Optimization of selected plant growth regulators on callus induction of Oryza sativa L. var. MR 219 / Siti Nur Adila Hamzah

This study was using Malaysian Rice 219 (MR 219), an indica rice from a cross between
MR 137 and MR 151. It was considered as recalcitrant variety because of low
potentiality of callusing and regeneration. The objective of this study was to develop an
effective protocol for obtaining MR 219 callus induction using different combinations
and concentrations of plant growth regulators (PGRs) which were 2,4-
Dichlorophenoxyacetic acid (2,4-D), Kinetin (KIN) and Naphthalene acetic acid (NAA)
as plant growth regulators ranging from 0.5 to 15.0 mg/L. The callus was induced from
the mature seeds of MR 219 on the MS media supplemented with 4.4 g/L of MS powder
with vitamins, 30.0 g/L of sucrose and 3.5 g/L of gelrite with addition of various PGRs
in different types, concentrations and combinations. All media supplemented with 2,4-
D had successfully induced the callus and 2.0 mg/L of 2,4-D was the best concentration
for the callus induction with 100% success rate and with the addition of 15.0 mg/L of
NAA, it provided less time taken for callus induction with better callus morphology
which resulted in less browning problems. The induced calli then were analysed through
reversed-phase HPLC for the presence of the desired secondary metabolites which was
ɣ-oryzanol. The chromatogram of the standard was shown to have six components of
ɣ-oryzanol through this reversed-phase HPLC method that used HPLC grade of
methanol: acetonitrile: dichloromethane: acetic acid (50:44:3:3 v/v) as mobile phases
and 40 minutes of isocratic elution with 1.4 ml/min of flow-rate through C18 column.
Through this study, there is a potential in maximizing the use of callus culture of
obtaining desired secondary metabolites for future researches.