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Abstract
Mokara orchid is a tropical species and easy to plant due to its vitality and endurance. The flowers are colorful and long-lasting. Thus, mokara has been intensively planted and propagated by both traditional and tissue culture methods. However, despite the rapid multiplication, the micropropagated mokara shoot and plantlets grow very slowly. In this report, chitosans extracted from shimp shell and squid pen with 3 molecular weight ranges (Mw <10, 30-50 and 80-100 kDa, coded as Mw10, Mw30 and Mw80; respectively) and 3 deacetylation degrees (72-75, 82-85 and 92-95%, coded as D70, D80 and D90; respectively) were added to the tissue culture medium to examine the ability to promote the tissue growth. As the result, chitosan originated from shrimp shell with Mw30 and D80 was more suitable for the purpose of enhancing shoot development. Applying this type of chitosan with the concentration of 20 ppm was the best for shoot multiplication and elongation. Thus, chitosan could be used as an elicitor for mokara in vitro growth.
Key words: chitosan, mokara orchid, growth, in vitro