Author: Ling Ding-hou, Chen Mei-fang, Chen Wan-ying and Ma Zhen-rong
J Integr Plant Biol 1989, 31 (4): -.
In the young inflorescence (panicle) culture of 22 species of 6 genera, i.e. Oryza, Echino- chloa, Pennisetum, Setaria, Panicum and Musa, it was found that the young inflorescences budded directly from explants in 19 species of all 6 genera in the culture medium containing NAA and kinetin, but no 2,4-D. According to the frequency and the speed of direct spikelet budding (DSB), these species could be classified into four groups (Table l). The response of the young panicles in the first group (Cultivar rice, O. spontanea, Echinochloa and some interspecific hybrids) was very rapid in the 2,4-D free medium. Within a week, the young panicles of the first group distinctly sweelled then the buds began to develop from the spikelets after 15 days of inoculation. The frequency of DSP in this group was more than 70%. The response of the young panicles in the second group (O. perenis (512), O. officinalis (525) O. punctata (544), O. nivara (1050) and O. rufipogon Ï O. nivara (648) was not as rapid as that of the first group. A frequency of DSP around 20% was observed after 30 days of inoculation. The response of the young panicles in the third group) O. australiansis, Panicum maximum, Musa X paradisiaca (ABA) was rather tardy and slow, the frequency of DSP being less than 10%. The duration of DSP was more than one month. In the fourth group, the young panicles did not respond to the medium in this experiment. Besides the spikelet budding, sometimes adventitious bud could develop from the cutting place of the panicle axis usually the budding from the spikelets inhibited the growth of adventitious buds, but in this case the growth of adventitious bud could suppress the DSP. Some spikelets budded directly from the panicles of Setaria and Echinoshloa which were cultured in the same test tube, while the other spikelets of the same panicle were flowering. Calli were formed from some spikelets of Panicum and Oryza, while the others of the same panicle in the same test tube were budding.