Micropropagation And Heavy Metal Content Of Begonia Pavonina (Ridl.)

This study were conducted to develop a micropropagation protocol for Begonia pavonina (Ridl.) and to analyze the heavy metals content in tissue culture derived and wild plants. Various media treatments were tested for shoot multiplication and root induction of B. pavonina. Results obtained showed that Murashige and Skoog (1962) basal medium (MS) supplemented with 0.1 mgL-1 6-Benzylamino-purine (BAP) produced higher mean number of shoots (7.60) and high mean length of shoots (2.20 cm). Studies on the effects of α-Naphthaleneacetic acid (NAA) and Indole-butyric-acid (IBA) on root induction showed that MS medium supplemented with 1.0 mgL-1 NAA gave the highest mean number of roots per shoot (14.47). Root formation can be seen as early as two weeks of incubation. The survival rate of this tissue cultured derived plants in the greenhouse after three months were about 80%. An efficient protocol for somatic embryogenesis from leaf explant of B. pavonina was also developed. Of the media tested, MS supplemented with 2.0 mgL-1 2,4-D and 1.0 mg L-1 BAP was found to be the most effective for the production of somatic embryos. Somatic embryos were successfully developed into plantlets when single embryos were transferred onto MS hormone-free medium. Plantlets were successfully transplanted in FRIM’s nursery. Heavy metals content in three different parts (leaves, stems and roots) of tissue cultured plants (in vitro) and wildings were analyzed using Inductively Coupled Plasma (ICP). The analyses showed that the level of heavy metal tested for both tissue cultured and wildings of B. pavonina were below the maximum permissible limits. Results also indicated that accumulation of heavy metal was higher in the roots, (both in wildings and tissue cultured plantlets) compared to stems and leaves. Zinc (Zn), Iron (Fe) and Manganese (Mn) were highly accumulated in tissue culture derived plantlets, while the content of Cadmium (Cd), Copper (Cu) and Lead (Pb) in tissue culture derived plantlets were lower compared to those of wildlings. Mercury (Hg) and Arsenic (As) were not detected in both tissue culture derived plantlets and wildings of B. pavonina. Histological analysis were done using a standard protocol by Malaysian Palm Oil Board (MPOB). The histological analysis of the embryogenic callus tissue of the B. pavonina explants showed that they were made up of small meristematic cells with dense cytoplasm, with small vacuoles and were very rich in soluble protein (which were stained blue with Naphthelene Blue Black). Three types of callus were identified, however, only Type 3 callus produced globular embryos after eight weeks of culture, and subsequently to the heart-shaped structures. From this study, it can be concluded that micropropagation B. pavonina can be accomplished via organogenesis and somatic embryogenesis. Analysis of heavy metals content in tissue culture derived plantlets and wildling were below the maximum permissible limits, hence proven safe to be eaten.

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