TRATAMENT WITH LOW TEMPERATURES APPLIED TO THE BULBS OF NARCISSUS POETICUS L FOR THE STIMULATION OF THE IN VITRO REGENERATION AND BULBIFICATION

Abstract

The object of the study was the ex situ conservation of Narcissus poëticus L specie deriving from the protected area of “the Forest with Daffodils from Alparea (Oşorhei village)” from Bihor County, a vulnerable specie, conserved in vitro, with the purpose of multiplying and reconstructing the area where it originates. The advantage of the method consists in obtaining a large number of explants, identical with the mother plant, being a unique method of multiplying asexual plants. Ex situ multiplication in free collections has some deficiencies (the destruction of the specie by the attack of some diseases, by natural disasters, etc.), which raised interest for the in vitro conservation, the method becoming a certitude. At the tuber-bulbous plants, obtaining the vegetal material for the multiplication (the bulbs) requires a period of low temperatures (vernalization stage). Narcissus poëticus L was cultivated in vitro from scale detached from the bulb, with the disk area, after the bulb donor of the explant was treated with cold up to 4 months. The explant was cultivated on four basal mediums: MSM, MS, Heller and Gamborg, with different hormonal variants. After about 4 months from the in vitro inoculation, it was followed the evolution of the explant in relation to the period of cold, to the dose of phytohormones and lass to the nature of the medium. We point out the necessity of the treatment with cold for Narcissus poëticus L specie, involved in eliminating the profound repose of the bulbous plants. The rhythm of regeneration after a month of treatment with cold at 6 oC proved weak; after 2 months of treatment at 4 oC it is in slight increase with the formation of real leaflets; and after 3 - 4 months of cold at 2 – 3 oC applied to the bulb donor of explants the rhythm of regeneration reaches up to 30 – 50 %, with caulogenesis and the formation of 3 - 4 bulbils/explant. We recommend in vitro multiplication of Narcissus poëticus L specie, after normal periods of vernalization, or the replacement of this period with a treatment with cold for about 4 months at 2 – 4 oC, and even with high doses of cytokinins, for the natural extracts within the medium for obtaining in vitro bulbils at a low cost.

Keywords

• Narcissus poëticus L.
• in situ
• in vitro
• vernalization
• treatment with cold
• rhythm of in vitro regeneration