ICAPS-2021

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Effect of edible sugar on in vitro growth and organogenesis of Dendrobium bigibbum x Dendrobium Thailand Black
(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Amarasinghe, V. L. P.; Panapitiya, P. D. D. M.; Leelarathne, N. D. C. S.; Priyadharshan, A I.S.; Senanayake, R. A. S. P.
The most popular propagation method of Dendrobium is in vitro micropropagation. However, using laboratory-grade sucrose as the carbon source in micropropagation is expensive for small- scale producers. Present study is aimed to assess the performance of edible sugar as an alternative carbon source to develop an effective, low-cost medium. Protocorm like bodies (PLBs) and plantlets of Dendrobium hybrid (Dendrobium bigibbum x Dendrobium Thailand Black) were cultured on basal MS medium containing different concentrations of sugar; 0.0, 15.0, 30.0, 45.0, 60.0, 75.0 and 90.0 g/L, (T1-T7). A modified MS medium (T8) containing sugar (30.0 g/L), BAP (2.5 mg/L) and NAA (0.5 mg/L) was also used to determine whether there is a comparable effect of sugar individually and when combined with plant growth regulators (PGRs). Growth performance was evaluated in regular intervals. MS medium containing sugar (45.0 g/L) was identified as the best medium for the growth and organogenesis of PLBs resulting in the highest weight accumulation of 20.31 g and 35 plantlets regeneration from 1.00 g of PLBs after two months of incubation. MS medium supplemented with 60.0 g/L of sugar was identified as the most successful medium for the plantlet growth with 17 of mean leaf generation, 33 of mean root generation and an average root length increment of 1.5 cm after four months of incubation. In conclusion, edible sugar can be recommended to use as a sucrose supplement for a cost-effective medium to promote successful in vitro growth and development of the Dendrobium hybrid even with the absence of PGRs.
An efficient culture medium for in vitro propagation of Chrysanthemum sp. using petals as explants
(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Amarasinghe, V. L. P.; Panapitiya, P. D. D. M.; Leelarathne, N. D. C. S.; Priyadharshan, A. I. S.
Chrysanthemum is a floricultural plant with high demand all over the world. To overcome shortcomings in the supply chain due to the slow rate of propagation and severe susceptibility to virus infections, multiple shoot regeneration using tissue culture has become a successful technique for Chrysanthemum propagation. Although different explant types can be used for in vitro culturing, the number of explants that can be obtained from a single mother plant is limited. Nevertheless, the use of petals (ray florets) as explants can reduce such restrictions since a single flower/flower bud provides a large number of ray florets at a time. Therefore, the objective of the current study was to find an effective culture medium for in vitro propagation of Chrysanthemum sp. using petals (ray florets) as explants. The basal MS media supplemented with different concentrations of BAP (Benzyl Amino Purine) (1.0 - 5.0 mg/L) and NAA (Naphthalene Acetic Acid) (0.1 and 0.2 mg/L) were used as the culture media and the growth regulator free MS medium was used as the control. The pH of the media was adjusted to 5.8. Surface sterilized petals of partially bloomed flower buds were cultured in media and maintained at 26±4 °C in the culture room under a 14 h photoperiod with irradiance (20 mol/m2/sec) provided by cool-white fluorescent lights. After 60 days, MS medium supplemented with BAP (1.00 mg/L) and NAA (0.10 mg/L) was identified as the most successful medium for shoot regeneration with 08 shoots derived from a single explant with 11 leaves per shoot. Meanwhile, MS medium supplemented with BAP (5.00 mg/L) and NAA (0.10 mg/L) was identified as the best medium for rooting with 04 roots per shoot/callus with a 7.3 cm root length. Further, media containing BAP (3.00 – 5.00 mg/L) and NAA (0.10 and 0.20 mg/L) were recognized as the media composition which can be used for both shoot and root regeneration at the same time. Even though there was a good root development, the shoot development in these media was not notable. Therefore as the conclusion, MS medium supplemented with BAP (1.00 mg/L) and NAA (0.10 mg/L) can be recommended as a successful medium for both shoot initiation and development while MS medium supplemented with BAP (5.00 mg/L) and NAA (0.10 mg/L) can be used as a successful medium for both in vitro root initiation and development of in vitro petal culturing of Chrysanthemum.