Mutagenesis and Flowering Promotion through Sodium Azide In Vitro Culture of Cymbidium faberi Rolfe

Abstract

Cymbidium faberi Rolfe is one of the traditional Chinese orchids with important ornamental value, and the cultivation of Cymbidium faberi Rolfe mutant strains with different appearances is essential to increase its economic value. However, at present, their acquisition largely relies on natural mutation. The objectives of this research were to mutagenize Cymbidium faberi Rolfe protocorm-like bodies (PLBs) and shoots in vitro using sodium azide (NaN3) and to screen and evaluate mutants in the mutagenized seedlings using morphological characteristics. Cymbidium faberi Rolfe PLBs and shoots were used as mutagenic materials. Mutations were induced by the addition of 0.0 (control), 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 mg·L−1 and 0.0 (control), 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, and 10.0 mg·L−1 NaN3 to a shoot-growth-inducing medium. The mortality rates of the PLBs and shoots increased with an increase in the NaN3 concentration. At 14 d of co-cultivation, the PLBs and shoots were most efficiently mutagenized with 1.5 mg·L−1 and 4.0 mg·L−1 NaN3, respectively. After the explants were cultured for 3 months, changes in leaf and flower morphology were observed in some mutants: shorter and thicker leaves, shorter node length, reduced height, and mid-translucent leaves compared with controls. Some Cymbidium faberi Rolfe bloomed prematurely, with single flowers with large, thick petal sepals and small inflorescences. Colors included light green throughout, with some exhibiting purple stamens. This suggests that NaN3 can effectively mutagenize Cymbidium faberi Rolfe PLBs and shoots to satisfy people’s demand for this plant’s ornamental properties while increasing its economic value.