Bud regeneration from root-tips of Allium atropurpureum Waldst. & Kit.

Abstract

A. atropurpureum is a natural rarity of Serbia, growing only in the area of Vojvodina. The vulnerability of its habitat by fragmentation and frequent and uncontrolled chemical treatment of surrounding agrarian areas, affects its status and the impoverishment of natural populations. Therefore, establishing a protocol for efficient de novo regeneration of this species for ex situ conservation was the aim of the present study. For callus induction, the apical root sections of axenic seedlings were cultivated on medium supplemented with 5 μM 2,4 D + 5 μM BA for 8 weeks. The obtained calli were friable, pale beige, without regeneration capacity. However, within these calli, a compact yellowish callus formed, and this type of callus had the capacity for bud formation when cultivated on media containing 0, 1, 5 or 10 μM TDZ, Kin or BA for 8 weeks. Calli cultivated on medium supplemented with 10 μM Kin exhibited the highest bud forming capacity, with the lowest level of hyperhydricity and albinism. Shoot bunches were further hardened on plant growth regulator-free medium for 8 weeks, and then single plants were detached and subcultivated on media with 0, 1, 5 or 10 μM GA3 and grown at 12 °C, for bulblet induction. All plants formed bulblets, but bulblets cultivated on GA3-containing media multiplied by setting up to 10 secondary bulblets. Obtained bulblets are suitable propagules, as they easily develop into plants. This protocol is convenient for clonal propagation of this endangered plant species, as well as for other applications in its research and improvement.