A reassessment of the phylogeny and circumscription of Zaluzianskya (Scrophulariaceae).

The genus Zaluzianskya (Scrophulariaceae s.s.) encompasses a diversity of floral and ecological traits. However, this diversity, as described by the current taxonomic circumscription of Zaluzianskya, is an underestimate. We present molecular data suggesting that this genus requires expansion via incorporation of species from other genera and recognition of unnamed cryptic species. This study advances prior molecular phylogenies of the southern African genus through the addition of DNA regions and 51 populations that had not previously been sampled in a published phylogeny. A total of 82 species of Zaluzianskya and related genera are included, adding 48 to those previously sampled. Results are presented from analyses of five DNA regions, including nuclear ITS and four rapidly evolving chloroplast regions (trnL-trnF, rpl16, rps16, and trnS-trnfM). Our primary finding is that the genus Phyllopodium is polyphyletic as currently circumscribed, with some species placed within Zaluzianskya and others grouping with Polycarena, indicating the need for further phylogenetic work on these genera. Preliminary support for the incorporation of Reyemia into Zaluzianskya is reinforced here by the first molecular analysis to include both species of Reyemia and a strong sampling of species across Zaluzianskya and major clades of tribe Limoselleae. The two disjunct, tropical African species of Zaluzianskya are also confirmed as members of this genus. Finally, a broad sampling of 21 populations of Z. microsiphon establishes their phylogenetic division into two to five separate lineages. Hybridization, coevolution, and cryptic speciation may each play a role in the evolution of Z. microsiphon. Further resolution within a clade comprising sections Nycterinia and Macrocalyx is needed to better understand their relationships.

Floral scent composition predicts bee pollination system in five butterfly bush (Buddleja, Scrophulariaceae) species.

Traditionally, plant-pollinator interactions have been interpreted as pollination syndrome. However, the validity of pollination syndrome has been widely doubted in modern studies of pollination ecology. The pollination ecology of five Asian Buddleja species, B. asiatica, B. crispa, B. forrestii, B. macrostachya and B. myriantha, in the Sino-Himalayan region in Asia, flowering in different local seasons, with scented inflorescences were investigated during 2011 and 2012. These five species exhibited diverse floral traits, with narrow and long corolla tubes and concealed nectar. According to their floral morphology, larger bees and Lepidoptera were expected to be the major pollinators. However, field observations showed that only larger bees (honeybee/bumblebee) were the primary pollinators, ranging from 77.95% to 97.90% of total visits. In this study, floral scents of each species were also analysed using coupled gas chromatography and mass spectrometry (GC-MS). Although the five Buddleja species emitted differentiated floral scent compositions, our results showed that floral scents of the five species are dominated by substances that can serve as attractive signals to bees, including species-specific scent compounds and principal compounds with larger relative amounts. This suggests that floral scent compositions are closely associated with the principal pollinator assemblages in these five species. Therefore, we conclude that floral scent compositions rather than floral morphology traits should be used to interpret plant-pollinator interactions in these Asian Buddleja species.

Geographical differentiation in floral traits across the distribution range of the Patagonian oil-secreting Calceolaria polyrhiza: do pollinators matter?

BACKGROUND AND AIMS: The underlying evolutionary processes of pollinator-driven floral diversification are still poorly understood. According to the Grant-Stebbins model speciation begins with adaptive local differentiation in the response to spatial heterogeneity in pollinators. Although this crucial process links the micro- and macroevolution of floral adaptation, it has received little attention. In this study geographical phenotypic variation was investigated in Patagonian Calceolaria polyrhiza and its pollinators, two oil-collecting bee species that differ in body size and geographical distribution. METHODS: Patterns of phenotypic variation were examined together with their relationships with pollinators and abiotic factors. Six floral and seven vegetative traits were measured in 45 populations distributed across the entire species range. Climatic and edaphic parameters were determined for 25 selected sites, 2-16 bees per site of the most frequent pollinator species were captured, and a critical flower-bee mechanical fitting trait involved in effective pollination was measured. Geographical patterns of phenotypic and environmental variation were examined using uni- and multivariate analyses. Decoupled geographical variation between corolla area and floral traits related to the mechanical fit of pollinators was explored using a Mantel test. KEY RESULTS: The body length of pollinators and the floral traits related to mechanical fit were strongly correlated with each other. Geographical variation of the mechanical-fit-related traits was decoupled from variation in corolla size; the latter had a geographical pattern consistent with that of the vegetative traits and was mainly affected by climatic gradients. CONCLUSIONS: The results are consistent with pollinators playing a key role in shaping floral phenotype at a geographical scale and promoting the differentiation of two floral ecotypes. The relationship between the critical floral-fit-related trait and bee length remained significant even in models that included various environmental variables and an allometric predictor (corolla area). The abiotic environment also has an important role, mainly affecting floral size. Decoupled geographical variation between floral mechanical-fit-related traits and floral size would represent a strategy to maintain plant-pollinator phenotypic matching in this environmentally heterogeneous area.

Protocol for inducing flower color somaclonal variation in Torenia (Torenia fournieri Lind.).

White or light purple flower color Torenia (Torenia fournieri Lind.) varieties were successfully developed from the parental variety having violet flowers. This was accomplished by reducing Fe micronutrient in the culture media for the induction of in vitro flowering. The flower induction was highest in modified Murashige and Skoog (MS) medium containing ½ strength of macroelements, microelements, organic additives, and full Fe (M1) when compared to MS medium containing ½ strength of macronutrients, micronutrients, full Fe, and full organic additives (M2). The flower color was stable in two new Torenia varieties through three generations ex vitro. The results showed a wide range of somaclonal variation in flower colors; early flowering occurred in MS medium containing ½ strength of macroelements, microelements, Fe, and full strength of organic additives (M3). The selection of desirable somaclones and their micropropagation in subsequent generations led to the development of new and stable Torenia lines.

[Anatomy and adaptation to environment study of endangered alpine medical plant Neopicrorhiza scrophulariiflora].

OBJECTIVE: To study the anatomical structure of endangered alpine medical plant Neopicrorhiza scrophulariiflora and the high altitude adaptability. METHODS: The leaf epidermis character as well as section structure of leaf, aerial stem and rhizome were observed by light microscopical technique. RESULTS: The leaf surface of Neopicrorhiza scrophulariiflora was covered with two kinds of glandular hair, and the stommata was anomocytic type. Moreover, the leaf was isolateral and differed from most of alpine plant. The aerial stem had well-developed mechanical tissue. The rhizome was distributed by well-developed cork layers and collenchyma. Large numbers of aerenchymas distributed widely in leaf, aerial stem and rhizome. CONCLUSION: There existed characteristic traits in Neopicrorhiza scrophulariiflora that adapted the alpine environment, however, there still had some particular character different from other alpine plant. Thus, the adaptive style of alpine plant to high altitude environment was diversity.

Pollen tube guidance by attractant molecules: LUREs.

Sexual reproduction in flowering plants requires pollen-tube guidance, which is thought to be mediated by chemoattractants derived from target ovules. To date, however, no convincing evidence has been reported of a particular molecule being the true attractant. Emerging data indicate that two synergid cells, which are on either side of the egg cell, emit a diffusible, species-specific signal to attract the pollen tube at the last step of pollen-tube guidance. Recently, it was demonstrated that LUREs (LURE1 and LURE2), cysteine-rich polypeptides secreted from the synergid cell, are the key molecules in pollen-tube guidance. In this review, we summarize the mechanism of pollen-tube guidance, with special focus on gametophytic guidance and the attractants.

The effects of floral mimics and models on each others' fitness.

Plants that lack floral rewards may nevertheless attract pollinators by mimicking the flowers of rewarding plants. It has been suggested that both mimics and models should suffer reduced fitness when mimics are abundant relative to their models. By manipulating the relative densities of an orchid mimic Disa nivea and its rewarding model Zaluzianskya microsiphon in small experimental patches within a larger population we demonstrated that the mimic does indeed suffer reduced pollination success when locally common relative to its model. Behavioural experiments suggest that this phenomenon results from the tendency of the long-proboscid fly pollinator to avoid visits to neighbouring plants when encountering the mimic. No negative effect of the mimic on the pollination success of the model was detected. We propose that changes in pollinator flight behaviour, rather than pollinator conditioning, are likely to account for negative frequency-dependent reproductive success in deceptive orchids.

Phloem loading in two Scrophulariaceae species. What can drive symplastic flow via plasmodesmata?

To determine the driving forces for symplastic sugar flux between mesophyll and phloem, gradients of sugar concentrations and osmotic pressure were studied in leaf tissues of two Scrophulariaceae species, Alonsoa meridionalis and Asarina barclaiana. A. meridionalis has a typical symplastic configuration of minor-vein phloem, i.e. intermediary companion cells with highly developed plasmodesmal connections to bundle-sheath cells. In A. barclaiana, two types of companion cells, modified intermediary cells and transfer cells, were found in minor-vein phloem, giving this species the potential to have a complex phloem-loading mode. We identified all phloem-transported carbohydrates in both species and analyzed the levels of carbohydrates in chloroplasts, vacuoles, and cytoplasm of mesophyll cells by nonaqueous fractionation. Osmotic pressure was measured in single epidermal and mesophyll cells and in whole leaves and compared with calculated values for phloem sap. In A. meridionalis, a 2-fold concentration gradient for sucrose between mesophyll and phloem was found. In A. barclaiana, the major transported carbohydrates, sucrose and antirrhinoside, were present in the phloem in 22- and 6-fold higher concentrations, respectively, than in the cytoplasm of mesophyll cells. The data show that diffusion of sugars along their concentration gradients is unlikely to be the major mechanism for symplastic phloem loading if this were to occur in these species. We conclude that in both A. meridionalis and A. barclaiana, apoplastic phloem loading is an indispensable mechanism and that symplastic entrance of solutes into the phloem may occur by mass flow. The conditions favoring symplastic mass flow into the phloem are discussed.

The Linderniaceae and Gratiolaceae are further lineages distinct from the Scrophulariaceae (Lamiales).

The Lamiales are one of the largest orders of angiosperms, with about 22,000 species. The Scrophulariaceae, as one of their most important families, has recently been shown to be polyphyletic. As a consequence, this family was re-classified and several groups of former scrophulariaceous genera now belong to different families, such as the Calceolariaceae, Plantaginaceae, or Phrymaceae. In the present study, relationships of the genera Craterostigma, Lindernia and its allies, hitherto classified within the Scrophulariaceae, were analyzed. Sequences of the chloroplast trnK intron and the matK gene (approximately 2.5 kb) were generated for representatives of all major lineages of the Lamiales and the former Scrophulariaceae. Bayesian and parsimony analyses revealed two isolated lineages, one of which consists of Lindernia and its allies, the other of Gratiola and allies. Gratiola was previously assumed to be related to Lindernia and was therefore included here. It is proposed to treat the two clades as separate families, Linderniaceae and Gratiolaceae. For the Linderniaceae, several morphological synapomorphies exist in addition to molecular data, such as conspicuous club-shaped stamen appendages.

The cycloidea gene can respond to a common dorsoventral prepattern in Antirrhinum.

Dorsoventral asymmetry in flowers of Antirrhinum depends on expression of the cycloidea gene in dorsal regions of floral meristems. To determine how cycloidea might be regulated we analysed its expression in several contexts. We show that cycloidea is activated shortly after floral induction, and that in addition to flowers, cycloidea can be asymmetrically expressed in shoots, even though these shoots show no marked dorsoventral asymmetry. Shoots expressing cycloidea include secondary branches lying just below the inflorescence, and shoots of floricaula mutants. Asymmetric cycloidea expression may also be observed within organ primordia, such as the sepals of terminal flowers produced by centroradialis mutants. Later expression of cycloidea within flowers can be modified by mutations in organ identity genes. Taken together, the results suggest that cycloidea can respond to a common dorsoventral pre-pattern in the apex and that the specific effects of cycloidea on the flower depend on interactions with floral-specific genes.

[Parmacognostical identification of Dodartia orientalis].

The descriptions, microsopical characters, UV of Dodartia orientalis L. were studied. It can provide a basis for the identification of D. orientalis.