Floral morphology and development in Aragoa (Plantaginaceae) and related members of the order Lamiales

Inflorescence and floral morphology and development were investigated in Aragoa (Plantaginaceae) and related genera. Each inflorescence of Aragoa is a reduced, axillary raceme, on which the actinomorphic floral apices generally arise successively. The inflorescences of Aragoa and Plantago are polytelic and lateral. The five sepals emerge from the abaxial to the adaxial side of the floral apex, but at maturity, the calyx is actinomorphic. The four stamens arise simultaneously and before emergence of the petals. The four petals emerge unidirectionally united, but the corolla becomes actinomorphic. Aestivation is cochlear ascendent. The two united carpels initiate simultaneously. The abaxial-adaxial inception of the calyx and corolla during early floral development in genera such as Aragoa, Digitalis, Plantago, and Veronica may indicate that the zygomorphic condition is ancestral in those genera. The tetramerous corolla, which is actinomorphic during middle and late development, and the presence of four stamens are possible synapomophies of the clade (Aragoa þ Plantago). Pentamery of the calyx and corolla appears to be plesiomorphic in the broader Aragoa- Angelonia clade. Characters related to development and morphology of inflorescences and flowers of Aragoa are essentially similar to those found in Plantago, which is consistent with the molecular-based sister group relationship between these genera.Peer reviewe

Structural colour from helicoidal cell-wall architecture in fruits of Margaritaria nobilis

The bright and intense blue-green coloration of the fruits of Margaritaria nobilis (Phyllanthaceae) was investigated using polarization-resolved spectroscopy and transmission electron microscopy. Optical measurements of freshly collected fruits revealed a strong circularly polarized reflection of the fruit that originates from a cellulose helicoidal cell wall structure in the pericarp cells. Hyperspectral microscopy was used to capture the iridescent effect at the single-cell level.This work was supported by the Leverhulme Trust (F/09- 741/G) and a BBSRC David Phillips fellowship (BB/K014617/1). P.V. acknowledges support from the US Air Force Office of Scientific Research under award number FA9550-10-1-0020. U.S. acknowledges support from the Adolphe Merkle foundation and the Swiss National Science Foundation through the National Centre of Competence in Research Bio-Inspired Materials

Sinocurculigo, a New Genus of Hypoxidaceae from China Based on Molecular and Morphological Evidence

, with eight species are distributed in China. Recently, we have found a hypoxid-like plant in China that is quite different in floral structure from any of the three genera and even of the known taxa in Hypoxidaceae. regions of 59 taxa in Hypoxidaceae and its alliance. Findings of the molecular investigation is consistent with those of the morphological analysis.

The mirror crack'd: both pigment and structure contribute to the glossy blue appearance of the mirror orchid, Ophrys speculum.

The Mediterranean orchid genus Ophrys is remarkable for its pseudocopulatory pollination mechanism; naïve male pollinators are attracted to the flowers by olfactory, visual and tactile cues. The most striking visual cue is a highly reflective, blue speculum region at the centre of the labellum, which mimics the corresponding female insect and reaches its strongest development in the mirror orchid, O. speculum. We explored the structure and properties of the much-discussed speculum by scanning and transmission electron microscopic examination of its ultrastructure, visible and ultraviolet (UV) angle-resolved spectrophotometry of the intact tissue, and mass spectrometry of extracted pigments. The speculum contrasts with the surrounding labellar epidermis in being flat-celled with a thick, smooth cuticle. The speculum is extremely glossy, reflecting intense white light in a specular direction, but at more oblique angles it predominantly reflects blue and UV light. Pigments in the speculum, dominantly the cyanidin 3-(3''-malonylglucoside), are less diverse than in the surrounding regions of the labellar epidermis and lack quercetin copigments. Several physical and biochemical processes interact to produce the striking and much-discussed optical effects in these flowers, but the blue colour is not produced by structural means and is not iridescent

The histochemistry of thiols and disulphides. IV. Protective fixation by organomercurial-formalin mixtures

Formation of mercaptides as the result of adding organomercuric salts to neutral formalin used for fixation was found to protect protein thiols from autoxidation, provided the tissues were washed in distilled and not tap water. Such bloking, in contrast to that given by HgCl 2 , could be reversed quantitatively by mercaptoethanol made strongly acid to keep it from reducing disulphides. However, some cleavage of disulphides by the mercurials themselves caused slight arbfactual thiol staining in a limited number of sites. Three of the nine compounds tested are sufficiently soluble to penetrate tissues with reasonable speed, stable enough to preclude more than incidental mercurial deposits and currently available commercially. Of them, the diuretic mercurial Mersalyl is at present the protecting, agent of choice since methyl- and ethylmercuric chlorides are too toxic to recommend for routine use.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42846/1/10735_2005_Article_BF01066541.pd