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Pollen wall morphogenesis in Tragopogon porrifolius L. (Compositae: Lactuceae) and its taxonomic significance

1987; Elsevier BV; Volume: 52; Issue: 2-3 Linguagem: Inglês

10.1016/0034-6667(87)90056-x

1879-0615

Stephen Blackmore, Susan H. Barnes,

Sesquiterpenes and Asteraceae Studies

Pollen development in Tragopogon porrifolius has been studied in the scanning electron microscope to establish the origin of taxonomically significant features. As in other members of the tribe recently investigated the echinolophate condition is shown to result from differential deposition of the tetrad callose wall and, subsequently, of primexine. Tragopogon differs from other Lactuceae in the absence of tectum and columellae in the lacunae, this also appears to be the result of differential primexine deposition. The development of onci and their extrusion at the apertures are described. The contribution of developmental studies of pollen grains to systematics is discussed.