Abstract Commensal relationships between wild plants and their dispersers play a key ecological and evolutionary role in community structure and function. While non-human dispersers are often ...considered critical to plant recruitment, human dispersers have received much less attention, especially when it comes to non-domesticated plants. Australia, as a continent historically characterized by economies reliant on non-domesticated plants, is thus a key system for exploring the ecological role of people as seed dispersers in the absence of agriculture. Here, we utilize a controlled observation research design, employing ecological surveys and ethnographic observations to examine how seed dispersal and landscape burning by Martu Aboriginal people affects the distribution of three preferred plants and one (edible, but non-preferred) control species. Using an information theoretic approach, we find that the three preferred plants show evidence of human dispersal, with the strongest evidence supporting anthropogenic dispersal for the wild bush tomato, Solanum diversiflorum .
The dioecious and andromonoecious Solanum taxa (the "S. dioicum group") of the Australian Monsoon Tropics have been the subject of phylogenetic and taxonomic study for decades, yet much of their ...basic biology is still unknown. This is especially true for plant-animal interactions, including the influence of fruit form and calyx morphology on seed dispersal. We combine field/greenhouse observations and specimen-based study with phylogenetic analysis of seven nuclear regions obtained via a microfluidic PCR-based enrichment strategy and high-throughput sequencing, and present the first species-tree hypothesis for the S. dioicum group. Our results suggest that epizoochorous trample burr seed dispersal (strongly linked to calyx accrescence) is far more common among Australian Solanum than previously thought and support the hypothesis that the combination of large fleshy fruits and endozoochorous dispersal represents a reversal in this study group. The general lack of direct evidence related to biotic dispersal (epizoochorous or endozoochorous) may be a function of declines and/or extinctions of vertebrate dispersers. Because of this, some taxa might now rely on secondary dispersal mechanisms (e.g. shakers, tumbleweeds, rafting) as a means to maintain current populations and establish new ones.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Synopsis Inclusive teaching is teaching in a way that reaches all students in the classroom; this is beneficial for everyone, particularly for those with minoritized identities. Instructors play a ...critical role in scaffolding how students are exposed to and learn science content in the classroom. In this manuscript, we discuss how biology instructors can make their classrooms more inclusive with regard to sex and gender diversity content. Many topics in biology are based on androcentric, heteronormative, and oppressive framing, even though those lenses are more reflective of our own history and culture than they are of the diversity we see in nature. Here, we summarize information presented in the SICB 2024 workshop titled “Incorporating sex diversity and gender inclusivity in biology undergraduate classrooms” and provide instructors with (a) rationale for why inclusive teaching matters, (b) guidance on how to challenge unscientific views and make their curricula more sex diverse and gender inclusive, and (c) practical and easy-to-implement strategies for discussing “contentious” topics in the classroom. Incorporation of this material will be beneficial for students, for science and medicine, and for accurately representing the diversity found across the tree of life.
Premise of research. Erigenia bulbosa, or the harbinger of spring, is one of the earliest-blooming wildflowers in eastern North America. As a spring ephemeral of forests and woodlands, it is a common ...species throughout the Midwest. In Pennsylvania, E. bulbosa exhibits an east-west disjunct distribution, where widespread western populations are contiguous with the midwestern range and a handful of smaller populations in the eastern part of the state are restricted to the lower Susquehanna River Valley. The relative isolation of the eastern populations suggests a possible conservation concern; the smaller, less connected populations may be threatened by fluctuations in size and the potential for low genetic diversity. As a consequence, establishing regulatory measures in Pennsylvania has been problematic because of disagreement regarding how to treat E. bulbosa during the Pennsylvania Department of Conservation and Natural Resources (PA DCNR) environmental review process. Currently, populations in the east are subject to regulation, while populations in the west are not.
Methodology. To better understand the population genetics of the species, we coupled field assessments of E. bulbosa with a population genomics approach. We sampled multiple individuals from eight populations and generated a genotyping-by-sequencing data set of single-nucleotide polymorphisms (SNPs) that we used to calculate population statistics (genetic variation FST, inbreeding coefficient FIS, and heterozygosity), estimate population structure (sparse nonnegative matrix factorization), identify clusters of genetically related individuals (discriminant analysis of principal components), estimate a NeighborNet, look at signatures of isolation by distance (IBD), and detect population differentiation (analysis of molecular variance) using the filtered SNP data set.
Pivotal results. Our data reveal structure in all populations and suggest genetic isolation between the groups of populations in the eastern and western portions of the state. Genetic groups identified using multivariate methods correspond to populations. Within populations, we estimate low levels of heterozygosity, a significant signature of IBD, and that most of the genetic variation we find is due to differences between populations.
Conclusions. Our results indicate that any conservation measures undertaken by the PA DCNR should be applied evenly throughout Pennsylvania. We expect that most populations will continue to be threatened by land use and other development activities. This work illustrates the strength of academic and nonacademic partnerships in fostering outcomes that inform conservation activities for local species of concern.
Premise
Five to six percent of angiosperm species exhibit a dioecious sexual system, with unisexual “male” or “female” flowers borne on separate plants. The consequent need for inter‐individual ...pollen exchange is a special challenge for taxa where pollen is the sole pollinator reward. Dioecious Australian Solanum assure visits from pollen‐foraging bees via production of inaperturate pollen in functionally female (morphologically bisexual) flowers. Biochemical composition of pollen from Australian Solanum has not been assessed nor compared to porate pollen from staminate flowers to reveal whether these flowers differ in their pollinator reward potential.
Methods
Porate pollen from male flowers and inaperturate pollen from functionally female flowers of two functionally dioecious Australian species were compared for protein and amino acid content. We also assessed pollen from bisexual and staminate flowers of a closely related andromonoecious species, in which all pollen is porate, as a comparison across co‐occurring sexual systems.
Results
In both functionally dioecious species, porate pollen grains from staminate flowers had significantly higher levels of proteins and amino acids than inaperturate pollen grains from functionally female flowers. Levels of proteins and amino acids were highest in bisexual and staminate flowers of the andromonoecious species.
Conclusions
Higher levels of proteins and amino acids in porate pollen of “male” flowers in our functionally dioecious Solanum species suggests a greater nutritive reward for bees foraging on “male” plants than for those foraging on functionally “female” plants. Greater reward in porate pollen (including andromonoecious species) may be connected to the potential to generate a pollen tube.
Solanum is one of the world's largest and economically most important plant genera, including 1245 currently accepted species and several major and minor crops (e.g., tomato, potato, brinjal ...eggplant, scarlet eggplant, Gboma eggplant, lulo, and pepino). Here we provide an overview of the evolution of 25 key morphological traits for the major and minor clades of this giant genus based on stochastic mapping using a well‐sampled recently published phylogeny of Solanum. The most evolutionarily labile traits (showing >100 transitions across the genus) relate to plant structure (growth form and sympodial unit structure), herbivore defence (glandular trichomes), pollination (corolla shape and colour), and dispersal (fruit colour). Ten further traits show evolutionary lability with 50–100 transitions across the genus (e.g., specialised underground organs, trichome structure, leaf type, inflorescence position and branching, stamen heteromorphism). Our results reveal a number of highly convergent traits in Solanum, including tubers, rhizomes, simple leaves, yellow corollas, heteromorphic anthers, dioecy, and dry fruits, and some unexpected pathways of trait evolution that could be explored in future studies. We show that informally named clades of Solanum can be morphologically defined by trait combinations providing a tool for identification and enabling predictive phylogenetic placement of unsampled species.
A new species of functionally dioecious bush tomato of Solanum subgenus Leptostemonum is described.
Solanum scalarium
Martine & T.M.Williams,
sp. nov.
, is a member of the taxonomically challenging ...“Kimberley dioecious clade” in Australia and differs from other species in the group in its spreading decumbent habit and conspicuously prickly male floral rachis. The species is so far known from one site in Judbarra/Gregory National Park in the Northern Territory. Ex situ crosses and confirmation of inaperturate pollen grains produced in morphologically cosexual flowers indicate that these flowers are functionally female and the species is functionally dioecious. The scientific name reflects the ladder-like appearance of the inflorescence rachis armature of male individuals, the stone staircase that provides access to the type locality at the Escarpment Lookout Walk, and the importance of maintaining equitable and safe access to outdoor spaces. The common name Garrarnawun Bush Tomato is proposed in recognition of the lookout point at this site, a traditional meeting place of the Wardaman and Nungali-Ngaliwurru peoples whose lands overlap in this area.
Premise
The ability to sequence genome‐scale data from herbarium specimens would allow for the economical development of data sets with broad taxonomic and geographic sampling that would otherwise ...not be possible. Here, we evaluate the utility of a basic double‐digest restriction site–associated DNA sequencing (ddRADseq) protocol using DNAs from four genera extracted from both silica‐dried and herbarium tissue.
Methods
DNAs from Draba, Boechera, Solidago, and Ilex were processed with a ddRADseq protocol. The effects of DNA degradation, taxon, and specimen age were assessed.
Results
Although taxon, preservation method, and specimen age affected data recovery, large phylogenetically informative data sets were obtained from the majority of samples.
Discussion
These results suggest that herbarium samples can be incorporated into ddRADseq project designs, and that specimen age can be used as a rapid on‐site guide for sample choice. The detailed protocol we provide will allow users to pursue herbarium‐based ddRADseq projects that minimize the expenses associated with fieldwork and sample evaluation.
section
is an ideal lineage to test the theoretical framework regarding proposed evolutionary benefits of outcrossing sexual systems in comparison to cosexuality. Theoretically, non-cosexual taxa ...should support more genetic diversity within populations, experience less inbreeding, and have less genetic structure due to a restricted ability to self-fertilize. However, many confounding factors present challenges for a confident inference that inherent differences in sexual systems influence observed genetic patterns among populations. This study provides a foundational baseline of the population genetics of several species of different sexual systems with the aim of generating hypotheses of any factor-including sexual system-that influences genetic patterns. Importantly, results indicate that dioecious
maintains less genetic structure and greater admixture among populations than cosexual
at the same three locations where they co-occur. This suggests that when certain conditions are met, the evolution of dioecy may have proceeded as a means to avoid genetic consequences of self-compatibility and may support hypotheses of benefits gained through differential resource allocation partitioned across sexes. Arguably, the most significant finding of this study is that all taxa are strongly inbred, possibly reflective of a shared response to recent climate shifts, such as the increased frequency and intensity of the region's fire regime.
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