Contribution to the Karyological Knowledge of Mediterranean Romulea Species (Iridaceae)

Eighteen chromosome counts are reported in nine Mediterranean Romulea species. Among them, four species have a wide distribution range (R. bulbocodium, R. columnae, R. ramiflora and R. rollii) and five are narrow central Mediterranean endemics (R. bocchierii, R. ligustica, R. linaresii, R. requienii and R. revelieri). Chromosome numbers range from 2n?=?3x?=?27 in one R. columnae accession to 2n?=?6x?=?54 in R. linaresii. Our results only partially agree with previous reports, and the chromosome number records of R. bocchierii, R. ligustica, R. linaresii subsp. linaresii and R. revelieri presented here are completely new. According to our data and contrary to previous statements, x?=?9 seems to be the basic chromosome number in this group of Mediterranean Romulea. Moreover, a highly significant negative correlation between the chromosome size and ploidy level was found.     

A revision of the genus Dolichos (Fabaceae,Papilionoideae, Phaseoleae), including Lesotho and Swaziland

A revision of the genus Dolichos in South Africa (Lesotho and Swaziland included) is presented. This legume genus, belonging to the bean tribe Phaseoleae, mainly has an African distribution, extending into Asia. In South Africa it is represented by nine species, two (D. sericeus and D. trilobus) of which extend into Tropical Africa. Dolichos is closely related to the genus Macrotyloma from which it can be distinguished by the short standard appendages, reticulate pollen and the generally purple flowers (standard appendages long, pollen tuberculate or spinulose and flowers yellow or orange in Macrotyloma). It also has affinities with the genera Dipogon and Lablab. The correct nomenclature, as well as complete synonymy, typification and distribution maps of all the species are provided.     

Light absorption patterns of intact Rosa flowers in relation to the flower colour

Absorption curves of fresh, intact petals from 18 rose cultivars and 2 species were measured and compared with visual evaluations of their colours and there was a reasonable correlation. The in vivo maxima of anthocyanin absorption were in the range of 520–560 nm. Five patterns of absorption spectrum in the visible region were recognized: (a) maximum range ca. 520–535 rim (red roses); (b) as (a) but low absorbance (pink roses); (c) absorption pattern varying with age of flowers; (d) absorption at long wavelengths in blue roses due to co-pigmentation of cyanin, flavonols; (e) absorption of carotenoids and anthocyanins together in yellow, orange or orange red flowers.     

Plant regeneration from seeds responds to phylogenetic relatedness and local adaptation in Mediterranean Romulea (Iridaceae) species

Seed germination is the most important transitional event between early stages in the life cycle of spermatophytes and understanding it is crucial to understand plant adaptation and evolution. However, so far seed germination of phylogenetically closely related species has been poorly investigated. To test the hypothises that phylogenetically related plant species have similar seed ecophysiological traits thereby reflecting certain habitat conditions as a result of local adaptation , we studied seed dormancy and germination in seven Mediterranean species in the genus Romulea (Iridaceae). Both the across‐species model and the model accounting for shared evolutionary history showed that cool temperatures (≤ 15°C) were the main factor that promoted seed germination. The absence of embryo growth before radicle emergence is consistent with a prompt germination response at cool temperatures. The range of temperature conditions for germination became wider after a period of warm stratification, denoting a weak primary dormancy. Altogether these results indicate that the studied species exhibit a Mediterranean germination syndrome, but with species‐specific germination requirements clustered in a way that follows the phylogenetic relatedness among those species. In addition, species with heavier seeds from humid habitats showed a wider range of conditions for germination at dispersal time than species from dry habitats possessing lighter seeds. We conclude that while phylogenetically related species showed very similar germination requirements, there are subtle ecologically meaningful differences, confirming the onset of adaptation to local ecological factors mediated by species relatedness.     

Bird-pollinated Macaronesian Lotus (Leguminosae) evolved within a group of entomophilous ancestors with post-anthesis flower color change

We analyzed the evolution of red/orange flowers in four putatively bird-pollinated species of Macaronesian Lotus, with the aim of investigating whether this floral trait evolved from a similar trait found in some entomophilous Lotus species, namely the ability to modify flower color to red after anthesis. First, we mapped the ability to modify flower color in this group on a well-resolved and densely sampled phylogenetic tree of the Macaronesian Lotus. Secondly, we determined differences in light reflectance and pigment composition between petals of (1) prechange and postchange flowers in bee-pollinated species and (2) between bee and putatively bird-pollinated species. Post-anthesis flower color change evolved three times within Macaronesian Lotus, and putatively bird-pollinated species evolved within a clade with this ability to change flower color to red after anthesis. The evolutionary transition to red/orange flowers in the putatively bird-pollinated species involved biochemical changes similar to those of the developmental transition to red postchange flowers. In both cases there are changes in the composition of flavonols and anthocyanidins within the same metabolic pathways, especially in the cyanidin branch of pigment production, but not the activation or inactivation of additional branches of this pathway. Post-anthesis color change in Lotus, from yellow to red, is thought to be an adaptation to reduce bee visits to already pollinated flowers. Our results are consistent with the hypothesis that constitutive red coloration for bird-pollination evolved from facultative red flower color change in Lotus. As red post-anthesis coloration is widespread in plants, this may possibly represent a widespread exaptive mechanism for the evolution of bird pollination.     

A new species of Dalea series Compactae (Leguminosae: Amorpheae) from northwestern Chihuahua,Mexico

Dalea janosensis, a new species from the northwestern periphery of the Mexican state of Chihuahua, is described and illustrated. It belongs to Dalea subgenus Dalea section Kuhnistera series Compactae and is morphologically similar to Dalea searlsiae, from which it differs in having a greater number of leaflets pairs, shorter peduncles, shorter spikes, persistent bracts, and shorter flowers.     

Embriogenesi nucellare in ovuli non sviluppati di alcune cultivar di arancio del gruppo navel

Abstract

Nucellar embryogenesis in undeveloped ovules in some navel orange cultivars. - Nucellar embryogenesis has been studied in some cultivars of navel orange, Citrus sinensis (L.) Osbeck. Histological observations have been carried out in undeveloped ovules excised 2, 4, 6, 8 months after anthesis. Ovules under study derived a) from flowers naturally pollinated or hand-pollinated with pollen of Poncirus trifoliata (L.) Raf.; b) from emasculated flowers, and c) from flowers deprived of stigma. In absence of pollination, as well as in absence of fertilization, the nucellar embryos reached the globular stage.     

Geissorhiza melanthera sp., nov. (Iridaceae: Crocoideae) from the southern African winter rainfall region with comments on its pollination by the bee-fly Megapalpus capensis (Bombyliidae)

The new species Geissorhiza melanthera is a member of sect. Engysiphon of subgenus Weihea and is distinguished by its beige-yellow flowers with the bases of the tepals and throat of the perianth tube bright red. The unscented flowers are zygomorphic with unilateral and declinate stamens and style extended horizontally. Its most striking feature is the black anthers with latrorse dehiscence and a portion of the connective visible on the adaxial surface. Field observations on two separate days showed the only visitor to be the bee-fly Megapalpus capensis (Diptera: Bombyliidae), which landed on the anthers and then moved toward the perianth tube, inserting its proboscis and thorax into the upper perianth tube, evidently foraging for nectar. Pollen loads on the ventral body of flies were passively transferred to receptive style branches of flowers visited later. This is the first record in Iridaceae of potentially pollinating visits by Megapalpus or any bee-fly.     

Origins of Japanese flowering cherry (Prunus subgenus Cerasus) cultivars revealed using nuclear SSR markers

Japanese flowering cherry (Prunus subgenus Cerasus) cultivars, which are characterized by beautiful flowers, have been developed through hybridization among wild Prunus taxa. The long history of cultivation has caused significant confusion over the origins of these cultivars. We conducted molecular analysis using nuclear simple sequence repeat (SSR) polymorphisms to trace cultivar origins. Bayesian clustering based on the STRUCTURE analysis using SSR genotypes revealed that many cultivars originated from hybridization between two or more wild species. This suggests that morphological variations among flowering cherry cultivars probably arose through a complex sequence of hybridizations. Our findings generally supported estimates of the origins of cultivars based on morphological study, although there were some exceptions.     

Alteration of flower color in Iris germanica L. ‘Fire Bride’ through ectopic expression of phytoene synthase gene (crtB) from Pantoea agglomerans

Key message

Genetic modulation of the carotenogenesis in I. germanica ‘Fire Bride’ by ectopic expression of a crtB gene causes several flower parts to develop novel orange and pink colors.

Abstract

Flower color in tall bearded irises (Iris germanica L.) is determined by two distinct biochemical pathways; the carotenoid pathway, which imparts yellow, orange and pink hues and the anthocyanin pathway, which produces blue, violet and maroon flowers. Red-flowered I. germanica do not exist in nature and conventional breeding methods have thus far failed to produce them. With a goal of developing iris cultivars with red flowers, we transformed a pink iris I. germanica, ‘Fire Bride’, with a bacterial phytoene synthase gene (crtB) from Pantoea agglomerans under the control of the promoter region of a gene for capsanthin–capsorubin synthase from Lilium lancifolium (Llccs). This approach aimed to increase the flux of metabolites into the carotenoid biosynthetic pathway and lead to elevated levels of lycopene and darker pink or red flowers. Iris callus tissue ectopically expressing the crtB gene exhibited a color change from yellow to pink-orange and red, due to accumulation of lycopene. Transgenic iris plants, regenerated from the crtB-transgenic calli, showed prominent color changes in the ovaries (green to orange), flower stalk (green to orange), and anthers (white to pink), while the standards and falls showed no significant differences in color when compared to control plants. HPLC and UHPLC analysis confirmed that the color changes were primarily due to the accumulation of lycopene. In this study, we showed that ectopic expression of a crtB can be used to successfully alter the color of certain flower parts in I. germanica ‘Fire Bride’ and produce new flower traits.     

Identification and expression analysis of chalcone synthase and dihydroflavonol 4-reductase in Clivia miniata

Clivia miniata is a popular breeding variety. The production of anthocyanin has been studied in Clivia species and the presence of key genes in anthocyanin production, chalcone synthase (CHS) and dihydroflavonol 4-reductase (DFR) confirmed. However, it is currently unknown to what extent these genes are expressed in different flower tissue during flower development. Thus the aim of this study was to determine the expression of CHS and DFR in C. miniata var. miniata, an orange flowered variety, and C. miniata var. citrina, a yellow flowered variety, in tepal, carpel and stamen at flower developmental stage two to six. As expected, the anthocyanin content in orange flowers was higher than that of yellow flowers. The expression of CHS and DFR correlated to anthocyanin content. Anthocyanin gene expression and production was found primarily in the tepal. There was a high correlation between CHS and DFR expression suggesting that these genes are subject to coordinate regulation in C. miniata.     

Cyanogenesis in Acacia pachyphloia

The cyanogenic glycoside, proacacipetalin, is reported from Acacia pachyphloia (Acacia subgenus Acacia). This represents the first record of a glycoside with an aliphatic aglycone from a species of Acacia indigenous to Australia. This finding reinforces the taxonomic distinctions between subgenus Acacia and subgenus Phyllodineae.     

REPRODUCTIVE MORPHOLOGY OF QUERCUS (FAGACEAE)

Details of inflorescence, floral, and fruit morphology have been studied in more than 120 species of Asiatic and American Quercus. Of the two subgenera, subgenus Cyclobalanopsis has fewer species but greater diversity of reproductive morphology than subgenus Quercus. Some character states of subgenus Cyclobalanopsis, such as more numerous stamens, male flowers sometimes grouped in dichasia, abortive ovules well developed, prominent intrusive septae in the nut, and lamellate cupules, are shared with Lithocarpus. The diversity of cupular sizes, coverage, and ornamentation raises questions about the adaptive nature, ecological function, and phylogeny of the cupule, which clearly has by now evolved as a structure with its own qualities.     

A new species of the bristletail genus Pedetontus silv. (Thysanura, Machilidae) from Thailand

A new bristletail species, Pedetontus phuketi sp. n., is described from Phuket Island, Thailand. It is most similar to P. hainanensis Yu, Zhang W.-W. et Zhang J.-Y., 2010 described from Hainan Island (China). The genus Pedetontus comprises 33 described species in two subgenera: Pedetontus s. str. (6 species) and Verhoeffilis (27 species). The subgenus Verhoeffilis has originated in the southeastern part of the Palaearctic Region. Its representatives migrated to North America in the Paleocene through the Bering Land Bridge which was sunken in the Eocene, so that the Nearctic centre of Pedetontus speciation became isolated and the subgenus Pedetontus s. str. has been formed. The Bering Land Bridge was formed at the end of the Miocene, and the backward migration of bristletails of the subgenus Pedetontus s. str. from the Nearctic to the Palaearctic occurred. Pedetontus palaearcticus was formed on Kamchatka. The southward migration of bristletails of the subgenus Verhoeffilis has led to formation of 10 Indo-Malayan species.     

Harvesting of Onion Grass,Romulea rosea L. by Sulphur‐crested Cockatoo,Cacatua galerita Latham

The harvesting of Onion Grass (Romulea rosea) corms by flocks of Sulphur‐crested Cockatoo (Cacatua galerita) is well known. Individual birds and large flocks feed on the weed in pastures, grasslands and recreational turf. Flocks of Sulphur‐crested Cockatoo were observed feeding on Onion Grass at seven sites along the Maribyrnong River at Keilor, Victoria. Flock size and feeding habits were noted, as were the depth of corms, the time taken to remove corms from the ground and the number of eaten and lifted but uneaten corms. From the data collected, it was estimated that an individual bird can extract and eat about 200 plants per hour and that even a small flock can consume several thousand plants in a feeding session. Corms were typically within 20 mm of the soil surface and were removed primarily by the cockatoo with its beak, but the left foot was sometimes used to excavate the corm from the soil. Flock feeding sessions lasted from about 0.5 to 2.5 hours, but feeding by individual or pairs of birds was often shorter. Plants that had been removed from the soil appeared to have intact corms, but all that was left were the outer scales. Of the plants removed from the soil, only 6% had intact corms attached. The removal of large numbers of Onion Grass plants could impact on their population numbers over time if there was repeated annual harvesting.     

Veronica: Acylated flavone glycosides as chemosystematic markers

HPLC/DAD and LC–MS of an extract of Veronica spicata (subgenus Pseudolysimachium, Plantaginaceae) revealed the presence of six 6-hydroxyluteolin glycosides acylated with phenolic acids, three of which are new compounds and which we called spicosides. A flavonoid survey of seven more species belonging to V. subgenus Pseudolysimachium and eight species of V. subgenus Pentasepalae showed that all the Pseudolysimachium species and four of the Pentasepalae species produced 6-hydroxyflavone glycosides, whereas the remaining four Pentasepalae species contained acetylated 8-hydroxyflavone glycosides instead. Spicosides appeared to be common in subgenus Pseudolysimachium (detected in five out of eight species), but we did not find them in subgenus Pentasepalae. Previously, acetylated 8-hydroxyflavone glycosides have been isolated from or detected in eight species of V. subgenus Pentasepalae (in 13 species altogether including the new results) and seven species of V. subgenus Pocilla. However, 6-hydroxyflavone glycosides occur in some other species of these subgenera. The results are discussed in an evolutionary context.     

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.     

Exploring the role of auxin in the androgynophore movement in Passiflora

The flowers of the species belonging to the genus Passiflorashow a range of features that are thought to have arisen as adaptations to different pollinators. Some Passiflora species belonging to the subgenus Decaloba sect. Xerogona, show touch-sensitive motile androgynophores. We tested the role of auxin polar transport in the modulation of the androgynophore movement by applying auxin (IAA) or an inhibitor of auxin polar transport (NPA) in the flowers. We recorded the movement of the androgynophore during mechano-stimulation and analyzed the duration, speed, and the angle formed by the androgynophore before and after the movement, and found that both IAA and NPA increase the amplitude of the movement in P. sanguinolenta. We hypothesize that auxin might have a role in modulating the fitness of these Decaloba species to different pollination syndromes and demonstrate that an interspecific hybrid between insect- and hummingbird-pollinated Xerogona species present a heterosis effect on the speed of the androgynophore movement.     

Analyses of cpDNA matK sequence data place Tillaea (Crassulaceae) within Crassula

Analysis of cpDNA matK sequences for a total of 43 members of the succulent plant family Crassulaceae, including 24 taxa of Crassula, recovered a well-supported clade comprising Crassula species that is sister to the remainder of the family. The resulting topologies do not support the monophyly of the currently recognized subgenera of Crassula, as one member of subgenus Disporocarpa (C. crenulata) is placed as sister to an otherwise monophyletic subgenus Crassula. The major synapomorphy that has been used to recognize the latter subgenus is a base chromosome number of x = 7 versus a base of x = 8 in the other subgenus. We cannot assess the utility of this feature for defining subgenus Crassula because a chromosome count of C. crenulata has yet to be published. The five accessions of the recently resurrected segregate genus Tillaea (of 24 total Crassula species) included here were placed in four separate, well-supported lineages, one of which is greatly removed from the other four accessions. This suggests that this genus is not valid and should not be recognized. An initial examination of the evolution of habit indicates that a perennial habit is ancestral and that the annual habit is a feature that has been derived at least twice in the genus.     

Chemical composition of the essential oil of Centaurea grinensis Reuter and Centaurea apiculata Ledeb: Growing wild in Croatia and Bulgaria,respectively and PCA analysis of subgenus Lopholoma (Cass.) Dobrocz

In the present study, the chemical composition of the essential oils from aerial parts of Centaurea grinensis Reuter (K) collected at ?uta Lova, near Senj (Croatia), and aerial parts (L1) and flowers (L2) of C. apiculata Ledeb. collected near Rebro village, near Breznik town, Znepole Region (Bulgaria), both belonging to subgenus Lopholoma (Cass.) Dobrocz, was evaluated by GC and GC-MS. The main components of K were 4-vinyl guaiacol (21.5%), hexadecanoic acid (16.2%), acetophenone (12.5%). Caryophyllene oxide (15.8%) together with sphathulenol (14.5%) and humulene epoxide II (9.4%) were recognized as the main constituent of both the aerial part (L1) and flowers (L2) of C. apiculata. Furthermore, a complete review on the composition of the essential oils of all the Centaurea taxa belonging to subgenus Lopholoma studied so far has been inserted and cluster analysis (PCA) was carried out.