It has been widely accepted that oxidation is a major cause of the degeneration of the exine layer of spore and pollen grain walls. Recently this factor has come into consideration regarding the fine structure of these walls (Afzelius, 1956). Afzelius demonstrated that oxidation may change a "granular laminated structure into an amorphous granular" one, the latter showing no additional effects ...

Gibberellins (GAs) play important roles in regulating reproductive development, especially anther development. Our previous studies revealed that the MYB transcriptional factor GAMYB, an important component of GA signaling in cereal aleurone cells, is also important for anther development. Here, we examined the physiological functions of GA during anther development through phenotypic analyses ...

The highly resistant biopolymer, sporopollenin, gives the outer wall (exine) of spores and pollen grains their unparalleled strength, shielding these structures from terrestrial stresses. Despite a limited understanding of the composition of sporopollenin, it appears that the synthesis of sporopollenin occurs in the tapetum and requires the transport of one or more sporopollenin constituents to...

The classification of the genera and tribes of the monocot family Haemodoraceae has been variable and uncertain. In order to provide additional taxonomic characters, SEhl and TEhl were used in describing the pollen ultrastructure of seventeen genera and nineteen species of the family. The Haemodoraceae as a whole, with the exception oflannria and Lophioka, is palynologically united by the absen...

Pollen grains are encased by a multilayered, multifunctional wall. The sporopollenin and pollen coat constituents of the outer pollen wall (exine) are contributed by surrounding sporophytic tapetal cells. Because the biosynthesis and development of the exine occurs in the innermost cell layers of the anther, direct observations of this process are difficult. The objective of this study was to i...

Ferns spores diverse in their characteristics such as shapes, types and sizes. These characteristis are commonly used for species identification instead of the roots, stems leaves. People can use to identify ferns species. Therefore, there is a need characterize structure growing mountain Gumitir coffee plantation area. The whole mount method was spore preparations. Parameters observed were typ...

BACKGROUND AND AIMS Water adhesion forces, water absorption capacity and permeability of the pine exine were investigated to consider a possible function of sporopollenin coatings in the control of water transport. METHODS The experiments were carried out with sporopollenin capsules obtained from pine pollen consisting of an empty central capsule and two sacci. Changes in the concentration of...

BACKGROUND AND AIMS Pollen characters have been widely used in defining evolutionary trends in orchids. In recent years, information on pollination biology and phylogenetic patterns within Orchidinae has become available. Hence, the aim of the presented work is to re-evaluate exine micromorphology of Orchidinae in light of recent phylogenetic studies and to test whether pollen micromorphology s...