Preliminary Study On The Geographical Distribution And Seed Germination Of Medical Ornamental Plants Ceratostigma Willmottianum Stapf

Ceratostigma willmottianum Stapf, which belongs to Ceratostigma Bunge (Plumbaginaceae family), is a deciduous subshrub known by its common name as Zi-jinlian in Chinese. As a medicinal and ornamental plant, Ceratostigma willmottianum has high medicinal value and has a broad prospect for landscape application. For its elegant compact plant-type and large amount of unique blue-violet flowers with long blooming period endow this plant with extremely high ornamental value. Besides, this vigorous plant has strong environment adaptability which can be used for many landscape applications. However, there is few systematic studies on this plant.We collected the specimen information of Ceratostigma willmottianum Stapf in 23 herbariums nationwide, to predict its potential regional distribution and analyze the climatic limiting factors of this distribution. Most importantly, we also analyzed the germination differences among Ceratostigma willmottianum seeds of from various regions, to explore the methods for breaking their seed dormancy. We hope it will provide scientific basis for plant breeding and landscape application of this species.The main results of this research are as follows:1.The collection of 140 specimen information of Ceratostigma willmottianum Stapf. We found that Ceratostigma willmottianum are mainly distributed in 46 counties in 5 provinces including Sichuan, Yunnan, Guizhou, Gansu province and Tibet Autonomous Region; and the rang of its vertical distribution is between 410 to 3800m. Interestingly, the results showed that the species distribute in widest areas in Sichuan, regardless of latitude and longitude, or even altitude.2.Ceratostigma willmottianum were found in the valley zone (600-1600m) of Minjiang and Fujiang River within Wenchuan, Maoxian and Beichuan. These plants always growed on sandy or humus soil, with PH 5-7. The accompanying plant species of Ceratostigma willmottianum were Lilium regale Wilson, Jasminum nudiflorum Lindl., Hypericum patulum Thunb. ex Murray, Iris L., Chrysanthemum L., Urtica L., Gramineae, Incarvillea arguta, Pteridophyta, Campylotropis polyantha, Buddleja lindleyana Fortune and Selaginella P. Beauv., etc.3. Seed of Campylotropis polyantha was black, with a long-egg form which had edges on its surface. It was usually 5.38±0.40 mm long and 1.92±0.17mm wide, the TKW (Thousand Kernel Weight) was about 9.17±0.46 g. There were large differences in size and weight among seeds from various regions, and some differences were also found in water absorption and germination, while no significant differences were found in the shape and seed vigor. The seed dormancy of Campylotropis polyantha belonged to husk obstruction. The germination rate and germination potential of seed was the highest treated with clean water at room temperature for 24h, and the value of germination rate and germination potential were 85.78% and 76.67%, respectively. There were some effects on the seed germination under the treatment of 200mg/L GA, and the value of germination rate and germination potential were 77% and 69.11%, respectively. Campylotropis polyantha from Pingwu had the highest germination rate and germination potential, and the value was 80.90% and 68.43%, respectively. While the survival rate of Campylotropis polyantha from Wenchuan was the highest, with a value at 98.6%.