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Mineral element composition in grain of awned and awnletted wheat (Triticum aestivum L.) cultivars tissue-specific iron speciation and phytate and non-phytate ligand ratio
Hiram Castillo Michel, Iztok Arčon, Paula Pongrac, Katarina Vogel-Mikuš, 2020, original scientific article

Abstract: In wheat (Triticum aestivum L.), the awns—the bristle-like structures extending from lemmas—are photosynthetically active. Compared to awned cultivars, awnletted cultivars produce more grains per unit area and per spike, resulting in significant reduction in grain size, but their mineral element composition remains unstudied. Nine awned and 11 awnletted cultivars were grown simultaneously in the field. With no difference in 1000-grain weight, a larger calcium and manganese—but smaller iron (Fe) concentrations—were found in whole grain of awned than in awnletted cultivars. Micro X-ray absorption near edge structure analysis of different tissues of frozen-hydrated grain cross-sections revealed that differences in total Fe concentration were not accompanied by differences in Fe speciation (64% of Fe existed as ferric and 36% as ferrous species) or Fe ligands (53% were phytate and 47% were non-phytate ligands). In contrast, there was a distinct tissue-specificity with pericarp containing the largest proportion (86%) of ferric species and nucellar projection (49%) the smallest. Phytate ligand was predominant in aleurone, scutellum and embryo (72%, 70%, and 56%, respectively), while nucellar projection and pericarp contained only non-phytate ligands. Assuming Fe bioavailability depends on Fe ligands, we conclude that Fe bioavailability from wheat grain is tissue specific.
Found in: ključnih besedah
Summary of found: ...phytate, iron, awn, X-ray fluorescence, X-ray absorption spectrometry, phosphorus, sulphur, nicotianamine...
Keywords: biofortification, phytate, iron, awn, X-ray fluorescence, X-ray absorption spectrometry, phosphorus, sulphur, nicotianamine
Published: 16.01.2020; Views: 559; Downloads: 0
.pdf Fulltext (2,63 MB)

The excess of phosphorus in soil reduces physiological performances over time but enhances prompt recovery of salt-stressed Arundo donax plants
Cristina Gonnelli, Roberto Tognetti, Mauro Centritto, Francesco Loreto, Cecilia Brunetti, Federico Brilli, Sara Pignattelli, Susanna Pollastri, Claudia Cocozza, 2020, original scientific article

Abstract: Arundo donax L. is an invasive grass species with high tolerance to a wide range of environmental stresses. The response of potted A. donax plants to soil stress characterized by prolonged exposure (43 days) to salinity (+Na), to high concentration of phosphorus (+P), and to the combination of high Na and P (+NaP) followed by 14 days of recovery under optimal nutrient solution, was investigated along the entire time-course of the experiment. After an exposure of 43 days, salinity induced a progressive decline in stomatal conductance that hampered A. donax growth through diffusional limitations to photosynthesis and, when combined with high P, reduced the electron transport rate. Isoprene emission from A. donax leaves was stimulated as Na+ concentration raised in leaves. Prolonged growth in P-enriched substrate did not significantly affect A. donax performance, but decreased isoprene emission from leaves. Prolonged exposure of A. donax to + NaP increased the leaf level of H2O2, stimulated the production of carbohydrates, phenylpropanoids, zeaxanthin and increased the de-epoxidation state of the xanthophylls. This might have resulted in a higher stress tolerance that allowed a fast and full recovery following stress relief. Moreover, the high amount of ABA-glucose ester accumulated in leaves of A. donax exposed to + NaP might have favored stomata re-opening further sustaining the observed prompt recovery of photosynthesis. Therefore, prolonged exposure to high P exacerbated the negative effects of salt stress in A. donax plants photosynthetic performances, but enhanced activation of physiological mechanisms that allowed a prompt and full recovery after stress.
Found in: ključnih besedah
Keywords: Arundo donax Phosphorus Salinity Stress tolerance Biomass production
Published: 20.04.2020; Views: 483; Downloads: 0
.pdf Fulltext (6,60 MB)

Impact of high or low levels of phosphorus and high sodium in soils on productivity and stress tolerance of Arundo donax plants
Claudia Cocozza, Federico Brilli, Laura Miozzi, Sara Pignattelli, Silvia Rotunno, Cecilia Brunetti, Cristiana Giordano, Susanna Pollastri, Mauro Centritto, Gian Paolo Accotto, Roberto Tognetti, Francesco Loreto, 2019, original scientific article

Abstract: The potential of Arundo donax to grow in degraded soils, characterized by excess of salinity (Na+), and phosphorus deficiency (-P) or excess (+P) also coupled with salinity (+NaP), was investigated by combining in vivo plant phenotyping, quantification of metabolites and ultrastructural imaging of leaves with a transcriptome-wide screening. Photosynthesis and growth were impaired by+Na, -P and+NaP. While+Na caused stomatal closure, enhanced biosynthesis of carotenoids, sucrose and isoprene and impaired anatomy of cell walls, +P negatively affected starch production and isoprene emission, and damaged chloroplasts. Finally, +NaP largely inhibited photosynthesis due to stomatal limitations, increased sugar content, induced/repressed a number of genes 10 time higher with respect to+P and+Na, and caused appearance of numerous and large plastoglobules and starch granules in chloroplasts. Our results show that A. donax is sensitive to unbalances of soil ion content, despite activation of defensive mechanisms that enhance plant resilience, growth and biomass production of A. donax under these conditions.
Found in: ključnih besedah
Keywords: Abiotic stress Giant reed Isoprene emission Phosphorus Salinity Transcriptome
Published: 20.04.2020; Views: 463; Downloads: 0
.pdf Fulltext (10,07 MB)

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