The mustard family (Brassicaceae) comprises several dozen monophyletic clades usually ranked as tribes. The tribe Boechereae plays a prominent role in plant research due to the incidence of apomixis ...and its close relationship to
. This tribe, largely confined to western North America, harbors nine genera and c. 130 species, with >90% of species belonging to the genus
. Hundreds of apomictic diploid and triploid
hybrids have spurred interest in this genus, but the remaining Boechereae genomes remain virtually unstudied. Here we report on comparative genome structure of six genera (
,
,
,
,
, and
) and three
species as revealed by comparative chromosome painting (CCP). All analyzed taxa shared the same seven-chromosome genome structure. Comparisons with the sister Halimolobeae tribe (
= 8) showed that the ancestral Boechereae genome (
= 7) was derived from an older
= 8 genome by descending dysploidy followed by the divergence of extant Boechereae taxa. As tribal divergence post-dated the origin of four tribe-specific chromosomes, it is proposed that these chromosomal rearrangements were a key evolutionary innovation underlaying the origin and diversification of the Boechereae in North America. Although most Boechereae genera exhibit genomic conservatism, intra-tribal cladogenesis has occasionally been accompanied by chromosomal rearrangements (particularly inversions). Recently, apomixis was reported in the Boechereae genera
and
. Here, we report sexual reproduction in diploid
, diploid
, and tetraploid
and aposporous apomixis in tetraploids of
and
. In sum, apomixis is now known to occur in five of the nine Boechereae genera.
Heritage Studies Sørensen, Marie Louise Stig; Carman, John
2009, 20090918, 2009-09-18
eBook
This is the first volume specifically dedicated to the consolidation and clarification of Heritage Studies as a distinct field with its own means of investigation. It presents the range of methods ...that can be used and illustrates their application through case studies from different parts of the world, including the UK and USA. The challenge that the collection makes explicit is that Heritage Studies must develop a stronger recognition of the scope and nature of its data and a concise yet explorative understanding of its analytical methods.
The methods considered fall within three broad categories: textual/discourse analysis, methods for investigating people’s attitudes and behaviour; and methods for exploring the material qualities of heritage. The methods discussed and illustrated range from techniques such as text analysis, interviews, participant observation, to semiotic analysis of heritage sites and the use of GIS. Each paper discusses the ways in which methods used in social analysis generally are explored and adapted to the specific demands that arise when applied to the investigation of heritage in its many forms.
Heritage Studies is a seminal volume that will help to define the field. The global perspective and the shared focus upon the development of reflexive methodologies ensure that the volume explores these central issues in a manner that is simultaneously case-specific and of general relevance.
Part 1: Setting the Scene 1. Introduction: Making the means transparent: reasons and reflections, Marie Louise Stig Sørensen and John Carman 2. Heritage Studies – an outline, Marie Louise Stig Sørensen and John Carman 3. Public Archaeology in United States in the early twenty-first century, Barbara Little Part 2: Heritage Methodologies: Investigating Texts 4. The history of heritage: a method in analyzing legislative historiography, Hilary Soderland 5. Means maketh the end – the context for the development of methodologies to assessing the state of the historic environment in the UK, Ian Baxter 6. Methods used to investigate the use of the past in the formation of regional identities, Ulrike Sommer Part 3: Heritage Methodologies: Investigating People 7. Reflections on the practice of ethnography within heritage tourism, Catherine Palmer 8. Heritage Ethnography as a specialised craft: Grasping maritime heritage in Bermuda, Charlotte Andrews 9. Between the lines and in the margins: interviewing people about attitudes to heritage and identity, Marie Louise Stig Sørensen 10. Walking a fine line: obtaining sensitive information using a valid methodology, Morag Kersel 11. Methods for investigating locals’ perceptions of a cultural heritage product for tourism: lessons from Botswana, Susan Keitumetse 12. The public archaeology of African America: reflections on pragmatic methods and their results, Carol McDavid Part 4: Heritage Methodologies: Investigating Things 13. The use of GIS in Landscape Heritage and Attitudes to Place- Digital Deep Maps, Matthew Fitzjohn 14. Making them draw: the use of drawings in research into public attitudes towards the past, Grete Lillehammer 15. The heritagescape: looking at heritage sites, Mary-Catherine Garden 16. The intangible presence: investigating battlefields, John Carman and Patricia Carman Part 5: Commentaries Commentary: the view from social anthropology; Paola Filippucci. Commentary: the view from environmental psychology; David Uzzell
'... if you are looking for a stimulating collection of case studies that have something to say about an almost exclusively archaeological understanding of heritage, this would be an excellent place to start.' – Conservation and Management of Archaeological Sites
Background and AimsDuring seed fill in cereals, nutrients are symplasmically unloaded to vascular parenchyma in ovules, but thereafter nutrient transport is less certain. In Zea mays, two mechanisms ...of nutrient passage through the chalaza and nucellus have been hypothesized, apoplasmic and symplasmic. In a recent study, nutrients first passed non-selectively to the chalazal apoplasm and were then selectively absorbed by the nucellus before being released to the endosperm apoplasm. This study reports that the promoter of OUTER CELL LAYER3 (PSbOCL3) from Sorghum bicolor (sorghum) directs gene expression to chalazal cells where the apoplasmic barrier is thought to form. The aims were to elucidate PSbOCL3 expression patterns in sorghum and relate them to processes of nutrient pathway development in kernels and to recognized functions of the homeodomain-leucine zipper (HD-Zip) IV transcription factor family to which the promoter belongs.MethodsPSbOCL3 was cloned and transformed into sorghum as a promoter–GUS (β-glucuronidase) construct. Plant tissues from control and transformed plants were then stained for GUS, and kernels were cleared and characterized using differential interference contrast microscopy.Key ResultsA symplasmic disconnect between the chalaza and nucellus during seed fill is inferred by the combination of two phenomena: differentiation of a distinct nucellar epidermis adjacent to the chalaza, and lysis of GUS-stained chalazal cells immediately proximal to the nucellar epidermis. Compression of the GUS-stained chalazal cells during kernel maturation produced the kernel abscission zone (closing layer).ConclusionsThe results suggest that the HD-Zip IV transcription factor SbOCL3 regulates kernel nutrition and abscission. The latter is consistent with evidence that members of this transcription factor group regulate silique abscission and dehiscence in Arabidopsis thaliana. Collectively, the findings suggest that processes of floral organ abscission are conserved among angiosperms and may in some respects differ from processes of leaf abscission.
The genus Boechera is one of the most difficult species complexes in North America, with about 70 sexual diploids and hundreds of apomictic taxa representing diverse combinations of nearly every ...known sexual genome. In this study, we set out to clarify the taxonomy of Boechera lignifera, which currently includes a small number of sexual diploid populations in addition to the widespread apomictic diploid upon which the name is based. Using data from cytological studies, microsatellite DNA analyses, geography, and morphology, we demonstrate that the apomictic populations are genetically quite divergent from the sexual diploids. We propose the name Boechera kelseyana to accommodate the sexual diploid taxon, which occurs entirely south of the geographic range of B. lignifera. Boechera kelseyana is consistently separable from B. lignifera based on pollen and seed morphology, the length and proximal orientation of fruiting pedicels, differences in the branching and orientation of trichomes on the lowers stems, and the number of flowers and cauline leaves on unbranched fertile stems.
Taking as its start-point a radical intervention in the field of archaeology and heritage—one that laid down a direct challenge to the unspoken discourse of property relations inherent in our ...management of cultural resources—this article considers how much has changed since that intervention. In particular, the article considers developments in the manner of legal regulation of archaeological heritage, the adoption of ideas from economics, and relations with communities that have taken place in archaeology. It identifies differences between the rhetoric of commentators and practitioners and their actual practice that we need to address if we seek truly to turn our field into one that serves the wider community rather than merely telling others how to be.
‘Sustainability’ is a concept that suffuses the present. Policy initiatives require ‘sustainability’ as one of the criteria by which projects are judged. In recognition of their role as interpreters ...and custodians of the past, archaeologists are one of the many groups contributing to the creation of ‘a sustainable historic environment’ and ‘sustainable communities’. Accordingly, sustainability is a concept that we perhaps need to incorporate into our activities as educators of future good citizens and into our training for the profession of archaeology. This paper seeks to address this issue, particularly in the light of Themes and Sessions relating to both sustainability and education at WAC8, but where the link between them remains unexamined.
Periodically archaeologists turn their gaze inwards towards their own field, to consider it as a craft activity or as a community of interest in its own right. The phrase 'archaeological community' ...is one widely used but rarely defined, and there is always a tendency towards the division of archaeology into a variety of distinct specialisms: yet one of the major aspects of academic life is in the construction of communities of shared interests. Here I draw upon my own experiences of encouraging others to become involved in efforts to develop those areas of enquiry that interest me. This includes the construction of formal networks but also more 'covert' activities by inserting contributions into conferences and sometimes publications where they may not have been initially welcomed. It was awkward and slightly dangerous work, especially early in my career, and I am not sure it always achieved what I intended.
Though many tissue-specific promoters have been identified, few have been associated specifically with the angiospermous megasporangium (nucellus). In the present study the 2000-bp regulatory region ...upstream to the watermelon,
Citrullus lanatus (Thunb.) Matsum & Nakai, gene
WM403 (GenBank accession no.
AF008925), which shows nucellus-specific expression, was cloned from watermelon gDNA and fused to the β-glucuronidase reporter gene (
GUS). The resulting plasmid,
WM403 Prom::GUS
+
, which also contained
NPTII, was transformed into
Arabidopsis thaliana ecotype Co1-0. Seedlings were selected on kanamycin-containing medium, and transformants were confirmed by PCR. GUS assays of T
3 transformants revealed weak promoter activation in epidermal layers of the placenta and locule septum during premeiotic ovule development but strong activation in the nucellus, embryo sac and early embryo, from early embryo sac formation to early globular embryo formation. Expression in seeds was absent thereafter. These results indicate that the
WM403 promoter may be useful in driving nucellus-specific gene expression in plants including candidate genes for important nucellus-specific traits such as apospory or adventitious embryony.
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