Synthetic Seed Production and Slow Growth Storage of In Vitro Cultured Plants of Iris pallida Lam

Abstract: Iris pallida Lam. is traditionally cultivated in Italy to sell its rhizomes to perfume-producing industries and is particularly sought-after because of its high content of irones, ketone compounds responsible for the violet smell of the orris essence. One of the critical aspects of its cultivation is the propagation method, performed by subdividing and replanting sections of the rhizome, which leads to the sacrifice of salable material. A solution is provided via in vitro propagation using the somatic embryogenesis technique, an effective method that allows the production of plants without the use of the rhizome. To facilitate the scale up of the activities of micropropagation companies, the method of slow growth storage (SGS) for orris plantlets and a somatic embryo encapsulation technique were developed for the first time. Orris plantlets were placed at 4 ◦C in the dark for 30, 60, 90 and 120 days and monitored 7 and 30 days after treatment. Synthetic seeds were obtained by encapsulating somatic orris embryos in sodium alginate beads, which were stored for 14 and 28 days at 4 ◦C and 24 ◦C. The results showed that it is possible to cold-preserve orris plantlets for up to 90 days without significant damages and that orris synthetic seeds can be produced and stored for a short-to-mid-term period. These conservation techniques can be useful for germplasm conservation and can also be integrated in the micropropagation cycle of orris, helping to solve issues related to the traditional propagation method.