Embryo culture of Vietnamese aromatic coconut (cocos nucifera L.) variety: Effect of natural factor and activated charcoal

Abstract

Coconut (Cocos nucifera L.) is called a “tree of life” since various items can be made from it. There is a high demand for coconut palm, specially two types of elite coconut: makapuno and aromatic coconut varieties. Many researches have studied regarding aromatic variety for the last 20 years, mainly focused on productivity and flavor preservation. However, the understanding of natural factor and activated charcoal (AC) has not been widely reported to supplement to embryo culture media of aromatic coconut. Therefore, this study was undertaken with the objective of evaluating the role of aromatic coconut water (CW) and activated charcoal in coconut embryo culture. Germination rate, length of shoot and fresh weight of coconut seedlings were recorded. Only Vietnamese aromatic coconut was used in this study. Sterilized embryos were inoculated in media supplemented with various AC treatments: 0, 1.25, and 2.5 g L-1. For second experiment, different concentrations of CW (0, 5, 10, 15 and 20 % (v/v)) were used. All embryos were then incubated in darkness for 4 weeks and subsequently transferred to nurtured under illumination for another 4 weeks. After 8 weeks, all seedlings were subcultured on semi-solid medium. Results showed that media supplemented with 2.5 g L-1 AC had highest germination capacity, fresh weight and normal shoot morphology. Moreover, media without CW gave positive results on germination rate, length of shoot and substantial weight. It was evident that AC enhances embryo growth and increases shoot formation. In contrast, it was showed that coconut water from the aromatics had some considerably inhibitory substances that decreased germination capacity and survival rate of coconut embryo. For further studies, root formation should be followed up, and photosynthesis rate of coconut embryo also will be evaluated.