木兰科植物种质超低温保存技术研究

In China, 46 Magnoliaceae taxa are critically endangered or endangered, which exceeds half of the world's critically endangered or endangered Magnoliaceae species. Most Magnoliaceae species produce non-orthodox seeds. Germination tests have been performed to determine the viability of 209 accessions of seeds of Magnoliaceae species stored in the Germplasm Bank of Wild Species (Kunming, China), 93% of which has a germination ratio of zero. This indicate that seeds of Magnoliaceae species could not be preserved in conventional seedbank. Cryopreservation is the only method for long-term preservation of species that produce non-orthodox seeds. However, reports on the cryopreservation of Magnoliaceae species are very limited . We have previously induced proembryogenic masses (PEMs) of Michelia yunnanensis and Michelia maudiae, and established cryopreservation protocol of PEMs and somatic embryo of Michelia yunnanensis. In this project, 10 Magnoliaceae species belonging to 4 genera, including endangered species and least concern species, were selected to conduct the induction of PEMs. The object of the PEMs indcution experiment is to establish PEMs cultures of at least 5 species. We then establish vitrification cryopreservation procedure for PEMs and somatic embryos of Magnoliaceae species using ‘indicator species’ strategy; and propose a primary cryopreservation procedure for zygotic embryos of Magnoliaceae species based on the cryopreservation of somatic embryos. This project provides cryopreservation procedure for the cryobanking of germplasm of Magnoliaceae species in China.

中国木兰科植物有46种处于极危和濒危状态，超过了该科植物全球极危和濒危数目的一半。木兰科植物种子多数属于非正常型。中国西南野生生物种质资源库209份低温保存的木兰科种子中93%的萌发率为零，表明常规的种子低温保存无法应用于木兰科植物。超低温保存是非正常型种子物种长期保存的唯一途径，但木兰科植物的超低温保存研究非常有限。在前期已经建立了云南含笑和深山含笑的proembryogenic masses (PEMs)、建立了云南含笑PEMs和体细胞胚的玻璃化超低温保存方案的基础上，本项目拟选择4个属中具有代表性并兼顾濒危种和受威胁程度较低的10种木兰科植物；诱导至少5个物种的PEMs；通过指示物种策略，建立起通用性的木兰科植物PEMs和体细胞胚的超低温保存方案；根据体细胞胚的超低温保存研究，给出合子胚的超低温保存方案。本研究为长期保存木兰科植物种质提供超低温保存技术方案。