She was a visitor

'She Was a Visitor' was the title of an exhibition held in December 2018 in Stirling, Scotland. The exhibition resulted from the final No.35 project, by artists Alexander Hetherington and Jane Topping. See also the associated book publication entitled 'Newspaper or (Memoirs of a spacewoman)' http://insight.cumbria.ac.uk/id/eprint/4294

The Making of Plant Armor : The Periderm

The periderm acts as armor protecting the plant's inner tissues from biotic and abiotic stress. It forms during the radial thickening of plant organs such as stems and roots and replaces the function of primary protective tissues such as the epidermis and the endodermis. A wound periderm also forms to heal and protect injured tissues. The periderm comprises a meristematic tissue called the phellogen, or cork cambium, and its derivatives: the lignosuberized phellem and the phelloderm. Research on the periderm hasmainly focused on the chemical composition of the phellem due to its relevance as a raw material for industrial processes. Today, there is increasing interest in the regulatory network underlying periderm development as a novel breeding trait to improve plant resilience and to sequester CO2. Here, we discuss our current understanding of periderm formation, focusing on aspects of periderm evolution, mechanisms of periderm ontogenesis, regulatory networks underlying phellogen initiation and cork differentiation, and future challenges of periderm research.Peer reviewe

An evidence-based 3D reconstruction of Asteroxylon mackiei, the most complex plant preserved from the Rhynie chert.

Funder: Biotechnology and Biological Sciences Research CouncilThe Early Devonian Rhynie chert preserves the earliest terrestrial ecosystem and informs our understanding of early life on land. However, our knowledge of the 3D structure, and development of these plants is still rudimentary. Here we used digital 3D reconstruction techniques to produce the first well-evidenced reconstruction of the structure and development of the rooting system of the lycopsid Asteroxylon mackiei, the most complex plant in the Rhynie chert. The reconstruction reveals the organisation of the three distinct axis types - leafy shoot axes, root-bearing axes, and rooting axes - in the body plan. Combining this reconstruction with developmental data from fossilised meristems, we demonstrate that the A. mackiei rooting axis - a transitional lycophyte organ between the rootless ancestral state and true roots - developed from root-bearing axes by anisotomous dichotomy. Our discovery demonstrates how this unique organ developed and highlights the value of evidence-based reconstructions for understanding the development and evolution of the first complex vascular plants on Earth

Multiple origins of dichotomous and lateral branching during root evolution

Roots of extant vascular plants proliferate through lateral branching (euphyllophytes) or dichotomy (lycophytes)1,2,3,4. The origin of these distinct modes of branching was key for plant evolution because they enabled the development of structurally and functionally different root systems that supported a diversity of shoot systems3,4,5,6. It has been unclear when lateral branching originated and how many times it evolved4,7,8. Here, we report that many euphyllophytes that were extant during the Devonian and Carboniferous periods developed dichotomous roots. Our data indicate that dichotomous root branching evolved in both lycophytes and euphyllophytes. Lateral roots then evolved at different times in three major lineages of extant euphyllophytes—the lignophytes, ferns and horsetails. The multiple origins of dichotomous and lateral root branching are extreme cases of convergent evolution that occurred during the Devonian and Carboniferous periods when the land-plant flora underwent a radiation in morphological diversity

Functional PTB phosphate transporters are present in streptophyte algae and early diverging land plants

International audienceTwo inorganic phosphate (Pi) uptake mechanisms operate in streptophytes and chloro-phytes, the two lineages of green plants. PHOSPHATE TRANSPORTER B (PTB) proteins are hypothesized to be the Na + /Pi symporters catalysing Pi uptake in chlorophytes, whereas PHOSPHATE TRANSPORTER 1 (PHT1) proteins are the H + /Pi symporters that carry out Pi uptake in angiosperms. PHT1 proteins are present in all streptophyte lineages. However, Pi uptake in streptophyte algae and marine angiosperms requires Na + influx, suggesting that Na + /Pi symporters also function in some streptophytes. We tested the hypothesis that Na + /Pi symporters exist in streptophytes. We identified PTB sequences in streptophyte genomes. Core PTB proteins are present at the plasma membrane of the liverwort Marchantia polymorpha. The expression of M. polymorpha core PTB proteins in the Saccharomyces cerevisiae pho2 mutant defective in high-affinity Pi transport rescues growth in low-Pi environments. Moreover, levels of core PTB mRNAs of M. polymorpha and the streptophyte alga Coleochaete nitellarum are higher in low-Pi than in Pi-replete conditions, consistent with a role in Pi uptake from the environment. We conclude that land plants inherited two Pi uptake mechanisms-mediated by the PTB and PHT1 proteins, respectively-from their streptophyte algal ancestor. Both systems operate in parallel in extant early diverging land plants

Do cladistic and morphometric data capture common patterns of morphological disparity?

The distinctly non-random diversity of organismal form manifests itself in discrete clusters of taxa that share a common body plan. As a result, analyses of disparity require a scalable comparative framework. The difficulties of applying geometric morphometrics to disparity analyses of groups with vastly divergent body plans are overcome partly by the use of cladistic characters. Character-based disparity analyses have become increasingly popular, but it is not clear how they are affected by character coding strategies or revisions of primary homology statements. Indeed, whether cladistic and morphometric data capture similar patterns of morphological variation remains a moot point. To address this issue, we employ both cladistic and geometric morphometric data in an exploratory study of disparity focussing on caecilian amphibians. Our results show no impact on relative intertaxon distances when different coding strategies for cladistic characters were used or when revised concepts of homology were considered. In all instances, we found no statistically significant difference between pairwise Euclidean and Procrustes distances, although the strength of the correlation among distance matrices varied. This suggests that cladistic and geometric morphometric data appear to summarize morphological variation in comparable ways. Our results support the use of cladistic data for characterizing organismal disparity

Randomized controlled trial of functional family therapy for offending and antisocial behaviour in UK Youth

Background: Youth offending and antisocial behavior (ASB) are associated with low quality mental health and relationships and usually lead to poor adult functioning; they are very costly for society. Family interventions are effective in children but there are few reliably effective and inexpensive interventions for adolescents. Functional Family Therapy (FFT) is an evidence-based intervention but seldom tested outside the US. Methods: 111 adolescents (10-17 years of age, M = 15.0, SD = 1.63) and their families were randomized to FFT + Management As Usual (MAU) (n=65) or to MAU (n=46). Assessments were made at baseline, 6, and 18 months after randomization and included interviews and questionnaires of parenting behaviors, Conduct Disorders and offending. Parent-child interaction was directly observed and police records obtained. Trial registration: ISCRTN27650478. Results: 89 (80%) were followed-up. In both groups, there were large reductions over time in all measures of offending and antisocial behavior (e.g. primary outcome p < 0.001), but no significant changes over time in parenting behavior or the parent-child relationship. However, there were no differences between intervention and control groups at 6 or 18 months on self-reported delinquency, police records of offending, symptoms or diagnoses of Conduct Disorders, parental monitoring or supervision, directly-observed child negative behavior, or parental positive or negative behavior. Against predictions, the intervention group showed lower levels of directly-observed child positive behavior at 18 months compared to controls. Conclusions: In contrast to most previous trials of FFT, FFT+MAU did not lead to greater reductions in youth ASB and offending compared to MAU alone, and did not lead to improvements in parenting or the parent-child relationship. This may be because the trial was more rigorously conducted than prior studies; equally, the possibility that MAU was effective requires further research

Unique cellular organization in the oldest root meristem

Roots and shoots of plant bodies develop from meristems—cell populations that self-renew and produce cells that undergo differentiation—located at the apices of axes [1].The oldest preserved root apices in which cellular anatomy can be imaged are found in nodules of permineralized fossil soils called coal balls [2], which formed in the Carboniferous coal swamp forests over 300 million years ago [3, 4, 5, 6, 7, 8 and 9]. However, no fossil root apices described to date were actively growing at the time of preservation [3, 4, 5, 6, 7, 8, 9 and 10]. Because the cellular organization of meristems changes when root growth stops, it has been impossible to compare cellular dynamics as stem cells transition to differentiated cells in extinct and extant taxa [11]. We predicted that meristems of actively growing roots would be preserved in coal balls. Here we report the discovery of the first fossilized remains of an actively growing root meristem from permineralized Carboniferous soil with detail of the stem cells and differentiating cells preserved. The cellular organization of the meristem is unique. The position of the Körper-Kappe boundary, discrete root cap, and presence of many anticlinal cell divisions within a broad promeristem distinguish it from all other known root meristems. This discovery is important because it demonstrates that the same general cellular dynamics are conserved between the oldest extinct and extant root meristems. However, its unique cellular organization demonstrates that extant root meristem organization and development represents only a subset of the diversity that has existed since roots first evolved.</p