The Intra-familial Relationships of Pentaphylacaceae s.l. as Revealed by DNA Sequence Analysis.

During the past three decades, molecular taxonomy has made considerable changes in the systematic delimitations of several families in the order Ericales which were formed earlier based on morphology. For instance, the Pentaphylacaceae s.l.

Anther development of maize (Zea mays) and longstamen rice (Oryza longistaminata) revealed by cryo-SEM, with foci on locular dehydration and pollen arrangement.

Key message: Pollen maturation in Poaceae. Another development has been extensively examined by various imaging tools, including transmission electron microscopy, scanning electron microscopy, and light microscopy, but none is capable of identifying liquid water. Cryo-scanning electron microscopy with high-pressure rapid freeze fixation is excellent in preserving structures at cellular level and differentiating gas- versus liquid-filled space, but rarely used in anther study.

Tandem oleosin genes in a cluster acquired in Brassicaceae created tapetosomes and conferred additive benefit of pollen vigor.

During evolution, genomes expanded via whole-genome, segmental, tandem, and individual-gene duplications, and the emerged redundant paralogs would be eliminated or retained owing to selective neutrality or adaptive benefit and further functional divergence. Here we show that tandem paralogs can contribute adaptive quantitative benefit and thus have been retained in a lineage-specific manner. In Brassicaceae, a tandem oleosin gene cluster of five to nine paralogs encodes ample tapetum-specific oleosins located in abundant organelles called tapetosomes in flower anthers.

Molecular taxonomy of Camellia (Theaceae) inferred from nrITS sequences.

Camellia, comprising more than 200 species, is the type genus of the family Theaceae. Currently, the interspecies relationship of the economically important genus is still a matter of great debate and controversy. In an attempt to help settle this dispute using molecular phylogeny, we analyzed ITS sequences of 112 species of Camellia.

Floral organogenesis and floral evolution of the Lecythidoideae (Lecythidaceae).

The subfamily Lecythidoideae of Lecythidaceae (Brazil nut family) is a dominant group in neotropical forests, especially those of Amazonia. New World members of the family have large showy flowers that are either polysymmetric or monosymmetric. In this study, floral organogenesis of all 10 neotropical genera was examined using SEM.

Comparative development of aseptate and septate anthers of Annonaceae.

We compared anther development in 13 genera and 15 species of Annonaceae to document the nature and development of anther septa. In aseptate anthers, all sporogenous initials proceed to sporogenesis and meiosis. In septate anthers, a small number of sporogenous initials, in a discontinuous distribution pattern, differentiate into sporogenous cells; the remaining initials become sterile and form cellular septa that partition each anther lobe into multiple sporangial chambers.

Tetrad pollen formation in Annona (Annonaceae): proexine formation andbinding mechanism.

Meiotic tetrads of Annona glabra and A. montana build up a well-developed proexine (protectum, probaculum, and pronexine) at the proximal side but only a thin pronexine at the distal side during the tetrad stage. The callosic envelope is only partially digested by the end of tetrad stage.