New insights into Trimezieae (Iridaceae) phylogeny: what do molecular data tell us?

BACKGROUND AND AIMS

The Neotropical tribe Trimezieae are taxonomically difficult. They are generally characterized by the absence of the features used to delimit their sister group Tigridieae. Delimiting the four genera that make up Trimezieae is also problematic. Previous family-level phylogenetic analyses have not examined the monophyly of the tribe or relationships within it. Reconstructing the phylogeny of Trimezieae will allow us to evaluate the status of the tribe and genera and to examine the suitability of characters traditionally used in their taxonomy.

METHODS

Maximum parsimony and Bayesian phylogenetic analyses are presented for 37 species representing all four genera of Trimezieae. Analyses were based on nrITS sequences and a combined plastid dataset. Ancestral character state reconstructions were used to investigate the evolution of ten morphological characters previously considered taxonomically useful.

KEY RESULTS

Analyses of nrITS and plastid datasets strongly support the monophyly of Trimezieae and recover four principal clades with varying levels of support; these clades do not correspond to the currently recognized genera. Relationships within the four clades are not consistently resolved, although the conflicting resolutions are not strongly supported in individual analyses. Ancestral character state reconstructions suggest considerable homoplasy, especially in the floral characters used to delimit Pseudotrimezia.

CONCLUSIONS

The results strongly support recognition of Trimezieae as a tribe but suggest that both generic- and species-level taxonomy need revision. Further molecular analyses, with increased sampling of taxa and markers, are needed to support any revision. Such analyses will help determine the causes of discordance between the plastid and nuclear data and provide a framework for identifying potential morphological synapomorphies for infra-tribal groups. The results also suggest Trimezieae provide a promising model for evolutionary research.

New constituents from the rhizomes of Egyptian Iris germanica L

Chemical investigation of the methanolic extract of the rhizomes of Iris germanica L. (Iridaceae) afforded two new compounds; irigenin S (7) and iriside A (12), together with ten known compounds: stigmasterol (1), a-irone (2), γ-irone (3), 3-hydroxy-5-methoxyacetophenone (4), irilone (5), irisolidone (6), irigenin (8), stigmasterol-3-O-β-D-glucopyranoside (9), irilone 4'-O-β-D-glucopyranoside (10) and iridin (11). Their structures were established by UV, IR, 1D (¹H and ¹³C) and 2D (¹H-¹H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to mass spectroscopic data and comparison with literature data. The methanolic extract was evaluated for its antimicrobial activity. Both the methanolic extract and the isolated flavonoids were tested for their anti-inflammatory activity.

Bacillus subtilis FZB24 affects flower quantity and quality of saffron (Crocus sativus)

The effect of Bacillus subtilis FZB24 on saffron ( Crocus sativus L.) was studied using saffron corms from Spain and the powdered form of B. SUBTILIS FZB24(R). Corms were soaked in water or in B. subtilis FZB24 spore solution for 15 min before sowing. Some corms were further soil drenched with the spore solution 6, 10 or 14 weeks after sowing. Growth and saffron stigma chemical composition were measured. Compared to untreated controls, application of B. subtilis FZB24 significantly increased leaf length, flowers per corm, weight of the first flower stigma, total stigma biomass; microbe addition also significantly decreased the time required for corms to sprout and the number of shoot sprouts. Compared to the controls, picrocrocin, crocetin and safranal compounds were significantly increased when the plants were soil drenched with the spore solution 14 weeks after sowing; in contrast crocin was highest in untreated controls. Results of this study suggest that application of B. subtilis FZB24 may provide some benefit to saffron growers by speeding corm growth (earlier shoot emergence) and increasing stigma biomass yield by 12 %. While some treatment conditions also increased saffron chemical composition, these were generally not the same treatments that simultaneously improved growth yields and thus, more study is required.

The role of beetle marks and flower colour on visitation by monkey beetles (hopliini) in the greater cape floral region, South Africa

BACKGROUND AND AIMS

A deviation from the classical beetle pollination syndrome of dull-coloured flowers with an unpleasant scent is found in the Greater Cape Floral Region of South Africa. Here, monkey beetles (Scarabaeidae) visit brightly coloured, odourless flowers with conspicuous dark spots and centres (beetle marks). The role of flower colour and markings in attracting monkey beetles is still poorly understood.

METHODS

Artificial model flowers with different marking patterns were used to test the effect of beetle marks on visitation by monkey beetles. To test whether monkey beetles are conditioned to the colour of the local matrix species, model flowers of different colours were placed in populations of three differently coloured species of Iridaceae.

KEY RESULTS

Among all three matrix species the presence of dark markings of some kind (either centres or spots) increased visitation rates but the different matrix species differed in whether the effect was due to a dark centre or to dark spots. Monkey beetles were not conditioned for the colour of the matrix species: model colour was not significant in the Hesperantha vaginata and in the Romulea monadelpha matrices, whereas yellow model flowers were preferred over orange ones in the orange-flowered Sparaxis elegans matrix.

CONCLUSIONS

This study is the first to demonstrate that beetle marks attract pollinating monkey beetles in the Greater Cape Floral Region. In contrast to plants with the classical beetle pollination syndrome that use floral scent as the most important attractant of pollinating beetles, plants with the monkey beetle pollination syndrome rely on visual signals, and, in some areas at least, monkey beetles favour flowers with dark beetle markings over unmarked flowers.