Anatomical study of the anther in Peganum harmala L. (Zygophyllaceae)

Abstract

The species Peganum harmala L. belong to the family Zygophyllaceae. This species is widely distributed in Libya as medicinal and poisonous plant. This study deals with anatomical structure of the anthers as well as the pollen development, through different stages of growth. The results of this study showed that the anther consist of 4-pollen sacs (tetrasporongiate), its wall development follows the dicotyledonous type. The anther wall consists of four types of different cell layers, these are, epidermis with one layer of cells, endothecium with radial fibrous thickening at maturity leading to the connection of each two sporangia, the anther splits longitudinally to shade out the pollen grains. The middle layer with 1-3 rows of cells, and tapetum with one layer of multinucleate irregular cells, the phenomena of cytomixis was observed. The sporogenous tissue under go meiosis resulting microspore tetrads, the microspore tetrads are of three types: tetrahedral, decussate, and isobilateral shapes. The pollen grains are tricolporate, ornamented, highly striped exine, and two-celled when shed out the anthers. The in situ germination of some pollen grains was observed.