Podophyllum peltatum) have been shown to be strongly heteroblastic (Holm, 1899; Jones & Watson, 2001) during the development of the leaf series, which consists of rhizome scales, bud scales, and a single or two foliage leaves in vegetative and reproductive shoots, respectively (Jones, 2001).
The spines of the long shoots might play a role in preventing predation, as it has been demonstrated in several spiny, heteroblastic species found mainly on islands (McGlone & Webb, 1981; Givnish et al., 1994; Bums & Dawson, 2006, 2009; among others).
orthologs of the factors controlling abaxial-adaxial and proximal-distal differentiation, as well as genes involved in leaf complexity will shed light on the regulation and conservation of these genetic modules in a heteroblastic species.
To demonstrate that heteroblastic changes are indeed functionally important under current ecological conditions, we face a prominent problem, since different processes are likely to co-occur during ontogeny.
The term "heteroblastic" (condition: 'heteroblasty') [from Greek blastos, shoot] was originally introduced by Goebel to describe a form of plant development, in which substantial differences between earlier ("Jugendform" = juvenile form) and later stages ("Folgeform", subsequent form) are observed as opposed to the "homoblastic" type of development with small and gradual changes (Goebel, 1898, 1913).
The consistency over three years in the position along the shoot of different leaf shapes suggests that the pattern of heteroblastic expression is not highly sensitive to yearly environmental fluctuation under these growth conditions.
A heteroblastic series of shape changes such as that in sororia, from less-lobed to lobed leaves, may have several functional consequences for the plant (see also Ray, 1990).
Changes of timing and rate of cell division during leaf development are the major developmental causes that lead to the formation of heteroblastic leaves on the same stem in some plants (Dengler, 1992; Kaplan, 1973a, 1980; Richards, 1983).
Comparative developmental analysis of the heteroblastic leaf series of axillary shoots of Acorus calamus L.