Pollen of Jatropha L. taxonomic and phylogenetic considerations

Abstract

We present a comprehensive review of the inaperturate (omniaperuturate) pollen by light and scanning electron microscopy of the various wild and cultivated species in the genusJatropha. The genus division in the sub-generaJatrophaandCurcasas well as in sections and sub-sections is discussed in this paper. This survey has brought out the taxonomic value of subtle variations in pollen exine features in the crotonoid pattern according to (1) size, shape, ornamentation types and density of clava or pila processes; and (2) presence or absence of free processes in lumina and their number, and details of brochi and muri. We also discuss the application of these features to taxonomic and phylogenetic classifications of theJatrophaspecies investigated so far. Pollen related aspects such as pollen viability, pollen germination, pollen conservation/banks, pollen as model in vitro system, pollen haploids and use of pollen in transformation are also contemplated for Jatropha improvement.