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About annbot

Ann Bot is a gestalt entity who works in the office for the Annals of Botany.

Bacteria and seed dormancy, nitrogen acquisition in grass species and the cellular basis of salt tolerance in halophytes – what’s new in Annals of Botany this week.

Lolium rigidum A potential role for endogenous microflora in dormancy release, cytokinin metabolism and the response to fluridone in Lolium rigidum seeds
Dormancy in annual ryegrass (Lolium rigidum) can be alleviated by warm stratification in the dark or by application of fluridone, an inhibitor of plant abscisic acid (ABA) biosynthesis via phytoene desaturase. However, germination and absolute ABA concentration are not strongly correlated. The aim of this study was to determine if cytokinins of both plant and bacterial origin are involved in mediating dormancy status and in the response to fluridone. Seeds lacking bacteria were no longer able to lose dormancy in the dark unless supplied with exogenous gibberellin or fluridone. It is probable that resident microflora contribute to dormancy status in L. rigidum seeds via a complex interaction between hormones of both plant and bacterial origin. This interaction needs to be taken into account in studies on endogenous seed hormones or the response of seeds to plant growth regulators.


Relationships between functional traits and inorganic nitrogen acquisition among eight contrasting European grass species
Leaf functional traits have been used as a basis to categoize plants across a range of resource-use specialization, from those that conserve available resources to those that exploit them. However, the extent to which the leaf functional traits used to define the resource-use strategies are related to root traits and are good indicators of the ability of the roots to take up nitrogen (N) are poorly known. This is an important question because interspecific differences in N uptake have been proposed as one mechanism by which species’ coexistence may be determined. This study investigated the relationships between functional traits and N uptake ability for grass species across a range of conservative to exploitative resource-use strategies. The results support the use of leaf traits as indicators of the N uptake ability across a broad range of grass species. The difficulties associated with assessing root properties are also highlighted, as root traits were only weakly correlated with leaf traits.


Sodium chloride toxicity and the cellular basis of salt tolerance in halophytes
Halophytes are the flora of saline soils. They adjust osmotically to soil salinity by accumulating ions and sequestering the vast majority of these (generally Na+ and Cl) in vacuoles, while in the cytoplasm organic solutes are accumulated to prevent adverse effects on metabolism. At high salinities, however, growth is inhibited. Possible causes are: toxicity to metabolism of Na+ and/or Cl in the cytoplasm; insufficient osmotic adjustment resulting in reduced net photosynthesis because of stomatal closure; reduced turgor for expansion growth; adverse cellular water relations if ions build up in the apoplast (cell walls) of leaves; diversion of energy needed to maintain solute homeostasis; sub-optimal levels of K+ (or other mineral nutrients) required for maintaining enzyme activities; possible damage from reactive oxygen species; or changes in hormonal concentrations. This review discusses the evidence for Na+ and Cl toxicity and the concept of tissue tolerance in relation to halophytes.


Zinc, meristem anatomy and seed germination – this week in Annals of Botany

Zinc concentration in young leaves In situ analysis of foliar zinc absorption and short-distance movement in fresh and hydrated leaves of tomato and citrus using synchrotron-based X-ray fluorescence microscopy
Globally, zinc deficiency is one of the most important nutritional factors limiting crop yield and quality. Despite widespread use of foliar-applied zinc fertilizers, much remains unknown regarding the movement of zinc from the foliar surface into the vascular structure for translocation into other tissues and the key factors affecting this diffusion. Using synchrotron-based X-ray fluorescence microscopy (µ-XRF), absorption of foliar-applied zinc nitrate or zinc hydroxide nitrate was examined in fresh leaves of tomato (Solanum lycopersicum) and citrus (Citrus reticulatus). The results advance our understanding of the factors that influence the efficacy of foliar zinc fertilizers and demonstrate the merits of an innovative methodology for studying foliar zinc translocation mechanisms.


How and why does the areole meristem move in Echinocereus (Cactaceae)?
In Cactaceae, the areole is the organ that forms the leaves, spines and buds. Apparently, the genus Echinocereus develops enclosed buds that break through the epidermis of the stem adjacent to the areole; this trait most likely represents a synapomorphy of Echinocereus. The development of the areole is investigated here in order to understand the anatomical modifications that lead to internal bud development and to supplement anatomical knowledge of plants that do not behave according to classical shoot theory. The enclosed areole meristem and internal bud development are understood to be an adaptation to protect the meristem and the bud from low temperatures.


Effects of germination time on seed morph ratio in a seed-dimorphic species and possible ecological significance
Diaspores of heteromorphic species may germinate at different times due to distinct dormancy-breaking and germination requirements, and this difference can influence life history traits. The primary aim of this study was to determine the effect of germination time of the two seed morphs of Suaeda corniculata subsp. mongolica on life history traits of the offspring. The flexible strategy of a species that produces different proportions of dimorphic seeds in response to variation in germination timing may favour the maintenance and regeneration of the population in its unpredictable environment.


The root-soil interface, ancient climates, sustainable agriculture – what’s new in Annals of Botany this week

The root-soil interface A multi-imaging approach to study the root-soil interface
Dynamic processes occurring at the soil–root interface crucially influence soil physical, chemical and biological properties at a local scale around the roots, and are technically challenging to capture in situ. This study presents a novel multi-imaging approach combining fluorescence and neutron radiography that is able to simultaneously monitor root growth, water content distribution, root respiration and root exudation.


Evidence for cryptic northern refugia in the last glacial period in Cryptomeria japonica
Distribution shifts and natural selection during past climatic changes are important factors in determining the genetic structure of forest species. In particular, climatic fluctuations during the Quaternary caused changes in the distribution ranges of plants, and thus affected their genetic structure. This study focusses on the responses of the conifer Cryptomeria japonica to past climatic changes during the last glacial maximum.


Sustainable intensification in agricultural systems
Agricultural systems are amended ecosystems with a variety of properties. Modern agroecosystems have tended towards high through-flow systems, with energy supplied by fossil fuels directed out of the system. In the coming decades, resource constraints over water, soil, biodiversity and land will affect agricultural systems. Sustainable agroecosystems are those tending to have a positive impact on natural, social and human capital, while unsustainable systems feed back to deplete these assets, leaving fewer for the future. Sustainable intensification a process or system where agricultural yields are increased without adverse environmental impact and without the conversion of additional non-agricultural land. This review analyses recent evidence of the impacts of sustainable intensification in both developing and industrialized countries, and demonstrates that both yield and natural capital dividends can occur.


Diversification and the evolution of dispersal ability in the Brassiceae
Dispersal and establishment ability can influence evolutionary processes such as geographic isolation, adaptive divergence and extinction probability. Through these population-level dynamics, dispersal ability may also influence macro-evolutionary processes such as species distributions and diversification. This study examined patterns of evolution of dispersal-related fruit traits, and how the evolution of these traits is correlated with shifts in geographic range size, habitat and diversification rates in the tribe Brassiceae (Brassicaceae).


Limonium, bursts of CO2 release and Na+/K+ homeostasis at the whole-plant level – What’s New in Annals of Botany this week

Type specimen of Limonium maritimum Taxonomic complexity in the halophyte Limonium vulgare and related taxa (Plumbaginaceae): insights from analysis of morphological, reproductive and karyological data
Limonium is a well-known example of a group of plants that is taxonomically complex due to certain biological characteristics that hamper species’ delineation. The closely related polyploid species Limonium vulgare Mill., L. humile Mill. and L. narbonense Mill. are defined species and can be used for studying patterns of morphological and reproductive variation. The first two taxa are usually found in Atlantic Europe and the third in the Mediterranean region, but a number of intermediate morphological forms may be present alongside typical examples of these species. This study attempts to elucidate morphological, floral and karyological diversity representative of these taxa in the Iberian Peninsula.


Bursts of CO2 released during freezing offer a new perspective on avoidance of winter embolism in trees
Woody plants can suffer from winter embolism as gas bubbles are formed in the water-conducting conduits when freezing occurs: gases are not soluble in ice, and the bubbles may expand and fill the conduits with air during thawing. A major assumption usually made in studies of winter embolism formation is that all of the gas dissolved in the xylem sap is trapped within the conduits and forms bubbles during freezing. The current study tested whether this assumption is actually valid, or whether efflux of gases from the stem during freezing reduces the occurrence of embolism.


ZxNHX controls Na+ and K+ homeostasis at the whole-plant level in Zygophyllum xanthoxylum through feedback regulation of the expression of genes involved in their transport
In order to cope with arid environments, the xerohalophyte Zygophyllum xanthoxylum efficiently compartmentalizes Na+ into vacuoles, mediated by ZxNHX, and maintains stability of K+ in its leaves. However, the function of ZxNHX in controlling Na+ and K+ homeostasis at the whole-plant level remains unclear. In this study, the role of ZxNHX in regulating the expression of genes involved in Na+ and K+ transport and spatial distribution was investigated.


Bizarre flowers, chloride ions and auxin, and the role of pectin in stomatal development – this week in Annals of Botany

Emmotum harleyi Floral structure of Emmotum (Icacinaceae sensu stricto or Emmotaceae), a phylogenetically isolated genus of lamiids with a unique pseudotrimerous gynoecium, bitegmic ovules and monosporangiate thecae
The Icacinaceae consist of a group of early branching lineages of lamiids whose relationships are not yet resolved and whose detailed floral morphology is poorly known. The most bizarre flowers occur in Emmotum: the gynoecium has three locules on one side and none on the other. It has been interpreted as consisting of three fertile and two sterile carpels or of one fertile carpel with two longitudinal septa and two sterile carpels. This study focuses on the outer and inner morphology of the gynoecium to resolve its disputed structure.


Molecular cloning of two novel peroxidases and their response to salt stress and salicylic acid in the living fossil Ginkgo biloba
Peroxidase isoenzymes play diverse roles in plant physiology, such as lignification and defence against pathogens. The actions and regulation of many peroxidases are not known with much accuracy. A number of studies have reported direct involvement of peroxidase isoenzymes in the oxidation of monolignols, which constitutes the last step in the lignin biosynthesis pathway. However, most of the available data concern only peroxidases and lignins from angiosperms. This study describes the molecular cloning of two novel peroxidases from the ‘living fossil’ Ginkgo biloba and their regulation by salt stress and salicylic acid.


Role of chloride ions in the promotion of auxin-induced growth of maize coleoptile segments
The mechanism of auxin action on ion transport in growing cells has not been determined in detail. In particular, little is known about the role of chloride in the auxin-induced growth of coleoptile cells. Moreover, the data that do exist in the literature are controversial. This study describes experiments carried out with maize, a classical model system for studies of plant cell elongation growth. These results suggest that chloride ions play a role in the IAA-induced growth of maize coleoptile segments.


Developmental changes in guard cell wall structure and pectin composition in the moss Funaria: implications for function and evolution of stomata
In seed plants, the ability of guard cell walls to move is imparted by pectins. Arabinan rhamnogalacturonan I (RG1) pectins confer flexibility while unesterified homogalacturonan (HG) pectins impart rigidity. Recognized as the first extant plants with stomata, mosses are key to understanding guard cell function and evolution. Moss stomata open and close for only a short period during capsule expansion. This study examines the ultrastructure and pectin composition of guard cell walls during development in Funaria hygrometrica and relates these features to the limited movement of stomata. This is the first study to demonstrate changes in pectin composition during stomatal development in any plant.


Arabidopsis growth, shading and halophyte-based agriculture – new in Annals of Botany this week

Growth rate distribution in the forming lateral root of arabidopsis Growth rate distribution in the forming lateral root of arabidopsis
Microscopic observations of lateral roots (LRs) in Arabidopsis thaliana reveal that the cross-sectional shape of the organ changes from its basal to its apical region. The founder cells for LRs are elongated along the parent root axis, and thus from the site of initiation the base of LRs resemble an ellipse. The circumference of the apical part of LRs is usually a circle. The objective of this study was to analyse the characteristics of changes in the growth field of LRs possessing various shapes in their basal regions. This is the first report of a description of growth of an asymmetric plant organ using the growth tensor method. The mathematical modelling adopted in the study provides new insights into plant organ formation and shape.


Contribution of above- and below-ground plant traits to the structure and function of grassland soil microbial communities
Abiotic properties of soil are known to be major drivers of the microbial community within it. Our understanding of how soil microbial properties are related to the functional structure and diversity of plant communities, however, is limited and largely restricted to above-ground plant traits, with the role of below-ground traits being poorly understood. This study investigates the relative contributions of soil abiotic properties and plant traits, both above-ground and below-ground, to variations in microbial processes involved in grassland nitrogen turnover.


Responses to shading of naturalized and non-naturalized exotic woody species
Recent studies have suggested that responses to shading gradients may play an important role in establishment success of exotic plants, but hitherto few studies have tested this. Therefore, a common-garden experiment was conducted using multiple Asian woody plant species that were introduced to Europe >100 years ago in order to test whether naturalized and non-naturalized species differ in their responses to shading. Specifically, a test was carried out to determine whether naturalized exotic woody species maintained better growth under shaded conditions, and whether they expressed greater (morphological and physiological) adaptive plasticity in response to shading, relative to non-naturalized species.


The development of halophyte-based agriculture: past and present
Freshwater comprises about a mere 2·5 % of total global water, of which approximately two-thirds is locked into glaciers at the polar ice caps and on mountains. In conjunction with this, in many instances irrigation with freshwater causes an increase in soil salinity due to overirrigation of agricultural land, inefficient water use and poor drainage of unsuitable soils. The problem of salinity was recognized a long time ago and, due to the importance of irrigated agriculture, numerous efforts have been devoted towards improving crop species for better utilization of saline soils and water. Irrigating plants with saline water is a challenge for practitioners and researchers throughout the world. This review critically analyses past and present halophyte-based production systems in the context of genetics, physiology, agrotechnical issues and product value. There are still difficulties that need to be overcome, such as direct germination in saline conditions or genotype selection. However, more and more research is being directed not only towards determining salt tolerance of halophytes, but also to the improvement of agricultural traits for long-term progress.


Lichens and their symbionts, seed size and much more – This Week in Annals of Botany

Morphology and anatomy of Trebouxia species isolated in axenic culture Photobiont selectivity leads to ecological tolerance and evolutionary divergence in a polymorphic complex of lichenized fungi
The integrity and evolution of lichen symbioses depend on a fine-tuned combination of algal and fungal genotypes. Geographically widespread species complexes of lichenized fungi can occur in habitats with slightly varying ecological conditions, and it remains unclear how this variation correlates with symbiont selectivity patterns in lichens. In an attempt to address this question, more than 300 samples were taken of the globally distributed and ecologically variable lichen-forming species complex Tephromela atra, together with closely allied species, in order to study genetic diversity and the selectivity patterns of their photobionts.


The presence of a below-ground neighbour alters within-plant seed size distribution in Phaseolus vulgaris
Considerable variation in seed size commonly exists within plants, and is believed to be favoured under natural selection. This study aims to examine the extent to which seed size distribution depends on the presence of competing neighbour plants. Below-ground neighbour presence affects within-plant seed size distribution in P. vulgaris. This effect appears to be non-resource-mediated, i.e. to be independent of neighbour-induced effects on resource availability. It implies that, based on current environmental cues, plants can make an anticipatory adjustment of their investment strategy in offspring as an adaptation to the local environment in the future.


Extensive long-distance pollen dispersal and highly outcrossed mating in historically small and disjunct populations of Acacia woodmaniorum (Fabaceae), a rare banded iron formation endemic
Understanding patterns of pollen dispersal and variation in mating systems provides insights into the evolutionary potential of plant species and how historically rare species with small disjunct populations persist over long time frames. This study aims to quantify the role of pollen dispersal and the mating system in maintaining contemporary levels of connectivity and facilitating persistence of small populations of the historically rare Acacia woodmaniorum.


An angiosperm-wide analysis of the gynodioecy-dioecy pathway
About 6 % of an estimated total of 240 000 species of angiosperms are dioecious. The main precursors of this sexual system are thought to be monoecy and gynodioecy. A previous angiosperm-wide study revealed that many dioecious species have evolved through the monoecy pathway; some case studies and a large body of theoretical research also provide evidence in support of the gynodioecy pathway. If plants have evolved through the gynodioecy pathway, gynodioecious and dioecious species should co-occur in the same genera. However, to date, no large-scale analysis has been conducted to determine the prevalence of the gynodioecy pathway in angiosperms. In this study, this gap in knowledge was addressed by performing an angiosperm-wide survey in order to test for co-occurrence as evidence of the gynodioecy pathway.


Arrangement of mixed-linkage glucan and glucuronoarabinoxylan in the cell walls of growing maize roots
Plant cell enlargement is unambiguously coupled to changes in cell wall architecture, and as such various studies have examined the modification of the proportions and structures of glucuronoarabinoxylan and mixed-linkage glucan in the course of cell elongation in grasses. However, there is still no clear understanding of the mutual arrangement of these matrix polymers with cellulose microfibrils and of the modification of this architecture during cell growth. This study aimed to determine the correspondence between the fine structure of grass cell walls and the course of the elongation process in roots of maize.


Seed dormancy and parasitic plants – this week in Annals of Botany

Acacia saligna Humidity-regulated dormancy onset in the Fabaceae: a conceptual model and its ecological implications for the Australian wattle Acacia saligna
Seed dormancy enhances fitness by preventing seeds from germinating when the probability of seedling survival and recruitment is low. The onset of physical dormancy is sensitive to humidity during ripening; however, the implications of this mechanism for seed bank dynamics have not been quantified. This study proposes a model that describes how humidity-regulated dormancy onset may control the accumulation of a dormant seed bank, and seed experiments are conducted to calibrate the model for an Australian Fabaceae, Acacia saligna. The model is used to investigate the impact of climate on seed dormancy and to forecast the ecological implications of human-induced climate change.


Arabinogalactan protein-rich cell walls, paramural deposits and ergastic globules define the hyaline bodies of rhinanthoid Orobanchaceae haustoria
Parasitic plants obtain nutrients from their hosts through organs called haustoria. The hyaline body is a specialized parenchymatous tissue occupying the central parts of haustoria in many Orobanchaceae species. The structure and functions of hyaline bodies are poorly understood despite their apparent necessity for the proper functioning of haustoria. This paper reports a cell wall-focused immunohistochemical study of the hyaline bodies of three species from the ecologically important clade of rhinanthoid Orobanchaceae.


Plants and Climate Change: Complexities and Surprises

Photo: BigStockPhoto.

Photo: BigStockPhoto.

Four decades of intensive research into anthropogenically induced shifts in CO2, precipitation, and temperature evidence important biological impacts on many plant species. As ecologists develop more sophisticated experiments however, many unexpected responses become apparent, suggesting that response to climate change in real world vegetation is more complex than the experiments and models of past decades could be expected to anticipate. Nonetheless, these complexities must be understood if we are to have any hope of predicting the effects of anthropogenic climate change on biological systems.

In this Symposium session at ESA 2014, we focus on surprises in plant responses, highlighting mismatches between theory, modelling, experimental and observational studies. We bring together expertise from multiple levels of study (from individual to ecosystems), using manifold approaches (from experimental to modelling to observational), and from ecological, evolutionary and paleo perspectives. Speakers span a range of career stages, from well-established to just finishing their PhDs and include perspectives from four continents (North America, Africa, Asia and Australia).

By bringing together this diversity of topics, approaches and perspectives, we aim to gain new insights and promote future interdisciplinary research on plant/climate interactions.

We hope you’ll be able to join us in Sacramento.

Camille Parmesan, Marine Institute, University of Plymouth, UK. and
Mick Hanley, School of Biological Sciences, University of Plymouth, UK.


13:30 – Richard Primack (University of Boston, USA) Autumn leaf phenology: A search for patterns using 1000 species at four botanical gardens

14:00 – Susan P. Harrison (University of California – Davis, USA) Ecological contingency in the effects of climate change on plant communities: reconciling experimental, historical, interannual, and geographic evidence

14:30 – Kumar P. Mainali (University of Texas at Austin, USA) Complex drivers of population dynamics across treeline: expected and unexpected responses in Himalayan systems

15:10 – Osvaldo Sala (Arizona State University, USA) Lags in the response of ecosystems to directional changes in water availability

15:40 – Tianhua He (Curtin University, Perth, Australia) In situ evolutionary adaptation of Australian plants to climate change

16:10 – Guy Midgley (Stellenbosch University, South Africa) Individualistic species vs. ecosystem responses in under changing climate and CO2 conditions

16:40 Panel Discussion

Annals of Botany Special Issue

The Annals of Botany journal expects to publish work presented at Sacramento as part of a special issue on Plants and Climate Change in the early part of 2015.
The journal welcomes submission of relevant papers from any plant biologist or ecologist for publication in this special issue. Please contact Mick Hanley (mehanley(at) for more details.

Orchid pollen, clover and salinity and Arabidopsis REM – This Week in Annals of Botany

Dactylorhiza maculata Desiccation tolerance, longevity and seed-siring ability of entomophilous pollen from UK native orchid species
Pollinator-limited seed-set in some terrestrial orchids is compensated for by the presence of long-lived flowers. This study tests the hypothesis that pollen from these insect-pollinated orchids should be desiccation tolerant and relatively long lived using four closely related UK terrestrial species; Anacamptis morio, Dactylorhiza fuchsii, D. maculata and Orchis mascula.


Heritability and quantitative genetic divergence of serotiny, a fire-persistence plant trait
Although it is well known that fire acts as a selective pressure shaping plant phenotypes, there are no quantitative estimates of the heritability of any trait related to plant persistence under recurrent fires, such as serotiny. In this study, the heritability of serotiny in Pinus halepensis is calculated, and an evaluation is made as to whether fire has left a selection signature on the level of serotiny among populations by comparing the genetic divergence of serotiny with the expected divergence of neutral molecular markers.


Leaf hydraulic vulnerability to drought is linked to site water availability across a broad range of species and climates
Vulnerability of the leaf hydraulic pathway to water-stress-induced dysfunction is a key component of drought tolerance in plants and may be important in defining species’ climatic range. However, the generality of the association between leaf hydraulic vulnerability and climate across species and sites remains to be tested.


Salinity-mediated cyanogenesis in white clover (Trifolium repens) affects trophic interactions
Increasing soil salinity poses a major plant stress in agro-ecosystems worldwide. Surprisingly little is known about the quantitative effect of elevated salinity on secondary metabolism in many agricultural crops. Such salt-mediated changes in defence-associated compounds may significantly alter the quality of food and forage plants as well as their resistance against pests. In this study, the effects of soil salinity on cyanogenesis in white clover (Trifolium repens), a forage crop of international importance, are analysed.


Analysis of the arabidopsis REM gene family predicts functions during flower development
The REM (Reproductive Meristem) gene family of Arabidopsis thaliana is part of the B3 DNA-binding domain superfamily. Despite the fact that several groups have worked on the REM genes for many years, little is known about the function of this transcription factor family. This study aims to identify a set of REM genes involved in flower development and to characterize their function.