect of yeast extract and chitosan with combination of yeast extract on the growth and morphological changes and production of phenolics in the in vitro plantlets of Curcuma mangga . Yeast extract did not show any effect on the biomass and shoot proliferation of in vitro plantlets. However, the plantlets showed morphological abnormality when exposed to higher concentration of yeast extract (3.5 mgL -1 and above) supplemented into the culture medium. Plantlets cultured in media supplemented with 3.5 and 5.0 mgL -1 of yeast extract showed higher radical scavenging activity (RSA) which also indicated that stress induced by yeast extract might elicit the production of secondary metabolites which acted as free radical scavenger in 1,1-diphenyl-2- picrylhydrazyl (DPPH) assay. The plantlets treated with different concentration of chitosan combined with 3.5 mgL -1 of yeast extract affected the biomass of C. mangga . The plantlets that were cultured in media supplemented with 150 mgL -1 of chitosan combined and 3.5 mgL -1 of yeast extract showed higher RSA towards DPPH as compared to the other treatments. Kinetic of DPPH free RSA from C. mangga extract was considered slow as compared to quercetin and the correlation between total phenolic content and RSA was poor (R 2 = 0.2293) for yeast extract and (R 2 = 0.0373) for chitosan combination with yeast extract. This indicated that the presence of phenolic compounds in the extracts were not the major factor contributing to the anti-oxidative activity of C. mangga. Key words: Curcuma mangga, in-vitro, elicitor, phenolics, anti-oxidative activities.

Sucrose, benzylaminopurine and photoperiod effects on in vitro culture of Kaempferia galanga Linn

Abstract Kaempferia galanga is a monocotyledonous plant of the Zingiberaceae family, commonly utilized for medicinal purposes. This study evaluates the effect of different concentrations of sucrose, benzylaminopurine (BA) and photoperiod on in vitro propagation of K. galanga. Murashige and Skoog (MS) medium supplemented with 5 mg L−1 BA and 30 g L−1 sucrose, and a photoperiod with 4 h of light induced the highest shoot proliferation (7.4 ± 1.0 shoots/explant) and the highest number of roots/shoot (31.3 ± 3.2). On the contrary, the maximum shoot height (4.7 ± 0.7 cm) and the highest number of leaves/shoot (4.7 ± 0.2) were obtained from cultures using MS medium supplemented with 30 g L−1 sucrose but without BA, and exposed to 16 h of light. Hence MS medium supplemented with 5 mg L−1 BA and 30 g L−1 sucrose, and incubated under a 4 h light/20 h dark photoperiod was chosen as the optimal protocol for mass multiplication of K. galanga. This in-vitro technique can facilitate the production of a large number of uniform plants of K. galanga, irrespective of the seasonal factor, and could be used as a tool for conservation of the species.

In vitro propagation of five Alocasia species

The influence of cytokinin, N6-benzyladenine, on shoot proliferation of five Alocasia species (A. amazonica, A. cuprea, A. robusta, A. longiloba and A. chaii) was investigated. In vitro propagation of these species was established using shoot tip explants. Murashige & Skoog (MS) medium supplemented with different concentrations of BA (N6-benzyladenine) ranging from 0, 2, 5, 10 mg/L was then used to establish the optimum medium for shoot proliferation for all the species. MS medium supplemented with 2.0 mg/L BA was optimum for the shoot proliferation. All the tested species showed varying results for shoot number and shoot height. A comparison between agar-gelled medium and shake flask system using liquid medium was carried out to evaluate the shoot growth and proliferation for all the tested species. For A. amazonica, A. cuprea, A. robusta and A. longiloba, shake flask system using liquid medium of the same constituents stimulated more shoot proliferation as compared to agar-gelled medium. However, for A. chaii there was no significant difference. All the in vitro plantlets with well developed roots and leaves were successfully acclimatized with more than 90% survival rate.

Micropropagation of Homalomena pineodora Sulaiman & Boyce (Araceae): a new species from Malaysia

Homalomena pineodora (family Araceae) is a species found to have impressive foliage characteristics which remain evergreen throughout the year. Therefore, H. pineodora can be grown as an ornamental plant. Generally H. pineodora needs 3-5 years to propagate and multiply. However, the demand for new ornamental plants is increasing worldwide and the quality of planting material is a basic need for boosting productivity. Therefore an efficient micropropagation protocol for large-scale production of H. pineodora was developed. In vitro shoot cultures were initiated from the rhizomatous buds on MS basal medium. The best conditions for propagating H. pineodora was found to be MS medium supplemented with 3% sucrose and 0.5 mg L-1 BA (6-benzyladenine) under 24 h of cool fluorescent light which produced an average of 3.8 shoot per explant. Presence of an auxin was not necessary for plantlet production. Liquid MS medium supplemented with 0.5 mg L-1 BA, enhanced the shoot production of H. pineodora as compared to agar-gelled medium with same composition. All the in vitro plantlets of H. pineodora were successfully acclimatized with 100% survival rate. Scanning electron microscopy confirmed the similarity of leaf microstructures between the in vitro and mother plants of H. pineodora.

ESTABLISHMENT OF A SHOOT PROLIFERATION PROTOCOL FOR BANANA (ABB GROUP) CV. ‘PISANG AWAK’ VIA TEMPORARY IMMERSION SYSTEM

□ Initial study of evaluating the factors affecting shoot proliferation of ‘Pisang Awak’ using temporary immersion system was carried out using four half shoots in each experimental unit as explants and repeated with four to seven experimental units for each factor. The inoculum size finally used for shoot proliferation was eight half-shoots for each experimental unit (250 mL culture flask) in MS liquid medium supplemented with 5.0 mg L−1 benzyladenine (BA) and 30 g L−1 sucrose, the shoot proliferation medium and an average of 4.9 ± 0.3 shoots was produced from each half-shoot explant after five weeks of culture. The final protocol for shoot proliferation using the temporary immersion system was established by inoculating eight half-shoot explants into the shoot proliferation medium adjusted to pH 5.7 with the inoculated shoots immersed once a day in the medium for 10 minutes. The cultures were incubated under continuous light for enhancement of shoot proliferation without vitrification.