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Background and Aims There are intrinsic conflicts between signalling to mutualists and concealing (camouflaging) from antagonists. Like animals, plants also use camouflage as a defence against herbivores. However, this can potentially reduce their attractiveness to pollinators. Methods Using Fritillaria delavayi , an alpine camouflaged plant with inter-population floral colour divergence, we tested the influence of floral trait differences on reproduction. We conducted pollination experiments, measured floral morphological characteristics, estimated floral colours perceived by pollinators, analysed floral scent and investigated reproductive success in five populations. Key Results We found that the reproduction of F. delavayi depends on pollinators. Under natural conditions, a flower-camouflaged population had 100 % fruit set and similar seed set to three out of four yellow-flowered populations. Bumblebees are important pollinators in the visually conspicuous yellow-flowered populations, whereas flies are the only pollinator in the flower-camouflaged population, visiting flowers more frequently than bumblebees. The camouflaged flowers cannot be discriminated from the rock background as perceived by pollinators, but may be located by flies through olfactory cues. Conclusions Collectively, our results demonstrate that the flower-camouflaged population has different reproductive traits from the visually conspicuous yellow-flowered populations. A pollinator shift from bumblebees to flies, combined with high visitation frequency, compensates for the attractiveness disadvantage in camouflaged plants. [ABSTRACT FROM AUTHOR]

When facilitating other species and sustaining plant community structures and biodiversity, alpine cushion plants simultaneously experience negative feedback effects from surrounding vegetation. However, the impact of surrounding vegetation on cushion dynamics remains poorly understood, particularly in terms of allelopathic potentials. To investigate the allelopathic potentials of surrounding vegetation on seedling establishment of the typical cushion plant Arenaria polytrichoides Edgew. along an elevational gradient, we extracted potential allelopathic compounds and tested their impacts on seed germination and seedling growth of A. polytrichoides. In addition, exclusion experiments using activated carbon were conducted to further elucidate these effects. Our results demonstrate that surrounding vegetation exhibits certain allelopathic potentials on A. polytrichoides seedling establishment, with variations observed based on elevation, source and concentration of allelopathy compounds, as well as growing season. Specifically, low-elevation vegetation exerts pronounced suppression on seedling establishment. Conversely, higher-elevation vegetation generally shows no effect on seed germination but stimulates seedling growth through allelopathy mechanisms. Moreover, aboveground vegetation predominantly inhibits both seed germination and seedling growth in low-elevation communities; however, the effects of belowground vegetation depend on elevation and extract concentration levels. The identified allelopathic potentials of surrounding vegetation significantly influence the population dynamics of cushion A. polytrichoides by potentially accelerating population degeneration in lower-elevation communities while ensuring consistent population recruitment and expansion in higher-elevation communities. [ABSTRACT FROM AUTHOR]

Nanopore sequencers can enrich or deplete the targeted DNA molecules in a library by reversing the voltage across individual nanopores. However, it requires substantial computational resources to achieve rapid operations in parallel at read-time sequencing. We present a deep learning framework, NanoDeep, to overcome these limitations by incorporating convolutional neural network and squeeze and excitation. We first showed that the raw squiggle derived from native DNA sequences determines the origin of microbial and human genomes. Then, we demonstrated that NanoDeep successfully classified bacterial reads from the pooled library with human sequence and showed enrichment for bacterial sequence compared with routine nanopore sequencing setting. Further, we showed that NanoDeep improves the sequencing efficiency and preserves the fidelity of bacterial genomes in the mock sample. In addition, NanoDeep performs well in the enrichment of metagenome sequences of gut samples, showing its potential applications in the enrichment of unknown microbiota. Our toolkit is available at https://github.com/lysovosyl/NanoDeep. [ABSTRACT FROM AUTHOR]

The prolonged interplay between orographic and climatic changes creates biogeographic barriers, resulting in the allopatric differentiation of plants in the Himalaya–Hengduan Mountains. Such consequences have led us to investigate the long-term Neogene–Quaternary geo-climatic history of the Eastern Himalaya–Hengduan Mountains. Narrowly distributed populations of Koenigia forrestii were sampled (ten populations, 97 individuals) and analysed for their genetic architecture, including phylogenetic reconstruction (based on plastome and plastid DNA/nuclear regions), molecular dating and demography, in combination with niche dynamics. We estimated that K. forrestii (stem age: 11.39 Mya) diverged into three non-overlapping distributed lineages during the Neogene–Quaternary periods (5.84–2.57 Mya), with Eastern Himalaya (EHa) being the first and most diverse lineage. 'Isolation by environment' revealed the existence of genetic structures that were significantly affected by the disparate environment. The presence of demographic events is well supported by the Bayesian skyline plot, indicating recent demographic expansion. Hence, lineage divergence and differentiation were mainly triggered by the heterogeneous environment associated with the biogeographic barriers due to the Tsangpo-Brahmaputra Grand Canyon, Mekong-Salween Divide and local mountain systems. Nevertheless, niche shift and local adaptation are the keys to determining the genetic architecture, demographic dynamics and diversification history of K. forrestii. [ABSTRACT FROM AUTHOR]

Understanding ncRNA–protein interaction is of critical importance to unveil ncRNAs' functions. Here, we propose an integrated package LION which comprises a new method for predicting ncRNA/lncRNA–protein interaction as well as a comprehensive strategy to meet the requirement of customisable prediction. Experimental results demonstrate that our method outperforms its competitors on multiple benchmark datasets. LION can also improve the performance of some widely used tools and build adaptable models for species- and tissue-specific prediction. We expect that LION will be a powerful and efficient tool for the prediction and analysis of ncRNA/lncRNA–protein interaction. The R Package LION is available on GitHub at https://github.com/HAN-Siyu/LION/. [ABSTRACT FROM AUTHOR]

Background and Aims Macro- and micromorphology of seeds are diagnostic characteristics of importance in delimiting taxa in Allium (Amaryllidaceae). However, there is no consensus on the phylogenetic significance of testa cell characteristics and whether they reflect the different evolutionary levels recognized in Allium. Methods Seeds of 95 species (98 samples) representing 14 subgenera and 58 sections of Allium were examined using scanning electron microscopy (SEM) for such traits as periclinal wall surface area of ten testa cells, distance between testa cells (macromorphology), testa cell shapes, and arrangement and structure of anticlinal and periclinal walls (micromorphology). The data matrix was subjected to cladistic analysis. The produced phylogenetic tree was examined against the molecular tree obtained from publically available ITS sequences. Key Results The periclinal wall surface area of ten testa cells and the distance between them, examined for the first time, were found useful for delimitation of species in Allium. Based on seed macro- and micromorphology, we present a taxonomic key and a hypothetical reconstruction of the migration routes during the early stages of evolution of Allium. Conclusions The ancestors of Allium originated in an area bounded by the Caucasus, Central Asia and Iran. The seed testa morphology-based evolutionary state of a species is determined by two parameters: the shape of the periclinal walls and curvature of the anticlinal walls. [ABSTRACT FROM AUTHOR]

A large number of studies have attempted to determine the mechanisms driving plant diversity and distribution on a global scale, but the diverse and endemic alpine herbs found in harsh environments, showing adaptive evolution, require more studies. Here, we selected 466 species from the genus Saussurea , one of the northern hemisphere's highest-altitude plant genera with high species richness and striking morphological traits, to explore the mechanisms driving speciation and adaptative evolution. We conducted phylogenetic signals analysis and ancestral character estimation to explore the phylogenetic significance of ecological factors. Moreover, we used spatial simultaneous autoregressive (SAR) error models, modified t -tests and partial regression models to quantify the relative effects of ecological factors and morphological diversity upon diversity and endemism of Saussurea. Phylogenetic analyses reveal that geological influences and climate stability exhibit significant phylogenetic signals and that Saussurea originated at a relatively high elevation. Regression models indicate that geological influences and climatic stability significantly affect the diversity and endemism patterns of Saussurea and its morphological innovations. Moreover, morphological innovations in an area show significant contributions to the local diversity and endemism of Saussurea. We conclude that geological influences (mean altitude and topographic heterogeneity), glacial–interglacial climate stability and phylogenetic conservatism have together promoted the speciation and adaptive evolution of the genus Saussurea. In addition, adaptively morphological innovations of alpine species also promote diversification in local regions. Our findings improve the understanding of the distribution pattern of diversity/endemism and adaptive evolution of alpine specie in the whole northern hemisphere. [ABSTRACT FROM AUTHOR]

To evaluate the phylogenetic patterns of the distribution and evolution of plant secondary metabolites (PSMs), we selected 8 classes of PSMs and mapped them onto an updated phylogenetic tree including 437 families of seed plants. A significant phylogenetic signal was detected in 17 of the 18 tested seed-plant clades for at least 1 of the 8 PSM classes using the D statistic. The phylogenetic signal, nevertheless, indicated weak clustering of PSMs compared to a random distribution across all seed plants. The observed signal suggests strong diversifying selection during seed-plant evolution and/or relatively weak evolutionary constraints on the evolution of PSMs. In the survey of the current phylogenetic distributions of PSMs, we found that multiple origins of PSM biosynthesis due to external selective forces for diverse genetic pathways may have played important roles. In contrast, a single origin of PSMs seems rather uncommon. The distribution patterns for PSMs observed in this study may also be useful in the search for natural compounds for medicinal purposes. [ABSTRACT FROM AUTHOR]

Long noncoding RNAs have been implicated in many biological processes, but their roles in liver regeneration still need to be illustrated. Therefore, we aimed to investigate the role of LINC00265 as a pivotal regulator of hepatocyte proliferation during liver regeneration. It was found that LINC00265 is significantly upregulated in rat liver tissues at various time points after 2/3 liver resection. LINC00265 knockdown inhibited hepatocyte proliferation, induced cell apoptosis and led to G2/M phase cell cycle arrestment. In rats subjected to surgery, LINC00265 knockdown decreased liver/body weight ratio, attenuated improvement from liver damage and reduced Ki67 and PCNA expression. Luciferase reporter assays confirmed that miR-28-5p was a direct target of LINC00265, and inhibition of miR-28-5p abolished the effect of LINC00265 knockdown. In summary, LINC00265 might maintain hepatocyte proliferation by targeting miR-28-5p during liver regeneration and should be considered as a promising therapeutic option for hepatocyte regeneration after liver resection. [ABSTRACT FROM AUTHOR]

Background and Aims Floral colour is a primary signal in plant–pollinator interactions. The association between red flowers and bird pollination is well known, explained by the 'bee avoidance' and 'bird attraction' hypotheses. Nevertheless, the relative importance of these two hypotheses has rarely been investigated on a large scale, even in terms of colour perception per se. Methods We collected reflectance spectra for 130 red flower species from different continents and ascertained their pollination systems. The spectra were analysed using colour vision models for bees and (three types of) birds, to estimate colour perception by these pollinators. The differences in colour conspicuousness (chromatic and achromatic contrast, purity) and in spectral properties between pollination systems and across continents were analysed. Key Results Compared with other floral colours, red flowers are very conspicuous to birds and much less conspicuous to bees. The red flowers pollinated by bees and by birds are more conspicuous to their respective pollinators. Compared with the bird flowers in the Old World, the New World ones are less conspicuous to bees and may be more conspicuous not only to violet-sensitive but also to ultraviolet-sensitive birds. These differences can be explained by the different properties of the secondary reflectance peak (SP). SP intensity is higher in red flowers pollinated by bees than those pollinated by birds (especially New World bird flowers). A transition from high SP to low SP in red flowers can induce chromatic contrast changes, with a greater effect on reducing attraction to bees than enhancing attraction to birds. Conclusions Shades of red flowers differ between pollination systems. Moreover, red bird flowers are more specialized in the New World than in the Old World. The evolution towards colour specialization is more likely to result in higher efficiency of bee avoidance than bird attraction [ABSTRACT FROM AUTHOR]

Unlike the well-understood alpine treeline, the upper range limits of tree taxa that do not reach the alpine treeline are largely unexplained. In this study, we explored the causes of the exceptionally high elevation (4270 m) occurrence of broad-leaved evergreen oaks (Quercus pannosa) in the south-eastern Himalayas. We assessed the course of freezing resistance of buds and leaves from winter to summer at the upper elevational limit of this oak species. Linked to leaf phenology, we analyzed freezing resistance and assessed minimum crown temperature for the past 65 years. We also examined potential carbon limitation at the range limit of this species. Last season buds and leaves operated at a safety margin of 5.5 and 11 K in mid-winter. Once fully dehardened early in July, last season foliage is damaged at −5.9 and new foliage at −4.6 °C. Bud break is timed for late June to early July when low temperature extremes historically were never below −3.0 °C. The monsoon regime ensures a long remaining season (149 days), thus compensating for the late onset of shoot growth. Compared with a site at 3450 m, specific leaf area is reduced, foliar non-structural carbohydrate concentrations are similar and the δ13C signal is higher, jointly suggesting that carbon limitation is unlikely at the range limit of this species. We also show that these oaks enter the growing season with fully intact (not embolized) xylem. We conclude that the interaction between phenology and freezing tolerance results in safe flushing, while still facilitating shoot maturation before winter. These factors jointly determine the upper range limit of this oak species. Our study illuminates an exceptional case of broad-leaved evergreen tree performance near the treeline, and by exploring a suite of traits, we can underpin the central role of flushing phenology in such a stressful environment. [ABSTRACT FROM AUTHOR]

Aims Bee-pollinated flowers are rarely red, presumably because bees (which lack red receptors) have difficulty detecting red targets. Although the response of bees to red colour has been investigated in lab experiments, most stimuli have been pure red, while the subtle diversity of red as perceived by humans (human-red) has received very limited attention. Here we test the hypothesis that ultraviolet (UV) reflected from human-red flowers enhances their attractiveness to bees, through increased chromatic contrast. Methods Using Onosma confertum (Boraginaceae), a plant with UV-reflecting red flowers that are pollinated by bumblebees, we investigated the effects of UV reflection on pollinator responses by conducting phenotypic manipulation experiments in the field. Colour preferences of flower-naïve bumblebees were also examined. Colour perception by bumblebees was estimated in terms of chromatic and achromatic contrast, based on two different colour perception models. Important Findings We found that both natural and flower-naïve bumblebees strongly preferred visiting UV-reflecting targets compared with UV-absorbing ones. Colour models show that the UV-reflecting flowers exhibit higher spectral purity and higher chromatic contrast against the foliage background, whereas they have similar achromatic contrast in terms of green receptor contrast. These results indicate that the component of UV reflection increases chromatic contrast in O. confertum , enhancing the visual attractiveness of these red flowers to bumblebees. We further infer that the secondary reflectance might be a necessary component in human-red flowers that are primarily pollinated by animals without red receptors, such as bees. [ABSTRACT FROM AUTHOR]

Specialized bracts of Himalayan 'glasshouse' plants are well known for adapting to diverse stresses in alpine environments, thus ensuring normal sexual reproduction. However, little information is available on how such specialized plants cope with the elevational increase in stress. In this study, we determine the elevational pattern of ultraviolet (UV) protection provided by the translucent bracts of Rheum nobile , a giant 'glasshouse' plant species, endemic to the high Himalayas, and examine its effect on pollen germination and pollen tube growth. Both UV-A and UV-B radiation in the open air increased with elevation, but their intensity beneath bracts remained constant with elevation, suggesting that the bracts of R. nobile growing at higher elevations have an increased ability to screen UV radiation. Enhanced UV-B radiation, equivalent to that experienced at higher elevations (4800 m a.s.l.) compared to that at lower elevations (4200 m a.s.l.), significantly reduced pollen germination and pollen tube growth. Pollen grains from plants at higher elevations were not more tolerant to UV-B radiation. UV absorbance and the content of flavonoids in bracts increased with elevation, but a similar trend was not found in either UV reflectance or adaxial trichome density, suggesting that bract UV absorbance may play a more active role than bract UV reflectance in helping plants cope with the increasing UV radiation. Our results indicate that the bracts of R. nobile have the ability to cope with enhanced UV radiation with increasing elevation through increased UV absorbance, thus protecting pollen grains from injury caused by higher levels of UV radiation, and consequently ensuring normal sexual reproduction in stressful high-alpine conditions. [ABSTRACT FROM AUTHOR]

Background Perennity of giant rosette species in combination with a single 'big bang' reproduction followed by death of the genetic individual is relatively rare among plants. Such long-lived monocarpic plants are usually slow growing and can be found in deserts, bogs or in alpine regions of the tropics or sub-tropics. Due to their longevity, monocarpic perennials risk losing everything before reproduction, which make them particularly susceptible to disturbances. Because of the inherent difficulties in assessing whether long-lived populations are growing or declining, usually neither their demography nor the consequences of increasing grazing pressure are known. Methods We used integral projection modelling (IPM) to measure the growth rate and passage time to flowering of Rheum nobile , a monocarpic perennial, and one of the most striking alpine plants from the high Himalayas. Rosettes which were no longer found due to disturbances or grazing by yaks were either treated as missing or as dead in two series of analysis, thereby simulating demography with and without the impact of grazing cattle. Data were collected from plants at 4500 m a.s.l. in Shangri-la County, Yunnan Province, south-west China. In four consecutive years (2011–2014) and in two populations, 372 and 369 individuals were measured, respectively, and size-dependent growth, survival and fecundity parameters were estimated. In addition, germination percentage, seedling survival and establishment probability were assessed. Key results The probability of survival, flowering and fecundity were strongly size dependent. Time to reach flowering size was 33.5 years [95 % confidence interval (CI) 21.9–43.3, stochastic estimate from pooled transitions and populations]. The stochastic population growth rate (λ s) of Rheum nobile was 1.013 (95 % CI 1.010–1.017). When disturbance by grazing cattle (yaks) was accounted for in the model, λ s dropped to values <1 (0.940, 95 % CI 0.938–0.943). Conclusion We conclude that natural populations of this unique species are viable, but that conservation efforts should be made to minimize disturbances by grazing and to protect this slow-growing flagship plant from the high Himalayas. [ABSTRACT FROM AUTHOR]

It has been hypothesized that geological and climatic changes in the Sino–Himalayan region played a significant role in evolutionary history. In this study, we tested this hypothesis by investigating the phylogeography of Excoecaria acerifolia (Euphorbiaceae), a riparian plant species that is widely distributed in the hot/warm-dry river valleys of the Sino–Himalayan region. Spatial analysis of molecular variance, a median-joining network and a Bayesian phylogenetic tree based on plastid DNA, all suggested three major lineages corresponding to the Jialing-Min-Dadu (JMD lineage), Jinsha-Yalong-Salween (JY lineage) and Yarlung Tsangpo-Mekong-Red-Nanpan (YMRN lineage) drainage basins. This was also generally supported by the results based on nuclear DNA. The divergence times of these three major lineages based on both datasets fell in the early Pleistocene, coinciding with the period of drainage reorganization events in the Sino–Himalayan region. The diversification times in the lineages were, however, dated back to the mid Pleistocene, corresponding to the Naynayxungla glaciation (0.72–0.50 Mya) and the penultimate glaciation (0.30–0.13 Mya), which were the most and second most severe glaciations in this region, respectively. Furthermore, mismatch analyses, neutrality test and ecological niche modelling suggest long-term demographic stability of the JY and JMD populations, with expansion only in the YMRN populations during the period(s) from the late penultimate glaciation (138.12 Kya) to the Last Interglacial (95.79 Kya), probably because of less extensive glaciations since the late Pleistocene and the gradually warming interglacial stage. Our study provides one of the few pieces of evidence indicating that combined historical drainage reorganization and climatic change since the Pleistocene might also have acted as important factors in the evolutionary history of riparian plants in the region. [ABSTRACT FROM AUTHOR]

In this study we aimed to delimit the boundaries of the Sibbaldia procumbens species complex, integrating morphological, geographical and molecular data at the population level. In total, 246 individuals were tested with simple sequence repeat (SSR) markers, and individuals were classified into three clusters. Stable variation in the morphology of leaflets, episepal and achenes was found between individuals from eastern and western Tibet, and this corresponds to the observed genetic structure when K = 2. The combined analysis of morphology and SSRs suggests three species should be recognized in the complex in China (S. procumbens , S. cuneata and S. aphanopetala). The ranges of these three species are mostly geographically separate from each other. Sibbaldia aphanopetala has often been treated as a variety of S. procumbens , but here we restore it to species rank. [ABSTRACT FROM AUTHOR]

Aims Understanding tree species richness at a global scale and the origin and maintenance of patterns of tree species richness across the world is crucial to preserving tree species diversity. The recently published global tree database (i.e. GlobalTreeSearch) is the only source with tree lists at both global and national scales. However, our review and assessment show that many species included in GlobalTreeSearch are not tree species. In addition, several thousands of tree species in the botanical literature have not been included in GlobalTreeSearch. The exact number of tree species in the world remains unknown. This study aims to correct errors with GlobalTreeSearch and to estimate the number of tree species in the world based on a large number of regional floras. Methods We standardized nomenclature and spellings of the species names according to The Plant List. We used 62 floristic sources, along with plant growth form and height, to assess the GlobalTreeSearch species checklist and to determine the degree to which GlobalTreeSearch incorrectly treated non-tree species as tree species. Important Findings Based on our review on 60.8% of the species in the GlobalTreeSearch database and the number of additional tree species that we have found from 62 continental, national, regional and local floristic sources, we found that about 8.7% of the species included in GlobalTreeSearch are not tree species (they are herbs, shrubs or vines). We estimate that there would be about 61 000 tree species (including approximately 5500 species that are primarily shrubs but occasionally trees) in the world. [ABSTRACT FROM AUTHOR]

Sageretia (Rhamnaceae) comprises c. 35 species of climbers and shrubs adapted to tropical and warm climates. The genus shows a disjunct distribution, with species in the Old and New Worlds. Aiming to trace the evolutionary history of Sageretia and understand its current Old–New World distribution pattern, we reconstructed phylogenetic relationships and biogeographical history of this taxon based on two nuclear (ITS, ETS) and three plastid (psbA - trnH, petA - psbJ and trnL - trnF) loci, against the backdrop of tribe Rhamneae. Phylogenetic analyses show that Sageretia is monophyletic and can be subdivided into three clades that are also supported by morphological and distributional data. Dating analyses and ancestral area reconstructions indicate that Sageretia probably originated in tropical Asia during the Eocene. Until the Miocene, it spread northwards, colonizing areas that became suitable due to the retreat of the arid belt, and it subsequently dispersed to the New World via the Beringian Land Bridge (BLB) and to Africa via Arabia. Global cooling, which began in the late Eocene, may have caused the split between the tropical Asian lineage (clade I) and its warm-range sister lineage (consisting of clades II and III), and the breaking of the BLB triggered the divergence of the warm-range lineage into Old World (clade II) and New World (clade III) lineages. [ABSTRACT FROM AUTHOR]

The East Asian flora (EAF) is a key biodiversity hotspot for understanding the origin and evolution of Northern Hemisphere floras, but there is an ongoing debate on whether it is a museum or a cradle for seed plants. Within the EAF, two main floras, the Sino-Himalayan Flora (mainly the Rhododendron Flora) and the Sino-Japanese Flora (mainly the Metasequoia Flora), have been recognized. Previous studies suggested that the EAF is ancient and the Metasequoia Flora is older than the Rhododendron Flora. To test this hypothesis, we synthesized molecular as well as fossil data on seed plants, focusing on the biogeographical origins and historical evolution of the EAF. We compared the ages of its two constituent floras, and examined the impact of the Asian monsoon and other environmental changes on the development of EAF through meta-analysis. Our results suggest that the EAF might be relatively young, with most of its clades originating since the Miocene. The Rhododendron Flora and the Metasequoia Flora are probably of a similar age. The formation and development of the Asian monsoon might have been the main factors that have driven the evolution of EAF. In the Rhododendron Flora, the north-south mountain chains increased the concentration of species and reduced extinction, and the barriers between the east and west have resulted in species differentiation, which triggered it to become a diversity center. The EAF appears to have multiple biogeographical origins, having closely affiliated not only with other floras in the Northern Hemisphere, but also with Gondwanan floras. [ABSTRACT FROM AUTHOR]

Background and Aims Although there has been much experimental work on leaf colour change associated with selection generated by abiotic environmental factors and antagonists, the role of leaf colour change in pollinator attraction has been largely ignored. We tested whether whitening of the apical leaves subtending the inflorescences of Saururus chinensis during flowering enhances pollinator attraction, and whether re-greening of the white leaves after flowering increases carbon assimilation and promotes seed development. Methods White leaves were removed or covered, and the effects of these manipulations on pollinator visitation and subsequent reproductive success were assessed. The net photosynthetic rates of leaves of different colour were measured and their photosynthetic contributions to seed development were evaluated. Key Results Saururus chinensis is able to self-pollinate autonomously, but depends largely on flies for pollination. White leaves had different reflectance spectra from green leaves, and white leaves attracted significantly more pollinators and led to significantly higher fruit and seed set. Although leaf whitening resulted in a reduction in photosynthetic capacity, it translated into only a small decrease in seed mass. When leaves had turned back from white to green after flowering their photosynthetic capacity was similar to that of 'normal' green leaves and promoted seed development. Conclusions The reversible leaf colour change in S. chinensis appears to be adaptive because it enhances pollination success during flowering, with a small photosynthetic cost, while re-greening of these leaves after flowering helps to meet the carbon requirements for seed development. [ABSTRACT FROM AUTHOR]

The evolution of species has always been a continuous process, the ideal BS should be the ultimate stage of species evolution, that is, 100% population level RI. Reproductive isolation (RI) is the core of biological species concept (BSC) [[1]]. [Extracted from the article]

Environmental conditions are known to affect the reproductive fitness of insects, as do host plants. Although the highly specialized bracts of Himalayan 'glasshouse' plants are thought to be an adaptive morphology that allows the plant to reproduce in harsh alpine environments, little information appears to exist concerning the benefit of these bracts for the pollinating insects. In this study, we examine whether the semi-translucent bracts of R heum alexandrae, a giant herb endemic to the alpine zone of the Hengduan Mountains in south-western China, enhance the reproductive fitness of its pollinator. R heum alexandrae depends mainly on mutualistic seed-consuming B radysia flies for pollination. Bracts increased interior temperature on sunny days, acted as a buffer against fluctuating air humidity, greatly decreased the intensities of ultraviolet B/ C radiation and provided shelter from strong winds. Bract removal significantly decreased adult oviposition and offspring performance of pollinators during flowering and fruiting, respectively. Our results indicate that the bracts of R. alexandrae enhance the reproductive fitness of its pollinating seed-consuming mutualist in alpine environments, which may be attributed to the positive effects of the bracts on the interior microenvironment. © 2015 The Linnean Society of London, B otanical J ournal of the L innean S ociety, 2015, 179, 349-359. [ABSTRACT FROM AUTHOR]

Background and Aims Variation in the relative female and male reproductive success of flowering plants is widespread, despite the fundamental hermaphroditic condition of the majority of species. In many hermaphroditic populations, environmental conditions and their influence on development and size can influence the gender expression of individuals through the formation of hermaphroditic and unisexual flowers. This study investigates the hypothesis that the bulbous, animal-pollinated, perennial Lilium apertum (Liliaceae) exhibits a form of size-dependent gender modification known as gender diphasy, in which the sexual expression of individuals depends on their size, with plants often changing sex between seasons. Methods Variation in floral traits was examined in relation to their size using marked individuals in natural populations, and also under glasshouse conditions. Measurements were taken of the height, flower number, floral sex expression, flower size, flower biomass and pollen production of individuals over consecutive years between 2009 and 2012 in seven populations in south-west China. Key Results Flowers of L. apertum are either perfect (hermaphroditic) or staminate (male) and, in any given season, plants exhibit one of three sex phenotypes: only hermaphrodite flowers, a mixture of hermaphroditic and male flowers, or only male flowers. Transitions between each of these sex phenotypes were observed over consecutive years and were commonly size-dependent, particularly transitions from small plants bearing only male flowers to those that were taller with hermaphroditic flowers. Hermaphroditic flowers were significantly larger, heavier and produced more pollen than male flowers. Conclusions The results for L. apertum are consistent with the ‘size advantage hypothesis’ developed for animal species with sex change. The theory predicts that when individuals are small they should exhibit the sex for which the costs of reproduction are less, and this usually involves the male phase. L. apertum provides an example of gender diphasy, a rare sexual system in flowering plants. [ABSTRACT FROM AUTHOR]

The systematic significance of the morphological structure of achenes in the Himalayan- Tibetan Plateau endemic genera Soroseris, Syncalathium and Parasyncalathium is described and discussed. The achene surface sculpturing of 15 samples representing 13 species of the three genera was investigated using scanning electronic microscopy ( SEM) to evaluate inter- and intrageneric relationships of the three genera. Characters such as cell arrangement, shape of the epidermis, type of ornamentation of the outer cell wall and degree of wax development are described. The results show that characters such as the shape of the epidermis and the type of ornamentation of the outer cell wall are distinct between the three genera and useful for species-level classification. Parasyncalathium souliei differs from Syncalathium, in which it has traditionally been placed, in the short, stout beak of the achene and especially in the obscure outline of the epidermal cells and their long acuminate, steeple-like, end walls. Combined with karyological and molecular data, the differences in achene morphology and sculpturing further support our recognition of Parasyncalathium as distinct from Syncalathium. The achene characters are not only useful for assessing relationships, but are also useful for delimiting species. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173, 476-486. [ABSTRACT FROM AUTHOR]

Background and Aims Pantropical intercontinental disjunction is a common biogeographical pattern in flowering plants exhibiting a discontinuous distribution primarily in tropical Asia, Africa and the Americas. Only a few plant groups with this pattern have been investigated at the generic level with molecular phylogenetic and biogeographical methods. Paederia (Rubiaceae) is a pantropical genus of 31 species of woody lianas, with the greatest species diversity in continental Asia and Madagascar and only two species from tropical America. The aim of this study was to reconstruct the biogeographical history of Paederia based on phylogenetic analyses to explore how the genus attained its pantropical distribution. Methods Maximum parsimony and Bayesian inference were used for phylogenetic analyses using sequences of five plastid markers (the rbcL gene, rps16 intron, trnT-F region, atpB-rbcL spacer and psbA-trnH spacer). Biogeographical inferences were based on a Bayesian uncorrelated lognormal relaxed molecular clock together with both Bayesian and likelihood ancestral area reconstructions. Key Results The data suggest an early diverged Asian lineage sister to the clade of the remaining species consisting of a predominantly Asian sub-clade and a primarily Malagasy sub-clade. Paederia is inferred to have originated in the Oligocene in tropical continental Asia. It then reached Africa in the early to middle Miocene, most probably via long-distance dispersal across the Indian Ocean. The two Neotropical species are inferred to have derived independently in the late Miocene from ancestors of Asia and East Africa, respectively. Conclusions The results demonstrate the importance of post-Boreotropical long-distance dispersals (across three major oceans) in shaping the global pantropical disjunction in some plants, such as Paederia, with small, winged diaspores adapted to long-distance dispersal by various agents including wind, ocean currents or birds. Overland migration is less likely to explain its palaeotropical disjunction between Asia and Africa. [ABSTRACT FROM PUBLISHER]

Mitchella is a small genus of the Rubiaceae with only two species. It is the only herbaceous semishrub of the family showing a disjunct distribution in eastern Asia and eastern North America, extending to Central America. Its phylogeny and biogeographical diversification remain poorly understood. In this study, we conducted phylogenetic and biogeographical analyses for Mitchella and its close relative Damnacanthus based on sequences of the nuclear internal transcribed spacer ( ITS) and four plastid markers ( rbcL, atpB-rbcL, rps16 and trnL-F). Mitchella is monophyletic, consisting of an eastern Asian M. undulata clade and a New World M. repens clade. Our results also support Michella as the closest relative to the eastern Asian Damnacanthus. The divergence time between the two intercontinental disjunct Mitchella species was dated to 7.73 Mya, with a 95% highest posterior density ( HPD) of 3.14−12.53 Mya, using the Bayesian relaxed clock estimation. Ancestral area reconstructions suggest that the genus originated in eastern Asia. The semishrub Mitchella appears to have arisen from its woody ancestor in eastern Asia and then migrated to North America via the Bering land bridge in the late Miocene. © 2013 The Linnean Society of London [ABSTRACT FROM AUTHOR]

Phylogenetic analyses were conducted for Astilbe ( Saxifragaceae), an Asian/eastern North American disjunct genus, using sequences of nuclear ribosomal internal transcribed spacer ( ITS) and plastid mat K, trnL-trn F and psb A-trnH regions. The monophyly of Astilbe is well supported by both ITS and plastid sequences. Topological incongruence was detected between the plastid and the ITS trees, particularly concerning the placement of the single North American species, A. biternata, which may be most probably explained by its origin involving hybridization and/or allopolyploidy with plastid capture. In Astilbe, all species with hermaphroditic flowers constitute a well-supported clade; dioecious species form a basal grade to the hermaphroditic clade. Astilbe was estimated to have split with Saxifragopsis from western North America at 20.69 Ma (95% HPD: 12.14-30.22 Ma) in the early Miocene. This intercontinental disjunction between Astilbe and Saxifragopsis most likely occurred via the Bering land bridge. The major clade of Astilbe (all species of the genus excluding A. platyphylla) was inferred to have a continental Asian origin. At least three subsequent migrations or dispersals were hypothesized to explain the expansion of Astilbe into North America, Japan and tropical Asian islands. The intercontinental disjunct lineage in Astilbe invokes a hybridization event either in eastern Asia or in North America. This disjunction in Astilbe may be explained by a Beringian migration around 3.54 Ma (95% high posterior density: 1.29-6.18 Ma) in the late Tertiary, although long-distance dispersal from eastern Asia to North America is also likely. The biogeographical connection between continental Asia, Taiwan, the Philippines and other tropical Asian islands in Astilbe provides evidence for the close floristic affinity between temperate or alpine south-western China and tropical Asia. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, ●●, ●●-●●. [ABSTRACT FROM AUTHOR]

Background and Aims To date, most floral nectarins (nectar proteins) are reported to function in nectar defence, particularly for insect-pollinated outcrossing species. We compared nectarin composition and abundance in selfing common tobacco (Nicotiana tobaccum) with outcrossing ornamental tobacco plants to elucidate the functional difference of nectarins in different reproductive systems. Methods Common tobacco (CT) nectarins were separated by SDS-PAGE and the N terminus of the most abundant nectarin was sequenced via Edman degradation. The full-length nectarin gene was amplified and cloned from genomic DNA and mRNA with hiTail-PCR and RACE (rapid amplification of cDNA ends), and expression patterns were then investigated in different tissues using semi-quantitative reverse transcriptase PCR. Additionally, high-performance liquid chromatography and enzymatic analyses of nectar sugar composition, and other biochemical traits and functions of the novel nectarin were studied. Key Results The most abundant nectarin in CT nectar is an acidic α-galactosidase, here designated NTα-Gal. This compound has a molecular mass of 40 013 Da and a theoretical pI of 5·33. NTα-Gal has a conserved α-Gal characteristic signature, encodes a mature protein of 364 amino acids and is expressed in different organs. Compared with 27 other melliferous plant species from different families, CT floral nectar demonstrated the highest α-Gal activity, which is inhibited by d-galactose. Raffinose family oligosaccharides were not detected in CT nectar, indicating that NTα-Gal does not function in post-secretory hydrolysis. Moreover, tobacco plant fruits did not develop intact skin with galactose inhibition of NTα-Gal activity in nectar, suggesting that NTα-Gal induces cell-wall surface restructuring during the initial stages of fruit development. Conclusions α-Gal was the most abundant nectarin in selfing CT plants, but was not detected in the nectar of strictly outcrossing sister tobacco species. No function was demonstrated in antimicrobial defence. Therefore, floral nectarins in selfing species maintain their functional significance in reproductive organ development. [ABSTRACT FROM AUTHOR]

Background and aims Pollination-induced floral changes, which have been widely documented in flowering plants, have been assumed to enhance the plant's reproductive success. However, our understanding of the causes and consequences of these changes is still limited. Using an alpine gynodioecious species, Cyananthus delavayi, we investigated the factors affecting floral closure and estimated the fitness consequences of floral closure. Methods The timings of floral closure and fertilization were determined. The effects of pollen load, pollen type (cross- or self-pollen) and floral morph (female or perfect flower) on the occurrence of floral closure were examined. Ovule fertilization and seed production were examined to investigate the causes and consequences of floral closure. Flowers were manipulated to prevent closing to detect potential benefits for female fitness. Key Results Floral closure, which could be induced by a very low pollen load, occurred within 4–7 h after pollination, immediately following fertilization. The proportion of closed flowers was influenced by pollen load and floral morph, but not by pollen type. Floral closure was more likely to occur in flowers with a higher proportion of fertilized ovules, but there was no significant difference in seed production between closed and open flowers. Those flowers in which closure was induced by natural pollination had low fruit set and seed production. Additionally, seed production was not influenced by closing-prevented manipulation when sufficient pollen deposition was received. Conclusions The occurrence of floral closure may be determined by the proportion of fertilized ovules, but this response can be too sensitive to ensure sufficient pollen deposition and can, to some extent, lead to a cost in female fitness. These results implied that the control of floral receptivity by the recipient flowers does not lead to an optimal fitness gain in C. delavayi. [ABSTRACT FROM AUTHOR]

The karyotypes of six species of Solms-laubachia and one each of Parrya and Desideria (Brassicaceae) from the Himalayan-Hengduan Mountains (Tibet, Sichuan and Yunnan provinces) were investigated. Chromosome counts of S. xerophyta, S. lanata, S. platycarpa and D. baiogoinensis are reported for the first time and found to be diploid with 2n = 14. Diploid counts were also made of S. retropilosa, a species previously known to be a tetraploid. The karyotype formulae of D. baiogoinensis, S. eurycarpa, S. pulcherrima, S. retropilosa, S. xerophyta and S. platycarpa are 2n = 14 = 6 m + 6sm + 2st, whereas those of S. lanata and P. nudicaulis are 2n = 14 = 6 m + 2sm + 6st and 2n = 14 = 8 m + 4sm + 2st, respectively. Karyotypes and counts of S. eurycarpa and S. pulcherrima are in agreement with prior studies. The relationships within Solms-laubachia and among the three genera are discussed. Speciation within Solms-laubachia may have been the result of primarily intrachromosomal variation at the diploid level, and the genus probably evolved within the Himalayan-Hengduan Mountains instead of migrating from other regions. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article which discusses the role of vitamin D metabolic enzymes expression in the reproductive system of the male.