Search

Plants require water and nutrients for survival, although the effects of their availabilities on plant fitness differ amongst species. Genome size variation, within and across species, is suspected to influence plant water and nutrient requirements, but little is known about how variations in these resources concurrently affect plant fitness based on genome size. We examined how genome size variation between autopolyploid cytotypes influences plant morphological and physiological traits, and whether cytotype‐specific trait responses differ based on water and/or nutrient availability.Diploid and autotetraploid Solidago gigantea (Giant Goldenrod) were grown in a greenhouse under four soil water:N+P treatments (L:L, L:H, H:L, H:H), and stomata characteristics (size, density), growth (above‐ and belowground biomass, R/S), and physiological (Anet, E, WUE) responses were measured.Resource availabilities and cytotype identity influenced some plant responses but their effects were independent of each other. Plants grown in high‐water and nutrient treatments were larger, plants grown in low‐water or high‐nutrient treatments had higher WUE but lower E, and Anet and E rates decreased as plants aged. Autotetraploids also had larger and fewer stomata, higher biomass and larger Anet than diploids.Nutrient and water availability could influence intra‐ and interspecific competitive outcomes. Although S. gigantea cytotypes were not differentially affected by resource treatments, genome size may influence cytogeographic range patterning and population establishment likelihood. For instance, the larger size of autotetraploid S. gigantea might render them more competitive for resources and niche space than diploids. [ABSTRACT FROM AUTHOR]

Zinc (Zn) is an indispensable element for rice growth. Zn deficiency results in brown blotches and streaks 2–3 weeks after transplanting, as well as stunting, reduced tillering, and low productivity of rice plants. These processes are controlled by different families of expressed genes.A comparative transcriptome profile analysis was conducted using the roots of two Zn deficiency tolerant varieties (UCP122 and KALIBORO26) and two sensitive varieties (IR26 and IR64) by merging data from untreated control (CK) and Zn deficiency treated samples.Results revealed a total of 4,688 differentially expressed genes (DEGs) between the normal Zn and deficient conditions, with 2,702 and 1,489 unique DEGs upregulated and downregulated, respectively. Functional enrichment analysis identified transcription factors (TFs), such as WRKY, MYB, ERF, and bHLH which are important in the regulation of the Zn deficiency response. Furthermore, chitinases, jasmonic acid, and phenylpropanoid pathways were found to be important in the Zn deficiency response. The metal tolerance protein (MTP) genes also appeared to play an important role in conferring tolerance to Zn deficiency. A heavy metal‐associated domain‐containing protein 7 was associated with tolerance to Zn deficiency and negatively regulated downstream genes.Collectively, our findings provide valuable expression patterns and candidate genes for the study of molecular mechanisms underlying the response to Zn deficiency and for improvements in breeding for tolerance to Zn deficiency in rice. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is an important nutrient that can restrict plant growth. However, the influence of P deficiency on elemental homeostasis and application of the growth rate hypothesis in higher plants remain to be assessed.Two shrubs, Zygophyllum xanthoxylum and Nitraria tangutorum, were used as experiment material and subjected to five P addition treatments: 0, 17.5, 35.0, 52.5 and 70.0 mg P·kg−1 soil.The biomass and relative growth rate of Z. xanthoxylum did not change with altered P supply. There was no significant difference in P concentration among the treatments for Z. xanthoxylum, but N. tangutorum showed an upward trend. The P stoichiometric homeostasis of Z. xanthoxylum was higher than that of N. tangutorum. For Z. xanthoxylum, available P in the rhizosphere improved significantly under extreme P deficiency conditions, and P concentrations in all treatments were lower than in N. tangutorum, showing that Z. xanthoxylum had stronger P absorption and P utilization capacity.No relationships between growth rate and C:N:P ratios were found in Z. xanthoxylum. The strong P efficiency, and high and stable dry matter accumulation, are likely contributors in maintaining stoichiometric homeostasis. In addition, the relatively high biomass accumulation and high P utilization efficiency for Z. xanthoxylum does not support the growth rate hypothesis for this species. [ABSTRACT FROM AUTHOR]

In polluted areas, plants may be exposed to supra‐optimal levels of the micronutrient molybdenum. The physiological basis of molybdenum phytotoxicity is poorly understood. Plants take up molybdenum as molybdate, which is a structural analogue of sulphate. Therefore, it is presumed that elevated molybdate concentrations may hamper the uptake and subsequent metabolism of sulphate, which may induce sulphur deficiency.In the current research, Chinese cabbage (Brassica pekinensis) seedlings were exposed to 50, 100, 150 and 200 μm Na2MoO4 for 9 days.Leaf chlorosis and a decreased plant growth occurred at concentrations ≥100 μm. Root growth was more affected than shoot growth. At ≥100 μm Na2MoO4, the sulphate uptake rate and capacity were increased, although only when expressed on a root fresh weight basis. When expressed on a whole plant fresh weight basis, which corrects for the impact of molybdate on the shoot‐to‐root ratio, the sulphate uptake rate and capacity remained unaffected. Molybdate concentrations ≥100 μm altered the mineral nutrient composition of plant tissues, although the levels of sulphur metabolites (sulphate, water‐soluble non‐protein thiols and total sulphur) were not altered. Moreover, the levels of nitrogen metabolites (nitrate, amino acids, proteins and total nitrogen), which are generally strongly affected by sulphate deprivation, were not affected. The root water‐soluble non‐protein thiol content was increased, and the tissue nitrate levels decreased, only at 200 μm Na2MoO4.Evidently, molybdenum toxicity in Chinese cabbage was not due to the direct interference of molybdate with the uptake and subsequent metabolism of sulphate. [ABSTRACT FROM AUTHOR]

Most aluminium (Al)‐accumulating species are found on soils with high Al saturation and low Ca availability (Ca poor). Callisthene fasciculata Mart. (Vochysiaceae), however, is an Al‐accumulating tree restricted to Ca‐rich soils with low Al saturation in the Brazilian Cerrado savanna. Here we tested its calcicole behaviour, and the possible role of organic acids in detoxification of Al during the early stages of plant development.We assessed growth, dry mass, nutrients, Al and organic acids in seedlings grown for 50 days on two contrasting Cerrado soils; one with high Ca concentrations and low Al saturation and the other with low Ca availability and high Al saturation.Relative to plants on Ca‐rich soil, plants on Ca‐poor soil had necrotic spots and bronzing of leaves. Roots and shoots contained reduced concentrations of P and Cu, but higher concentrations of Fe, Al and citrate. Despite lower concentrations in the soil, Ca and Mg increased in shoots. Shoot concentrations of oxalate were also higher.We confirmed C. fasciculata as an Al‐accumulating species with calcicole behaviour. The increased concentrations of organic acids in plants with higher Al accumulation suggest that high availability of soluble Al does not prevent occurrence of this species on soils with high Al saturation. Instead, the absence of C. fasciculata from Ca‐poor soils is probably due to imbalances in tissue Fe, Cu and Zn imposed by this soil type. [ABSTRACT FROM AUTHOR]

Accumulation of NaCl in soil causes osmotic stress in plants, and sodium (Na+) and chloride (Cl−) cause ion toxicity, but also reduce the potassium (K+) uptake by plant roots and stimulate the K+ efflux through the cell membrane. Thus, decreased K+/Na+ ratio in plant tissue lead us to hypothesise that elevated levels of K+ in nutrient medium enhance this ratio in plant tissue and cytosol to improve enzyme activation, osmoregulation and charge balance.In this study, wheat was cultivated at different concentrations of K+ (2.2, 4.4 or 8.8 mm) with or without salinity (1, 60 or 120 mm NaCl) and the effects on growth, root and shoot Na+ and K+ distribution and grain yield were determined. Also, the cytosolic Na+ concentration was investigated, as well as photosynthesis rate and water potential.Salinity reduced fresh weight of both shoots and roots and dry weight of roots. The grain yield was significantly reduced under Na+ stress and improved with elevated K+ fertilisation. Elevated K+ level during cultivation prevented the accumulation of Na+ into the cytosol of both shoot and root protoplasts. Wheat growth at vegetative stage was transiently reduced at the highest K+ concentration, perhaps due to plants' efforts to overcome a high solute concentration in the plant tissue, nevertheless grain yield was increased at both K+ levels.In conclusion, a moderately elevated K+ application to wheat seedlings reduces tissue as well as cytosolic Na+ concentration and enhances wheat growth and grain yield by mitigating the deleterious effects of Na+ toxicity. [ABSTRACT FROM AUTHOR]

Phosphorus (P) nutrition of beech ecosystems depends on soil processes, plant internal P cycling and P acquisition. P uptake of trees in the field is currently not validated due to the lack of an experimental approach applicable in natural forests. Application of radiolabelled tracers such as 33P and 32P is limited to special research sites and not allowed in natural environments. Moreover, only one stable isotope of P, namely 31P, exists. One alternative tool to measure P acquisition in the field could be the use of 18O‐labelled 31P‐phosphate (31P18O43−). Phosphate (Pi) uptake rates calculated from the 18O enrichment of dried root material after application of 31Pi18O43−via nutrient solution was always lower compared to 33P incorporation, did not show increasing rates of Pi uptake at P deficiency under controlled conditions, and did not reveal seasonal fluctuations in the field. Consequently, a clear correlation between 33P‐based and 18O‐based Pi uptake by roots could not be established. Comparison of Pi uptake rates achieved from 33P‐Pi and 18O‐Pi application led to the conclusion of high Pi metabolism in roots after Pi uptake. The replacement of 18O by 16O from water in 18O‐Pi during root influx, but most probably after Pi uptake into roots, due to metabolic activities, indicates high and fast turnover of Pi. Hence, the use of 18O‐Pi as an alternative tool to estimate Pi acquisition of trees in the field must consider the increase of 18O abundance in root water that was disregarded in dried root material. [ABSTRACT FROM AUTHOR]

Abstract: Phosphorus (P) is an important macronutrient with critical functions in plants. Phosphate (Pi) transporters, which mediate Pi acquisition and Pi translocation within the plant, are key factors in Pi deficiency responses. However, their relevance for adaptation to long‐term Pi limitation under agronomic conditions, particularly in wheat, remains unknown. Here, we describe the identification of the complete Pi transporter gene family (Pht1) in wheat (Triticum aestivum). Gene expression profiles were compared for hydroponic and field‐grown plant tissues of wheat at multiple development stages. Cis‐element analysis of selected Pht1 promoter regions was performed. A broad range of expression patterns of individual TaPht1 genes was observed in relation to tissue specificity and the nutrient supply in the soil or in liquid culture, as well as an influence of the experimental system. The expression patterns indicate the involvement of specific transporters in Pi uptake, and in Pi transport and remobilisation within the plant, at different growth developmental stages. Specifically, the influence of Pi nutrition indicates a complex regulatory pattern of TaPht1 gene transcript abundances as a response to low Pi availability in different culture systems, correlating with the existence of different cis‐acting promoter elements. [ABSTRACT FROM AUTHOR]

Amino acids represent an important component in the diet of the Venus flytrap ( Dionaea muscipula), and supply plants with much needed nitrogen resources upon capture of insect prey. Little is known about the significance of prey-derived carbon backbones of amino acids for the success of Dionaea's carnivorous life-style., The present study aimed at characterizing the metabolic fate of 15N and 13C in amino acids acquired from double-labeled insect powder. We tracked changes in plant amino acid pools and their δ13C- and δ15N-signatures over a period of five weeks after feeding, as affected by contrasting feeding intensity and tissue type ( i.e., fed and non-fed traps and attached petioles of Dionaea)., Isotope signatures ( i.e., δ13C and δ15N) of plant amino acid pools were strongly correlated, explaining 60% of observed variation. Residual variation was related to contrasting effects of tissue type, feeding intensity and elapsed time since feeding. Synthesis of nitrogen-rich transport compounds ( i.e., amides) during peak time of prey digestion increased 15N- relative to 13C- abundances in amino acid pools. After completion of prey digestion, 13C in amino acid pools was progressively exchanged for newly fixed 12C. The latter process was most evident for non-fed traps and attached petioles of plants that had received ample insect powder., We argue that prey-derived amino acids contribute to respiratory energy gain and loss of 13CO2 during conversion into transport compounds ( i.e., 2 days after feeding), and that amino-nitrogen helps boost photosynthetic carbon gain later on ( i.e., 5 weeks after feeding). [ABSTRACT FROM AUTHOR]

Glycine max L. (soybean) is one of the major crops of the world. Although the process of biomineralisation has been reported in some organs of soybean, we now report the description and quantification of calcium oxalate crystals in vegetative and reproductive organs of soybean during its life cycle, as they act as an important source of calcium to the soil, once the harvesting is finished., Through diaphanisation, cross-sectioning, optical and scanning electron microscopy analysis of the organs, morphology, size and location of the crystals were identified. In addition, crystal density (n° crystals·mm−2) and the input of crystals to soil (n° crystals·ha−1) were calculated., Soybean produced prismatic calcium oxalate crystals in vegetative and reproductive organs, generally associated with vascular bundles, resulting in a potencial transfer to the soil of 81.4 x 107 crystals·ha−1 throughout its life cycle. Pods were the organs with higher calcium oxalate crystal production (1112.7 ± 384.6 crystals·mm−2), but with the smaller size (12.3 ± 2.1 μm long). However, cotyledons were the organs that produce the larger crystals (21.3 ± 3.5 μm long), but in lesser amounts (150.9 ± 64.4 crystals·mm−2). In leaves, although crystal size did not differ from vegetative to reproductive stage (14.5 ± 4.2 and 14.5 ± 4 μm in length, respectively), the crystal density increased (293.2 and 409 crystals·mm−2, respectively)., These results will contribute to knowledge of the amount of calcium oxalate crystals involved in the process of Ca recycling through cultivated vegetation in fields from humid plains at medium latitudes, which therefore have biological, botanical, biogeochemical and pedological relevance. [ABSTRACT FROM AUTHOR]

Grasses accumulate high amounts of silica deposits in tissues of all their organs, especially at mature stage. However, when and under which conditions do grass seedlings begin to produce these silica deposits and their relation with anatomy and development is little known. Here we investigated the silicification process in the first leaves and roots of seedlings of Bothriochloa laguroides grown in different substrate and Si treatments., The distribution and content of silica deposits in the organs of the seedlings grown under different conditions were analyzed through staining techniques and SEM-EDAX analyses., Leaf silica deposits were accumulated 3-4 days after the first leaf emergence, also under low silica solution (0.17-0.2 mM). Their location was mainly restricted to short costal cells from basal sectors, and scarcely in trichomes and xylem at tips. Silica content in leaves increased with the age of the seedlings. Roots presented dome-shaped silica aggregates, between 4-12 μm of diameter, located in the inner tangential wall of endodermal cells and similar to those produced at maturity., Silicification begins early in the first photosynthetic leaf, and silica distribution is opposite to that found in mature plants, mainly restricted to basal sectors, probably acting as a reinforcing element. The fast incorporation of solid amorphous silica in leaves and roots, may be useful for farm applications in species that are Si-fertilized. [ABSTRACT FROM AUTHOR]

Being the principal product of photosynthesis, sucrose is involved in many metabolic processes in plants. As magnesium (Mg) is phloem mobile, an inverse relationship between Mg shortage and sugar accumulation in leaves is often observed., Mg deficiency effects on carbohydrate contents and invertase activities were determined in Sulla carnosa Desf. Plants were grown hydroponically at different Mg concentrations (0.00, 0.01, 0.05 and 1.50 mM Mg) for one month., Mineral analysis showed that Mg contents were drastically diminished in shoots and roots mainly at 0.01 and 0.00 mM Mg. This decline was adversely associated with a significant increase of sucrose, fructose and mainly glucose in shoots of plants exposed to severe deficiency. By contrast, sugar contents were severely reduced in roots of these plants indicating an alteration of carbohydrate partitioning between shoots and roots of Mg-deficient plants. Cell wall invertase activity was highly enhanced in roots of Mg-deficient plants, while the vacuolar invertase activity was reduced at 0.00 mM Mg. This decrease of vacuolar invertase activity may indicate the sensibility of roots to Mg starvation resulting from sucrose transport inhibition. 14CO2 labeling experiments were in accordance with these findings showing an inhibition of sucrose transport from source leaves to sink tissues (roots) under Mg depletion., The obtained results confirm previous findings about Mg involvement in photosynthate loading into phloem and add new insights into mechanisms evolved by S. carnosa to cope with Mg shortage in particular the increase of the activity of cell wall invertase. [ABSTRACT FROM AUTHOR]

Duckweed can be used for bioremediation of selenium (Se) polluted water because of its capability of absorbing minerals from growing media. However, the presence of Se in the media may affect the growth of the duckweed. Landoltia punctata 7449 has been studied for its changes in chemical and biological properties with the presence of Se in the media., The duckweed was cultivated over a 12-day period at different initial concentrations of selenite (Na2SeO3) from 0 to 80 μmol·l−1. The growth rate, the organic and total Se contents, the activity of antioxidant enzymes, the photosynthetic pigment contents, the chlorophyll a fluorescence OJIP transient, and the ultrastructure of the duckweed were monitored during the experiment., The results have shown that Se at low concentrations of ≤20 μmol·l−1 promoted the growth of the L. punctata and inhibited lipid peroxidation. Substantial increases in duckweed growth rate and organic Se content in the duckweed were observed at low Se concentrations. The anti-oxidative effect occurred likely with the increases in guaiacol peroxidase, catalase and superoxide dismutase activities as well as the amount of photosynthetic pigments. However, negative impact to the duckweed was observed when the L. punctata was exposed to high Se concentrations (≥40 μmol·l−1), in which the duckweed growth was inhibited by the selenium., The results indicate that L. punctata 7449 can be used for bioremediation of selenium (Se) polluted water when the Se concentration is ≤20 μmol·l−1. [ABSTRACT FROM AUTHOR]

In this opinion article we examine the relationship between penetrometer resistance and soil depth in the field. Assuming that root growth is inhibited at penetrometer resistances > 2.5 MPa, we conclude that in most circumstances the increases in penetrometer resistance with depth are sufficiently great to confine most deep roots to elongating in existing structural pores. We suggest that deep rooting is more likely related to the interaction between root architecture and soil structure than it is to the ability of a root to deform strong soil. Although the ability of roots to deform strong soil is an important trait, we propose it is more closely related to root exploration of surface layers than deep rooting. [ABSTRACT FROM AUTHOR]

Depending on their specificity to gypsum, plants can be classified as gypsophiles (gypsum exclusive) and gypsovags (non-exclusive). The former may further be segregated into wide and narrow gypsophiles, depending on the breadth of their distribution area. Narrow gypsum endemics have a putative similar chemical composition to plants non-exclusive to gypsum ( i.e. gypsovags), which may indicate their similar ecological strategy as stress-tolerant plant refugees on gypsum. However, this hypothesis awaits testing in different regions of the world. We compared the chemical composition of four narrow gypsum endemics, one widely distributed gypsophile and six gypsovags from Turkey. Further, we explored the plasticity in chemical composition of Turkish gypsovags growing on high- and low-gypsum content soils. Differences were explored with multivariate analyses ( RDA) and mixed models ( REML). Narrow gypsum endemics segregated from gypsovags in their chemical composition according to RDAs (mainly due to higher K and ash content in the former). Nevertheless, differences were small and disappeared when different nutrients were analysed individually. All the gypsovags studied accumulated more S and ash when growing on high-gypsum than on low-gypsum soils. Similar to narrow gypsum endemics from other regions of the world, most local gypsum endemics from Turkey show a similar chemical composition to gypsovags. This may indicate a shared ecological strategy as stress-tolerant plants not specifically adapted to gypsum. Nevertheless, the narrow gypsum endemic Gypsophila parva showed a chemical composition typical of gypsum specialists, indicating that various strategies are feasible within narrowly distributed gypsophiles. [ABSTRACT FROM AUTHOR]

Enhanced soil ammonium () concentrations in wetlands often lead to graminoid dominance, but species composition is highly variable. Although is readily taken up as a nutrient, several wetland species are known to be sensitive to high concentrations or even suffer toxicity, particularly at low soil pH. More knowledge about differential graminoid responses to high availability in relation to soil pH can help to better understand vegetation changes. The responses of two wetland graminoids, Juncus acutiflorus and Carex disticha, to high (2 mmol·l−1) versus control (20 μmol·l−1) concentrations were tested in a controlled hydroponic set up, at two pH values (4 and 6). A high concentration did not change total biomass for these species at either pH, but increased C allocation to shoots and increased P uptake, leading to K and Ca limitation, depending on pH treatment. More than 50% of N taken up by C. disticha was invested in N-rich amino acids with decreasing C:N ratio, but only 10% for J. acutiflorus. Although both species appeared to be well adapted to high loadings in the short term, C. disticha showed higher classic detoxifying responses that are early warning indicators for decreased tolerance in the long term. In general, the efficient aboveground biomass allocation, P uptake and N detoxification explain the competitive strength of wetland graminoids at the expense of overall biodiversity at high loading. In addition, differential responses to enhanced affect interspecific competition among graminoids and lead to a shift in vegetation composition. [ABSTRACT FROM AUTHOR]

The transition zone between terrestrial and freshwater habitats is highly dynamic, with large variability in environmental characteristics. Here, we investigate how these characteristics influence the nutritional status and performance of plant life forms inhabiting this zone. Specifically, we hypothesised that: (i) tissue nutrient content differs among submerged, amphibious and terrestrial species, with higher content in submerged species; and (ii) PNUE gradually increases from submerged over amphibious to terrestrial species, reflecting differences in the availability of N and P relative to inorganic C across the land-water ecotone. We found that tissue nutrient content was generally higher in submerged species and C:N and C:P ratios indicated that content was limiting for growth for ca. 20% of plant individuals, particularly those belonging to amphibious and terrestrial species groups. As predicted, the PNUE increased from submerged over amphibious to terrestrial species. We suggest that this pattern reflects that amphibious and terrestrial species allocate proportionally more nutrients into processes of importance for photosynthesis at saturating CO2 availability, i.e. enzymes involved in substrate regeneration, compared to submerged species that are acclimated to lower availability of CO2 in the aquatic environment. Our results indicate that enhanced nutrient loading may affect relative abundance of the three species groups in the land-water ecotone of stream ecosystems. Thus, species of amphibious and terrestrial species groups are likely to benefit more from enhanced nutrient availability in terms of faster growth compared to aquatic species, and that this can be detrimental to aquatic species growing in the land-water ecotone, e.g. Ranunculus and Callitriche. [ABSTRACT FROM AUTHOR]

Rising atmospheric CO2 concentrations (e[ CO2]) are presumed to have a significant impact on plant growth and yield and also on mineral nutrient composition, and therefore, on nutritional quality of crops and vegetables. To assess the relevance of these effects in future agroecosystems it is important to understand how e[ CO2] interacts with other environmental factors. In the present study, we examined the interactive effects of e[ CO2] with temperature and the form in which nitrogen is supplied (nitrate or ammonium nitrate) on growth, amino acid content and mineral nutrient composition of Chinese cabbage ( Brassica pekinensis Rupr.), a crop characterised by its high nutritional value and increasing relevance for human nutrition in many developing countries. Higher temperature, ammonium nitrate and e[ CO2] had a positive impact on net photosynthesis and growth. A stimulating effect of e[ CO2] on growth was only observed if the temperature was high (21/18 °C, day/night), and an interaction of e[ CO2] with N form was only observed if the temperature was ambient (15/12 °C, day/night). Mineral nutrient composition was affected in a complex manner by all three factors and their interaction. These results demonstrate how much the effect of e[ CO2] on mineral quality of crops depends on other environmental factors. Changes in temperature, adapting N fertilisation and the oxidation state of N have the potential to counteract the mineral depletion caused by e[ CO2]. [ABSTRACT FROM AUTHOR]

Increasing the duration of leaf photosynthesis during grain filling using slow-senescing functional stay-green phenotypes is a possible route for increasing grain yields in wheat ( Triticum aestivum L.). However, delayed senescence may negatively affect nutrient remobilisation and hence reduce grain protein concentrations and grain quality. A novel NAC1-type transcription factor (hereafter Ta NAC-S) was identified in wheat, with gene expression located primarily in leaf/sheath tissues, which decreased during post-anthesis leaf senescence. Expression of Ta NAC-S in the second leaf correlated with delayed senescence in two doubled-haploid lines of an Avalon × Cadenza population (lines 112 and 181), which were distinct for leaf senescence. Transgenic wheat plants overexpressing Ta NAC-S resulted in delayed leaf senescence (stay-green phenotype). Grain yield, aboveground biomass, harvest index and total grain N content were unaffected, but NAC over-expressing lines had higher grain N concentrations at similar grain yields compared to non-transgenic controls. These results indicate that Ta NAC-S is a negative regulator of leaf senescence, and that delayed leaf senescence may lead not only to increased grain yields but also to increased grain protein concentrations. [ABSTRACT FROM AUTHOR]

Characterising the adaptability in nature of plant stoichiometric patterns across geographic or environmental gradients is important in advancing our understanding of the organisation of plant-nutrient relationships. We examined correlations between plant nutrient traits, latitude, longitude, climate and soil variables in 34 populations of Oryza rufipogon across its range. We further compared the responses of population transplants at two experimental gardens: one beyond its northern natural range and another near the southern limit, to assess the nature of geographic variation in plant nutrients. The study showed that leaf P of O. rufipogon in the field was negatively correlated with latitude and largely depended on temperature and soil P availability. Leaf N was not related to latitude but was significantly correlated with precipitation and soil N concentration. Leaf N:P ratio was largely determined by absorption efficiency of P. Transplantation revealed that there were no significant associations of leaf nutrients with geographic, climatic or soil variables of origin in either of the experimental gardens, indicating phenotypic plasticity. However, examination of relationships between response ratios of leaf nutrients and change ratio of climate and soil environments, as well as norms of reaction in the transplantation experiment, revealed more complexity, suggesting both substantial genotypic diversity and the existence of genotype × environment interactions in these populations of O. rufipogon. These data indicate that adaptive plasticity response of plants to temperature and soil P availability significantly explain the observed shifts in leaf N, P and N:P of O. rufipogon along latitudinal gradients. [ABSTRACT FROM AUTHOR]

The contribution of antioxidant defence systems in different tolerance to direct and bicarbonate-induced Fe deficiency was evaluated in two pea cultivars (Kelvedon, tolerant and Lincoln, susceptible). Fe deficiency enhanced lipid peroxidation and H2O2 concentration in roots of both cultivars, particularly in the sensitive one grown under bicarbonate supply. The results obtained on antioxidant activities ( SOD, CAT, POD) suggest that H2O2 accumulation could be due to an overproduction of this ROS and, at the same time, to a poor capacity to detoxify it. Moreover, under bicarbonate supply the activity of POD isoforms was reduced only in the sensitive cultivar, while in the tolerant one a new isoform was detected, suggesting that POD activity might be an important contributor to pea tolerance to Fe deficiency. The presence of bicarbonate also resulted in stimulation of GR, MDHAR and DHAR activities, part of the ASC- GSH pathway, which was higher in the tolerant cultivar than in the sensitive one. Overall, while in the absence of Fe only slight differences were reported between the two cultivars, the adaptation of Kelvedon to the presence of bicarbonate seems to be related to its greater ability to enhance the antioxidant response at the root level. [ABSTRACT FROM AUTHOR]

Halophytes are potential gene sources for genetic manipulation of economically important crop species. This study addresses the physiological responses of a widespread halophyte, Prosopis strombulifera ( Lam.) Benth to salinity. We hypothesised that increasing concentrations of the two major salts present in soils of central Argentina ( Na2SO4, NaCl, or their iso-osmotic mixture) would produce distinct physiological responses. We used hydroponically grown P. strombulifera to test this hypothesis, analysing growth parameters, water relations, photosynthetic pigments, cations and anions. These plants showed a halophytic response to NaCl, but strong general inhibition of growth in response to iso-osmotic solutions containing Na2SO4. The explanation for the adaptive success of P. strombulifera in high NaCl conditions seems to be related to a delicate balance between Na + accumulation (and its use for osmotic adjustment) and efficient compartmentalisation in vacuoles, the ability of the whole plant to ensure sufficient K+ supply by maintaining high K +/ Na + discrimination, and maintenance of normal Ca2 + levels in leaves. The three salt treatments had different effects on the accumulation of ions. Findings in bi-saline-treated plants were of particular interest, where most of the physiological parameters studied showed partial alleviation of SO42−-induced toxicity by Cl−. Thus, discussions on physiological responses to salinity could be further expanded in a way that more closely mimics natural salt environments. [ABSTRACT FROM AUTHOR]

The toxicity of high copper ( Cu) concentrations in the root environment of Chinese cabbage ( Brassica pekinensis) was little influenced by the sulphur nutritional status of the plant. However, Cu toxicity removed the correlation between sulphur metabolism-related gene expression and the suggested regulatory metabolites. At high tissue Cu levels, there was no relation between sulphur metabolite levels viz. total sulphur, sulphate and water-soluble non-protein thiols, and the expression and activity of sulphate transporters and expression of APS reductase under sulphate-sufficient or-deprived conditions, in the presence or absence of H2 S. This indicated that the regulatory signal transduction pathway of sulphate transporters was overruled or by-passed upon exposure to elevated Cu concentrations. [ABSTRACT FROM AUTHOR]

Phosphorus ( P) acquisition, cycling and use efficiency has been investigated intensively with herbaceous plants. It is known that local as well as systemic signalling contributes to the control of P acquisition. Woody plants are long-lived organisms that adapt their life cycle to the changing environment during their annual growth cycle. Little is known about P acquisition and P cycling in perennial plants, especially regarding storage and mobilisation, its control by systemic and environmental factors, and its interaction with the largely closed ecosystem-level P cycle. The present report presents a view on open questions on plant internal P cycling in woody plants. [ABSTRACT FROM AUTHOR]

The use of plant genetic resources (PGR)-wild relatives, landraces, and isolated breeding gene pools-has had substantial impacts on wheat breeding for resistance to biotic and abiotic stresses, while increasing nutritional value, end-use quality, and grain yield. In the Global South, post-Green Revolution genetic yield gains are generally achieved with minimal additional inputs. As a result, production has increased, and millions of hectares of natural ecosystems have been spared. Without PGR-derived disease resistance, fungicide use would have easily doubled, massively increasing selection pressure for fungicide resistance. It is estimated that in wheat, a billion liters of fungicide application have been avoided just since 2000. This review presents examples of successful use of PGR including the relentless battle against wheat rust epidemics/pandemics, defending against diseases that jump species barriers like blast, biofortification giving nutrient-dense varieties and the use of novel genetic variation for improving polygenic traits like climate resilience. Crop breeding genepools urgently need to be diversified to increase yields across a range of environments (>200 Mha globally), under less predictable weather and biotic stress pressure, while increasing input use efficiency. Given that the ~0.8 m PGR in wheat collections worldwide are relatively untapped and massive impacts of the tiny fraction studied, larger scale screenings and introgression promise solutions to emerging challenges, facilitated by advanced phenomic and genomic tools. The first translocations in wheat to modify rhizosphere microbiome interaction (reducing biological nitrification, reducing greenhouse gases, and increasing nitrogen use efficiency) is a landmark proof of concept. Phenomics and next-generation sequencing have already elucidated exotic haplotypes associated with biotic and complex abiotic traits now mainstreamed in breeding. Big data from decades of global yield trials can elucidate the benefits of PGR across environments. This kind of impact cannot be achieved without widescale sharing of germplasm and other breeding technologies through networks and public-private partnerships in a pre-competitive space., (© 2024 The Author(s). Global Change Biology published by John Wiley & Sons Ltd.)

Wheat is a major staple food crop worldwide because of the unique properties of wheat flour. High molecular weight glutenin subunits (HMW-GSs), which are among the most critical determinants of wheat flour quality, are responsible for the formation of glutenin polymeric structures via interchain disulfide bonds. We herein describe the identification of a new HMW-GS Dy10 allele ( Dy10-m619SN ) . The amino acid substitution (serine-to-asparagine) encoded in this allele resulted in a partial post-translational cleavage that produced two new peptides. These new peptides disrupted the interactions among gluten proteins because of the associated changes to the number of available cysteine residues for interchain disulfide bonds. Consequently, Dy10-m619SN expression decreased the size of glutenin polymers and weakened glutens, which resulted in wheat dough with improved cookie-making quality, without changes to the glutenin-to-gliadin ratio. In this study, we clarified the post-translational processing of HMW-GSs and revealed a new genetic resource useful for wheat breeding., Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-021-01238-9., (© The Author(s), under exclusive licence to Springer Nature B.V. 2021.)

A diverse panel of 245 wheat genotypes, derived from crosses between landraces from the Watkins collection representing global diversity in the early 20th century and the modern wheat cultivar Paragon, was grown at two field sites in the UK in 2015-16 and the concentrations of zinc and iron determined in wholegrain using inductively coupled plasma-mass spectrometry (ICP-MS). Zinc concentrations in wholegrain varied from 24-49 mg kg-1 and were correlated with iron concentration (r = 0.64) and grain protein content (r = 0.14). However, the correlation with yield was low (r = -0.16) indicating little yield dilution. A sub-set of 24 wheat lines were selected from 245 wheat genotypes and characterised for Zn and Fe concentrations in wholegrain and white flour over two sites and years. White flours from 24 selected lines contained 8-15 mg kg-1 of zinc, which was positively correlated with the wholegrain Zn concentration (r = 0.79, averaged across sites and years). This demonstrates the potential to exploit the diversity in landraces to increase the concentration of Zn in wholegrain and flour of modern high yielding bread wheat cultivars., Competing Interests: The authors have declared that no competing interests exist

In the field, wheat experiences a combination of physical and nutrient stresses. There has been a tendency to study root impedance and water stress in separation and less is known about how they might interact. In this study, we investigated the effect of root impedance on the growth of three wheat varieties (Cadenza, Xi19 and Battalion) at different levels of nitrate availability, from 0-20 mM nitrate, in sand culture. This model system allows soil strength to be increased while maintaining adequate water availability. In a separate pot experiment, we grew the same wheat varieties in a loamy sand where soil was allowed to dry sufficiently to both reduce water potential and increase root impedance. This pot experiment also had a range of nitrate availabilities 0-20 mM nitrate. Once the seedlings were established we limited water supply to apply a matric potential of approximately -200 kPa to the roots. Soil drying increased the penetrometer resistance from approximately 300 kPa to more than 1 MPa. There were differences between the two experimental systems; growth was smaller in the soil-based experiment compared to the sand culture. However, the effects of the experimental treatment, root impedance or water withholding, relative to the control were comparable. Our data confirmed that leaf elongation in Cadenza (carrying the tall Rht allele) was the most sensitive to root impedance. Leaf stunting occurred irrespective of nitrate availability. Leaf elongation in the Xi19 and Battalion (carrying the semi-dwarf Rht allele) was less sensitive to root impedance and drought than Candenza. We suggest that the critical stress in a pot experiment where the soil was allowed to dry to approximately -200 kPa was root impedance and not water availability.

Wheat has been domesticated into a large number of agricultural environments and has the ability to adapt to diverse environments. To understand this process, we survey genotype, repeat content, and DNA methylation across a bread wheat landrace collection representing global genetic diversity. We identify independent variation in methylation, genotype, and transposon copy number. We show that these, so far unexploited, sources of variation have had a significant impact on the wheat genome and that ancestral methylation states become preferentially "hard coded" as single nucleotide polymorphisms (SNPs) via 5-methylcytosine deamination. These mechanisms also drive local adaption, impacting important traits such as heading date and salt tolerance. Methylation and transposon diversity could therefore be used alongside SNP-based markers for breeding., (© 2018 Gardiner et al.; Published by Cold Spring Harbor Laboratory Press.)