X-ray fluorescence spectroscopy (XRF) is an analytical tool used to determine the elemental composition in a myriad of sample matrices. Due to the XRF non-destructive feature, this technique may ...allow time-resolved plant tissue analyses under in vivo conditions, and additionally, the combination with other non-destructive techniques. In this study, we employed handheld and benchtop XRF to evaluate the elemental distribution changes in living plant tissues exposed to X-rays, as well as real-time uptake kinetics of Zn(aq) and Mn(aq) in soybean (Glycine max (L.) Merrill) stem and leaves, for 48 hours, combined with transpiration rate assessment on leaves by an infrared gas analyzer (IRGA). We found higher Zn content than Mn in stems. The latter micronutrient, in turn, presented higher concentration in leaf veins. Besides, both micronutrients were more concentrated in the first trifolium (i.e., youngest leaf) of soybean plants. Moreover, the transpiration rate was more influenced by circadian cycles than Zn and Mn uptake. Thus, XRF represents a convenient tool for in vivo nutritional studies in plants, and it can be coupled successfully to other analytical techniques.
Elephant grass (Pennisetum purpureum) exhibits high biomass production, is readily accepted by animals, and demonstrates good adaptation to the various soil types. Consequently, the utilization of P. ...purpureum shows promise in amending surface and subsurface soil acidity, thereby contributing to increased crop yield while enhancing water and nutrient utilization efficiency. In this study, the effects of corrective processes involving limestone and plastering on the root anatomy of P. purpureum were investigated. Roots subjected to different treatments were fixed, dehydrated, and embedded in historesin. Subsequently, samples were sectioned in a microtome, stained with toluidine blue for the conventional analysis, or submitted to the histochemical test. The qualitative and quantitative anatomical analyses were conducted to evaluate the impact of liming and plastering on the root structure of P. purpureum. The results showed that liming led to an increase in both the number and diameter of vessel elements, while plastering reduced these parameters compared to the acidic soils. Additionally, liming induced the formation of suberized endodermal cell walls. These findings highlight the significance of effective soil management to obtain P. purpureum plants with a well-developed vascular system, thereby promoting optimal plant performance in agricultural crops.
The deficiency of calcium (Ca) reduces the quality and shelf life of fruits. In this scenario, although foliar spraying of Ca
has been used, altogether with soil fertilization, as an alternative to ...prevent deficiencies, little is known regarding its absorption dynamics by plant leaves. Herein, in vivo microprobe X-ray fluorescence was employed aiming to monitor the foliar absorption of CaCl
, Ca-citrate complex, and Ca
(PO
)
nanoparticles with and without using adjuvant. We also investigated whether Sr
can be employed as Ca
proxy in foliar absorption studies. Moreover, the impact of treatments on the cuticle structure was evaluated by scanning electron microscopy. For this study, 45-day-old tomato (
L., cv. Micro-Tom) plants were used as a model species. After 100 h, the leaves absorbed 90, 18, and 4% of aqueous CaCl
, Ca-citrate, and Ca
(PO
)
nanoparticles, respectively. The addition of adjuvant increased the absorption of Ca-citrate to 28%, decreased that of CaCl
to 77%, and did not affect Ca
(PO
)
. CaCl
displayed an exponential decay absorption profile with half-lives of 15 h and 5 h without and with adjuvant, respectively. Ca-citrate and Ca
(PO
)
exhibited absorption profiles that were closer to a linear behavior. Sr
was a suitable Ca
tracer because of its similar absorption profiles. Furthermore, the use of adjuvant affected the epicuticular crystal structure. Our findings reveal that CaCl
was the most efficient Ca
source. The effects caused by adjuvant suggest that CaCl
and Ca-citrate were absorbed mostly through hydrophilic and lipophilic pathways.
Citrus postbloom fruit drop, caused by
spp., is an important disease in the Americas. The pathogen infects citrus flowers, produces orange-brown lesions on petals, and may cause the abscission of ...young fruit. In diseased flowers, the calyxes remain attached to the peduncle after the young fruit drop. No anatomical and microanalysis studies have been conducted to determine whether calyx tissues can be infected by
spp. and why calyxes remain attached to the peduncle. Based on light microscopy, we demonstrate that the ovary abscission zone exhibits a separation region composed of layers of thickened lignified walled cells, indicating that abscission involves the disruption of cell walls. The first layers of the protective zone (PZ) are composed of densely packed cells with suberized walls produced by the wound meristem. Beneath the PZ, there is a compact mass of small cells that accumulate starch grains. X-ray fluorescence microanalysis (µ-XRF) confirmed the increased accumulation of calcium in the receptacle of the persistent calyxes compared to non-inoculated citrus flowers. Moreover, the peduncle pith and the receptacle exhibit hypertrophied cells with thick walls that may be related to calyx retention. Fungal structures are not observed inside the persistent calyx tissues.
This study aimed to investigate the roles of selenium (Se) application on the profile of photosynthetic pigments, oxidant metabolism, flavonoids biosynthesis, nodulation, and its relation to ...agronomic traits of peanut plants. Two independent experiments were carried out: one conducted in soil and the other in a nutrient solution. When the plants reached the V2 growth stage, five Se doses (0, 7.5, 15, 30, and 45 μg kg−1) and four Se concentrations (0, 5, 10, and 15 μmol L−1) were supplied as sodium selenate. The concentration of photosynthetic pigments, activity of antioxidant enzymes and the concentration of total sugars in peanut leaves increased in response to Se fertilization. In addition, Se improves nitrogen assimilation efficiency by increasing nitrate reductase activity which results in a higher concentration of ureides, amino acids and proteins. Se increases the synthesis of daidzein and genistein in the root, resulting in a greater number of nodules and concentration and transport of ureides to the leaves. Se-treated plants showed greater growth, biomass accumulation in shoots and roots, yield and Se concentration in leaves and grains. Our results contribute to food security and also to increase knowledge about the effects of Se on physiology, biochemistry and biological nitrogen fixation in legume plants.
•Se enhances enzymatic and non-enzymatic antioxidant metabolism of peanut plants increasing protection against abiotic stress.•Nitrogen assimilation enzymes are boosted by Se increasing amino acids, protein and crop yield of peanut plants.•Se increases isoflavonoids synthesis, nodulation and ureide production.
Enhancing the initial stages of plant growth by using polymeric gels for seed priming presents a significant challenge. This study aimed to investigate a microgel derived from ...polyetheramine-poly(propylene oxide) (PPO) and a bisepoxide (referred to as micro-PPO) as a promising alternative to optimize the seed germination process. The micro-PPO integrated with an iron micronutrient showed a positive impact on seed germination compared with control (Fe solutions) in which the root length yield improved up to 39%. Therefore, the element map by synchrotron-based X-ray fluorescence shows that the Fe intensities in the seed primers with the micro-PPO-Fe gel are about 3-fold higher than those in the control group, leading to a gradual distribution of Fe species through most internal embryo tissues. The use of micro-PPO for seed priming underscores their potential for industrial applications due to the nontoxicity results in zebrafish assays and environmentally friendly synthesis of the water-dispersible monomers employed.Enhancing the initial stages of plant growth by using polymeric gels for seed priming presents a significant challenge. This study aimed to investigate a microgel derived from polyetheramine-poly(propylene oxide) (PPO) and a bisepoxide (referred to as micro-PPO) as a promising alternative to optimize the seed germination process. The micro-PPO integrated with an iron micronutrient showed a positive impact on seed germination compared with control (Fe solutions) in which the root length yield improved up to 39%. Therefore, the element map by synchrotron-based X-ray fluorescence shows that the Fe intensities in the seed primers with the micro-PPO-Fe gel are about 3-fold higher than those in the control group, leading to a gradual distribution of Fe species through most internal embryo tissues. The use of micro-PPO for seed priming underscores their potential for industrial applications due to the nontoxicity results in zebrafish assays and environmentally friendly synthesis of the water-dispersible monomers employed.
Understanding the mechanisms of absorption and transport of foliar nutrition is a key step towards the development of advanced fertilization methods. This study employed X-ray fluorescence (XRF) and ...X-ray absorption near edge spectroscopy (XANES) to trace the in vivo absorption and transport of ZnO and ZnSO4(aq) to soybean leaves (Glycine max). XRF maps monitored over 48 h showed a shape change of the dried ZnSO4(aq) droplet, indicating Zn2+ absorption. Conversely, these maps did not show short movement of Zn from ZnO. XRF measurements on petioles of leaves that received Zn2+ treatments clarified that the Zn absorption and transport in the form of ZnSO4(aq) was faster that of ZnO. Solubility was the major factor driving ZnSO4(aq) absorption. XANES speciation showed that in planta Zn is transported coordinated with organic acids. Because plants demand Zn during their entire lifecycle, the utilization of sources with different solubilities can increase Zn use efficiency.
•Multielemental evaluation using a chemometric approach.•Increase in Rh-Lα load values due to water absorption.•Identification of the multielemental spatial distribution using XRF.•Determination of ...correlations in hyperspectral data.
Laboratory microprobe X-ray fluorescence (μ-XRF) spectrometry is a powerful analytical technique able to detect trace elements in biological samples. The present study compared univariate and multivariate strategies to investigate the elements detected with μ-XRF during soybean (Glycine max (L.) Merrill) germination. The conventional approach, i.e., univariate, showed that the studied micronutrients (Mn, Fe, and Zn) were located mainly on the radicle tip, while the macronutrients (P, S, K, and Ca) were spread through the seed. The score maps, as well the correlation maps from a covariance matrix, were able to evaluate variations of chemical elements, such as P, S, K, Ca, Fe, Mn, Zn, and Rh-scattering effects through the embryo, leading the first glance at elemental distribution and remobilization during soybean seed germination.
Phytoextraction of rare earth elements (REE) from contaminated soils has gained importance during the last few decades. The Poços de Caldas municipality in Brazil is known for its mineral richness, ...including large reserves of REE. In this study, we report light REE (La, Ce, Sm, Pr, and Nd) in soils and plants collected in an area. Composite soil samples and plant individuals were collected, and total concentrations of LREE in soils were determined by wavelength dispersive X-ray fluorescence (WDXRF). The plant available LREE concentrations in soils were estimated upon the acetic acid method (F1 fractions) of the stepwise sequential extraction procedure, together with plant content that was analysed by inductively coupled plasma mass spectrometry (ICP-MS). The total sum concentrations of tested LREE in soils varied from 5.6 up to 37.9 g kg
−1
, the bioavailable fraction was
ca
. 1%, and a linear relationship was found between them. The only exception was Sm, whose availability was lesser and did not show a linear relationship. The concentration of LREE in non-accumulator plants varied from 1.3–950 mg kg
−1
for Ce, La 1.1–99 mg kg
−1
, Sm 0.04–9.31 mg kg
−1
, Pr 0.1–24.1 mg kg
−1
, and Nd 0.55–81 mg kg
−1
. The concentration of LREE among shoots did not show a linear relation either with the available fraction or total content. The screening also revealed
Christella dentata
(Forssk.) Brownsey & Jermy,
Thelypteridaceae
family, as a promising hyperaccumulator species. The concentrations of LREE among shoots of six individuals of this species were in the ranges from 115 to 1872 mg kg
−1
for Ce, La 190–703 mg kg
−1
, Sm 9–48 mg kg
−1
, Pr 32–144 mg kg
−1
, and Nd 105–478 mg kg
−1
.
X-ray fluorescence spectroscopy (XRF) is a powerful technique for the in vivo assessment of plant tissues. However, the potential X-ray exposure damages might affect the structure and elemental ...composition of living plant tissues, leading to artefacts in the recorded data. Herein, we exposed in vivo soybean (Glycine max (L.) Merrill) leaves to several X-ray doses through a polychromatic benchtop microprobe X-ray fluorescence spectrometer, modulating the photon flux density by adjusting either the beam size, current, or exposure time. Changes in the irradiated plant tissues' structure, ultrastructure, and physiology were investigated through light and transmission electron microscopy (TEM). Depending on X-ray exposure dose, decreased K and X-ray scattering intensities and increased Ca, P, and Mn signals on soybean leaves were recorded. Anatomical analysis indicated the necrosis of epidermal and mesophyll cells on the irradiated spots, where TEM images revealed the collapse of cytoplasm and cell wall breaking. Furthermore, the histochemical analysis detected the production of reactive oxygen species and the inhibition of chlorophyll autofluorescence in these areas. Under certain X-ray exposure conditions, e.g. high photon flux density and long exposure time, XRF measurements may affect the soybean leaves structures, elemental composition, and cellular ultrastructure, inducing programmed cell death. Our characterization shed light on the plant's responses to the X-ray-induced radiation damage and might help to establish proper X-ray radiation limits and novel strategies for in vivo benchtop-XRF analysis of vegetal materials.
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