Tag Archives: Plant Science

Growth responses of the mangrove Avicennia marina to salinity

Avicennia marina Halophytic plants are characterized by enhanced growth under saline conditions. A recent study in Annals of Botany combines physiological and anatomical analyses to identify processes underlying growth responses of the mangrove Avicennia marina to salinities ranging from fresh to seawater conditions.

Following pre-exhaustion of cotyledonary reserves under optimal conditions (50% seawater), seedlings of A. marina were grown hydroponically in dilutions of seawater amended with nutrients. Whole-plant growth characteristics were analysed in relation to dry mass accumulation and its allocation to different plant parts. Gas exchange characteristics and stable carbon isotopic composition of leaves were measured to evaluate water use in relation to carbon gain. Stem and leaf hydraulic anatomy were measured in relation to plant water use and growth.

The results identified stem and leaf transport systems as central to understanding the integrated growth responses to variation in salinity from fresh to seawater conditions. Avicennia marina is revealed as an obligate halophyte, requiring saline conditions for development of the transport systems needed to sustain water use and carbon gain.

Growth responses of the mangrove Avicennia marina to salinity: development and function of shoot hydraulic systems require saline conditions. Annals of Botany January 19 2015 doi: 10.1093/aob/mcu257

Phytomonas: Trypanosomatids Adapted to Plant Environments

Phytomonas Over 100 years after trypanosomatids were first discovered in plant tissues, Phytomonas parasites have now been isolated across the globe from members of 24 different plant families. Most identified species have not been associated with any plant pathology and to date only two species are definitively known to cause plant disease. These diseases (wilt of palm and coffee phloem necrosis) are problematic in areas of South America where they threaten the economies of developing countries. In contrast to their mammalian infective relatives, our knowledge of the biology of Phytomonas parasites and how they interact with their plant hosts is limited. This review draws together a century of research into plant trypanosomatids, from the first isolations and experimental infections to the recent publication of the first Phytomonas genomes. The availability of genomic data for these plant parasites opens a new avenue for comparative investigations into trypanosomatid biology and provides fresh insight into how this important group of parasites have adapted to survive in a spectrum of hosts from crocodiles to coconuts.

Phytomonas: Trypanosomatids Adapted to Plant Environments. (2015) PLoS Pathog 11(1): e1004484. doi: 10.1371/journal.ppat.1004484

Thirsty? Then suck on a stone!

Golden gypsum crystals

Golden Gypsum Crystals from Winnipeg. Image: Rob Lavinsky/Wikimedia Commons

Whilst it is claimed that only the taxman can get blood out of a stone, it seems that some plants can abstract water from stone-like minerals.

Arguably, ahead of light, water is the most important abiotic factor that plants need and obtain from the environment. Although water is essential to plant life, it is not always available in sufficient amounts, and plants have evolved many adaptations that enable them to cope with water-limited environments – e.g. xerophytes in extremely arid areas, and halophytes in saline habitats. One strategy that was hitherto unrecognised is the extraordinary (I don’t think that’s too strong a word to use) ability of some plants to obtain large parts of their life-giving and -sustaining water from a mineral in the soil.

Analysing the isotopic composition of xylem sap in the rock rose Helianthemum squamatum, Sara Palacio et al. showed that it was similar to that of the water of crystallization in gypsum – CaSO4.2H2O, an inorganic mineral common in the plant’s environment. And, significantly, the composition of the water in the xylem differed from that of free water – i.e. that which is freely available within the soil (albeit in short supply!), the more usually assumed water source for plants. This therefore provided strong evidence that the plants were using the mineral as a water source – especially in the summer months when it accounted for 70–90% of the water used by these shallow-rooted plants.

Several other ‘coexisting shallow-rooted, sub-shrub species’ (the gypsum-specialist Lepidium subulatum – a gypsophyte – and the ‘non-specialists’ Linum suffruticosum and Helianthemum syriacum) behaved in an isotopically similar way to H. squamatum, suggesting that this phenomenon may be a widespread strategy of water-extraction by plants in this environment.

Although it is as yet unclear how the plants get hold of the water from this unusual source, it is suggested that high temperatures in the environment may cause the water to evaporate from the mineral when it can then be acquired by the plant.

Whilst this is a neat enough solution (pun recognised, but not intended!) for life on Earth, the authors conclude that ‘given the widespread occurrence of gypsum in dry lands throughout the Earth and in Mars, these results may have important implications for arid land reclamation and exobiology’. So, botanical research that may truly be ‘out of this world’!

[Intrigued by these intriguing gypsophytes? Then why not indulge your interest and read more of Sara Palacio et al.’s research in ‘Plants living on gypsum: beyond the specialist model’? – Ed.]

Phylogenetic relationships in Epidendroideae (Orchidaceae), one of the great flowering plant radiations

Annals of Botany The largest subfamily of orchids, Epidendroideae, represents one of the most significant diversifications among flowering plants in terms of pollination strategy, vegetative adaptation and number of species. Although many groups in the subfamily have been resolved, significant relationships in the tree remain unclear, limiting conclusions about diversification and creating uncertainty in the classification. This study brings together DNA sequences from nuclear, plastid and mitochrondrial genomes in order to clarify relationships, to test associations of key characters with diversification and to improve the classification.

All tested characters show significant association with speciation in Epidendroideae, suggesting that no single character accounts for the success of this group. Rather, it appears that a succession of key features appeared that have contributed to diversification, sometimes in parallel.

J.V. Freudenstein and M.W. Chase (2015) Phylogenetic relationships in Epidendroideae (Orchidaceae), one of the great flowering plant radiations. Annals of Botany, January 11, 2015 doi: 10.1093/aob/mcu253

Diversity, distribution and roles of osmoprotective compounds accumulated in halophytes under abiotic stress

Annals of Botany Osmolytes are low-molecular-weight organic solutes, a broad group that encompasses a variety of compounds such as amino acids, tertiary sulphonium and quaternary ammonium compounds, sugars and polyhydric alcohols. Osmolytes are accumulated in the cytoplasm of halophytic species in order to balance the osmotic potential of the Na+ and Cl− accumulated in the vacuole. The advantages of the accumulation of osmolytes are that they keep the main physiological functions of the cell active, the induction of their biosynthesis is controlled by environmental cues, and they can be synthesized at all developmental stages. In addition to their role in osmoregulation, osmolytes have crucial functions in protecting subcellular structures and in scavenging reactive oxygen species.

This review discusses the diversity of osmolytes among halophytes and their distribution within taxonomic groups, the intrinsic and extrinsic factors that influence their accumulation, and their role in osmoregulation and osmoprotection. Increasing the osmolyte content in plants is an interesting strategy to improve the growth and yield of crops upon exposure to salinity. Examples of transgenic plants as well as exogenous applications of some osmolytes are also discussed. Finally, the potential use of osmolytes in protein stabilization and solvation in biotechnology, including the pharmaceutical industry and medicine, are considered.

Slama, I., Abdelly, C., Bouchereau, A., Flowers, T., & Savouré, A. Diversity, distribution and roles of osmoprotective compounds accumulated in halophytes under abiotic stress. (2015) Annals of Botany, January 5, 2015 doi: 10.1093/aob/mcu239

Strasburger’s Plant Sciences [Including Prokaryotes and Fungi]

rev-Strasburger2013BookCover

 

 

 

 

 

By Andreas Bresinsky Christian Körner, Joachim W. Kadereit Gunther Neuhaus and Uwe Sonnewald. Springer, 2013

One of my first botany memories was buying a second-hand copy of Strasburger’s Lehrbuch der Botanik – in German – and marvelling at the many images that illustrated that weighty tome. Attempts to translate passages of interest were painfully slow with my elementary science German, so I never managed to appreciate the text of that textbook. Whether that experience influenced me towards a career in botany we’ll probably never know, but it certainly left a lasting impression.

Eduard Strasburger – that book’s eponymous originator – was a Polish-German botanist and one of the most notable plant scientists of the 19th century. Amongst his many botanical achievements – which ranged from sexual reproduction to the ascent of sap – he is widely considered to be the founder of modern plant cell biology (Volkmann et al., 2012). However, one of his most enduring legacies is the textbook that still bears his name over 100 years since his death in 1912. As the present book’s Preface advises, Strasburger’s Lehrbuch der Botanik für Hochschulen was first published in 1894, and has “greatly influenced university teaching in Germany and neighboring [US English prevails throughout the text] countries, and its 36 editions also mirror the dynamic history of the plant sciences”. Although still published under Eduard Strasburger’s name, it has always been a “multi-author effort, and Strasburger himself invited his colleagues at the Botanical Institute of Bonn University as contributors to the first edition.” Having had my attempts to penetrate the German version of this iconic textbook thwarted, the opportunity to review an English language edition was one I didn’t want to pass up.

In keeping with Strasburger’s multi-author vision for the book (which is probably more in the nature of a project that has evolved since its authorship has changed several times during its 120-year existence), the present 1,302 paged text [hereafter referred to as Strasburger 2013] containing 1158 illustrations over two volumes is divided into four parts, each a reflection of the breadth of knowledge and interests of the author(s) responsible for their compilation. Thus, in Volume 1 we have Part I Structure by Gunther Neuhaus with four chapters entitled, Molecular Basics: The Building Blocks of Cells; The Structure and Ultrastructure of the Cell; The Tissues of Vascular Plants; and Morphology and Anatomy of Vascular Plants. Part II Physiology by Uwe Sonnewald covers Physiology of Metabolism; of Development; of Movement; and Allelophysiology [“the diversity of physiological relationships that plants have with other organisms” – p. 9 of Introduction]. Volume 2’s sections are Part III Evolution and Systematics co-authored by Joachim W. Kadereit and Andreas Bresinsky, with chapters on Evolution; and Systematics and Phylogeny. Finally, Part IV Ecology by Christian Körner, whose four chapters cover: Basics of Plant Ecology; Plant–Environment Interactions; Ecology of Populations and Vegetation; and Vegetation of the Earth. The second volume concludes with a Timeline, Sources [References] [which supplement further reading associated with individual chapters], and the Index. The first volume commences with a 10-page Introduction which considers such notions as what Botany is, what is life?, the special position of Biology, and classification and significance of plant sciences. Scattered throughout both volumes are 34 ‘Boxes’ [which provide more specialist information on such concepts as “Cell fractionation”, “Types of stele”, “Important units in photobiology”, “Thale cress: Arabidopsis thaliana”, and “Effects of CO2 on plant growth”], and 14 ‘Topical Insights’ [presumably the “additional contributions by renowned experts in the field” per the publisher’s flyer, and which range from Christophe Benning’s “Galactolipids and membrane remodelling” to “Forest structure and gap models” by Hank Shugart via “The origin and early evolution of flowers” by Peter Endress and James Doyle and “Leaf nitrogen: A key to photosynthetic performance” by John Evans].

I’ve reviewed several English language plant biology/botany texts over the years and in my view Strasburger 2013 is probably unique. For example, it takes a rather broad interpretation of the subject matter of plant sciences (yes, I note the use of this binomial rather than the term ‘botany’ in its German antecedants) to include algae (which is reasonable since green algal ancestors are probably progenitors of the true Kingdom Plantae), fungi, and prokaryotes. Whilst inclusion of eukaryotic fungi may also be considered reasonable in a botany text (they are not animals and are plant-like in some respects…), incorporation of prokaryotes is unexpected; although these organisms feature mainly in the Evolution and Systematics part of Strasburger 2013. Wisely anticipating that concern, the book admirably defends its stance in the Preface thus, “The inclusion of bacteria, archaea, and the various lineages referred to as fungi may not be justified from a phylogenetic perspective when dealing with plants, but is necessary considering the important evolutionary and ecological interactions between plants and these organisms”. I can’t argue with that.

Part I’s Structure and Ultrastructure of the Cell is a comprehensive section which is reminiscent of Gunning (2009) (but with coverage here of cell walls!). And both The Tissues of Vascular Plants, and Morphology and Anatomy of Vascular Plants chapters could give Esau’s Plant Anatomy: Meristems, Cells, and Tissues of the Plant Body (Evert, 2006) a good run for its money, and incorporate more detail than is common in competing general plant science texts e.g. Raven Plant Biology (Evert and Eichhorn, 2012) and Botany: An introduction to Plant Biology (Mauseth, 2014). Part II Physiology compares favourably with Plant Physiology (Taiz and Zeiger, 2010) and with the likes of Physiological Plant Ecology (Larcher, 2003) or Plant Physiological Ecology (Lambers et al., 2008). Part III’s systematics section is a substantial contribution extending from prokaryotes to the Plant Kingdom, and its angiosperm section alone is reminiscent of Judd et al. (2007). But, and intriguingly, the term Kingdom is used in place of the more usual (and more widely understood?) term Domain. Hence, Strasburger 2013 talks of 3 Kingdoms (Domains) (e.g. p. 680), which would probably confuse those of us who are used to viewing the living world as consisting of 5 kingdoms but subsumed within three Domains. And chapters in Part IV’s substantial ecology section also bear comparison with the texts of Larcher (2003) and Lambers et al. (2008), whilst the Vegetation of the Earth chapter is a near-encyclopaedic compendium of coloured photographic images of the planet’s varied habitats.

However, throughout the tome there is no great emphasis on molecular biology – in the sense of relating developmental or physiological phenomena to the genes implicated therein, so Strasburger 2013 is no competition for the likes of Plant Biology (Smith et al., 2010) or The Molecular Life of Plants (Jones et al., 2013) (nor even Taiz and Zeiger (2010) or Evert and Eichhorn (2013) in this respect). Although, Strasburger 2013’s scope is broader than the former three of those four texts, this seems to be a serious omission at worst; a missed opportunity at best. It is undeniable that the molecular-genetic dimension is an important – essential, indeed – component of our modern day understanding of plant biological processes and phenomena, especially at the sub-cellular and biochemical/physiological level, which are a major focus of Parts I and II. In this respect Strasburger 2013 probably doesn’t fully “mirror the dynamic history of the plant sciences” (2nd paragraph of Preface), and is therefore a little out of step with some of its major English-language textbook competitors. But, how serious a deficiency this will be viewed by potential readers of Strasburger 2013 will depend on what they want from a botany – sorry, plant science – textbook (and how happy they will be to pay £449.50 for this idiosyncratic text).

An interesting inclusion in Strasburger 2013 is the 3.5 pages of ‘Timeline’ [“a selection of important contributions to Plant Sciences (Botany) from their origins up to the year 2000”], which extends from Theophrastus’ Enquiry into Plants of c. 300 BCE to the end of the second millennium CE’s sequencing of Arabidopsis thaliana‘s genome by The Arabidopsis Genome Initiative. But why does stop at 2000? For a book published in 2013 you’d expect at least some mention of 13 year’s additional noteworthy botanical achievements post-2000 (they do exist). Or, at least, to extend the timeline until 2008, the year of publication of Strasburger’s 36th German language edition upon which Strasburger 2013 is based.

The 14 Topical Insights are a nice touch. Scattered throughout, but integrated within, the book’s 14 chapters (but, no, not one per chapter!), they reflect a similar development one has witnessed more generally in plant biology textbooks in recent years. In all cases they are an attempt to promote that all-important topicality that helps to ensure the book has that ‘cutting-edge’ feel and is appropriately up-to-date (which should ensure that it is recommended, bought and hopefully read). It was therefore good to read about scientists other than the books’ co-authors, and on a range of interesting and relevant topics. One that caught my eye was Todd Dawson’s contribution entitled “From where do plants take their water?” which examined the use of stable isotopes of hydrogen and oxygen in water in plant physiology/ecology. Because the ratios of the different isotopes vary in water molecules from different sources, and are in turn reflected in the isotopic composition of water within the plant, this approach can be used to determine which sources of water plants actually exploit in the environment. Although published too late for inclusion in Strasburger 2013, that piece seems to anticipate Palacio et al. (2014)’s revelation that certain plants use the water of crystallisation associated with the mineral gypsum as a major source of water. How insightful and topical is that!

The impressive 30 pages of 3-columned Index extends from the curiously spelt – and therefore alphabetically misplaced – “Aacetate [sic.]-malonate pathway” and “Aautotrophy [sic.]” to” Zygotene” and “Zygotic embryo”, and has entries listed under every letter of the alphabet. However, I found no mention in the index – which presumably also means no inclusion and coverage within the text* – of strigolactones [“chemical signals for fungal symbionts and parasitic weeds in plant roots” – Akiyama and Hayashi, 2006]. In view of Strasburger 2013’s inclusion of Fungi within its pages to emphasise allelophysiology, this omission is unexpected, and arguably difficult to defend (and incidentally impacts upon one’s view of the up-to-dateness of the 36th German edition of Strasburger…). Surprisingly also, since Strasburger 2013 features William Bond’s Topical Insight entitled “A world without fire”, and in view of the book’s strong ecophysiological dimension, the Index has no entry for karrikins (and which are presumably therefore not covered within the text*). Karrikins are “a group of plant growth regulators of the butenolide class found in the smoke of burning plant material”. They are therefore compounds which have considerable plant science interest and ecological significance, and – one would have thought – are ideal for inclusion in Strasburger 2013. But, and before this is challenged by those who – rightly – state that these compounds weren’t named karrikins (e.g. Chiwocha et al., 2009) until after the 2008 publication date of the 36th German edition of Strasburger upon which this English translation is based, their omission from this English edition is still an issue because it is quite clear that Strasburger 2013 is not constrained by that 2008 date. Supporting that view is Bond’s own Topical Insight which cites references from 2008, 2009, and 2010 (and e.g. Körner’s chapter 14 in Strasburger 2013’s main text includes several 2011 and 2012-published references). Which accords with the Publisher’s statement that Strasburger 2013 is based upon, and not a direct translation of, the 2008 German edition. With more optimism I also searched the Index for forisome(s), ATP-independent contractile proteins in the sieve elements of some plants (which are exciting interest because of their potential exploitation as a so-called biomimetic ‘smart material’). These sub-cellular structures were named shortly after the start of the current millennium by Knoblauch et al. (2003), and so well before the all-important year of 2008. Sadly, that term was not found either (and which presumably also indicates that any mention thereof is absent from Strasburger 2013’s main text*). What this comparatively simplistic scrutiny of the Index reveals is that, although some attempts to include more up-to-date references than the 2008 German Strasburger edition permitted have taken place (and which are laudable), and notwithstanding the inclusion of the Topical Insights with some post-2008 references, one should not infer that the whole of the main text is as up-to-date as its 2013 publication date suggests; Strasburger 2013 still seems largely rooted in the ‘noughties’. And these forisome, karrikin and strigolactone revelations are illustrative of the main issue I have with Strasburger 2013

This 2013 English translation is based on the 36th German language edition of Strasburger published in 2008. As the first English version since the 1976 translation of the 30th German Edition, Strasburger 2013 is to be welcomed. However, given that gap of nearly 40-years, and encouraged by having seen some attempts to update the text for researches/references post-2008, it seems a great pity that the publisher didn’t wait just a little longer to provide an English translation of 2014’s 37th German Edition of Strasburger (wherein one hopes such issues as forisomes, karrikins and strigolactones will have been addressed…). That tome should be as up-to-date as it can reasonably be expected to be and would arguably be a more fitting re-entry of Springer into the highly competitive English language plant science textbook market after an absence of nearly four decades. Given that English is not only a global lingua franca, but is also the international language of science, and that English is spoken by approx. 335 million people (cf. c. 78 million for German), one can’t help but think that a ‘Strasburger 2014’ (or even Strasburger 2015 – but don’t leave it any longer or we’ll have issues of Strasburger 2013 up-to-datedness again!) might have been a better way to extend – and expand? – Strasburger’s legacy beyond “Germany and neighboring countries” (2nd paragraph of Preface) by tapping into that much larger community of anglophone plant scientists, particularly in the USA.

References

Akiyama K, Hayashi H (2006) Strigolactones: Chemical Signals for Fungal Symbionts and Parasitic Weeds in Plant Roots. Annals of Botany 97: 925–931.

Chiwocha SDS, Dixon KW, Flematti GR, et al. (2009) Karrikins: A new family of plant growth regulators in smoke. Plant Science 177: 252–256.

Evert RF (2006) Esau’s Plant Anatomy: Meristems, Cells, and Tissues of the Plant Body: Their Structure, Function, and Development, 3e. John Wiley & Sons Ltd.

Evert RF, Eichhorn SE (2012) Raven Biology of Plants, 8e. WH Freeman.

Gunning BES (2009) Plant Cell Biology on DVD. Springer.

Jones R, Ougham H, Thomas H, Waaland S (2013) The Molecular Life of Plants. John Wiley & Sons Ltd.

Judd, WS, Campbell CS, Kellogg EA, Stevens PF, Donoghue MJ (2007) Plant Systematics: A Phylogenetic Approach, 3e. Sinauer Associates.

Knoblauch M, Noll GA, Müller T, et al. (2003) ATP-independent contractile proteins from plants. Nature Materials 2: 600–603.

Lambers, H, Chapin III, FS, Pons, TL (2008) Plant Physiological Ecology. Springer.

Larcher W (2003) Physiological Plant Ecology, 4e. Springer.

Mauseth JD (2014) Botany: An introduction to Plant Biology, 5e. Jones & Bartlett.

Palacio S, Azorín J, Montserrat-Martí G, Ferrio JP (2014) The crystallization water of gypsum rocks is a relevant water source for plants. Nature Communications 5:4660 doi: 10.1038/ncomms5660.

Smith AM, Coupland G, Dolan L, et al. (2010) Plant Biology. Garland Science.

Taiz L, Zeiger E (2010) Plant Physiology, 5e. Sinauer Associates Inc.

Volkmann D, Baluška F, Menzel D (2012) Eduard Strasburger (1844-1912): founder of modern plant cell biology. Protoplasma 249: 1163-1172.

*   NB this review based upon a limited-functionality ebook version of Strasburger 2013, which did not permit searching of the text.

Allometric partitioning and the relationship between above- and below-ground plant biomass

Annals of Botany The relationship between above- and below-ground plant biomass is of considerable interest to researchers attempting to model global climate change and nutrient cycles as well as those interested in evolutionary organographic relationships across taxonomically and ecologically diverse species. Empirical studies and allometric partitioning theory indicate that plant above-ground biomass scales, on average, one-to-one with below-ground biomass at the level of individual trees and at the level of entire forest communities. However, the ability of the allometric partitioning theory to predict the biomass allocation patterns of understorey plants has not been established because most previous empirical tests have focused on canopy tree species or very large shrubs.

In order to test the allometric partitioning theory further, a new paper in Annals of Botany examines 1,586 understorey sub-tropical forest plants from 30 sites in south-east China. The results support the allometric partitioning theory’s prediction that above-ground biomass scales nearly one-to-one with below-ground biomass and that plant biomass partitioning for individual plants and at the community level share a strikingly similar pattern, at least for the understorey plants examined in this study. Furthermore, variation in environmental conditions appears to affect the numerical values of normalization constants, but not the scaling exponents of the relationship. This feature of the results suggests that plant size is the primary driver of the biomass allocation pattern for understorey plants in sub-tropical forests.

Dongliang Cheng, Quanlin Zhong, Karl J. Niklas, Yuzhu Ma, Yusheng Yang and Jianhua Zhang (2015) Isometric scaling of above- and below-ground biomass at the individual and community levels in the understorey of a sub-tropical forest. Annals of Botany (2015) doi: 10.1093/aob/mcu238

Phylogeny and biogeography of wild roses

Phylogeny and biogeography of wild roses The genus Rosa (with 150–200 species) is widely distributed throughout temperate and sub-tropical habitats from the northern hemisphere to tropical Asia, with only one tropical African species. In order to better understand the evolution of roses, this study examines infrageneric relationships with respect to conventional taxonomy, considers the extent of allopolyploidization and infers macroevolutionary processes that have led to the current distribution of the genus.

The ancestral area reconstruction suggests that despite an early presence on the American continent, most extant American species are the results of a later re-colonization from Asia, probably through the Bering Land Bridge. The results suggest more recent exchanges between Asia and western North America than with eastern North America. The current distribution of roses from the Synstylae lineage in Europe is probably the result of a migration from Asia approx. 30 million years ago, after the closure of the Turgai strait. Directions for a new sectional classification of the genus Rosa are proposed, and the analyses provide an evolutionary framework for future studies on this notoriously difficult genus.

Fougère-Danezan, M., Joly, S., Bruneau, A., Gao, X. F., & Zhang, L. B. (2014) Phylogeny and biogeography of wild roses with specific attention to polyploids. Annals of Botany, December 29, 2014, doi: 10.1093/aob/mcu245

Some good stuff in the recent edition of CBE Life Sciences Education

Diversity of flowering plant species
High School Students’ Learning and Perceptions of Phylogenetics of Flowering Plants. CBE Life Sci Educ vol. 13 no. 4 653-665 doi: 10.1187/cbe.14-04-0074
Basic phylogenetics and associated “tree thinking” are often minimized or excluded in formal school curricula. Informal settings provide an opportunity to extend the K–12 school curriculum, introducing learners to new ideas, piquing interest in science, and fostering scientific literacy. Similarly, university researchers participating in science, technology, engineering, and mathematics (STEM) outreach activities increase awareness of college and career options and highlight interdisciplinary fields of science research and augment the science curriculum. To aid in this effort, we designed a 6-h module in which students utilized 12 flowering plant species to generate morphological and molecular phylogenies using biological techniques and bioinformatics tools. The phylogenetics module was implemented with 83 high school students during a weeklong university STEM immersion program and aimed to increase student understanding of phylogenetics and coevolution of plants and pollinators. Student response reflected positive engagement and learning gains as evidenced through content assessments, program evaluation surveys, and program artifacts. We present the results of the first year of implementation and discuss modifications for future use in our immersion programs as well as in multiple course settings at the high school and undergraduate levels.

 

Student Interpretations of Phylogenetic Trees in an Introductory Biology Course. CBE Life Sci Educ vol. 13 no. 4 666-676 doi: 10.1187/cbe.14-01-0003
Phylogenetic trees are widely used visual representations in the biological sciences and the most important visual representations in evolutionary biology. Therefore, phylogenetic trees have also become an important component of biology education. We sought to characterize reasoning used by introductory biology students in interpreting taxa relatedness on phylogenetic trees, to measure the prevalence of correct taxa-relatedness interpretations, and to determine how student reasoning and correctness change in response to instruction and over time. Counting synapomorphies and nodes between taxa were the most common forms of incorrect reasoning, which presents a pedagogical dilemma concerning labeled synapomorphies on phylogenetic trees. Students also independently generated an alternative form of correct reasoning using monophyletic groups, the use of which decreased in popularity over time. Approximately half of all students were able to correctly interpret taxa relatedness on phylogenetic trees, and many memorized correct reasoning without understanding its application. Broad initial instruction that allowed students to generate inferences on their own contributed very little to phylogenetic tree understanding, while targeted instruction on evolutionary relationships improved understanding to some extent. Phylogenetic trees, which can directly affect student understanding of evolution, appear to offer introductory biology instructors a formidable pedagogical challenge.

 

For they are jolly good fellows

The Royal Society/Wikimedia Commons.

The Royal Society/Wikimedia Commons.

We’d like to add our words of congratulations to two recently appointed plant-biological Fellows of the Royal Society (of London for Improving Natural Knowledge), Professor Liam Dolan FRS (Sherardian Professor of Botany, Department of Plant Sciences, University of Oxford, UK) and Professor David Beerling FRS (Professor of Palaeoclimatology, Department of Animal and Plant Sciences, University of Sheffield, UK). Fittingly, Dolan has been so honoured because his ‘pivotal discoveries illuminate our understanding of the interrelationships between the development of plants, their evolution and the Earth System’ (e.g. Victor Jones and Liam Dolan, 2012Timothy Lenton et al.,  2012). Beerling has received his accolade in view of how ‘his integration of ecosystem processes into a broad geosciences framework established the importance of the terrestrial biosphere in Earth’s climate history’ (e.g. Laura Llorens et al., 2009*; Beerling, 2012). In addition to their research activities both have also taken time out to help spread the botanical message and enthuse the next generation of plant biologists, Dolan in the highly regarded undergraduate textbook Plant Biology, and Beerling with The Emerald Planet. Dolan and Beerling join approximately 1600 other Fellows in the self-governing fellowship that is the Royal Society, and which includes ‘many of the world’s most distinguished scientists drawn from all areas of science, engineering, and medicine’. Well done to these most deserving botanists!

 

* It’s also rather gratifying to think that having their work published in the Annals of Botany will have helped both gentlemen attain fellowship!

[And congratulations, too, to those UK researchers working in plant sciences (including fungi…) who’ve been named in the global Top 1%. This listing of ‘Highly Cited Researchers 2014’ names more than 3000 people selected by having writing the greatest numbers of ‘reports officially designated by Essential Science IndicatorsSM as Highly Cited Papers’. I counted four female and 11 male notables from addresses – ‘primary affiliations’ – in north, central, west and south of England, but none from Scotland (or Wales or Northern Ireland). However, I am intrigued by included scientist ‘Philip J. White’, whose primary affiliation is shown as King Saud University, Saudi Arabia (KSU), because I found no mention of this notable person on KSU’s website. So, I wonder if this could actually be the Philip J. White currently at The James Hutton Institute (Invergowrie, Scotland, UK). That P. J. White has many other affiliations – Special Professor in Plant Ion Transport at the University of Nottingham (UK), Adjunct Professor at the University of Western Australia, Visiting Associate Professor at the Comenius University, Bratislava (Slovakia), Visiting Professor of the Brazilian Research Council, and an Honorary Lecturer at the University of Dundee (Scotland) – so maybe KSU was amongst those at the time the census was taken? Or perhaps there’s been a mistake? Or there’s another Philip J. White who is even more highly cited than James Hutton’s? So, will P. J. White please get in touch and put the record straight? – Ed.]

[Ed. – we are pleased to be able to report that the mystery has now been solved. The PJ White referred to is indeed Philip White of the James Hutton Institute who is also a Professor in Biology at the King Saud University. And we are more than happy to advise that the same PJ White is a co-author on one of the Annals of Botany’s most highly downloaded papers – White PJ and Broadley MR, Calcium in plants; Annals of Botany 92: 487-511, 2003.].