Genetics and evolution of leaf development

Origins of compound leaves

 

Although many flowering plant families contain species with compound leaves, simple-leaved plants predominate. The simplest explanation for this is that compound leaves evolved independently in several distinct angiosperm lineages. For example, tomato and potato are members of the family Solanaceae that have compound leaves, probably derived from simple-leaved solanaceous ancestors. Independently of this, an ancestral legume lineage evolved compound leaves, which were then variously modified to the bipinnate, tendrilled, or simplified forms of the species we see today.  Likewise, compound leaves were independently derived in many other dicot and monocot families. The 3 and 5-fingered yams, in the genus Dioscorea, are an example of compound-leaved monocots.

 

An alternative explanation, though less parsimonious, is that compound leaves were the ancestral angiosperm leaf form and this feature was lost in simple-leaved lineages. Fossils of Archaefructaceae, an extinct, basal angiosperm family with compound leaves, were recently uncovered in China (Figure 3). The discovery of this family, as well as the fact that compound leaves are characteristic of pre-angiosperm plants, support this alternative explanation.

 

It should be borne in mind, however, that Archaefructus lived in water. The dissected leaf morphology of Archaefructus is typical of plants with an aquatic habit.

 

 

 

Figure 3. An illustration of Archaefructus sinensis.

 

 

 

 

 

 

 

 

Please refer to these articles for further details:

Sun G, Ji Q, Dilcher DL, Zheng S, Nixon KC, Wang X  (2002). Archaefructaceae, a new basal angiosperm family. Science 296: 899-904. 

Friis EM, Doyle JA, Endress PK, Leng Q  (2003). Archaefructus - angiosperm precursor or specialized early angiosperm? Trends in Plant Science 8: 369-373.


 

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