海南岛十倍体油茶资源分布及评价

Distribution and Evaluation of Decaploid Camellia Resources in Hainan Island

油茶(Camellia)作为海南岛的传统植物油料资源,在海南生长的大多为常绿中小型乔木,白花大果油茶在海南岛各地区均有广泛分布。本研究通过对海南全岛各市县分布有30龄以上油茶居群调查取样,采用流式细胞术及染色体制片技术进行倍性鉴定。研究表明:在调查采样的23个居群中,鉴定十倍体16份,八倍体7份,涵盖海南16个市县,其中有12个县市(儋州、陵水、琼海、五指山、定安、澄迈、屯昌、临高、昌江、乐东、琼中、保亭)发现了十倍体的油茶居群,超100龄以上的油茶古树及热带雨林野生油茶居群鉴定均为十倍体,而八倍体居群普遍在60龄以下且可溯源为人工栽培,此次调查居群中未发现其他倍性油茶资源。由此可见,海南岛油茶资源分布主要为十倍体和八倍体,而十倍体是本岛原生油茶资源,八倍体树龄未超60年,为20世纪60—70年代从广东等地引种的越南油茶,两类油茶生长适应性均表现良好。鉴于山茶属油茶组在其他油茶分布区并未发现十倍体油茶树种,海南岛大范围十倍体油茶的分布及热带雨林十倍体野生油茶居群的发现,论证了十倍体油茶种应是海南岛区域性原生树种,由海南独特的热带岛屿季风性气候等生态因子演化形成。其资源分布范围为海南岛18°38′42″N~19°49′53″N,108°51′0″E~110°29′46″E,海拔4.17~1090 m。

As a traditional oleaginous resource on Hainan Island,the camellia species predominantly exist as evergreen trees of small to medium stature.The large-fruit camellia with white flowers is widely distributed across various regions of Hainan Island.This study conducted a survey and sampling of camellia populations aged 30 years and above across all municipalities and counties of Hainan Island.Ploidy identification was carried out using flow cytometry and chro-mosome squashing techniques.The research revealed that among the 23 populations surveyed,16 were identified as decaploid and 7 as octoploid,covering 16 municipalities and counties across the island.Decaploid camellia populations were found in 12 counties and cities(Danzhou,Lingshui,Qionghai,Wuzhishan,Ding'an,Chengmai,Tunchang,Lingao,Changjiang,Ledong,Qiongzhong,Baoting),including ancient trees over 100 years old and wild camellia populations in tropical rainforests,all of which were identified as decaploid.In contrast,the octoploid populations were generally un-der 60 years of age and traced back to artificial cultivation,with no other ploidy camellia resources found in the sur-veyed populations.It is evident that the camellia resources on Hainan Island are primarily composed of decaploids and octoploids,with the decaploids being indigenous to the island and the octoploids,not exceeding 60 years of age,being introduced from regions such as Guangdong and Vietnam during the 1960s to 1970s.Both types of camellia have dem-onstrated good adaptability to the growth conditions.Given that decaploid camellia trees have not been found in other camellia distribution areas,the widespread distribution of decaploid camellias on Hainan Island and the discovery of decaploid wild camellia populations in tropical rainforests suggest that the decaploid camellia species are indigenous regional species of Hainan Island,evolved due to unique ecological factors such as the island’s tropical monsoon cli-mate.The distribution range of the resources spans from 18°38′42″N to 19°49′53″N and from 108°51′0″E to 110°29′46″E,at altitudes ranging from 4.17 m to 1090 m.