梧桐科梅蓝的研究兼论属的系统位置

梅蓝(Melhania hamiltoniana Wall．)是梅蓝属在中国的唯一代表,仅限于云南元江干热河谷一个极为有限的区域内;国外也间断出现于缅甸中部伊洛瓦底江河谷。梅蓝在形态特征和分布上是属内一个特殊的种类。梅蓝种子小,长1.5-2.5mm,子叶折扇状,2深裂;外种皮4-5层细胞厚,最外1—2层细胞显著伸长、变大,内种皮4-5层细胞厚;背腹叶,中脉维管束2束,叶柄维管束1束,圆形;气孔限于下表皮,气孔器为不等细胞型;木材管孔大小不均匀,由2或更多管孔组成复管孔,木薄壁组织极少;射线异型(Kribs IIB),具瓦形细胞;体细胞染色体数60, 属小型染色体;花粉粒球形,64.7×62.7μm,2—l孔,外壁具刺。根据梅蓝及本属的其它资料,与梧桐科和锦葵科相关类群比较,除外部形态的个别特征以外,梅蓝属的外部形态、解剖、花粉形态及染色体基数等综合特征支持梅蓝属应该保留在梧桐科Dombeyeae族,不宜移至锦葵科。

A NEW ANTITUMOR GLYCOCYCLOHEXAPEPTIDE AND ARBORANE TYPE NEW TRITERPENOIDS FROM RUBIA YUNNANENSIS

The roots of Rubia yunnanensis Diels,known as"Xiao Hong Sheng",are used as antitumor drug in Yunnan.From methanol extract of the plant,a new glycocyclohexpeptide and a cyclohexapeptide (deoxybouvadiv)with high antitumor activity,together with ten arborane type triterpenoids including seven new ones,were isolated and their structures were elucidated on the basis of spectral and chemical methods.