Studies On Flower Development And Fertility In Torenia Fournieri Lind

The differentiation and development processes of flower bud in Torenia fournieri Lind were characterized and some experiments were conducted to investigate the flower fertility. The main results are as follows:1. Seeds were germinated in different time from January to October of 2004 and the duration of onset of flowering was observed. It took 67 days from sowing to the onset of the flower when the seeds were germinated in January and only 34 days for those germinated in August.2. It was found that the flowering time was regulated by photoperiods. The onset of the flowering was delayed when 30 and 40-day-old plants were transferred to a short -day condition.3. Torenia fournieri Lind has typical 4 whorls of the flower organs. From the appearing of the primordia to the time before flowering, flower bud differentiation and development has been divided into 16 stages by correlating morphological and cytological traits of the flower buds. During stages 1~4 the flower bud underwent initiation of flower organ primordia; Stage 5~6 were characterized by a faster cell division and differentiation in the flower buds. Stage 7 was defined as a meiosis stage of microspore mother cells and stage 13 as a meiosis stage of megasporocyte. The duration of the 16 stages was about 18 days.4. Pollen viability was evaluated by pollen germination experiment. The result showed that the pollen viability was about 63% in June and July and dropped to 48% in August. It was in November and December that pollen viability was 14% and 15%, respectively. Pollen viability was affected by the climate in the nature.5. Pollen grains were harvested from the plants of outside and wereincubated in 4℃ , 25℃and 37℃. Pollen viability was detected every 2 hours after incubation. It was found that the viability declined faster at 37℃ than that at 4℃ or 25℃.6. The stigma of the flower had receptivity on the second day after blooming. Pollen germination could be observed when 2-day-old stigma were pollinated by 1-day-pollen from another flower. And seed-setting ratio reached to 97%. The reason of low ratio of seed-setting in Torenia fournieri Lind was discussed.