TOWARDS "IN VITRO" PROPAGATION OF BULBOUS IRIS

Bulbs of 9cm circumference were stored at 30°C until use. Tunics and root initials were removed. The bulbs were cut longitudinally to give two symmetrical parts, which were surface sterilized in 1% sodium hypochlorite in water for half an hour, followed by three rinses with sterilized water. Subsequently, the half bulbs were cut longitudinally in three sections of equal size. From these sections two types of explants were cut, i.e., single outer and double inner scales, both attached to a piece of basal plate. Care was taken to remove the apex and axillary buds. Both explants were transferred to standard culture tubes containing 14ml of the following medium: MS macro and micro nutrients at half strength, 3% sucrose, 100mg/l meso-inositol, 0.04mg/l aneurin-HCl, 1% agar, pH 6.0. The abaxial site of the explants were placed on the medium. The tubes were placed in a dark culture room at 20°C. After appearance of adventitious plantlets the tubes were transferred to 5°C for 4 weeks and replaced at 20°C for at least 4 weeks. This method yields ca. 80 bulblets per bulb, that can be planted in soil after storage at 30°C for 8–10 weeks. The half-time of sprouting (9–14 days) and the success of sprouting (85–100%) depend on the size of the bulblet. The propagation factor may be increased by subculture of the originally formed plantlets on the same medium containing 0.3 mg/l of both NAA and BA.

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