Artificial Propagation and Reintroduction of Dayaoshania cotinifolia W. T. Wang, an Extremely Small Population in China

Dayaoshania cotinifolia W. T. Wang is a perennial herb which is an endemic species in the Guangxi Zhuang Autonomous Region, China. It is a relatively primitive species of the Gesneriaceae. It was listed as one of the prioritized protected key wild plants of China and a critical endangered species because of its small population, narrow distribution, and disturbance of human activity. We collected some fruits of D. cotinifolia to South China Botanical Garden for seed germination test. It showed that gibberellin (GA3) could enhance seed germination, which indicated that the seed has dormancy period after seeds become matured. In another test, we inoculated the sterilized seeds on MS medium for in vitro culture. Half a month later, the seed germinated and the initiate cotyledons were used as explants to induce adventitious shoots. After that, an efficient in vitro propagation and regeneration system via shoot organogenesis was established from young leaf explants. Plantlets were transplanted to a mixture of sand, vermiculite, and humus (1:1:1) with 92% survived. We have totally propagated 1000 relatively strong plantlets, and they were transplanted in the mountain slopes in May of 2013 in Jinxiu Yaoshan Nature Reserve. About 452 plants were still alive after 1 year as we returned to investigate the reintroduction area. One and half years later, about 126 plants had grown up and flowered and even seed reproduction was noted. In October 2017, over 500 plantlets from cutting propagation of leaves were transplanted in Jinxiu Yaoshan Nature Reserve. Three hundred eighty plants were still alive after 1 year later, and most of them flowered and seed reproduction was also noted. These results indicated that reintroduction of D. cotinifolia was successful.