Evaluation of the characteristics of Iris ferdowsii seed germination, a new species, in danger of extinction and native to Iran

Selection of the most appropriate method of propagation is one of the basic principles in the preservation of wild plants as a genetic source. Investigation of the germination behavior of wild species is an important and necessary step in their domestication process. Unfortunately, Iris ferdowsii is in danger of extinction according to the criteria and classification of the Red List of the International Union for Conservation of Nature (IUCN), due to geographical distribution, separated plant populations, and reduced suitable habitats. Seed germination is one of the critical stages of the growth cycle of plants considerably affecting their population. In order to evaluate the seed germination indices of Iris ferdowsii, an experiment was conducted in a completely randomized design with three replications. Experimental treatments included control and 98% sulfuric acid for 5-, 10-, and 15-minutes treatment, 10 M, 15 M, and 20 M sodium hydroxide for 10 minutes, seed coat removal, and micropyle removal. In each replication, 25 seeds were used. After applying the experimental treatments, the seeds were placed at 25±1 °C for one month and then at 6±1 °C for three months. The results showed that the percentage of seed germination in the micropyle removal treatment was increased by 75% compared to the control treatment. In addition, the highest germination rate and the highest daily mean germination were observed in this treatment. Also, using of sodium hydroxide (20 M) for 10 minutes, and seed coat removal treatment, increased the seed germination percentage from zero to 31.00% and 32.66%, respectively. In general, the best treatment for seed germination in Iris ferdowsii is the removal of seed micropyle. The mechanical dormancy and chemical dormancy due to the presence of growth inhibitors in the endosperm prevent the germination of Iris seeds. As a result, removal of the endosperm without any damage to the seed embryo will accelerate seed germination.