Diversity, development and evolution of archegonia in land plants

We review the diversity and development of archegonia, the female reproductive organs of land-plant gametophytes. The archegonium is a uniquely land-plant structure, and studies of its evolution benefit from use of a comparative approach in a phylogenetic context. Archegonia of most land plants share a common developmental motif, here termed a T-shaped pattern. A primary axial cell produces a primary cover cell and a central cell by horizontal division. The upper cell usually divides vertically and the lower one horizontally. In mosses such as Atrichum, the T-shaped stage is shifted towards the end of archegonium development, whereas in vascular plants it appears at the beginning of development, but these stages are still probably homologous. The fully exposed archegonia are traditionally viewed as an ancestral (plesiomorphic) condition in land plants, but there is no direct support for this view. We speculate that the fully exposed condition is derived and synapomorphic for setaphytes (mosses and liverworts). The fully sunken hornwort archegonia may be similar to the ancestral type of land-plant archegonia. Developmental evidence suggests that archegonium necks of setaphytes and tracheophytes are not homologous to each other. The neck wall of pteridophytes is composed of four-celled tiers, and one such tier is present in gymnosperms with motile male gametes. Neck-cell arrangement is much more plastic in archegonia of gymnosperms with sperm cell delivery by pollen tube (siphonogamy), in which the neck plays a role similar to pollen-tube transmitting tissue of angiosperms. Angiosperm synergids are probably homologues of gymnosperm neck cells, and the angiosperm egg cell is probably homologous to the ventral canal cell of gymnosperms. Developmental genetic bases of archegonium diversity in land plants remain to be understood. Even descriptive developmental data are currently missing or controversial for some key lineages of land plants.

Comparison of Sonication with Maceration on Antioxidant Potency of Anthocyanin and Karotenoid of Tamarillo (Solanum betaceaum Cav.)

Tamarillo is an underutilized fruit in Indonesia, despite the fact that it contains two pigments (anthocyanin and carotenoid) with different properties (polar and non polar). Besides, there is a scarce information about extraction of anthocyanin and carotenoid of Tamarillo using sonication extraction. This study was aimed to investigate the comparison of extraction methods of sonication with maceration on antioxidant potency of anthocyanin and carotenoid of Tamarillo. Two pigmen types (anthocyanin and carotenoid) were extracted using two different methods (sonication and maceration). The parameters of analysis were yield, antioxidant activity (DPPH) with IC50, Ferric Reducing Antioxidant Power (FRAP), anthocyanin total, carotenoid total, phenolic total and scanning electron microscope of cover cell of material. The antioxidant potencies for both anthocyanin and carotenoid by sonication method were higher than those of obtained by maceration method. The results showed that both sonication and maceration were suitable for extraction of anthocyanin and carotenoid from Tamarillo.

Haraldiophyllum erosum comb. nov. (Delesseriaceae, Rhodophyta) from Southern and Western Australia

Nitophyllum erosum Harvey (Delesseriaceae, Rhodophyta) is a branched, monostromatic red alga that is readily recognised by its distinctive fringe of branched, multicellular processes. It has been considered to be a member of the genus Myriograrnrne Kylin, since it was thought to have carposporangia borne in short chains, a feature partially diagnostic for that genus. Recent collections of female and cystocarpic material have allowed us to ascertain the structure of the procarp, a feature important in generic placement. The procarp includes two periaxial cells, of which one acts as a cover cell while the other functions as the supporting cell, ultimately bearing two sterile cell groups and a four-celled carpogonial branch. In addition, the carposporophyte includes a distinctive fusion cell that incorporates gametophytic cells from the floor of the cystocarpic cavity, and the carposporangia are single and terminal on gonimoblast filaments. This combination of characters is diagnostic of the genus Haraldiophyllurn, a genus to which we transfer this species as Haraldiophyllum erosurn (Harvey) Millar & Huisman. comb. nov.