Promotion by Jasmonic acid of bulb formation in shoot cultures of Narcissus triandrus L.

The in vitro bulb formation by shoot clump cultures of N. triandrus on media with jasmonic acid (JA) alone or in association with both 2-isopentenyladenine (2-iP) or naphthalene acetic acid (NAA) and on medium with only NAA was studied. The media with JA plus 2-iP or JA plus NAA caused a high multiplication of leaves, significantly higher on that with 2-iP. Leaf proliferation was low on medium with JA alone. The media containing JA promoted the formation of a bulb at the base of the leaves and the bulbs attained different sizes. On the medium with JA plus NAA, the number of bulbs that reached up to 5 mm in diameter was higher than that on the medium with JA plus 2-iP, but the highest number was formed on the medium with JA alone. The medium with NAA alone led to the formation of few small bulbs that were elongated instead of roundish as those formed on media with JA. Further culture of the bulbs on a growth medium suitable to their enlargement increased their size but the dimensions attained were dependent upon the medium initially used for bulb formation. Bulbs derived from medium with JA alone attained the largest diameter. Almost all the bulbs grown on the growth medium were rooted. Data described here show that JA promotes in vitro bulb formation in shoot cultures of N. triandrus and suggests that JA might play an important role in the formation and enlargement of bulbs in Narcissus plants.