Abstract
Malacocarpus crithmifolius is an endangered rare relict with small size populations grown in a limited area. The purpose of this study was to initiate in vitro and micro replication of Malacocarpus crithmifolius. The vegetative and reproductive explants and Murashige & Skoog medium (MS) supplemented with different concentrations and combinations of cytokinin and auxins were used. The response reaction of different explants and the plant growth regulators' effects on shooting frequency, the number of shoots, callusogenesis, and rooting percent were investigated. Culturing generative explants on the MS medium containing 6-Benzylaminopurine (BAP) combined with indole-3-acetic acid (IAA) or indole-butyric acid (IBA) led to direct shoot regeneration. The bud mass appeared in the leaf axil under inflorescences after one week of cultivation on the initiated medium. The replication was reached by micro-cutting of induced additional shoots and 3-fold passaging them on the fresh mediums. The average multiplication result at MS with BAP in combination with 1-Naphthaleneacetic acid (NAA) or IAA composed 5.85 after three months of cultivation. In conclusion, the applicable explant and phytohormonal composition of nutrient medium for initiation and micropropagation of M. crithmifolius were developed.