Despite these differences, cycad pollen still possesses traits similar to anemophilous germplasm in that: a) it lacks a pollenkitt, a liquid fatty substance on the covering pollen grain that attracts insects in entomophilous angiosperms; b) most have an orbicule, which is a small acellular structure of sporopollenin
(Pacini et al., 1999); and c) it has a multi-layered, thick sporoderm (Pacini, et al., 1999), which enables it to withstand desiccation, possibly as a result of this gymnosperm's prolonged pollination period.
vulgaris contains 50-60% proteins and 19 amino acids that among them, there are eight essential amino acids, Vitamins ([B.sub.6], [B1.sub.2], E, and C), minerals such as potassium, sodium, magnesium, iron, copper, calcium, and selenium, methylcobalamin, sporopollenin
, and unsaturated fatty acids ([alpha]- and [gamma]-linoleic acid).
Homologs in other plants of most of these genes have been associated with the process of pollen wall development, such as suberin biosynthesis [43, 44], cutin biosynthesis [45-47], pollen sporopollenin
biosynthesis , and pollen exine formation [49-51].
Pollen is surrounded by a complex protective outer membrane called exine, that is characterized for being resistant and firm, and composed of Sporopollenin
, which are biopolymers as cutin (composed of fatty acids to protect the cell surface), suberin (polymer of long-chain fatty acids) and lignins (phenolic compounds) (Zuluaga et al., 2014).
in the cell wall of Chlorella and other algae: ultrastructure, chemistry and incorporation of 14C-acetate, studied in synchronous culture.
Palynomorphs are infact sporopollenin
bearing acid resistant microfossils  which are well preserved in a number of depositional environments like sandstone, shales, mudstones etc.
Thick and hard extine with spike and deposit of sporopollenin
began to grow from the outside of the thin and soft intine.
Although specific literature has often reported the use of additives, such as albumin and polyethylene glycol (SOARES et al., 2003), sporopollenin
(YILMAZ et al., 2010), zeolite (VIDINHA et al., 2006), calixarene derivatives (SAHIN et al., 2009), ionic liquid (SOUZA et al., 2013), the use of ionic liquids (IL) in all areas of chemical industries has an excellent prospective due to their unique properties (KESKIN et al., 2007).
Other potential sources of alkylnaphthalene include the thermal degradation of spores, coals, and sporopollenin
(Allan and Larter, 1981), and of kerogens and cyclic sesquiterpenoids present in resinous components (Anderson et al, 1992).
After the dissolution of the callose wall, the sporopollenin
wall begins to form.
Orbicules and the ektexine are homologous sporopollenin
concretions in Spermatophyta.
is as effective as cholestyramine in binding neurotoxins and more effective in binding toxic metals than any other natural substance.