广义马鞭草科花器官发生的研究

Floral Organogenesis in Verbenaceae sensu lato

对广义马鞭草科 (Verbenaceae)的 3个主要亚科的花器官早期发生进行了比较研究 ,发现花器官发生的两种不同类型 :在马鞭草亚科中 ,存在从远轴至近轴单向发生的顺序 ,首先远轴位置的萼片、花瓣、雄蕊相继发生 ,此时近轴位置的萼片、花瓣和雄蕊尚未出现或处于更幼小的时期 ;在牡荆亚科和莸亚科中表现为向心轮状发生的顺序 ,萼片同时或依次出现 ,萼片发生完成后 ,有一段转向花瓣形成的时间间隔 ,5枚花瓣几乎在同一时间出现 ,随后是 4枚雄蕊同时发生。花器官发生的研究结果与形态学和rbcL序列分析所得出的系统学推断一致 ,支持马鞭草亚科和其余亚科不能形成一个单系群的观点。

The early floral ontogeny of three subfamilies, viz. Verbenoideae, Viticoideae and Caryopteridoideae of Verbenaceae (s.l.), was compared. Two differently initiated patterns were found. In the present species of Verbenoideae, there is a unidirectional sequence of organogenesis, from abaxial to adaxial side of the floral apex. While the abaxial paired sepal, petal and stamen arise sequentially, the adaxial paired sepal, petal and stamen do not appear or appear in a much earlier stage. The centripetal whorled sequence of organogenesis appears in Viticoideae and Caryopteridoideae, where sepal primordia arise simultaneously or successively (from adaxial to abaxial). After completion of sepal initiation a plastochron is indicated, during which time a change to the induction of petal takes place, and five petals appear simultaneously, followed by initiation of four stamens. Events of floral organogenesis support the phylogeny inferred from morphological data and rbcL sequence analysis, i.e. the subfamily Verbenoideae does not form a monophyletic group with the subfamilies Viticoideae and Caryopteridoideae.