Botanical Studies最新文献

Background: The inconsistency between morphological and genetic evidence has consistently presented a challenge in taxonomy. The genus Aspidistra (Asparagaceae) comprises perennial herbs found primarily in eastern and southeastern Asia. This group has received limited systematic study despite the continuous publications of new species in recent years. Most species of Aspidistra have narrow distributions, and a large number of them are endemic. This study examined five Aspidistra species in Taiwan, which are part of a total of around 200 Aspidistra species found throughout Asia. In this study, we sampled all Aspidistra taxa in Taiwan to explore their phylogenetic relationships. We utilized transcriptome data for phylogenetic reconstruction and employed gene genealogy interrogation (GGI) to identify conflicts between gene trees and the species tree. Additionally, we tested nine evolutionary scenarios for these taxa by incorporating population-level genetic data. We obtained a well-supported species tree but also detected a high proportion of incomplete lineage sorting (ILS) phenomena.

Results: The results revealed that the two varieties of A. daibuensis failed to form monophyly despite morphological similarities. However, about 20.8% of the genes did not reject the topology that grouped them together. Among these genes, we identified positive signals in photosynthesis-related genes, suggesting their similarities arose from convergent evolution. Furthermore, we used a phylogenetic signal test to identify the evolutionary meaningful traits and found that the stigma width can reflect the phylogenetic relationships among these species.

Conclusions: Our study provides new insights into the evolutionary dynamics and taxonomy of Aspidistra in Taiwan, revealing key genetic and morphological patterns shaping species divergence. Phylogenetic analysis revealed substantial ILS, with numerous genes supporting alternative tree topologies. Despite morphological similarities, A. daibuensis var. daibuensis and var. longkiauensis exhibit non-monophyletic relationships, challenging their previous classification. Genes associated with chloroplastic function and photomorphogenic adaptation suggest convergent evolution. Moreover, stigma shape emerges as a robust diagnostic trait for species delimitation. These findings underscore the complex interplay of genetics, morphology, and adaptation, emphasizing the need for further integrative research.

Background and objectives: Araceae family is known for its entomophilous reproductive strategies, involving olfactory-driven pollinator attraction and diverse floral rewards. In the Neotropics, genera with unisexually-flowered inflorescences, feature short anthesis and intense thermogenesis, while those with bisexual flowers typically have longer anthesis and varied strategies. However, Monsteroideae, with short anthesis, remains an exception and is underexplored. This study focuses on the floral morphology, pollination ecology, and reproductive strategies of Stenospermation weberbaueri to enhance understanding of Neotropical aroid dynamics.

Material and methods: A natural population of S. weberbaueri was investigated in the Colombian Andes. Detailed examinations of inflorescence morphology, floral development and population phenology were conducted. Over a 1-year period, flowering and fruiting phenology were recorded, the reproductive system was assessed through controlled pollination experiments, and spadix temperatures were monitored during anthesis. Floral scent samples were collected and characterized using headspace and Gas Chromatography coupled to Mass Spectrometry methods, while pollen morphology and its position on floral visitor's body were described using scanning electron microscopy. Attractiveness assays with baited traps were employed to attract scent-oriented floral visitors.

Key results: The reproductive sequence of S. weberbaueri consists of six stages over 50 days. Anthesis, lasting three days, involves thermogenesis, spathe movements, floral chamber formation, and scent emission to attract and retain visitors. Temperature increases are synchronized with flowering, peaking at 5.4-7.2 °C above ambient during the male phase of anthesis. We identified 3-pentanol as a novel floral scent component in Araceae, which attracts Cyclanthura sp., the primary pollinators of S. weberbaueri. Controlled pollination experiments confirmed that S. weberbaueri cannot self-pollinate or undergo apomixis. We make the first report of brood-site pollination mutualism in Stenospermation and in the subfamily Monsteroideae.

Conclusions: This is the first comprehensive account of the pollination biology of genera Stenospermation, indicating a mutual dependence between S. weberbaueri and Cyclanthura sp., with weevils serving as pollen vectors and laying eggs on deciduous spathes. This BSPM in aroids, involving ectophagous and detritivorous larvae, highlights the complex interplay of floral traits-centered on long-range olfactory signals combined with putative visual and thermal signals-to attract specialized pollinators.

Background: Marine-derived microorganisms are renowned for producing structurally diverse secondary metabolites with notable biological activities, serving as a promising reservoir for pharmaceutical development. In this study, the fungal strain Westerdykella dispersa Ca4-13, isolated from the edible oyster Crassostrea angulata, was investigated for its potential anti-inflammatory and cytoprotective properties using BV-2 microglial cells as a model system.

Results: Metabolite profiling of the solid-state fermented products of W. dispersa Ca4-13 yielded seven compounds 1-7. Their structures were elucidated using NMR and MS techniques, revealing three previously undescribed cytochalasins, namely westerchalasin A (1), westerchalasin B (2), and westerchalasin C (3), along with four known compounds 4-7. Among these, westerchalasin B (2) and westerchalasin C (3) significantly exhibited nitric oxide (NO) production production in LPS-stimulated BV-2 microglial cells, with IC₅₀ values of 11.1 ± 0.4 and 9.9 ± 0.4 µM, respectively. Western blot analysis demonstrated that compounds 2 and 3 significantly downregulated inducible nitric oxide synthase (iNOS) expression at a concentration of 20 µM. Moreover, molecular docking analysis revealed that compound 3 exhibited a high binding affinity for iNOS synthase (ΔG = -18.8104 kcal/mol). The strong interaction was attributed to of hydrogen bonds between the catalytic residue Arg375 and the C-18 carbonyl group of the cycloundecene moiety, as well as Pi-alkyl interactions with Trp367, which contributed to enhanced stability of the complex.

Conclusions: This study reported the isolation and structural elucidation of three novel cytochalasins 1-3 from W. dispersa Ca4-13. Notably, compounds 2 and 3 demonstrated anti-inflammatory activity by inhibiting NO production and iNOS expression in LPS-stimulated BV-2 microglial cells. Molecular docking analysis further confirmed strong interactions between compound 3 and key iNOS residues. Given the crucial role of neuroinflammation in neurodegenerative disorders, these findings suggested that compounds 2 and 3 may possess dual neuroprotective properties, warranting further exploration for therapeutic applications.

Background: Understanding the reproductive barriers in natural plant hybrids is fundamental for comprehending mechanisms of speciation and evolutionary divergence. Most studies focus on reproductive barriers and gene exchange material between parental species, whereas fewer emphasize the biological significance of hybrid viability and their ability to interbreed with each other or with the parental species. To address this gap, the present study focuses on the hybrid Serapias x kelleri and its parental species, Serapias vomeracea and Serapias cordigera to evaluate reproductive success and the role of prezygotic and postzygotic barriers. Specifically, the purpose of this study was to investigate and evaluate the reproductive success, the biological and evolutionary implications of Serapias x kelleri, in terms of fruit production and seeds produced through hand pollination of any possible bidirectional cross combinations between hybrid plants and both parental species.

Results: Controlled manual crosses between hybrids and parental species to assess fruit and viable seed production were conducted. Results revealed no prezygotic barriers, as all pollinated flowers formed fruit. However, postzygotic barriers were evident, with significant variability in viable seed production. Hybrid self-crosses showed the lowest seed viability (0.6%), indicating strong postzygotic isolation and possible inbreeding depression. Crosses between hybrids and parental species exhibited a variable embryo production, with average values ​​ranging from 5,6% to 29,1%. Remarkable is the fact that when the hybrid acts as a pollen donor, the percentage of viable seeds with embryos is higher, with average values ​​ranging from 18.9% to 29.1%. Opposite, when the hybrid receives pollen from one of the parental species, the values ​​of viable seeds decrease dramatically, with averages that do not exceed 10%. These data clearly show an asymmetric reproductive capacity of the hybrid, with significantly higher success when acting as the pollen parent compared to the maternal parent.

Conclusions: This study emphasizes the critical role of reproductive barriers in maintaining species integrity within the Serapias genus. Natural hybrids such as S. x kelleri can facilitate gene flow between parental species. However, strong postzygotic barriers significantly limit their fertility, thereby driving evolutionary divergence and preserving the genetic identity of each species. These barriers consequently reduce the likelihood of speciation.

Background: Understanding plant adaptation to extreme environments is crucial for conservation and evolutionary biology. Ammopiptanthus mongolicus, a drought-resistant evergreen shrub native to northwestern China, provides an excellent model for studying genetic and ecological responses to arid conditions. Climatic fluctuations, especially during the Quaternary, have shaped its distribution and genetic diversity, influencing its ability to survive in desert environments. However, the mechanisms underlying its adaptation remain insufficiently explored.

Main body: We synthesize findings from previous genomic, ecological, and biogeographical studies to evaluate the adaptive mechanisms of A. mongolicus and assess the conservation implications for desert plant populations. Northwestern China encompasses vast arid regions characterized by extreme environmental conditions, including low precipitation, high evaporation rates, and significant temperature fluctuations. The uplift of the Qinghai-Tibet Plateau increased aridity by blocking moist air, leading to the transformation of humid forests into drought-resistant deserts. Ammopiptanthus mongolicus, a broad-leaved evergreen shrub, serves as a model for studying plant adaptation to arid environments. Genomic studies have identified several genes and pathways associated with drought and cold adaptation in this species. Core populations of A. mongolicus inhabit stable environments and exhibit high genetic diversity, whereas marginal populations endure extreme conditions and show strong local adaptations and distinct genetic traits. In this review, we hypothesize that the geographical distribution of core and peripheral populations may shift in response to future climate change, with peripheral populations potentially serving as sources of adaptive alleles for extreme climatic conditions.

Conclusions: Marginal populations of A. mongolicus are essential reservoirs of adaptive traits, providing genetic resources for coping with environmental stressors such as drought and cold. However, they face a higher risk of local extinction due to genetic load and habitat fragmentation. Gene flow between core and marginal populations may be crucial for maintaining genetic diversity and adaptive potential. Conservation strategies should prioritize protecting marginal populations to reduce genetic load, enhance resilience, and preserve genetic diversity in response to intensifying climate change.

Background: The cognitive decline is one of the age-associated physical dysfunctions and also found in Alzheimer's disease (AD). The whole plants of Dicliptera chinensis (L.) Nees (DC) are belonged to edible materials as fresh vegetables, and dried DC powders as tea materials or used as folk medicines for clearing heat and removing toxic substance in Taiwan. However, DC extracts and the active compounds on anti-ageing and attenuating cognitive declines are not clear.

Results: The dried powders of the whole DC plants are extracted with 95% ethanol to get DC-95EE. The DC-95EE is partitioned in sequences to get ethyl acetate fraction, butanol fraction (BuOH fraction), and water faction. Two flavone C-glycosides (vicenin II and schaftoside) are purified from the BuOH fraction. It is found that the pre-treatments of DC-95EE, BuOH fraction, and vicenin II and schaftoside show to elevate cell viabilities, reduce the senescence-associated β-galactosidase (SAβG) activity and intracellular reactive oxygen species (ROS) levels in galactose-treated SH-SY5Y neuronal cell models. The pre-treatments of vicenin II or schaftoside also show to lower ageing-associated p16 and p21 gene expressions and enhance SIRT-1 gene expressions in galactose-treated SH-SY5Y cells. The DC-95EE, vicenin II, and schaftoside show dose-dependent anti-acetylcholinesterase activities. The oral administrations of DC-95EE (200 mg/kg) and purified schaftoside (25 and 50 mg/kg) daily for 7 days ameliorate cognitive declines in scopolamine-induced ICR mice evaluated by Morris water maze. The quantification of vicenin II and schaftoside, respectively, account for 2.53% and 8.17% of DC-95EE by HPLC quantifications, which may be active compounds in the DC-95EE for anti-ageing activities.

Conclusion: The DC-95EE exhibit anti-ageing in neuron cell models and attenuate cognitive declines in mice models, which may be potentials in developing functional foods for anti-ageing purposes and need further investigations.

Background: Crop wild relatives (CWR) represent a valuable resource for ensuring food security. Although they are negatively affected by the loss of habitats due to climate change and land use change, they are underrepresented in conservation programmes. The establishment of genetic reserve (GR) networks has been put forward as an approach to protect CWR. The objective of this study was to identify CWR hotspots in Germany, which are suitable candidates for the establishment of GRs. CWR observation data were collected on a national scale from various sources and a hotspot analysis was performed to identify potential GR sites. A number of these sites were visited and the plant species occurring were recorded.

Results: 76 GR candidate sites were identified. The sites are distributed across the biogeographic regions of Germany and could conserve 73% of all CWR and 85% of the CWR that were assigned a conservation priority for Germany. Our on-site surveys for 27 GR candidates found discrepancies between the species records available and the species currently occurring.

Conclusions: We propose five hectares as an appropriate size for GRs, as such an area can be monitored and the number of stakeholders involved is usually low. The discrepancies concerning species records highlight the need for more frequent, regular nationwide CWR monitoring as a prerequisite for their conservation. Our results further suggest that GRs should also be set up outside of protected areas to protect CWR efficiently.

Background: Powdery mildews (Erysiphaceae, Ascomycota) belong to the most important plant pathogenic fungi that cause stress to forest and fruit trees and lead to a considerable loss of economic crops worldwide as well as in Taiwan. The checklist of Erysiphaceae in Taiwan is an important basis to control these pathogens. However, it has been published 25 years ago without any updating, while taxonomic concepts of genera and species changed and many new fungus and host records have been published. We update the checklist of Erysiphaceae by applying new taxonomical concepts and we add several new host records worldwide or for Taiwan based on own, recent collections.

Results: The updated checklist of powdery mildew in Taiwan is presented including data on 13 species of Erysiphaceae on 28 species of host plants. Doubtful records are marked as such and proposed for further investigation. For agricultural application, information on the usage of host plants was added to the checklist. Besides, over twenty specimens of Erysiphaceae on common plants in Taiwan recently collected by the authors were identified based on ITS sequences and anamorphic morphology. Among the collections, twelve represented new host records worldwide, while seventeen were new host records for Taiwan. Six species of Erysiphaceae were found in Taiwan for the first time.

Conclusions: The checklist of Erysiphaceae in Taiwan is an important basis for taxonomic and biogeographical studies as well as for quarantine sanctions referring to powdery mildews. Our results reveal that the host spectra of these pathogens are still incompletely known worldwide. Moreover, the list includes some doubtful old records that might be synonyms or wrong identifications. Morphological characteristics and ITS sequences are usually useful for the identification of Erysiphaceae. Several species in certain genera, however, cannot be distinguished since the variation in sequence data of those closely related species is quite low. New collections and re-investigation of old specimens are imperative to clarify some doubtful records.