Abstract:
Objective In order to enrich the breeding methods of Lagerstroemia speciosa, the optimum conditions of ethyl methane sulfonate (EMS) mutagenesis were studied.
Method The seeds of L. speciosa were used as the study material to compare and analyze the effects of different combinations of EMS concentrations and treatment times on seed germination and seedling growth of L. speciosa.
Result EMS treatment could inhibit the germination of L. speciosa seeds. The EMS concentration and treatment time had significant impacts on the degree of inhibition. All seeds were killed by treating with 20 g·L−1 EMS for 12 h. The starting time of seed germination was delayed and the germination duration became longer with the increase of EMS concentration and treatment time. The inhibition of hypocotyl and radicle growth was more significant. The relative lethal rates of the 16 g·L−1 EMS treatment for 12 h and the 18 g·L−1 EMS treatment for 10 h were 47.99% and 55.02%, respectively, which were the closest to the lethal concentration 50(LC50). Consequently, the two treatment combinations could be chosen for EMS mutagenesis of L. speciosa. The growth of L. speciosa seedlings was inhibited by EMS treatment, with the greatest impact observed at 20 g·L−1 EMS treatment for 8 h. The plant height, crown width, ground diameter and leaf area were 8.28 cm, 9.66 cm, 1.70 mm and 29.32 cm2 respectively. The leaf shape index was found to be the highest after 20 g·L−1 EMS treatment for 10 h, with a value of 2.44.
Conclusion In this study, the treatment combinations with relative lethal rates close to the LC50 in EMS mutagenesis of L. speciosa seeds are determined, which could provide a basis for the cultivation of new varieties of this plant.