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To ensure comparability among leaf fresh mass measurements it is important to handle the leaves in a standardized manner. In the present work constraints of a commonly used method to achieve full turgor, storage between damp paper towels, were investigated. After overnight rehydration in a saturated atmosphere, the fresh mass of leaves of 14 species was measured, and the leaves were stored between paper towels (two treatments: moist and wet) at 4 °C. Their mass was measured after 24, 48, and 72 h. Leaf fresh mass increased during the first 24 h of storage between moist paper towels by an average of 1.8%, between wet towels by 3.3%. Among the species, the increase of leaf fresh mass between moist towels correlated with the species' desiccation propensity, indicating that it was rehydration from water loss during initial handling. On the other hand, between wet towels the fresh mass increase was associated with the species' leaf tissue structure, and it continued to increase beyond 24 h, indicating that the increase was a result of water penetration into the leaf air spaces. It is concluded that storage between moist paper towels results in reliable values of leaf fresh mass, and that desiccated leaves rehydrate well between moist towels. However, care has to be taken to avoid too wet conditions as they may lead to erroneously high fresh mass values, especially in species with large air spaces. Furthermore, exposure to unsaturated atmospheric conditions during handling has to be minimized. [ABSTRACT FROM PUBLISHER]

Cadmium (Cd) tolerance seems to be a constitutive species-level trait in Arabidopsis halleri. In order to identify genes potentially implicated in Cd tolerance, a backcross (BC1) segregating population was produced from crosses between A. halleri ssp. halleri and its closest non-tolerant relative A. lyrata ssp. petraea. The most sensitive and tolerant genotypes of the BC1 were analysed on a transcriptome-wide scale by cDNA-amplified fragment length polymorphism (AFLP). A hundred and thirty-four genes expressed more in the root of tolerant genotypes than in sensitive genotypes were identified. Most of the identified genes showed no regulation in their expression when exposed to Cd in a hydroponic culture medium and belonged to diverse functional classes, including reactive oxygen species (ROS) detoxification, cellular repair, metal sequestration, water transport, signal transduction, transcription regulation, and protein degradation, which are discussed. [ABSTRACT FROM PUBLISHER]

Cysteine proteinases are involved in various physiological and developmental processes in plants. Two cDNAs from senescent and non-senescent tobacco leaves were isolated with degenerate primers designed from conserved regions of plant senescence-associated cysteine proteinases using rapid amplification of cDNA ends (RACE). Both sequences encode papain-like cysteine proteinases: the 833 bp fragment (NtCP1) encoding a C-terminus partial sequence of a putative tobacco cysteine proteinase gene whereas the 1300 bp fragment (NtCP2) is a full-length cysteine proteinase. On the amino acid sequence level, NtCP1 has a high similarity with other senescence-associated cysteine proteinases. It is expressed only in senescent leaves. It is not induced in mature green leaves upon exposure to drought or heat. These results suggest that it might be a good developmental senescence marker in tobacco. By contrast, NtCP2 has a high similarity to KDEL-tailed cysteine proteinases and is expressed in mature green leaves. Both drought and heat decreased NtCP2 transcript abundance in mature green leaves. It is concluded that NtCP1 is a senescence-specific cysteine proteinase whereas NtCP2 fulfils roles in green leaves that might be similar to those of KDEL-tailed cysteine proteinases involved, for example, in programmed cell death. [ABSTRACT FROM PUBLISHER]

In peach (Prunus persica L. Batsch.) the degradation of the pectic compounds of the cell wall is considered to be the principal component responsible for fruit softening. Many genes encoding enzymes acting on the different polymers of the pectic matrix have been shown to be highly expressed during the late phases of softening, with polygalacturonase being the most important. Nevertheless, it is known that softening starts well before the ethylene climacteric rise which occurs concomitant with the maximal expression of the pectolytic enzymes. The cloning and characterization of PpEG4, an endo-β-1,4-glucanase (EGase) gene preferentially expressed in preclimacteric fruits, are presented here. PpEG4 belongs to the group of EGases containing, at their carboxy-terminus, a peptide similar to the cellulose binding domain of microbial origin. This EGase is also expressed during abscission of both leaves and fruits. The effect of exogenous ethylene treatments on PpEG4 transcription is null in young fruits and negative in preclimacteric ones, while it is positive in abscission zones. Thus, the expression of PpEG4 seems to be more dependent on the type of separation process rather than being influenced by a direct hormone action. The ability of the PpEG4 regulatory sequences to drive transcription in cells undergoing separation events is also maintained in tomato, where about 3 kb of the gene promoter could drive the expression of gusA in preclimacteric fruits and in the fruit abscission zones. [ABSTRACT FROM PUBLISHER]

C4 photosynthesis is a complex specialization that enhances carbon gain in hot, often arid habitats where photorespiration rates can be high. Certain features unique to C4 photosynthesis may reduce the potential for phenotypic plasticity and photosynthetic acclimation to environmental change relative to what is possible with C3 photosynthesis. During acclimation, the structural and physiological integrity of the mesophyll–bundle sheath (M-BS) complex has to be maintained if C4 photosynthesis is to function efficiently in the new environment. Disruption of the M-BS structure could interfere with metabolic co-ordination between the C3 and C4 cycles, decrease metabolite flow rate between the tissues, increase CO2 leakage from the bundle sheath, and slow enzyme activity. C4 plants have substantial acclimation potential, but in most cases lag behind the acclimation responses in C3 plants. For example, some C4 species are unable to maintain high quantum yields when grown in low-light conditions. Others fail to reduce carboxylase content in shade, leaving substantial over-capacity of Rubisco and PEP carboxylase in place. Shade-tolerant C4 grasses lack the capacity for maintaining a high state of photosynthetic induction following sunflecks, and thus may be poorly suited to exploit subsequent sunflecks compared with C3 species. In total, the evidence indicates that C4 photosynthesis is less phenotypically plastic than C3 photosynthesis, and this may contribute to the more restricted ecological and geographical distribution of C4 plants across the Earth. [ABSTRACT FROM PUBLISHER]

Currently, the major thrust of plant physiology research is to identify and understand the regulation of genes that might be relevant in plant development and growth. The dominance of a genocentric view of plant behaviour has, unfortunately, resulted in the development of major disconnects in the classical view of plant physiology as a partnership between fundamental and practical research contributing to improved plant production. One disconnect is that much of the genocentric research appears to be organized and executed without regard to the practical needs of enhancing plant performance under applied conditions. Although practical benefits from genocentric research are often claimed, basic assumptions guiding much research and the experimental protocols used are commonly not relevant for real-world plant production. A second disconnect is a failure fully to appreciate the lessons learned in 40 years of classical plant physiology research concerning the role of physiological processes in altering whole plant performance. Regulation of plant systems has proved to be complex and redundant. Alteration of a single physiological process is compensated or dampened so that commonly very little change in plant growth and yield results from modification of a single physiological process. Based on a few successful projects employing classical plant physiology to achieve crop yield increase, key characteristics for research projects that truly seek to increase plant performance in production systems are identified. Basically, the partnership between the fundamental and practical research long espoused for plant physiology needs to be re-established in an intimate and meaningful way. [ABSTRACT FROM PUBLISHER]

Bruchins, mono and bis (3-hydroxypropanoate) esters of long chain α,ω-diols, are a recently discovered class of insect elicitors that stimulate cell division and neoplasm formation when applied to pods of peas and certain other legumes. Differential display analysis resulted in the identification of an mRNA whose level was increased by the application of Bruchin B to pea pods. The corresponding amplification product was cloned and sequenced and a full length cDNA sequence was obtained. This cDNA and the gene from which it was derived were assigned the name CYP93C18 based upon sequence similarities to the cytochrome P450 mono-oxygenase CYP93C subfamily, which contains isoflavone synthase genes from legumes. RNA gel blots and quantitative RT-PCR demonstrated that expression of CYP93C18 increased within 8 h of bruchin treatment to a maximum of 100–200-fold of the level in untreated pods, and then declined. The up-regulation of CYP93C18 was followed by an increase in the level of the isoflavone phytoalexin, pisatin. Pisatin was detectable in the bruchin-treated pods after 16 h and reached a maximum between 32 h and 64 h. This, the first report of induction of phytoalexin biosynthesis by an insect elicitor, suggests that Bruchin B not only stimulates neoplasm formation, but also activates other plant defence responses. [ABSTRACT FROM PUBLISHER]

Medicago truncatula is a model legume plant that interacts symbiotically with Sinorhizobium meliloti, the alfalfa symbiont. This process involves a molecular dialogue between the bacterium and the plant. Legume roots exude flavonoids that induce the expression of a set of rhizobial genes, the nod genes, which are essential for nodulation and determination of the host range. In turn, nod genes control the synthesis of lipo-chito-oligosaccharides (LCOs), Nod factors, which are bacteria-to-plant signal molecules mediating recognition and nodule organogenesis. M. truncatula roots or seeds have been treated with Nod factors and hydroponically growing seedlings have been inoculated with a limiting population of S. meliloti. It has been shown that submicromolar concentrations of Nod factors increase the number of nodules per plant on M. truncatula. Compared with roots, this increase is more noticeable when seeds are treated. M. truncatula seeds are receptive to submicromolar concentrations of Nod factors, suggesting the possibility of a high affinity LCO perception system in seeds or embryos as well. [ABSTRACT FROM PUBLISHER]

Progress in understanding the network of mechanisms involved in maize primary root growth maintenance under water deficits is reviewed. These include the adjustment of growth zone dimensions, turgor maintenance by osmotic adjustment, and enhanced cell wall loosening. The role of the hormone abscisic acid (ABA) in maintaining root growth under water deficits is also addressed. The research has taken advantage of kinematic analysis, i.e. characterization of spatial and temporal patterns of cell expansion within the root growth zone. This approach revealed different growth responses to water deficits and ABA deficiency in distinct regions of the root tip. In the apical 3 mm region, elongation is maintained at well-watered rates under severe water deficit, although only in ABA-sufficient roots, whereas the region from 3–7 mm from the apex exhibits maximum elongation in well-watered roots, but progressive inhibition of elongation in roots under water deficit. This knowledge has greatly facilitated discovery of the mechanisms involved in regulating the responses. The spatial resolution with which this system has been characterized and the physiological knowledge gained to date provide a unique and powerful underpinning for functional genomics studies. Characterization of water deficit-induced changes in transcript populations and cell wall protein profiles within the growth zone of the maize primary root is in progress. Initial results from EST and unigene analyses in the tips of well-watered and water-stressed roots highlight the strength of the kinematic approach to transcript profiling. [ABSTRACT FROM PUBLISHER]

Water-use efficiency (WUE) is critical in determining the adaptation and productivity of plants in water-limited areas, either under the present climate or future global change. Data on WUE are often highly variable and a unifying and quantitative approach is needed to analyse and predict WUE for different environments. Hsiao has already proposed a set of paradigm equations based on leaf gas exchange for this purpose, calculating WUE (ratio of assimilation to transpiration) relative to the WUE for a chosen reference situation. This study tests the validity and applicability of these equations to cotton and sweet corn stands with full canopies in the open field. Measured were evapotranspiration and downward flux of atmospheric CO2 into the canopy, soil CO2 efflux, canopy temperature, and CO2 and vapour pressure of the air surrounding the canopy. With the measured mean WUE and conditions at midday serving as the reference, WUE for other times was predicted from the air CO2 and water vapour data, intercellular water vapour pressure calculated from canopy temperature, and an assumed ratio of Ci/Ca based on leaf gas-exchange data. Provided that the stomatal response to humidity as it affected the Ci/Ca ratio was accounted for, the equations predicted the moment-by-moment changes in canopy WUE of cotton over daily cycles reasonably well, and also the variation in midday WUE from day-to-day over a 47 d period. The prediction for sweet corn was fairly good for most parts of the day except the early morning. Measurement uncertainties and possible causes of the differences between predicted and measured WUE are discussed. Overall, the results indicate that the equations may be suitable to simulate changes in WUE without upscaling, and also demonstrate clearly the importance of stomatal response to humidity in determining stand WUE in the field. [ABSTRACT FROM PUBLISHER]

Plants experience drought by a limitation of water supply and by enhanced transpiration. Both processes tend to decrease the plant's water potential, but affect growth responses in the root and leaf differently. The evaluation of the underlying mechanisms lead to a discussion of recent studies on biophysical aspects of cell expansion at a cellular, tissue and organ level. Two processes enable roots to compensate rapidly effects of water deficits originating in the medium: (I) adjustment of the minimum pressure in cells required for expansion (yield threshold), and (ii) solute transport within the elongation zone. Limitations of root growth are discussed with respect to hydraulic, mechanical, and solute relations in the root elongation zone. It is argued that the variable nature of both the yield threshold and solute transport challenges the applicability of the Lockhart concept to determine growth-related parameters from steady conditions of turgor and growth. On a whole organ level, the attenuation of xylem pressure along the root is important for the differential response of root and leaf growth. Experimental evidence is presented for the hydraulic separation of the elongation zones, which is closely related to root development and functioning. The data obtained over the past few years have been used to extend mathematical models of growth and water transport in roots. [ABSTRACT FROM PUBLISHER]

Jasmonate is a well-known defence hormone for plants, but it is also necessary for growth and development. Indeed, the identification of the COI1 receptor was based on the jasmonate-triggered response of root growth inhibition. In this special issue, a collection of review papers and two research papers discuss the current state of progress in this field, covering areas from seed germination and flowering to the Jasminum sambac genome. [ABSTRACT FROM AUTHOR]

Accurate measurement of plant transpiration is critical to gaining a better understanding of plant water use and exploration of the influence of plants on regional and even global climate. Heat tracer-based sap flow (HTSF) techniques are currently the dominant method to estimate plant transpiration at the individual plant level. However, the majority of current research focuses on specific applications or the evaluation of the method itself, and there is a lack of an overall analysis of HTSF methods. The objectives of this study were: (i) to briefly review the theories and categories of the various HTSF methods, and (ii) to undertake a bibliometric analysis of the use of HTSF methods in measuring plant transpiration. Each HTSF method is described mathematically and their application and pros and cons are briefly discussed. A bibliometric analysis was conducted using 3964 papers published between 1992 and 2020 archived in the Web of Science core collection. The analysis identified publication trends, the most productive authors, organizations, and countries, as well as the most utilized HTSF method (i.e., thermal dissipation) and journals in which these papers were published. In addition, world distribution maps of the use of HTSF methods and tree species measured were drawn based on 741 selected publications with in situ measurements. [ABSTRACT FROM AUTHOR]

Using a field to lab approach, mature deep-rooting traits in wheat were correlated to root phenotypes measured on young plants from controlled conditions. Mature deep-rooting root traits of 20 wheat genotypes at maturity were established via coring in three field trials across 2 years. Field traits were correlated to phenotypes expressed by the 20 genotypes after growth in four commonly used lab screens: (i) soil tubes for root emergence, elongation, length, and branching at four ages to 34 days after sowing (DAS); (ii) paper pouches 7 DAS and (iii) agar chambers for primary root (PR) number and angles at 8 DAS; and (iv) soil baskets for PR and nodal root (NR) number and angle at 42 DAS. Correlations between lab and field root traits (r 2=0.45–0.73) were highly inconsistent, with many traits uncorrelated and no one lab phenotype correlating similarly across three field experiments. Phenotypes most positively associated with deep field roots were: longest PR and NR axiles from the soil tube screen at 20 DAS; and narrow PR angle and wide NR angle from soil baskets at 42 DAS. Paper and agar PR angles were positively and significantly correlated to each other, but only wide outer PRs in the paper screen correlated positively to shallower field root traits. NR phenotypes in soil baskets were not predicted by PR phenotypes in any screen, suggesting independent developmental controls and value in measuring both root types in lab screens. Strong temporal and edaphic effects on mature root traits, and a lack of understanding of root trait changes during plant development, are major challenges in creating controlled-environment root screens for mature root traits in the field. [ABSTRACT FROM AUTHOR]

Melatonin is a highly conserved and ubiquitous molecule that operates upstream of a broad array of receptors in animal systems. Since melatonin was discovered in plants in 1995, hundreds of papers have been published revealing its role in plant growth, development, and adaptive responses to the environment. This paper summarizes the current state of knowledge of melatonin's involvement in regulating plant ion homeostasis and abiotic stress tolerance. The major topics covered here are: (i) melatonin's control of H+-ATPase activity and its implication for plant adaptive responses to various abiotic stresses; (ii) regulation of the reactive oxygen species (ROS)–Ca2+ hub by melatonin and its role in stress signaling; and (iii) melatonin's regulation of ionic homeostasis via hormonal cross-talk. We also show that the properties of the melatonin molecule allow its direct scavenging of ROS, thus preventing negative effects of ROS-induced activation of ion channels. The above 'desensitization' may play a critical role in preventing stress-induced K+ loss from the cytosol as well as maintaining basic levels of cytosolic Ca2+ required for optimal cell operation. Future studies should focus on revealing the molecular identity of transporters that could be directly regulated by melatonin and providing a bioinformatic analysis of evolutionary aspects of melatonin sensing and signaling. [ABSTRACT FROM AUTHOR]

Compares the effectiveness of high pressure flow meter and evaporative flux methods of measuring plant hydraulic conductances in six crop species grown in pots under quasi-steady-state condition. Effects of temperature and evaporative flux density on hydraulic conductances; Diurnal changes in evaporative flux, leaf water potential and hydraulic conductances.

Above- and belowground linkages are responsible for some of the most important ecosystem processes in unmanaged terrestrial systems including net primary production, decomposition, and carbon sequestration. Global change biology is currently altering above- and belowground interactions, reducing ecosystem services provided by natural systems. Less is known regarding how above- and belowground linkages impact climate resilience, especially in intentionally managed cropping systems. Waterlogged or flooded conditions will continue to increase across the Midwestern USA due to climate change. The objective of this paper is to explore what is currently known regarding above- and belowground linkages and how they impact biological, biochemical, and physiological processes in systems experiencing waterlogged conditions. We also identify key above- and belowground processes that are critical for climate resilience in Midwestern cropping systems by exploring various interactions that occur within unmanaged landscapes. Above- and belowground interactions that support plant growth and development, foster multi-trophic-level interactions, and stimulate balanced nutrient cycling are critical for crops experiencing waterlogged conditions. Moreover, incorporating ecological principles such as increasing plant diversity by incorporating crop rotations and adaptive management via delayed planting dates and adjustments in nutrient management will be critical for fostering climate resilience in row-crop agriculture moving forward. [ABSTRACT FROM AUTHOR]

Describes a system which uses a microcomputer to control peristaltic irrigation pumps to supply nutrients to a plot of cultivated ryegrass, Lolium perenne. Use of dosing frequencies between five minutes and once a day; Calculation of nitrate solutions.

Twenty-five years ago, a seminal paper demonstrated that warm temperatures increase auxin levels to promote hypocotyl growth in Arabidopsis thaliana. Here we highlight recent advances in auxin-mediated thermomorphogenesis and identify unanswered questions. In the warmth, PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and PIF7 bind the YUCCA8 gene promoter and, in concert with histone modifications, enhance its expression to increase auxin synthesis in the cotyledons. Once transported to the hypocotyl, auxin promotes cell elongation. The meta-analysis of expression of auxin-related genes in seedlings exposed to temperatures ranging from cold to hot shows complex patterns of response. Changes in auxin only partially account for these responses. The expression of many SMALL AUXIN UP RNA (SAUR) genes reaches a maximum in the warmth, decreasing towards both temperature extremes in correlation with the rate of hypocotyl growth. Warm temperatures enhance primary root growth, the response requires auxin, and the hormone levels increase in the root tip but the impacts on cell division and cell expansion are not clear. A deeper understanding of auxin-mediated temperature control of plant architecture is necessary to face the challenge of global warming. [ABSTRACT FROM AUTHOR]

Salinity as well as drought are increasing problems in agriculture. Durum wheat (Triticum turgidum L. ssp. durum Desf.) is relatively salt sensitive compared with bread wheat (Triticum aestivum L.), and yields poorly on saline soil. Field studies indicate that roots of durum wheat do not proliferate as extensively as bread wheat in saline soil. In order to look for genetic diversity in root growth within durum wheat, a screening method was developed to identify genetic variation in rates of root growth in a saline solution gradient similar to that found in many saline fields. Seedlings were grown in rolls of germination paper in plastic tubes 37 cm tall, with a gradient of salt concentration increasing towards the bottom of the tubes which contained from 50–200 mM NaCl with complete nutrients. Seedlings were grown in the light to the two leaf stage, and transpiration and evaporation were minimized so that the salinity gradient was maintained. An NaCl concentration of 150 mM at the bottom was found suitable to identify genetic variation. This corresponds to a level of salinity in the field that reduces shoot growth by 50% or more. The screen inhibited seminal axile root length more than branch root length in three out of four genotypes, highlighting changes in root system architecture caused by a saline gradient that is genotype dependent. This method can be extended to other species to identify variation in root elongation in response to gradients in salt, nutrients, or toxic elements. [ABSTRACT FROM PUBLISHER]

Water will be a major limitation to food production in the 21st century, and drought issues already prevail in many parts of the world. Finding solutions to ensure that farmers harvest profitable crops, and secure food supplies for families and feed for animals that will provide for them through to the next season are urgent necessities. The Interdrought community has been addressing this issue for almost 30 years in a series of international conferences, characterized by a multi-disciplinary approach across the domains of molecular biology, physiology, genetics, agronomy, breeding, environmental and social sciences, policy, and systems modeling. This special issue presents papers from the 7th edition of the conference, the first to be held in Africa, that paid special attention to drought in a smallholder context, adding a 'system' dimension to the crop focus from the previous Interdrought events (Varshney et al. , 2018 ; Hammer et al. , 2021). [ABSTRACT FROM AUTHOR]

Water scarcity is already set to be one of the main issues of the 21st century, because of competing needs between civil, industrial, and agricultural use. Agriculture is currently the largest user of water, but its share is bound to decrease as societies develop and clearly it needs to become more water efficient. Improving water use efficiency (WUE) at the plant level is important, but translating this at the farm/landscape level presents considerable challenges. As we move up from the scale of cells, organs, and plants to more integrated scales such as plots, fields, farm systems, and landscapes, other factors such as trade-offs need to be considered to try to improve WUE. These include choices of crop variety/species, farm management practices, landscape design, infrastructure development, and ecosystem functions, where human decisions matter. This review is a cross-disciplinary attempt to analyse approaches to addressing WUE at these different scales, including definitions of the metrics of analysis and consideration of trade-offs. The equations we present in this perspectives paper use similar metrics across scales to make them easier to connect and are developed to highlight which levers, at different scales, can improve WUE. We also refer to models operating at these different scales to assess WUE. While our entry point is plants and crops, we scale up the analysis of WUE to farm systems and landscapes. [ABSTRACT FROM AUTHOR]

This Community Resource paper introduces the range of materials developed by the INDEPTH (Impact of Nuclear Domains on Gene Expression and Plant Traits) COST Action made available through the INDEPTH Academy. Recent rapid growth in understanding of the significance of epigenetic controls in plant and crop science has led to a need for shared, high-quality resources, standardization of protocols, and repositories for open access data. The INDEPTH Academy provides a range of masterclass tutorials, standardized protocols, and teaching webinars, together with a rapidly developing repository to support imaging and spatial analysis of the nucleus and deep learning for automated analysis. These resources were developed partly as a response to the COVID-19 pandemic, but also driven by needs and opportunities identified by the INDEPTH community of ~200 researchers in 80 laboratories from 32 countries. This community report outlines the resources produced and how they will be extended beyond the INDEPTH project, but also aims to encourage the wider community to engage with epigenetics and nuclear structure by accessing these resources. [ABSTRACT FROM AUTHOR]

The functional role of pits between living and dead cells has been inferred from anatomical studies but amassing physiological evidence has been challenging. Centrifugation methods were used to strip water from xylem conduits, permitting a more quantitative gravimetric determination of the water and solid contents of cell walls than is possible by more traditional methods. Quantitative anatomical evidence was used to evaluate the water volume in xylem conduits and the water content of living cells. Quantitative perfusion of stems with polyethylene glycol of different molecular weight was used to determine the solute-free space. We measured the portioning of water and solute-free space among anatomical components in stems and demonstrated that lignin impeded the free movement of solutes with molecular weight >300. Hence, movement of large solutes from living cells to xylem conduits is necessarily confined to pit structures that permit transmembrane solute transport via primary walls without lignin. The functional role of pits was additionally indicated by combining data in this paper with previous studies of unusual osmotic relationships in woody species that lack pits between dead wood fibers and vessels. The absence of pits, combined with the evidence of exclusion of solutes of molecular weight >300, explains the unexpected osmotic properties. [ABSTRACT FROM AUTHOR]

In the literature, Helianthus annuus L. (sunflower) movements are generally described as heliotropic. It is generally believed that the leaves and flowers of the growing H. annuus plant track the sun as the sun moves across the sky from east to west. This paper, however, challenges current interpretation regarding H. annuus movements, as the literature generally excludes the rotation of the earth around its own axis, gravity, and the possible role of gravitation. The general exclusion of the earth's rotation in the literature may also have resulted in flawed research design in studies conducted on H. annuus movements, which in turn may have directed researchers towards the misinterpretation of results. This paper aims to include the possible role of the Earth's rotation, gravity, and gravitation when describing H. annuus movements and to provide possible alternative explanations for the results achieved by researchers. This paper further includes concepts and examples relevant to plant movements, such as the rhythms often associated with plant movements, the physiology of plant movements, referring to turgor pressure as the main force behind plant movements, and plant rhythmic clocks and their characteristics, in order to explain the alternative views and to relate them to H. annuus movements. [ABSTRACT FROM AUTHOR]

I selected my favourite image from a paper by Professor Friedrich Laibach, the founder of Arabidopsis research. His paper from 1951 is the first paper dealing with natural variation for flowering time in this species, a topic many scientists including myself, have followed up and has resulted in large steps forward in our understanding of flowering time regulation. How this topic came to be of interest in my laboratory in Wageningen is described in this short overview. [ABSTRACT FROM AUTHOR]

A correction to the article "Peroxisomal membrane manganese superoxide dismutase: characterization of the isozyme from watermelon," that was published in a previous issue of the journal is presented.

A correction to the articles "Leafy-like gene in the long-day plant, Silene coeli-rosa is dramatically up-regulated in evoked shoot apical meristems but does not complement the Arabidopsis lfy mutant" and "Localization of myoinositol phosphate synthase (GmMIPS-1) during the early stages of soybean seed development," published in a previous issue is presented.

This document is a correction to an article titled "Limited trait responses of a tropical seagrass to the combination of increasing pCO2 and warming" published in the Journal of Experimental Botany. The authors have identified mistakes in the discussion and Table 5 of the original paper. The correction provides the accurate information regarding the effect of temperature on biochemical composition in below-ground tissues, as well as the functional traits that respond to pCO2 and high temperatures. The authors have made the necessary corrections to the original version of the paper. [Extracted from the article]

The orientation growth of coleoptiles of dark‐grown seedlings of rye (Secale cereale L. cv. Marder II), when grown under various conditions, was analysed with respect to the gravivector (‘gravitropic setpoint angle’, GSA). Coleoptiles growing through moist vermiculite attain and maintain a GSA with an average of about 180°, i.e. a vertical orientation. Seedlings growing uncovered either on the surface of vermiculite or positionally fixed on filter paper attain and maintain a GSA of 140–150° (i.e. deviating from the vertical by an average of 30–40°). Changing the position of the embryo relative to the horizontally fixed seed kernel or of the angle of the seed with respect to gravity during germination (±40° relative to the horizontal) had no significant effect on the subsequent GSA of both covered and uncovered seedlings. The GSA of uncovered coleoptiles could be restored close to 180° by treatment of the seedlings with ethylene, either applied via ethephon or 1‐aminocyclopropane‐1‐carboxylic acid (ACC) as well as by fruit‐released ethylene. The results are discussed with respect to the mechanism of the regulation of gravitropic growth of grass seedlings. [ABSTRACT FROM PUBLISHER]

In this paper, we describe the thought process and initial data behind the development of an imaging platform (LeasyScan) combined with lysimetric capacity, to assess canopy traits affecting water use (leaf area, leaf area index, transpiration). LeasyScan is based on a novel 3D scanning technique to capture leaf area development continuously, a scanner-to-plant concept to increase imaging throughput and analytical scales to combine gravimetric transpiration measurements. The paper presents how the technology functions, how data are visualised via a web-based interface and how data extraction and analysis is interfaced through ‘R’ libraries. Close agreement between scanned and observed leaf area data of individual plants in different crops was found (R2 between 0.86 and 0.94). Similar agreement was found when comparing scanned and observed area of plants cultivated at densities reflecting field conditions (R2 between 0.80 and 0.96). An example in monitoring plant transpiration by the analytical scales is presented. The last section illustrates some of the early ongoing applications of the platform to target key phenotypes: (i) the comparison of the leaf area development pattern of fine mapping recombinants of pearl millet; (ii) the leaf area development pattern of pearl millet breeding material targeted to different agro-ecological zones; (iii) the assessment of the transpiration response to high VPD in sorghum and pearl millet. This new platform has the potential to phenotype for traits controlling plant water use at a high rate and precision, of critical importance for drought adaptation, and creates an opportunity to harness their genetics for the breeding of improved varieties. [ABSTRACT FROM AUTHOR]

In a previous paper we clarified the roles of veins in determining leaf function. Here we contribute further data and address the concerns of Blonder et al. (2014), and provide guidance for phenotypic modelling.It has been recently proposed that leaf vein length per area (VLA) is the major determinant of leaf mass per area (LMA), and would thereby determine other traits of the leaf economic spectrum (LES), such as photosynthetic rate per mass (Amass), nitrogen concentration per mass (Nmass) and leaf lifespan (LL). In a previous paper we argued that this ‘vein origin’ hypothesis was supported only by a mathematical model with predestined outcomes, and that we found no support for the ‘vein origin’ hypothesis in our analyses of compiled data. In contrast to the ‘vein origin’ hypothesis, empirical evidence indicated that VLA and LMA are independent mechanistically, and VLA (among other vein traits) contributes to a higher photosynthetic rate per area (Aarea), which scales up to driving a higher Amass, all independently of LMA, Nmass and LL. In their reply to our paper, Blonder et al. (2014) raised questions about our analysis of their model, but did not address our main point, that the data did not support their hypothesis. In this paper we provide further analysis of an extended data set, which again robustly demonstrates the mechanistic independence of LMA from VLA, and thus does not support the ‘vein origin’ hypothesis. We also address the four specific points raised by Blonder et al. (2014) regarding our analyses. We additionally show how this debate provides critical guidance for improved modelling of LES traits and other networks of phenotypic traits that determine plant performance under contrasting environments. [ABSTRACT FROM PUBLISHER]

Predominantly linear relations between germination rate and temperature (over specific ranges) have hitherto been found among the main crop plants. Given linearity, accumulated temperature above a base (Tb) is a reliable predictor of germination time. In contrast, this paper shows marked non-linearities in the response of germination to temperature for four oilseed rape cultivars, two ‘double high’ (Martina and Askari) and ‘two double low’ (Rocket and Express). Linear regressions of 1/time to germination of given percentiles indicate Tb is about 3 °C for all cultivars. However, consistent deviations from linearity occur especially at low temperature, such that germination time at 5°C is up to twice as fast as predicted from a linear model. Moreover, two of the cultivars show an increasing proportion of seeds not germinating as temperature is lowered. These seeds were still viable as demonstrated by their ability to germinate when transferred to warmer temperature. The consequence of non-linearity was to increase the spread of time over which seeds germinated at low temperature. This paper defines the effects and indicates the margin of error likely to follow from applying linear rate/temperature models to whole populations. The findings have implications for the propensity of different oilseed rape cultivars to become volunteer weeds and feral populations. [ABSTRACT FROM PUBLISHER]