Pollen wall stratification and pollination

Pollen and Stigma Structure and Function: The Role of Diversity in Pollination

“…Similarly, cashew trees produce four types of pollen that are comparable in dimensions, structure, and staining characteristics but different in their abilities to germinate on and penetrate the stigma (Wunnachit et al, 1992). Beyond these extreme examples, many studies have argued for pollinator preference in the evolutionary selection for a given pollen characteristic, reporting correlations between such characteristics as size or surface features and pollination by beetles, flies, bees, moths, or birds (Skvarla et al, 1978;Hesse, 2000). The evolutionary selection of other pollen characteristics appears linked to their delivery by abiotic vectors; 20% of all angiosperm families contain wind-or waterpollinated flowers (Ackerman, 2000).…”

The Pollination of Mid Mesozoic Seed Plants and the Early History of Long-proboscid Insects1,2,3

“…Pollinia are known in several angiosperm lineages, such as orchids (Micheneau et al, 2009), but do not occur in gymnosperms. Similarly, certain surface ornamentation and exine ultrastructure indicate entomophily in modern angiosperms (Osborn et al, 1991a;Hesse, 2000) and in fossil gnetophytes where taeniate pollen preferentially occur in Permian insect guts (Krassilov et al, 2007). 5.…”

Pollen morphology within theMonodoraclade, a diverse group of five African Annonaceae genera

“…For instance, pollen ornamentation has in some cases been shown to be correlated with the type of pollen vector (e.g. Hesse, 2000;Osborn et al, 1991;Tanaka et al, 2004). However, very little is known about pollinators within the Monodora clade.…”