Science Diliman, Vol 3 (1990)

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Tissue Culture of Pittosporum resiniferum Hemsl. (Petroleum nut tree)

Cecilia Vargas-Zamora

Abstract


It has been reported that Pittosporum species are very difficult or even unsuccessful to be propagated by seeds (Veneracion and Costales, 1982) and the seeds of P. resiniferum are very difficult to germinate (Balcos, F., 1987). So this plant will be best propagated by tissue culture.

Explants (blade with midrib or without midrib and leaf tip, 6 x 5 mm) from very young leaf of P. resiniferum produced more significant results about 90-100% compared to the 20-80% of explants from young leaf. However, leaf blade with midrib (from very young leaf) produced culture growth earlier than any of the explants tried; and plant lets were formed after subcultures of 5-8 weeks old growing explants in 1l of Revised Murashige and Skoog's supplemented with 10 mg Benzyl adenine (BA), 0.25 naphthalene acetic acid (NAA), and 0.25 dichlorophenoxy acetic acid (2,4-D).

The explants (blade with midrib) from very young leaf became enlarged, fleshy and green after 21 days culture and later produced an excellent and remarkable cabbage-like callus growths. After 30 days culture, these calli became green and friable to very friable creamy greenish-yellow and roots (whitish structures) were observed. These culture growth characteristics were also observed after 40 days. Whereas, these morphological callus characteristics were observed in explants from blade and leaf tip of very young leaf, only after 40 days culture.

The best culture medium is 1l of Revised Murashige and Skoog's (RMS) agar medium supplemented with 10 mg benzyl adenine (BA), 0.25 naphthalene acetic acid (NAA), and 0.25 dichlorophenoxy acetic acid (2,4-D) at pH 5.7 exposed to light laboratory condition.

Other treatments were tried in the tissue culture of its plant parts, such as: agar media with 1l RMS supplemented with different concentration, of growth regulators such as Benzyl adenine (BA), Kinetin (Ki), naphthalene acetic acid (NAA), indole-butyric acid (IBA), (2,4-D) and gibberellic acid (GA3) and with or without coconut water as adjuvant from mature fruits (CW) and young fruits (cw) from 20, 25, 30, 35,50, and 100 mI. In these treatments, sorne did not form any callus growth.

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