Biology subjects

Montanha, G. S.

Publications and source records attributed to Montanha, G. S..

8 recordsLinked to original sources

bioRxiv2025

Assessing the effects of fertilisation on the yield, protein, and oil content of soybean seeds: a metadata analysis

For a comprehensive study on balancing yield and grain composition, a meta-analysis of 48 peer-reviewed studies evaluated the effects of soil and foliar fertilization on soybean (Glycine max L.) yield, protein, and oil content. The metadata includes fertilizer type, application method, yield (kg ha-1), and concentration of protein (%) and oil (%). The data show that foliar and soil N fertilization increased grain yield by 13.7% and 14.2%, respectively (p < 0.05), compared to the control. However, it did not significantly affect the protein (38.4 {+/-} 3.4%) or oil (20.2 {+/-} 2.3%) content. High variability in experimental designs and the underrepresentation of foliar strategies make it difficult to draw broad conclusions. These findings showed the need for standardized field and controlled trials to balance increased yield with quality and to guide nutrient management.

plant biology↗

bioRxiv2025

Resolving the Foliar Calcium Mobility Paradox: Enhancing Foliar Calcium Transport in Tomato Using Osmotic Regulators

Highlight- In vivo XRF measurements in the petiole confirmed Sr transport to distal tomato tissues. - XRF imaging revealed the distribution of Sr in tomato fruits following foliar application. - Foliar formulations supplemented with osmotic regulators improved Sr absorption and translocation. - Sucrose enhanced both short- and long-distance transport of Sr to tomato fruits. - Sucrose significantly enhanced Sr{superscript 2} accumulation in seeds and the apical mesocarp, the regions most affected by Ca deficiency symptoms The study demonstrates a novel approach for enhancing phloem transport to fruit of foliar-applied Ca Calcium (Ca) deficiency can impair fruit development even under optimal soil Ca levels due to its transpiration-dependent transport. Reduced fruit transpiration may limit Ca delivery to fruits, leading to lower Ca content in the fruit and diminished quality. Foliar application of Ca offers a potential strategy to mitigate these effects; however, its low mobility in the phloem often limits treatment efficacy. To address this, we employed X-ray fluorescence spectroscopy (XRF) to investigate the penetration and transport of foliar-applied Ca, using strontium (Sr) as a physiological tracer. Additionally, we evaluated the influence of osmotic regulators, sucrose, mannitol, glycerol, and potassium, on Ca transport. Results showed that Sr was effectively translocated to distal tissues. While potassium and mannitol had no significant impact on transport kinetics, sucrose and glycerol enhanced Sr movement. XRF imaging of leaf tissue revealed that Sr was primarily transported through the apoplast toward the leaf margin. Moreover, foliar application of Sr combined with sucrose significantly increased Sr accumulation in seeds and in the apical portion of tomato fruits. These findings suggest that, contrary to the common assumption of limited foliar Ca mobility, sucrose, can acts as an effective osmotic regulator, enhancing both short-range movement within leaf tissue and long-distance translocation to fruit.

plant biology↗

bioRxiv2025

Double knockout of rice OsVIT1 and OsVIT2 genes reveals a trade-off between iron biofortification and iron excess tolerance

Rice (Oryza sativa L.) is a staple food for half of the worlds population, but lacks essential nutrients such as iron (Fe). Fe deficiency is one of the most common nutritional problems in humans, and biofortification of rice grains is a cost-effective approach to deliver more Fe to peoples diet. Two Vacuolar Iron Transporters, OsVIT1 and OsVIT2, were shown to negatively regulate Fe translocation to rice developing panicles, as single mutants osvit1 and osvit2 have increased Fe concentration in seeds. Importantly, rice plants are frequently cultivated in waterlogged soils that are highly reductive and prone to Fe3+ reduction to the more soluble Fe2+, which can accumulate and cause Fe toxicity. Little is known about which genes control Fe excess detoxification. OsVIT1 and OsVIT2 transport Fe into the vacuole, and OsVIT2 is induced under Fe excess, but whether they play a role in Fe detoxification was not demonstrated. We generated double mutants osvit1osvit2 using CRISPR-Cas9 to test whether loss of function of both genes could increase Fe concentration in seeds, and to test whether their loss of function has impact in rice Fe excess tolerance. We showed that osvit1osvit2 double mutants accumulated more Fe in brown rice. Fe accumulation was clear in embryo scutellum and plumule, suggesting VIT transporters have a role in determining Fe spatial distribution. We also showed that root uptake contributed significantly for increased Fe accumulation in osvit1osvit2 seeds, suggesting OsVIT1 and OsVIT2 are involved in sequestering Fe in vegetative tissues and decreasing translocation. Strikingly, we found that osvit1osvit2 plants were more sensitive to Fe excess, revealing a trade-off between Fe biofortification and Fe excess tolerance. Our data indicates OsVIT1 and OsVIT2 are key for Fe excess detoxification, which should be considered in their use as targets for biofortification.

plant biology↗

bioRxiv2025

How the rhizosphere chemistry explains the effectiveness of radish in reclaiming legacy phosphorus compared to maize

Background and aimsAround 50% of phosphorus (P) applied to tropical soils is not used by plants and become part of the legacy P. Some cover crops can extract this P. But how do they do this and which form do they extract most? MethodsRadish (Raphanus sativus L.) and maize (Zea mays L.) were planted in rhizoboxes and tubes containing a mixture of sand, kaolinite, hematite, and boehmite, the later and former bearing sorbed phosphate. The structure and composition of the root-soil interface were determined by scanning electron microscopy (SEM) and Fourier- transform infrared spectroscopy (FTIR). Additionally, synchrotron-based microprobe X-ray fluorescence ({micro}XRF) was employed to assess the spatial distribution of Al, Fe, and P. The P speciation at the rhizosphere was evaluated using microprobe X-ray absorption near edge structure ({micro}XANES). ResultsThe chemical images revealed that both plants depleted more of the Al-bound P than Fe-bound P, with radish demonstrated a higher efficiency compared to maize. The total P uptake by radish from Al-bound P was 42% higher than that uptake from Fe-bound P. Additionally, radish absorbed 34% to 90% more total P compared to maize, indicating a significant difference between the two crops. The superior capacity exhibited by radish seems to be connected to organic acids and total carbon exudation, which the latter was 2.14-fold more than maize. ConclusionRadish uptakes greater Al-bound P than Fe-bound P. This insight could help in proper management of soils where P is predominantly bound to Al and significantly increases P use efficiency.

plant biology↗

bioRxiv2025

Storage protein biosynthesis is affected by ionome composition in soybean (Glycine max (L.) Merrill) seeds

Soybean seeds are a significant source of protein for human and animal nutrition, primarily due to seed storage proteins (SSPs) from the albumin and globulin families, which are predominantly located in protein storage vacuoles within cotyledon cells. This study characterised the dynamics of protein and mineral nutrient accumulation in four soybean genotypes with contrasting protein content--two transgenic (tg1 and tg2) and two conventional (ct1 and ct2)--from the beginning of seed filling (R5.5) through to maturity (R8) under field conditions. Profiles of globulin SSPs (glycinin and {beta}-conglycinin), as well as the protein and elemental distribution in mature seed cotyledons were examined. Results revealed that genotypes with higher protein content showed increased S and Zn concentrations and a higher glycinin:{beta}-conglycinin ratio. Subcellular analyses further indicated co-localisation of proteins and Zn within cotyledon cells. Our findings reveal a complex association between S and Zn accumulation and SSPs biosynthesis, indicating that their availability can limit the SSP content. HIGHLIGHTSoybean seed genotypes containing higher sulphur (S) and zinc (Zn) content in the cotyledonary cells exhibit a distinct storage proteins profile by increasing the abundance of sulphur-amino acids rich globulins.

plant biology↗

bioRxiv2022

May mineral composition trigger or limit the protein content in soybean (Glycine max (L.) Merrill) seeds? Insights from a survey on 95 varieties cultivated in Brazil

Background and AimsSoybean (Glycine max (L.) Merrill) stands out as the major source of protein and oil for human and animal nutrition. Nevertheless, the increase in soybean yield has been accompanied by a reduction in its protein content in the last few decades. Since this might be influenced by the elemental composition of the seeds, we herein aimed at determining the profile of mineral nutrients and protein of 95 soybean varieties broadly cultivated in Brazil, the worlds biggest soybean producer and exporter, to identify possible nutritional triggers for the protein content. MethodsEnergy dispersive fluorescence spectroscopy (EDXRF) was employed to determine the concentration of macro, i.e., (K), phosphorus (P), sulphur (S), calcium (Ca), and micronutrients, i.e., iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu). The protein content was evaluated in soybean seeds by the Dumas method. The correlational and clustering assessment between nutrients and protein were determined through both univariate and multivariate non-parametric tests. ResultsBoth protein and nutrient concentrations are not homogeneous across soybean seed varieties, and a clear positive association between protein and sulphur (S), zinc (Zn), and manganese (Mn) concentrations were observed. ConclusionThe recorded results suggest that sulphur (S), zinc (Zn), and manganese (Mn) are the limiting nutrients for higher protein content in soybean seeds.

plant biology↗

bioRxiv2022

Microprobe-XRF assessment of nutrient distribution in soybean, cowpea, and kidney bean seeds: a Fabaceae family case study

The present study explored the microprobe X-ray fluorescence spectroscopy ({micro}-XRF) for quantitative and space-resolved distribution of macro, i.e., K, P, S, and Ca, and micronutrients, i.e., Fe, Zn, and Mn elemental composition in the cross-sectioned seeds of cowpea (Vigna unguiculata L.), kidney bean (Phaseolus vulgaris L.), and soybean (Glycine max L.) seeds, important agricultural species within the Fabaceae family. It unveils that both macro and micronutrients were heterogeneously distributed across seed tissues. Most of the P and S, Fe, Zn, and Mn were mainly found at the embryo axis tissues in all three Fabaceae species, whereas K was spread along the cotyledon and Ca was mostly observed trapped at the seed coat region. Furthermore, the Pearson correlation coefficient revealed a strong spatial correlation between P and S, and K and S in cowpea and soybean seed tissues, whereas Zn and Mn association was also recorded. Therefore, the {micro}-XRF technique demonstrates to be an important tool for assessing seed nutrient distribution, thus subsidizing the understanding of the physiological role of nutrients in seeds and fostering innovative approaches for nutrient supply and biofortification.

biochemistry↗

bioRxiv2022

Physiological responses of plants to in vivo XRF radiation damage: insights from elemental, histochemical, anatomical and ultrastructural analyses

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 soybean (Glycine max (L.) Merrill) leaves to several X-ray doses through a polychromatic benchtop microprobe X-ray fluorescence spectrometer, modulating the photon flux by adjusting either the beam size, focus, or exposure time. The structure, ultrastructure and physiological responses of the irradiated plant tissues were investigated through light and transmission electron microscopy (TEM). Depending on the dose, the X-ray exposure induced decreased K and X-ray scattering intensities, and increased Ca, P, and Mn signals on soybean leaves. Anatomical analysis indicated necrosis of the 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, as well as inhibition of chlorophyll autofluorescence in these areas. Under certain X-ray exposure conditions, e.g., high photon flux and exposure time, XRF measurements may affect the soybean leaves structures, elemental composition, and cellular ultrastructure, and induce programmed cell death. These results shed light on the characterization of the radiation damage, and thus, help to assess the X-ray radiation limits and strategies for in vivo for XRF analysis. HighlightBy exposing soybean leaves to several X-ray doses, we show that the characteristic X-ray induced elemental changes stem from plants physiological signalling or responses rather than only sample dehydration.

plant biology↗