TITLE:
Advances in D. melanoxylon Investigations towards Tissue Culture: Problems and Limitations
AUTHORS:
Washa B. Washa, A. M. S. Nyomora
KEYWORDS:
Dalbergia melanoxylon, Tissue Culture, Callus Induction, Explants, Murashige and Skoog
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.24,
November
27,
2014
ABSTRACT: The first attempt on D. melanoxylon tissue culture was conducted from 2010 to 2013 at a high level of expectations.
A total of 500 seeds were sterilized at different concentration of reagents and
inoculated at different strength of the Murashige and Skoog medium for
germination to obtain disease free explants for callus induction trials. A
total of 400 nodal segments obtained from germinated seeds were sterilized at
different concentration of reagents and inoculated at different hormonal
combinations to induce callus formation for seedling multiplication. Results
from this tissue culture attempt set a foundation for tissue culture success in D. melanoxylon on the future
research. Only 19.8% of seeds inoculated in half strength of Murashige and
Skoog medium germinated within 7 days while only 6.8% of seeds inoculated in
full strength of Murashige and Skoog medium germinated within 6 days. This
germination was at sterilization of 20 minutes in 35% ethanol and 20 minutes in
2.6% sodium hypochlorite. A total of 1% of inoculated D. melanoxylon seedling fragments in Murashige and Skoog media
supplemented with hormone combination
at 2.0 mg/l BAP + 0.5 mg/l NAA developed callus after16 days from the
inoculation day. The final weight of the callus at the last record was 0.62 g.
In this induction ex-plants were surface sterilized in 35% ethanol for 20
minutes and 2.6% sodium hypochlorite solution for 20 minutes. The color of
callus was green and friable in nature. Other hormonal combinations in this
case did not induce callus production. These results suggested that the
problems which affect seed germination in the natural environment are also
reflected on germination in the Murashige and Skoog medium and in callus
induction. Vulnerability to fungal attack is a limitation for successful callus
induction and germination in the culture room. More research under improved
sterile conditions is needed to improve callus percentage for seedling
multiplication.