Plant Diversity最新文献

Plants and their interaction partners offer unparalleled views of evolutionary ecology. Nectar larceny, entailing nectar extraction without pollinating, is thought to be an example of a harmful, antagonistic behavior, but the precise consequences of floral larceny on plant reproductive success remain contentious. We conducted a comprehensive meta-analysis of 153 studies across 120 plant species, using 14 moderators to assess the effects of floral larceny on plant reproductive success and examine the key moderators. We found that floral larceny negatively impacts flower traits, pollinator visitation, pollen deposition, and fruit set, while having a neutral effect on critical female fitness indicators, such as seed set and seed quality, as well as on male fitness. By altering pollinator behavior, floral larceny may reduce geitonogamy, potentially enhancing genetic diversity. Additionally, factors such as pollinator type, plant mating system, and pollen limitation were identified as key moderators of these effects. Our analysis reveals an ultimately neutral effect of floral larceny on plant reproductive success, with potential benefits in certain contexts. These findings suggest that floral larceny plays a complex and multifaceted role within plant-pollinator interactions, facilitating the evolutionary stability and coexistence of floral larcenists and host plants.

Exotic plant invasions and increased atmospheric carbon dioxide (CO₂) concentration have been determined to independently affect soil nematodes, a key component of soil biota. However, little is known about the long-term effects of these two global change factors and their interactive effects. Over three consecutive years, we cultivated invasive alien plant Xanthium strumarium and its two phylogenetically related natives under both ambient (aCO₂) and elevated (eCO₂) atmospheric CO₂ concentrations, and determined the effects of the invader and natives on soil nematodes under different CO₂ concentrations and the relevant mechanism. The abundance of total soil nematodes and that of the dominant trophic group (herbivores) were significantly affected by plant species and CO₂ concentration, and these effects were dependent on the experimental duration, however, the Shannon-diversity of nematodes was not affected by these factors. Under aCO₂, both invasive and native species significantly increased the total nematode abundance and that of the dominant trophic group with increasing experimental duration, and the amplitude of the increase was greater under the invader relative to the natives. The eCO₂ increased total nematode abundance (second year) and that of the dominant trophic group (third year) under the invader, but not under the natives (or even decreased) with increasing experimental duration. Root litter had greater effects on soil nematode abundance than leaf litter and root exudates did. This study indicates that eCO₂ would aggravate effects of invasive plants on soil nematodes by increasing abundance, and these effects would vary with the duration.

The island rule, a general pattern of dwarfism in large species to gigantism in small species on islands relative to mainland, is typically seen as a macroevolutionary phenomenon. However, whether the ecological processes associated with abiotic and biotic factors generate a pattern of plant size variation similar to the island rule remains unknown. We measured plant height for 29,623 individuals of 50 common woody plant species across 43 islands in the Zhoushan Archipelago (8500 years old and yet to undergo major evolutionary adaptation) and the adjacent mainlands in China. We found pronounced variations in plant height, similar to those of the island rule. Interestingly, islands with low resource availability, such as low soil organic matter content and low precipitation, had a high degree of dwarfism; islands experiencing high environmental stress, such as high soil pH, had a high degree of dwarfism; and islands experiencing less plant-plant competition had a high degree of gigantism. The magnitude of plant dwarfism was higher on small and remote islands than on larger and nearer islands. These results highlight the importance of ecological processes associated with abiotic and biotic conditions in shaping the island rule-like patterns of plant size variation. Since our studied archipelago is too young to undergo major evolution, ecological processes likely played a prominent role in generating the observed pattern, challenging the notion that the evolutionary process is the dominant factor underlying the island rule. Future studies on the island rule need to perform experiments to disentangle evolutionary from ecological mechanisms.

The future distribution of invading species depends on the climate space available and certain life history traits that facilitate invasion. Here, to predict the spread potential of plant species introduced in North America north of Mexico (NAM), we compiled distribution and life history data (i.e., seed size, life form, and photosynthetic pathways) for 3021 exotic plant species introduced to NAM. We comparatively examined the species' range size and climate space in both native and exotic regions and the role of key life history traits. We found that large climate space for most exotic plants is still available in NAM. The range sizes in global exotic regions could better predict the current range sizes in NAM than those in global native regions or global native plus exotic regions. C3 species had larger ranges on average than C4 and CAM plants, and herbaceous species consistently showed stronger relationships in range size between native and exotic regions than woody species, as was the case within the C3 species group. Seed size was negatively related to range size both in native regions and in NAM. However, seed size surprisingly showed a positive correlation with global exotic range size and no correlation with the current actual global (native plus exotic) range size. Our findings underline the importance of species' native distribution and life history traits in predicting the spread of exotic species. Future studies should continue to identify potential climate space and use underappreciated species traits to better predict species invasions under changing climate.

Integrative data from plastid and nuclear loci are increasingly utilized to resolve species boundaries and phylogenetic relationships within major angiosperm clades. Debregeasia (Urticaceae), an economically important genus, presents challenges in species delimitation due to its overlapping morphological traits and unstable taxonomic assignments. Here, we analyzed 14 morphological traits and generated 12 data matrices from the plastomes and nrDNA using genome skimming from the nine recognized morphospecies to clarify species boundaries and assess barcode performance in Debregeasia. We also used a universal set of 353 nuclear genes to explore reticulate evolution and biogeographic history of Debregeasia. Plastomes of Debregeasia exhibited the typical quadripartite structure with conserved gene content and marginal independent variations in the SC/IR boundary at inter- and intra-specific levels. Three Debregeasia species were non-monophyletic and could not be discerned by any barcode; however, ultra-barcodes identified the remaining six (67%), outperforming standard barcodes (56%). Our phylogenetic analyses placed Debregeasia wallichiana outside the genus and suggested six monophyletic clades in Debregeasia, although the placement between Debregeasia hekouensis and Debregeasia libera varied. There was extensive trait overlap in key morphologically diagnostic characters, with reticulation analysis showing potentially pervasive hybridization, likely influenced by speciation patterns and overlaps between species ranges. We inferred that Debregeasia crown diversification began at ca. 12.82 Ma (95% HPD: 11.54-14.63 Ma) in the mid-Miocene within Australia, followed by vicariance and later long-distance dispersal, mainly out of southern China. Our findings highlight the utility of genomic data with integrative lines of evidence to refine species delimitation and explore evolutionary relationships in complex plant lineages.

Invasive alien species (IAS) significantly threaten global biodiversity and ecosystem stability. Despite increasing management efforts, a critical knowledge gap existed in understanding commonalities and disparities among national strategies. We analyzed several IAS management lists from 23 countries and the European Union, focusing specifically on vascular plant species within these lists. List composition, characteristics, and associated management measures were analyzed. Key patterns in species prioritization across national lists and intercontinental exchange of invasive alien plants (IAPs) were identified. Pistia stratiotes, Pontederia crassipes, Salvinia molesta, Cabomba caroliniana, Ulex europaeus were identified as globally recognized threats, being listed by at least 33.3% of analyzed countries and invading five or more continents. Aquatic plants were found to be more frequently included in management lists. A significant directional invasion pattern between the Eastern and Western Hemispheres was identified. Species native to Asia were observed to dominate as significant donors of IAPs across continents. The analysis of list management strategies highlighted substantial gaps in achieving Target 6 of the Kunming-Montreal Global Biodiversity Framework, particularly in species prioritization and inclusion of potential IAPs. In response to these challenges, a tiered classification system for invasive alien species list was proposed, encompassing High-Priority, Watchlist, Potential, and Priority Site categories, which aimed at enhancing management effectiveness by tailoring strategies to different invasion stages and ecological contexts. This study could contribute to understanding global IAPs management strategies and serve as a reference for policymakers and conservation managers to identify priority IAPs and refine management approaches.

Latitudinal patterns of tree β-diversity reveal important insights into the biogeographical processes that influence forest ecosystems. Although previous studies have extensively documented β-diversity within relatively small spatial extents, the potential drivers of β-diversity along latitudinal gradients are still not well understood at larger spatial extents. In this study, we determined whether tree β-diversity is correlated with latitude in forests of southeastern China, and if so, what ecological processes contribute to these patterns of tree β-diversity. We specifically aimed to disentangle the relative contributions from interspecific aggregation and environmental filtering across various spatial extents. We delineated regional communities comprising multiple nearby national forest inventory (NFI) plots around random focal plots. The number of NFI plots in a regional community served as a surrogate for spatial extent. We also used a null model to simulate randomly assembled communities and quantify the deviation (β-deviation) between observed and expected β-diversity. We found that β-diversity decreased along a latitudinal gradient and that this pattern was clearer at larger spatial extents. In addition, latitudinal patterns of β-deviation were explained by the degree of species spatial aggregation. We also identified environmental factors that drive β-deviation in these forests, including precipitation, seasonality, and temperature variation. At larger spatial extents, these environmental variables explained up to 84% of the β-deviation. Our results reinforce that ecological processes are scale-dependent and collectively contribute to the β-gradient in subtropical forests. We recommend that conservation efforts maintain diverse forests and heterogeneous environments at multiple spatial extents to mitigate the adverse effects of climate change.

Single-stranded DNA-binding proteins (SSBs) play essential roles in the replication, recombination and repair processes of organellar DNA molecules. In Arabidopsis thaliana, SSBs are encoded by a small family of two genes (SSB1 and SSB2). However, the functional divergence of these two SSB copies in plants remains largely unknown, and detailed studies regarding their roles in the replication and recombination of organellar genomes are still incomplete. In this study, phylogenetic, gene structure and protein motif analyses all suggested that SSB1 and SSB2 probably diverged during the early evolution of seed plants. Based on accurate long-read sequencing results, ssb1 and ssb2 mutants had decreased copy numbers for both mitochondrial DNA (mtDNA) and plastid DNA (ptDNA), accompanied by a slight increase in structural rearrangements mediated by intermediate-sized repeats in mt genome and small-scale variants in both genomes. Our findings provide an important foundation for further investigating the effects of DNA dosage in the regulation of mutation frequencies in plant organellar genomes.

Rivers are crucial in the spread of invasive plants. Invasive plants alter their seed traits to adapt to environmental changes and promote invasion. Studying the trait changes in invasive plant seeds may improve the understanding of their propagation mechanisms along the river and provide appropriate control measures. In this study, seven Ambrosia trifida populations along the Liaohe River were used as study subjects. The results showed that the seven A. trifida populations were closely related and exhibited a certain gene exchange, but the absence of evidence of directed gene flow among populations did not confirm that rivers were the medium of seed dispersal of A. trifida. Along the Liaohe River, from top to bottom, the positive view area, length, width, perimeter, and thousand seed weight of A. trifida seeds showed an increasing trend. The total nitrogen and phosphorus contents in the river water of the A. trifida population in the lower reaches of the Liaohe River were higher than those at the other sites. Furthermore, along the river, from top to bottom, the available nitrogen, total nitrogen, total potassium, available potassium, and organic matter contents in the soil in which A. trifida populations grew showed significant increasing trends. River structure, water quality, and soil nutrients had direct and indirect effects on seed morphology. Soil total nitrogen, available potassium, and organic matter had significant positive effects on seed positive view area and perimeter, suggesting that the maternal effect played a critical role in shaping seed morphology. Our analysis showed that soil nutrients along the river may be the primary driver that governs changes in A. trifida seed traits.

Rapid growth is an innovative trait of woody bamboos that has been widely studied. However, the genetic basis and evolution of this trait are poorly understood. Taking advantage of genomic resources of 11 representative bamboos at different ploidal levels, we integrated morphological, physiological, and transcriptomic datasets to investigate rapid growth. In particular, these bamboos include two large-sized and a small-sized woody species, compared with a diploid herbaceous species. Our results showed that gibberellin A1 was important for the rapid shoot growth of the world's largest bamboo, Dendrocalamus sinicus, and indicated that two gibberellins (GAs)-related genes, KAO and SLRL1, were key to the rapid shoot growth and culm size in woody bamboos. The expression of GAs-related genes exhibited significant subgenome asymmetry with subgenomes A and C demonstrating expression dominance in the large-sized woody bamboos while the generally submissive subgenomes B and D dominating in the small-sized species. The subgenome asymmetry was found to be correlated with the subgenome-specific gene structure, particularly UTRs and core promoters. Our study provides novel insights into the molecular mechanism and evolution of rapid shoot growth following allopolyploidization in woody bamboos, particularly via subgenome asymmetry. These findings are helpful for understanding of how polyploidization in general and subgenome asymmetry in particular contributed to the origin of innovative traits in plants.