Abstract: 【Objective】In order to optimize tissue culture system of Japanese lawngrass (Zoysia japonica Steud.), and to improve plantlet regeneration rate and to establish high efficient plant regeneration from seed-derived callus, mature caryopses were used as explants. 【Method】The effect of hormone, basical media, cultivation condition, L-proline, Cu2+ on callus induction, maintenance and plantlet regeneration were investigated. 【Result】The results are as follows: (1) The addition of 500 mg·L-1 L-proline to the media was beneficial to callus induction. The addition of BA to the media was disadvantageous to callus induction. Lower concentration NAA increased callus induction rate. The best media for callus induction was ND＋2,4-D 3.0 mg·L-1＋NAA 0.2 mg·L-1 and the ratio of callus induction was 57.3%. (2) The best media for callus subculture was MSD+ 2,4-D 1.0 mg·L-1. (3) The best differentiation media was MSD＋NAA 0.3 mg·L-1+ KT 0.5 mg·L-1+ BA 0.05 mg·L-1 and the ratio of differentiation was 36.7%.【Conclusion】The in vitro system of Japanese lawngrass was optimized and the main factors affecting seed-derived callus induction and regeneration were primarily traced.

Key words: Zoysia japonica, Mature caryopses, Plant regeneration, Callus