Abstract
The pollen coat is made up of substances secreted or released in the locule when tapetum cells disintegrate, and it fills the cavities between the baculae of the exine. The tapetum is characterized by the accumulation of lipid deposits in tapetosomes and elaioplasts. We exhibited in detail the appearance and behavior of elaioplasts and tapetosomes before and after the tapetum cells breakdown, using ultrastructural observation of wild type Arabidopsis. Furthermore, we observed the tapetum of mutants known as pollen coat less phenotype, exhibiting sterility. The cer1 mutants, a mutational loss of alkanes by impaired in the VLCFAs pathway, fused tapetosomes and elaioplasts in intact tapetam cells at the late dicellular pollen stage, although wild type fused them after tapetum breakdown. Furthermore, we indicated that the main lipid components of tapetosomes and elaioplasts are originated in MVA biosynthesis upstream of squalene.
