珙桐的生物生态特性和人工引种促花研究

Biology and ecology characteristics and man-made promotion blossom in introduced areas of Davidia involucrata

珙桐是我国特有单型植物,世界著名的观赏树种,其自然分布区为26°45′～32°45′N,98°6′～111°20′E,垂直分布为600～3 200 m。组成珙桐林的种子植物以北温带和东亚分布属占优势,物种组成丰富,呈现多种珍稀、古老、特有成分共存一处的罕见特征。国内外引种珙桐的历史很长,最早可追溯到1871年英国丘园的Henry,截止目前,全球累计引种单位达30家以上。引种栽培区也大大拓展了天然分布界限和原有的生态环境,引种北限达55°N以北(丹麦哥本哈根),引种地海拔最低至50 m以下(郑州、北京和哥本哈根),引种土壤也从原产地的酸性土壤(pH4.5～6.5)引到了碱性土壤(pH6.5～8.4)。珙桐的开花特征也从原产地的20年以上开花结实,到通过人工嫁接缩短到5～6年可大量现花,应用原产地嫁接培育加梯度引种方法珙桐引入地开花结实获得了初步成功,可见,珙桐既是一个有待进一步驯化的物种,又是一个适应性、生态幅度有相当潜力的树种,在园林绿化中有着广阔的应用前景。

Davidia involucrate is a single type originate and famous ornamental plant in China.It distributes in north latitude 26°45′～32°45′,east longitude 98°06′～111°20′ and vertical altitude 600～3 200 m.The primary genus of seed plants in Davidia involucrate forest is genus distributed in north temperate zone and east Asia,and the community is compound with rare,ancient and special species.The introduction history abroad is long,and the earliest one was carried out by Henry in English botanical garden in 1871.There are more than 30 units introduced it so far.The introduced areas are expanded outside of its natural distribution areas and original areas,which north latitude is 55°（Copenhagen,Denmark） and altitude is lower than 50 m（Zhengzhou,Beijing and Copenhagen）,and the soil is alkaline（pH 6.5～8.4） instead of the original acid one（pH4.5～6.5）.The blossom and fruiting period is reduced from 20 years to 5～6 years by grafting in original area.Meanwhile,the blossom and fruiting in introduced areas is accomplished primarily by using graft techniques and gradient breeding.Therefore,Davidia involucrate is a species with large scope of adaptation and ecology range,and is with singnificant prospective in landscape garden.