يعرض 1 - 10 نتائج من 56 نتيجة بحث عن '"remobilization"', وقت الاستعلام: 0.78s تنقيح النتائج
  1. 1

    المصدر: Journal of Integrative Agriculture, Vol 20, Iss 12, Pp 3277-3288 (2021)

    الوصف: Increasing zinc (Zn) concentration in wheat grain is important to minimize human dietary Zn deficiency. This study aimed to investigate the effect of foliar Zn and soil nitrogen (N) applications on the accumulation and distribution of N and Zn in grain pearling fractions, N remobilization, and the relationships between nutrient concentration in the vegetative tissues and grain or its fractions in two cropping years in the North China Plain. The results showed a progressive decrease in N and Zn concentrations from the outer to the inner parts of grain, with most of the accumulation in the core endosperm. Foliar Zn application significantly increased N concentration in the pericarp, and soil N application increased N concentration in each grain fraction. Both treatments significantly increased core endosperm Zn concentration. Foliar Zn had no effect on grain N and Zn distribution. Soil N application made N concentrated in the aleurone, promoted Zn translocation to the core endosperm and also increased N remobilization and its efficiency from the shoot to the grain, but no improved contribution to grain was found. N concentration in grain and its fractions were positively correlated with N in vegetative organs at anthesis and maturity, while positive correlations were obtained between N concentration in the pericarp and progressive central area of the endosperm and Zn concentration in the core endosperm. Thus, foliar Zn and soil N applications effectively increased yield and N and Zn concentrations in the wheat grain, particularly in the endosperm, and could be promising strategies to address Zn deficiency.

  2. 2

    المصدر: Crop Journal, Vol 9, Iss 6, Pp 1397-1407 (2021)

    الوصف: Increased grain yield (GY) and grain protein concentration (GPC) are the two main targets of efforts to improve wheat (Triticum aestivum L.) production in the North China Plain (NCP). We conducted a three-year field experiment in the 2014–2017 winter wheat growing seasons to compare the effects of conventional irrigation practice (CI) and micro-sprinkling irrigation combined with nitrogen (N) fertilizer (MSI) on GY, GPC, and protein yield (PY). Across the three years, GY, GPC, and PY increased by 10.5%–16.7%, 5.4%–8.0%, and 18.8%–24.6%, respectively, under MSI relative to CI. The higher GY under MSI was due primarily to increased thousand-kernel weight (TKW). The chlorophyll content of leaves was higher under MSI during the mid–late grain filling period, increasing the contribution of post-anthesis dry matter accumulation to GY, with consequent increases in total dry matter accumulation and harvest index compared to CI. During the mid–late grain filling period, the canopy temperature was markedly lower and the relative humidity was higher under MSI than under CI. The duration and rate of filling during the mid–late grain filling period were also higher under MSI than CI, resulting in higher TKW. MSI increased the contribution of post-anthesis N accumulation to grain N but reduced the pre-anthesis remobilization of N in leaves, the primary site of photosynthetic activity, possibly helping maintain photosynthate production in leaves during grain filling. Total N at maturity was higher under MSI than CI, although there was little difference in N harvest index. The higher GPC under MSI than under CI was due to a larger increase in grain N accumulation than in GY. Overall, MSI simultaneously increased both GY and GPC in winter wheat grown in the NCP.

  3. 3

    المصدر: Journal of Experimental Botany

    الوصف: Senescence is a complex trait under genetic and environmental control, in which resources are remobilized from vegetative tissue into grain. Delayed senescence, or ‘staygreen’ traits, can confer stress tolerance, with extended photosynthetic activity hypothetically sustaining grain filling. The genetics of senescence regulation are largely unknown, with senescence variation often correlated with phenological traits. Here, we confirm staygreen phenotypes of two Triticum aestivum cv. Paragon ethyl methane sulfonate mutants previously identified during a forward genetic screen and selected for their agronomic performance, similar phenology, and differential senescence phenotypes. Grain filling experiments confirmed a positive relationship between onset of senescence and grain fill duration, reporting an associated ~14% increase in final dry grain weight for one mutant (P
    Two staygreen mutants were identified for which grain fill duration and grain weight were enhanced. Independent amino acid substitutions within NAC subdomain IV of NAM-1 homoeologues are proposed as causative.

  4. 4

    المصدر: Biosystems Diversity, Vol 28, Iss 1, Pp 113-118 (2020)

    الوصف: The patterns of the distribution of nutrients in kiwiberry (Actinidia arguta (Siebold & Zucc.) Planch. ex Miq.), family Actinidiaceae (Gilg & Werderm), leaves growing under different soil and climatic conditions (Ukraine and China) were studied. Using scanning electron microscopy, significant differences were shown in the distribution of assimilates and mineral nutrients in the leaves of kiwiberry cultivated under different climate and soil conditions (Kyiv city, Ukraine and Jiamusi, China). The leaves of plants grown in China have higher concentration of all of the studied nutrients exception for silicon. The differences found in the content of macro- and microelements in plant tissues are consistent with their total content in the soil, and depend on the synthesis of low molecular weight organic compounds, namely, hydroxybenzoic, benzoic and triterpene acids. An increase in the silicon content in the leaves of kiwiberry plants grown in Ukraine indicates the moisture deficit in the soil. This conclusion is confirmed by the anatomical differences viz. the presence of additional integumentary formations and fewer stomata number per 1 mm2 of leaf surface. The specific feature of ‘Perlyna sadu’ cultivar was high concentrations of sodium and aluminum in the foliar tissues, regardless of the place of growth. The analysis of the distribution of nutrients in the leaves located along the stem showed remobilization of the former within the three layers: the lower one nourishes the roots, the upper one nourishes the leaves in the active growth phase and the middle one allocates the assimilates in both directions. A significant positive relationship was found between the biosynthesis of photosynthetic pigments and electrophysiological activity, especially for the leaves of the lower zone. The revealed differentiation into layers differing in polarity of bioelectric potentials and the distribution of assimilates suggests functional differentiation of the kiwiberry leaves. In particular, the leaves of the lower layer perform a storage function. The middle part is less conservative and characterized by higher sensitivity to environmental factors performs a mainly synthetic function. The upper layer performs an active growth function. The results of the comparative analysis of the indicators of the number of chloroplasts in the mesophyll cells proved that the obtained dependence can be used as a diagnostic criterion in assessing the predicted plant productivity at the early stages of their development.

  5. 5

    المصدر: Plant Biotechnology Journal

    الوصف: Summary Vegetative storage proteins (VSPs) are known to serve as nitrogen reserves in many dicot plants but remain undiscovered in grasses, most widely grown group of crops globally. We identified and characterized a VSP in maize and demonstrated that its overexpression improved drought tolerance. Nitrogen supplementation selectively induced a mesophyll lipoxygenase (ZmLOX6), which was targeted to chloroplasts by a novel N‐terminal transit peptide of 62 amino acids. When ectopically expressed under the control of various tissue‐specific promoters, it accumulated to a fivefold higher level upon expression in the mesophyll cells than the wild‐type plants. Constitutive expression or targeted expression specifically to the bundle sheath cells increased its accumulation by less than twofold. The overexpressed ZmLOX6 was remobilized from the leaves like other major proteins during grain development. Evaluated in the field over locations and years, transgenic hybrids overexpressing ZmLOX6 in the mesophyll cells significantly outyielded nontransgenic sibs under managed drought stress imposed at flowering. Additional storage of nitrogen as a VSP in maize leaves ameliorated the effect of drought on grain yield.

  6. 6

    المصدر: Frontiers in Plant Science
    Frontiers in Plant Science, Vol 11 (2020)
    CONICET Digital (CONICET)
    Consejo Nacional de Investigaciones Científicas y Técnicas
    instacron:CONICET
    SEDICI (UNLP)
    Universidad Nacional de La Plata
    instacron:UNLP

    الوصف: Foliar fungal diseases affect yield and quality of bread wheat (Triticum aestivum L.) causing important losses. They may impact differently on crop growth-rate, modifying nitrogen (N) dynamics and carbohydrate accumulation in the grain. The relationship between N and carbohydrates accumulation determines the grain protein concentration which impacts on the gluten concentration and rheological properties of the wheat flour. In addition, types of fungicides and N fertilization can influence the intensity of foliar diseases and have an effect on the milling and end-use quality, depending on the bread-making aptitude of the genotypes, the nutritional habit of the pathogens involved the amount and time of the infections, environmental factors and interactions between these factors. In that way, N fertilization may increase or decrease the severity of the diseases depending on the nutritional habit of the pathogen. Some fungicides, such as strobilurins and carboxamides, produce high levels of disease control, and prolong the healthy leaf area duration which translates into important yield responses potentially compromising the grain protein concentration by additional carbohydrate production with consequences in the bread-making quality. Furthermore, infections caused by biotrophic pathogens can be more detrimental to N accumulation than to dry matter deposition, whereas the reverse has been generally true for diseases caused by necrotrophic pathogens. The time of infection could also affect yield components and N dynamics differentially. Early epidemics may reduce the number of grains per area and the N remobilization, whereas late epidemics may affect the thousand kernel weight and mainly the N absorption post-flowering. A review updating findings of the effects of infections caused by foliar fungal pathogens of different nutritional habits and the incidence of several factors modifying these effects on the above-ground biomass generation, N dynamics, protein and gluten concentration, milling, rheological properties, loaf volume and other quality-related trait is summarized. Three main pathogens were especially taken as representative of biotrophic (Puccinia triticina), necrotrophic (Pyrenophora tritici-repentis) and hemibiotrophic (Zymoseptoria tritici) nutritional habit, as recent information is available and some general models of their effects are proposed. New challenges for researchers to minimize the impact of foliar diseases on end-use quality are also discussed.
    Facultad de Ciencias Agrarias y Forestales

    وصف الملف: application/pdf

  7. 7

    المصدر: Annals of Botany

    الوصف: Background and Aims Sulphur (S) is an essential macronutrient involved in numerous metabolic pathways required for plant growth. Crops of the plant family Brassicaceae require more S compared with other crops for optimum growth and yield, with most S ultimately sequestered in the mature seeds as the storage proteins cruciferin and napin, along with the unique S-rich secondary metabolite glucosinolate (GSL). It is well established that S assimilation primarily takes place in the shoots rather than roots, and that sulphate is the major form in which S is transported and stored in plants. We carried out a developmental S audit to establish the net fluxes of S in two lines of Brassica juncea mustard where seed GSL content differed but resulted in no yield penalty. Methods We quantified S pools (sulphate, GSL and total S) in different organs at multiple growth stages until maturity, which also allowed us to test the hypothesis that leaf S, accumulated as a primary S sink, becomes remobilized as a secondary source to meet the requirements of GSL as the dominant seed S sink. Key Results Maximum plant sulphate accumulation had occurred by floral initiation in both lines, at which time most of the sulphate was found in the leaves, confirming its role as the primary S sink. Up to 52 % of total sulphate accumulated by the low-GSL plants was lost through senesced leaves. In contrast, S from senescing leaves of the high-GSL line was remobilized to other tissues, with GSL accumulating in the seed from commencement of silique filling until maturity. Conclusion We have established that leaf S compounds that accumulated as primary S sinks at early developmental stages in condiment type B. juncea become remobilized as a secondary S source to meet the demand for GSL as the dominant seed S sink at maturity.

  8. 8

    المصدر: Frontiers in Plant Science, Vol 11 (2020)
    Frontiers in Plant Science

    الوصف: Glyphosate (GP)-based herbicides have been widely applied to crops for weed control and pre-harvest desiccation. The objective of this research was to evaluate the effects of pre-harvest GP application on maize or how it physiologically alters this crop. Here, we applied four GP treatment (Control, GP150, GP200, and GP250) on maize lines of Z58 and PH6WC belonging to different maturity groups at grain-filling stages form DAP30 to DAP45. GP application significantly decreased the grain moisture content at harvest by 22–35% for Z58 and by 15–41% for PH6WC. However, the responses of grain weight to glyphosate vary with inbred lines and application time. A high concentration of glyphosate (GP250) reduced the grain weight of Z58 and low concentrations (GP150 and GP200) did not affect, while the grain weight of PH6WC significantly decreased under glyphosate treatment. In summary, our results revealed that timely and appropriate GP application lowers grain moisture content without causing seed yield and quality loss. GP application adversely affected photosynthesis by promoting maturation and leaf senescence. Meanwhile, it also enhanced non-structural carbohydrate (soluble sugars and starch) remobilization from the vegetative organs to the grains. Hence, GP treatment coordinates plant senescence and assimilate remobilization. RNA sequencing revealed that glyphosate regulated the transcript levels of sugar signaling-related genes and induced assimilate repartitioning in grains. This work indicates the practical significance of GP application for maize seed production and harvest, which highlights the contributions of source-sink communication to maize yield in response to external stress or pre-harvest desiccant application.

  9. 9

    المصدر: Frontiers in Plant Science

    الوصف: As the last step of leaf development, senescence is a molecular process involving cell death mechanism. Leaf senescence is trigged by both internal age-dependent factors and environmental stresses. It must be tightly regulated for the plant to adopt a proper response to environmental variation and to allow the plant to recycle nutrients stored in senescing organs. However, little is known about factors that regulate both nutrients fluxes and plant senescence. Taking advantage of variation for natural leaf senescence between Arabidopsis thaliana accessions, Col-0 and Ct-1, we did a fine mapping of a quantitative trait loci for leaf senescence and identified ACCELERATED CELL DEATH 6 (ACD6) as the causal gene. Using two near-isogeneic lines, differing solely around the ACD6 locus, we showed that ACD6 regulates rosette growth, leaf chlorophyll content, as well as leaf nitrogen and carbon percentages. To unravel the role of ACD6 in N remobilization, the two isogenic lines and acd6 mutant were grown and labeled with 15N at the vegetative stage in order to determine 15N partitioning between plant organs at harvest. Results showed that N remobilization efficiency was significantly lower in all the genotypes with lower ACD6 activity irrespective of plant growth and productivity. Measurement of N uptake at vegetative and reproductive stages revealed that ACD6 did not modify N uptake efficiency but enhanced nitrogen translocation from root to silique. In this study, we have evidenced a new role of ACD6 in regulating both sequential and monocarpic senescences and disrupting the balance between N remobilization and N uptake that is required for a good seed filling.

  10. 10

    المصدر: Food and Energy Security, Vol 9, Iss 4, Pp n/a-n/a (2020)

    الوصف: Zinc (Zn) concentration in wheat grains is generally low, with an average value of around 28–30 mg/kg. Therefore, increasing wheat grain Zn concentration for better human health is the focus of HarvestPlus global initiatives. Source–sink interactions have been intensively studied for decades to enhance crop yield potential, but less on grain nutritional quality. This review applies concepts of source, sink, and their interactions to the study of wheat grain Zn nutrition and biofortification. Increasing Zn sources to wheat (via soil and foliar application) could directly enlarge available Zn in vegetative tissues and grain Zn sink. Rational nitrogen (N) supply increases grain Zn accumulation (N‐Zn synergism), but phosphorus (P) input generally decreases (P‐Zn antagonism), and the potassium (K) effect is unclear. Conventional and genetic breeding have potential to stimulate Zn flow from source to sink (uptake from soil, root‐to‐shoot translocation, and remobilization). However, a rational manipulation to establish a well‐coordinated source–sink relationship is required to finally realize the grain Zn target (40–50 mg/kg) and increase on‐farm crop yield. Future studies should focus more on fertilization modes adopted by farmers (uses of compound, slow/controlled release, and organic and microbial fertilizers) and develop integrated agronomic and genetic strategies for Zn biofortification. A highly systematic and mechanistic model includes (a) migration paths of Zn (particularly from leaves to different grain parts) using isotopic labeling methods, (b) cross‐talks between Zn and carbon, N, P, K, or other divalent cations, (c) inherent physiological and biochemical processes of enzymes and signaling phytohormones, and (d) complex genetic systems governing Zn homeostasis and their relationships with other nutrients, signaling molecules, and increase or dilution/penalty of yield under different environmental conditions (soil, water, and future climatic changes) and managements (breeding and fertilization). These aspects require further elucidation to fully unravel the “black box” of Zn flow from source to sink.

    وصف الملف: application/pdf