Cellular organisation and differentiation of organelles in pre-meiotic rice anthers

Abstract

Pre-meiotic cellular organisation of rice anthers has a great significance in pollen formation. We have used a combination of confocal laser and transmission electron microscopy (TEM) to characterise and differentiate organelles in pre-meiotic rice anthers. Along with the characteristic organelles in the cytoplasm the epidermal cells of the pre-meiotic rice anther are coated on their outer surface by a conspicuous bi-lamellate cuticle. Chloroplasts of the endothecium contain immature grana, thylakoids and also starch granules. These plastids clearly contain photosynthetic pigments as shown by autofluorescence in confocal microscope studies. Both confocal and TEM studies reveal clusters of mitochondria in the middle layer. The tapetum contains electron opaque ribosomes, bundles of mitochondria and plastids. The nuclei of the tapetum occupy a large volume of the cytoplasm indicating the onset of mitotic prophase. Intense Rhodamine 123 staining reveals that a major portion of the structurally indistinguishable organelles that were seen throughout the densely ribosomic cytoplasm of sporogenous cells are mitochondria.

A Germ Cell–Specific Gene of theARGONAUTEFamily Is Essential for the Progression of Premeiotic Mitosis and Meiosis during Sporogenesis in Rice

“…When anther walls transitioned from three-to four-layered, at which time the tapetal cells had differentiated, densely stained mitochondria became conspicuous in the cytoplasm of mutant SCs, unlike in the wild-type SCs (Figures 5A and 5B). In wild-type SCs, most mitochondria were composed of indistinct cristae and lessstained matrix ( Figure 5C) (Mamun et al, 2005). On the other hand, the inner wall cells of wild-type and mutant anthers had mitochondria with a very similar appearance, with inflated cristae and densely stained matrix ( Figures 5D and 5F).…”

Two ATP Binding Cassette G (ABCG) Transporters, OsABCG26 and OsABCG15, Collaboratively Regulate Rice Male Reproduction

“…In plant vegetative organs, such as stems and leaves, it is believed that cuticular lipid biosynthesis occurs exclusively within epidermal cells (Sieber et al, 2000;Nawrath, 2002;Panikashvili et al, 2007). Previous reports showed that plastids could not been found in anther epidermal cells (Mamun et al, 2005a(Mamun et al, , 2005b, which implies that lipid de novo synthesis cannot occur within anther epidermal cells. Therefore, it is not surprising that several tapetum-expressed lipid metabolism genes are involved in anther cuticle formation (Li et al, 2010;Shi et al, 2011;Yang et al, 2014).…”

Cellular organisation in meiotic and early post-meiotic rice anthers

“…Glutaraldehyde and paraformaldehyde fixed anthers were embedded in spur's resin, and sections were cut in series with a microtome and stained with uranyl acetate and lead citrate (Mamun et al, 2005). The sections were examined with a Zeiss 902 electron microscope at 80 kV in the Electron Microscope Unit, The University of Sydney, Australia.…”

“…Anthers were stained with Rhodamine 123 (Molecular Probes, Eugene, OR, USA) at 10 mg l ÿ1 as previously described (Mamun et al, 2005). A Zeiss LSM 410 confocal attached to a Zeiss Axiovert 200 microscope, or a Zeiss LSM 5 Pascal confocal microscope attached to a Zeiss Axiovert 200M (Carl Zeiss, Germany), was used to collect longitudinal optical sections of the anthers.…”

“…Doongara, a low-temperature sensitive Australian rice cultivar, was selected and grown in hydroponic culture medium as previously described (Mamun et al, 2005). Panicles were collected from the plants at an auricle distance of !ÿ10 mm to 0 mm, which corresponds approximately to the transition from meiocytes to tetrad microspores in rice anther development, and were placed in B & K medium (Brewbaker and Kwack, 1963) in separate vials until the anthers were transferred to fixative for microscopy.…”