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Search Results (223)

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19 pages, 7857 KiB  
Article
Exogenous MnSO4 Improves Productivity of Degenerated Volvariella volvacea by Regulating Antioxidant Activity
by Qiaoli Wang, Wenpei Wang, Yonghui Wang, Jinmin Yun, Yubin Zhang and Fengyun Zhao
J. Fungi 2024, 10(12), 825; https://doi.org/10.3390/jof10120825 - 27 Nov 2024
Viewed by 557
Abstract
Manganese is one of the trace elements necessary for organisms to maintain normal biological activities and is also a cofactor for manganese superoxide dismutase (Mn-SOD) and manganese peroxidase (MnP). In order to find a simple and effective method to rejuvenate the degenerated V. volvacea [...] Read more.
Manganese is one of the trace elements necessary for organisms to maintain normal biological activities and is also a cofactor for manganese superoxide dismutase (Mn-SOD) and manganese peroxidase (MnP). In order to find a simple and effective method to rejuvenate the degenerated V. volvacea strains, we explored the effect of the exogenous addition of MnSO4 on the antioxidant vigour and productivity of degenerated strains of V. volvacea. The results showed that the exogenous MnSO4 had no significant effect on the non-degenerated strain T0, but it could effectively increase the mycelial growth rate, mycelial biomass, and LBL decolouring ability of the degenerated strains T10 and T19, and reduce the production cycle and increased the biological efficiency of T10; it helped the severely degenerated T19 to regrow its fruiting body; and it also significantly increased the viability of the matrix-degrading enzymes such as EG, Lac, Xyl, etc. of T10 and T19. Meanwhile, exogenous MnSO4 significantly increased the activity of GPX, GR, CAT, SOD, and the content of GSH, polyphenols, minerals, and polysaccharides in T10 and T19 strains, which resulted in a significant decrease in the accumulation of ROS, such as O2 and H2O2 in T10 and T19. The correlation analysis showed that there was a significant correlation between antioxidant activity and the production ability of V. volvacea. This study can provide theoretical reference and technical support for the rejuvenation research of degenerated strains of V. volvacea and other edible fungi. Full article
(This article belongs to the Special Issue Breeding and Metabolism of Edible Fungi)
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<p>Effect of different concentrations of MnSO<sub>4</sub> on the colony diameter of strain T10.</p>
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<p>Effect of MnSO<sub>4</sub> on the morphology (<b>A</b>), mycelial growth rate and biomass (<b>B</b>) of <span class="html-italic">V. volvacea</span> colonies. * represents a significant difference within the same group (<span class="html-italic">p</span> &lt; 0.05).</p>
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<p>Effect of MnSO<sub>4</sub> on decolourization ability of <span class="html-italic">V. volvacea</span> LBL. (<b>A</b>): Medium colour, (<b>B</b>): Medium pH, (<b>C</b>): Decolourization rate, (<b>D</b>): Correlation between pH and OD value, orange line: Linear fit of B “LBL medium pH”, blue line: LBL medium pH. * represents a significant difference within the same group (<span class="html-italic">p</span> &lt; 0.05).</p>
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<p>Effect of MnSO<sub>4</sub> on production traits of <span class="html-italic">V. volvacea</span>. (<b>A</b>): Time of primordia formation, (<b>B</b>): The production cycle, (<b>C</b>): Average weight of a fruiting body, (<b>D</b>): The biological efficiency. * represents a significant difference within the same group (<span class="html-italic">p &lt; 0.05</span>).</p>
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<p>Effect of MnSO<sub>4</sub> on matrix-degrading enzyme activity. (<b>A</b>): FPA, (<b>B</b>): BGL, (<b>C</b>): CBH, (<b>D</b>): EG, (<b>E</b>): Lac, (<b>F</b>): MnP, (<b>G</b>): Xyl, (<b>H</b>): HMA.CK: control group, MnSO<sub>4</sub>: MnSO<sub>4</sub> treatment group, * represents a significant difference within the same group (<span class="html-italic">p</span> &lt; 0.05).</p>
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<p>Effect of MnSO<sub>4</sub> on antioxidant enzyme activity of <span class="html-italic">V. volvacea</span> mycelia.(<b>A</b>): SOD, (<b>B</b>): CAT, (<b>C</b>): GPX, (<b>D</b>): GR. * represents a significant difference within the same group (<span class="html-italic">p</span> &lt; 0.05).</p>
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<p>Effect of MnSO<sub>4</sub> on crude polysaccharide (<b>A</b>), polyphenol (<b>B</b>) and flavonoid contents (<b>C</b>), GSH (<b>D</b>), GSSG (<b>E</b>) of <span class="html-italic">V. volvacea</span> mycelia. CK: control group, MnSO<sub>4</sub>: MnSO<sub>4</sub> treatment group, * represents a significant difference within the same group (<span class="html-italic">p</span> &lt; 0.05).</p>
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<p>Effect of MnSO<sub>4</sub> on O<sub>2</sub><sup>−</sup> (<b>A</b>) and H<sub>2</sub>O<sub>2</sub> (<b>B</b>) contents of <span class="html-italic">V. volvacea</span> mycelia. * represents a significant difference within the same group (<span class="html-italic">p</span> &lt; 0.05).</p>
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<p>Correlation analysis between indicators of <span class="html-italic">V. volvacea</span> strains. * represents a significant difference within the same group (<span class="html-italic">p</span> &lt; 0.05).</p>
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<p>Principal component analysis of <span class="html-italic">V. volvacea</span> samples. (<b>A</b>): Loading plot, (<b>B</b>): Score plot.</p>
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<p>Pathway diagram for the revitalization of degenerated strains by exogenous addition of MnSO<sub>4</sub>.</p>
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19 pages, 1623 KiB  
Article
Effect of Pre-Sowing Seed Stimulation on Maize Seedling Vigour
by Paulina Pipiak, Katarzyna Sieczyńska, Dorota Gendaszewska and Monika Skwarek-Fadecka
Int. J. Mol. Sci. 2024, 25(22), 12480; https://doi.org/10.3390/ijms252212480 - 20 Nov 2024
Viewed by 678
Abstract
The aim of this study was to investigate the effects of treating maize (Zea mays L.) seeds with fish collagen hydrolysate (FC) and keratin (KE) derived from animal waste by-products of leather and meat production, as well as poly(hexamethylene biguanide) hydrochloride (P) [...] Read more.
The aim of this study was to investigate the effects of treating maize (Zea mays L.) seeds with fish collagen hydrolysate (FC) and keratin (KE) derived from animal waste by-products of leather and meat production, as well as poly(hexamethylene biguanide) hydrochloride (P) and bentonite (B). This research is in line with the search for new, environmentally friendly methods to increase yields of industrial crops in a way that is compatible with sustainable development. The effect of the binders used was investigated by analysing the grown maize seedlings by determining changes in parameters of chlorophyll fluorescence, photosynthetic pigments, elemental composition and FTIR analysis on maize shoots. The results indicated a slightly higher fresh weight (FW) of shoots in plants treated with fish collagen, PHMB and bentonite (FC+P+B) and FW of roots in plants treated with keratin, PHMB and bentonite (KE+P+B). Unexpectedly, the FW and dry weight (DW) of both roots and shoots of all bentonite-treated plants were significantly higher than the corresponding non-bentonite-treated groups. In addition, changes in chlorophyll-a fluorescence were observed for the keratin, PHMB and bentonite variants. This study showed that the proposed materials could be promising seed pelleting agents to improve seed growth and yield. Full article
(This article belongs to the Section Molecular Plant Sciences)
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<p>Fresh weight (FW; (<b>A</b>)) and dry weight (DW; (<b>B</b>)) of shoots and fresh weight (FW; (<b>D</b>)) and dry weight (DW; (<b>E</b>)) of roots of 21-day-old maize plants (<b>C</b>) subjected to different seed treatments. Values followed by different letters within a given binding agent treatment (NT, FC+P or KE+P) are significantly different (<span class="html-italic">p</span> &lt; 0.05; ANOVA followed by Tukey’s post hoc test; <span class="html-italic">n</span> = 8); values within a given bentonite treatment (H+B, FC+P+B or KE+P+B) are significantly different (* for <span class="html-italic">p</span> &lt; 0.05, ** for <span class="html-italic">p</span> &lt; 0.01; Student’s <span class="html-italic">t</span>-test; <span class="html-italic">n</span> = 8). NT—non-treated seeds, FC—fish collagen-treated seeds, KE—keratin-treated seeds, P-PHMB—poly(hexamethylene biguanide) hydrochloride-treated seeds, H—water-treated seeds, B—bentonite-treated seeds.</p>
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<p>Changes in chlorophyll fluorescence parameters in 21−day−old maize plants exposed to different seed coating treatments. Values followed by different letters within the given binding agent treatment (NT; (<b>A</b>), FC+P; (<b>B</b>) or KE+P; (<b>C</b>)) are significantly different (<span class="html-italic">p</span> &lt; 0.05; ANOVA followed by Tukey’s post hoc test; <span class="html-italic">n</span> = 5). The colour of the letter-based statistical indicators refers to each experimental variant as indicated in the legend. Abbreviations: Fo−basic fluorescence, Fm−maximal fluorescence, Fv−maximal variable fluorescence, Fm′−maximal fluorescence for the light-adapted state, Fv/Fm−maximum photochemical quantum yield of PSII in the dark-adapted state, Fv/Fo−efficiency of the water-splitting complex on the donor side of PSII, Rfd−vitality index, ФPSII—quantum efficiency of PSII, qP−photochemical fluorescence quenching, NPQ−non-photochemical fluorescence quenching.</p>
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<p>Content of chlorophyll <span class="html-italic">a + b</span> (Chl <span class="html-italic">a + b</span>) (<b>A</b>), carotenoids (Cars) (<b>B</b>), ratio of chlorophyll <span class="html-italic">a + b</span> to carotenoids (Chl <span class="html-italic">a + b</span>/Cars) (<b>C</b>), porphyrins: protoporphyrin (Proto) (<b>D</b>), Mg−protoporphyrin (Mg−proto) (<b>E</b>) and protochlorophyllide (Pchlide) (<b>F</b>) in leaf discs of 21−day−old maize plants. Values followed by different letters within a given binding agent treatment (NT, FC+P or KE+P) are significantly different (<span class="html-italic">p</span> &lt; 0.05; ANOVA followed by Duncan’s post hoc test; <span class="html-italic">n</span> = 4). NT−non-treated seeds, FC−fish collagen-treated seeds, KE−keratin-treated seeds, P−PHMB-poly(hexamethylene biguanide) hydrochloride-treated seeds, H−water-treated seeds, B−bentonite-treated seeds.</p>
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<p>FTIR spectra of 21−day−old maize leaves of the tested variants and the control sample: NT (black line), H+B (red line), FC+B (blue line), FC+P+B (pink line), KE+P (green line), KE+P+B (yellow line).</p>
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16 pages, 6754 KiB  
Article
The Synergistic Impact of a Novel Plant Growth-Promoting Rhizobacterial Consortium and Ascophyllum nodosum Seaweed Extract on Rhizosphere Microbiome Dynamics and Growth Enhancement in Oryza sativa L. RD79
by Pisit Thamvithayakorn, Cherdchai Phosri, Louisa Robinson-Boyer, Puenisara Limnonthakul, John H. Doonan and Nuttika Suwannasai
Agronomy 2024, 14(11), 2698; https://doi.org/10.3390/agronomy14112698 - 15 Nov 2024
Viewed by 680
Abstract
This study investigated the combined effects of novel plant growth-promoting rhizobacteria (PGPR)—Agrobacterium pusense NC2, Kosakonia oryzae WN104, and Phytobacter sp. WL65—and Ascophyllum nodosum seaweed extract (ANE) as biostimulants (PGPR-ANE) on rice growth, yield, and rhizosphere bacterial communities using the RD79 cultivar. The [...] Read more.
This study investigated the combined effects of novel plant growth-promoting rhizobacteria (PGPR)—Agrobacterium pusense NC2, Kosakonia oryzae WN104, and Phytobacter sp. WL65—and Ascophyllum nodosum seaweed extract (ANE) as biostimulants (PGPR-ANE) on rice growth, yield, and rhizosphere bacterial communities using the RD79 cultivar. The biostimulants significantly enhanced plant growth, shoot and root length, and seedling vigour; however, seed germination was not affected. In pot experiments, biostimulant application significantly increased the richness and evenness of bacterial communities in the rhizosphere, resulting in improvements in rice growth and yield, with increases in plant height (9.6–17.7%), panicle length (14.3–17.9%), and seeds per panicle (48.0–53.0%). Notably, biostimulant treatments also increased post-harvest soil nutrient levels, with nitrogen increasing by 7.7–19.2%, phosphorus by 43.4–161.4%, and potassium by 16.9–70.4% compared to the control. Principal coordinate analysis revealed distinct differences in bacterial composition between the tillering and harvesting stages, as well as between biostimulant treatments and the control. Beneficial bacterial families, including Xanthobacteraceae, Beijerinckiaceae, Acetobacteraceae, Acidobacteriaceae, and Hyphomicrobiaceae, increased in number from the tillering to harvesting stages, likely contributing to soil health improvements. Conversely, methanogenic bacterial families, such as Methanobacteriaceae and Methanosarcinaceae, decreased in number compared to the control. These findings highlight the dynamic responses of the rhizosphere microbiome to biostimulant treatments and underscore their potential benefits for promoting sustainable and productive agriculture. Full article
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<p>Alpha-diversity analyses of three biostimulant treatments, ANE, PGPR, and PGPR-ANE, along with control, during both tillering (S1) and harvesting (S2) stages using Chao1 (<b>A</b>,<b>B</b>) and Shannon (<b>C</b>,<b>D</b>) indices. (<b>A</b>,<b>C</b>) Analysis of each stage and treatment separately. (<b>B</b>,<b>D</b>) Combined analysis of both stages within each treatment.</p>
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<p>The relative abundances of PGPR-associated and methanogenic bacterial families in rhizosphere soils compared across the three biostimulant treatments, ANE, PGPR, and PGPR-ANE, as well as the control (UI), during both the tillering (S1) and harvesting (S2) stages.</p>
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<p>Comparative microbial community in rice rhizosphere soil across growth stages and treatments. (<b>A</b>) PCoA of microbial communities at tillering and harvesting stages. (<b>B</b>) PCoA of microbial communities by treatment at tillering stage (S1) and harvesting stage (S2). (<b>C</b>,<b>D</b>) LEfSe analysis highlighting differential abundances of taxa across treatments at tillering (S1) and harvesting (S2) stages. (<b>E</b>,<b>F</b>) Venn diagram of shared and unique families at tillering (S1) and harvesting (S2) stages across treatments.</p>
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14 pages, 1873 KiB  
Article
Association of Seedling Vigour and Salinity Tolerance in Field Pea
by Babu R. Pandey, Ramesh R. Puri, Arun S. K. Shunmugam, Dianne Noy and Garry M. Rosewarne
Plants 2024, 13(22), 3140; https://doi.org/10.3390/plants13223140 - 8 Nov 2024
Viewed by 612
Abstract
Soil salinity results in reduced productivity in field peas, making soil salinity tolerance a critical breeding objective. In this study, four pot experiments were carried out in semi-controlled environments over four consecutive years to assess the contribution of seedling vigour to salinity tolerance [...] Read more.
Soil salinity results in reduced productivity in field peas, making soil salinity tolerance a critical breeding objective. In this study, four pot experiments were carried out in semi-controlled environments over four consecutive years to assess the contribution of seedling vigour to salinity tolerance at the seedling stage. Split-plot designs were used to assess the effect of salt stress (sodium chloride solution at 16 dSm−1) and control conditions. Extensive sets of advanced breeding lines were used in 2018–2020 to assess growth differences in relation to the treatment, with elemental analysis used on a subset of 15 lines in 2021. A salt tolerance index (STI) was defined as a proportion of shoot biomass under salt stress (DWstress) relative to the shoot dry weight under control (DWctrl). Visual scores of salt stress were recorded on a 1–10 scale (1 = tolerant, 10 = susceptible) from salt stress treatments. The consistent positive and significant correlations (p < 0.01) between shoot DWctrl and DWstress indicated that vigorous genotypes maintained higher shoot DWstress. Both the shoot DWctrl and shoot DWstress had negative and significant (p < 0.01) correlations with visual scores of salt stress. Shoot DWstress showed strong positive correlations with STI (p < 0.01). Both the shoot DWctrl and Shoot DWstress had negative correlations (p < 0.01) with shoot Na+ whereas shoot DWstress had a positive correlation (p < 0.05) with root Na+ concentration. The results indicated that seedling vigour (measured as shoot DWctrl) contributed to salinity tolerance by maintaining improved shoot DWstress, limiting Na+ deposition in shoot and enduring less tissue damage in field pea seedlings. Additional field evaluations are required to establish the correlations of tolerance at seedling stage with yield under saline conditions. The insights obtained from this study may assist field pea breeders in identifying salt-tolerant parent plants, offspring, and breeding lines during the initial growth phases. Full article
(This article belongs to the Section Crop Physiology and Crop Production)
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<p>Typical differences in plant growth among selected check varieties under control and salt stress. Plants were grown under control and salt stress for four weeks. The pictures were taken before the harvest in 2021. Maki is a susceptible and PBA Percy is moderately tolerant check variety.</p>
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<p>Effect of salt treatment on elemental concentrations in shoot and root in 2021. Contents of elements in shoot (<b>a</b>–<b>c</b>) and roots (<b>f</b>–<b>h</b>), ratios of elements in shoot (<b>d</b>,<b>e</b>), ratios of elements in root (<b>i</b>,<b>j</b>). The bottom, middle and top line of the box plot represent the first, second and the quartiles of the data, respectively. Differences between the treatments were tested with analysis of variance (ANOVA). ***, **, and * indicate that the means were significantly different at 0.001, 0.01, and 0.05 level of significance, respectively.</p>
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<p>Effect of salt stress on elemental concentration of tolerant and susceptible genotypes in field pea shoot and root. Values are mean values ± standard error of mean (SE). The means of the tolerant and susceptible groups were tested using a <span class="html-italic">t</span>-test. The same alphabet above the bars are not statistically significant at 0.05 level of significance. n = 27 and 18 for the susceptible and tolerant group, respectively.</p>
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<p>Biplot of 15 field pea genotypes, based on the variance in 11 traits, explained by two PC axes (Dim 1 and Dim 2). The numbers 1 to 15 indicate genotype ranks in ascending order of salt tolerance index.</p>
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14 pages, 688 KiB  
Review
One Hundred Years of Progress and Pitfalls: Maximising Heterosis through Increasing Multi-Locus Nuclear Heterozygosity
by Brendan F. Hallahan
Biology 2024, 13(10), 817; https://doi.org/10.3390/biology13100817 - 12 Oct 2024
Viewed by 976
Abstract
The improvement in quantitative traits (e.g., yield, size) in F1 offspring over parent lines is described as hybrid vigour, or heterosis. There exists a fascinating relationship between parental genetic distance and genome dosage (polyploidy), and heterosis effects. The contribution of nuclear heterozygosity [...] Read more.
The improvement in quantitative traits (e.g., yield, size) in F1 offspring over parent lines is described as hybrid vigour, or heterosis. There exists a fascinating relationship between parental genetic distance and genome dosage (polyploidy), and heterosis effects. The contribution of nuclear heterozygosity to heterosis is not uniform across diploid and polyploid crops, even within same species, thus demonstrating that polyploid crops should be part of any discussion on the mechanisms of heterosis. This review examines the records of correlating heterosis with parental genetic distance and the influence of adding supplementary genomes in wide crosses. Increasing nuclear heterozygosity through parental genetic distance has been shown to be an imperfect predictor for heterosis in a variety of commercial crops such as maize, rice, and pepper. However, increasing the ploidy level raises the maximum number of alleles that can be harboured at any one locus, and studies on crops such as oilseed rape, potato, alfalfa, maize, and rice have demonstrated that heterosis may be maximised upon increasing multi-locus nuclear heterozygosity. The novel heterotic phenotypes observed above the diploid level will contribute to our understanding on the mechanisms of heterosis and aid plant breeders in achieving the righteous goal of producing more food with fewer inputs. Full article
(This article belongs to the Section Plant Science)
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<p>F<sub>1</sub> autotetraploid from a double-cross can harbour four different alleles at a locus. An autotetraploid contains four identical chromosome sets within its nucleus. Let us propose a hypothetical gene at a certain locus that has four different alleles, denoted a, b, c, and d. Inbred (100% homozygous) lines will possess a mono-allelic locus for this gene, i.e., a simplex genotype meaning four identical copies of one allele (aaaa and bbbb). Following cross-fertilisation, the single cross F<sub>1</sub> hybrid will possess a di-allelic locus for this gene, i.e., a duplex genotype meaning two copies of two different alleles (aabb). This single cross F<sub>1</sub> hybrid can be crossed to a different inbred line (cccc) and the resulting three-way cross F<sub>1</sub> hybrid will possess a tri-allelic locus for this gene, i.e., a trigenic genotype meaning one copy of two different alleles and two identical copies of one allele (abcc). Alternatively, the single cross F<sub>1</sub> hybrid can be crossed to a different single cross F<sub>1</sub> hybrid (ccdd) and the resulting double-cross F<sub>1</sub> hybrid will possess a tetra-allelic locus, i.e., a tetragenic genotype meaning one copy of four different alleles (abcd). The increasing intensity of the colour pink reflects the increasing levels of heterozygosity.</p>
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27 pages, 5359 KiB  
Article
Opportunities for the Early Diagnosis and Selection of Scots Pine with Potential Resistance to Root and Butt Rot Disease
by Valentyna Dyshko, Ivan Ustskiy, Piotr Borowik and Tomasz Oszako
Forests 2024, 15(10), 1789; https://doi.org/10.3390/f15101789 - 11 Oct 2024
Viewed by 629
Abstract
Pine stands affected by root and butt rot (Heterobasidion annosum s.l.) contain pines (Pinus sylvestris L.) that can survive for a long time without showing external symptoms of the disease (‘conditionally resistant’ refers to trees that survive without symptoms despite [...] Read more.
Pine stands affected by root and butt rot (Heterobasidion annosum s.l.) contain pines (Pinus sylvestris L.) that can survive for a long time without showing external symptoms of the disease (‘conditionally resistant’ refers to trees that survive without symptoms despite infection). The establishment of stands from the seeds of such trees can significantly increase the effectiveness of artificial afforestation. Since the growth and development of pine trees is determined to a certain extent by the number of cotyledons after seed germination, this article examines this trait in the progeny of trees that are potentially resistant and those that have already been attacked by root pathogens. The number of cotyledons and the resilience of trees is fascinating and not generally known. Presumably, the number of cotyledons can be linked to disease resistance based on increased vigour. Biologically, a larger area for carbon assimilation leads to better photosynthetic efficiency and the production of more assimilates (sugars) necessary to trigger defence processes in the event of infection. From an ecological point of view, this can give tree populations in areas potentially threatened by root system diseases a chance of survival. The aim of this study was to analyze the potential of using the number of cotyledons and other seedling characteristics to predict the resistance of trees to root and butt rot disease. The collected data show that the seedlings from the group of diseased trees exhibited lower growth rates and vigour. However, the seedlings from the group of potentially resistant trees are similar to the control, meaning the trees that show no disease symptoms because they have not come into contact with the pathogen. Our observations suggest that monitoring germinating cotyledons could serve as an early diagnostic tool to identify disease-resistant pines, although further research is needed. Full article
(This article belongs to the Section Forest Health)
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<p>Conceptual diagram of the idea of the reported experiment.</p>
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<p>Often one (<b>a</b>–<b>c</b>) or a group (<b>d</b>) of living, asyptomatic trees remains in the gap that has arisen in the stand. The cause of the death of the other trees is the fungus <span class="html-italic">Hetereobasidion</span> spp., whose fruiting bodies grow on the remaining stumps (<b>c</b>). The dead trees initially remain standing (<b>b</b>) and are then blown over by the wind (<b>c</b>,<b>e</b>).</p>
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<p>Photos of seeds and seedlings taken during the experiment. (<b>a</b>) Seeds counted and prepared for weighing. (<b>b</b>) Germinated seedlings in a Petri dish. (<b>c</b>) Seedlings prepared for measurements. (<b>d</b>) A single seedling.</p>
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<p>Weight of batches of 50 seeds compared to the treatment variant.</p>
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<p>Number of germinated seeds in lots of 100 from each of the considered trees versus the treatment variant.</p>
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<p>The average weight of a batch of 50 seeds collected from a tree compared to the proportion of germinated seeds. Ninety percent confidence ellipses are plotted as a guide.</p>
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<p>Mean number of cotyledons in seedlings germinated from trees from different experimental treatment categories. Visualisation of the variability of the mean values by tree from which the seeds were collected.</p>
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<p>Mean stem length of the germinated seedlings of trees belonging to different experimental treatment categories. Visualisation of the variability of the mean values according to the tree from which the seeds were collected.</p>
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<p>Mean root length of germinated seedlings of trees belonging to different experimental treatment categories. Visualisation of the variability of the mean values depending on the tree from which the seeds were collected.</p>
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<p>Mean needle length of germinated seedlings of trees belonging to different experimental treatment categories. Visualisation of the variability of the mean values according to the tree from which the seeds were collected.</p>
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<p>Mean ratio of stem/root length proportion of germinated seedlings of trees belonging to different experimental treatment categories. Visualisation of the variability of the mean values by tree from which the seeds were collected.</p>
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<p>Proportion of seedlings from seeds of a given tree compared to the number of developed cotyledons. Comparison between treatment groups.</p>
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<p>The ratio between stem and root length compared to the number of developed cotyledons in the seedling. Comparison between the treatment groups.</p>
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<p>Phases of mitosis in apical meristems of roots of tree seedlings with different resistance to <span class="html-italic">Heterobasidion</span> under a light microscope (100× magnification).</p>
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14 pages, 1926 KiB  
Article
Characterization of Nitrogen-Fixing Cyanobacterial Consortia Isolated from the Rhizosphere of Carica papaya
by Yadenis Ortega Díaz, Liliana Gomez Luna, Yilan Fung Boix, Yadira Silveira Font, Jorge González Aguilera, Obert Marín-Sánchez, Abel Walter Zambrano-Cabanillas, Olegario Marín-Machuca, Sheda Méndez-Ancca and Carlos Enrique Chinchay Barragán
Agronomy 2024, 14(9), 2132; https://doi.org/10.3390/agronomy14092132 - 19 Sep 2024
Viewed by 706
Abstract
Nitrogen-fixing cyanobacterial consortia are an alternative to the indiscriminate use of chemical fertilizers that affect the environment, fix atmospheric nitrogen, and can therefore be used as plant growth promoters, synthesize various substances such as auxins, vitamins, and total proteins, and fix atmospheric biofertilizers [...] Read more.
Nitrogen-fixing cyanobacterial consortia are an alternative to the indiscriminate use of chemical fertilizers that affect the environment, fix atmospheric nitrogen, and can therefore be used as plant growth promoters, synthesize various substances such as auxins, vitamins, and total proteins, and fix atmospheric biofertilizers and soil conditioners. The present study aimed to obtain and develop, by biotechnological means, two consortia of cyanobacteria isolated from the root and rhizosphere of Carica papaya grown in sandy loam soil. The culture was carried out in Blue Green Medium without modified nitrogen (BG110), with aeration of 0.32 L min−1, at a light intensity of 48.83 μEm−2s−1, and a temperature of 22 ± 2 °C. Two consortia consisting of Nostoc commune, Aphanothece minutissima, Planktothrix sp. (C1), Nostoc commune, Calothrix sp., and Aphanothece minutissima (C2) were isolated and morphologically identified. The effective development of these consortia was verified at the laboratory level by obtaining biomass in dry weight as well as photosynthetic pigments, proteins, carbohydrates, and lipids. Germination parameters were determined in seeds of Cucumis sativus L. var. Market plus treated with the nitrogen-fixing cyanobacteria consortia, obtaining a higher germination percentage (>90%), greater root length (>6 cm), and higher vigour index I (513), II (13.02) for the C2 consortium. This broadens the spectrum of rhizosphere-derived microorganisms with potential as growth biostimulators. Full article
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<p>(<b>A</b>) Colonies of cyanobacteria from the root of <span class="html-italic">Carica papaya</span>. (<b>B</b>) Colonies of cyanobacteria from the rhizosphere soil of <span class="html-italic">Carica papaya</span>.</p>
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<p>Cyanobacteria isolated, cultured, and taxonomically identified (bars = 20 µm), obtained by brightfield optical microscopy. Brightfield optical microscopy of the (<b>A</b>) first consortium (C1) <span class="html-italic">Nostoc commune</span> (N), <span class="html-italic">Aphanothece minutissima</span> (A), and <span class="html-italic">Planktothrix</span> sp. (P) and (<b>B</b>) second consortium (C2) <span class="html-italic">Nostoc commune</span>, <span class="html-italic">Calothrix</span> sp. (C), and <span class="html-italic">Aphanothece minutissima</span>.</p>
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<p>Evaluation of the total protein, total carbohydrate, and total lipid content per weight of biomass of consortia C1 and C2 at 21 culture days. The error bars represent the standard deviation determined with independent replicates (n = 3). Asterisks (*) represent significant differences (Student’s test, <span class="html-italic">p</span> ≤ 0.05) between C1 and C2 in the same time period.</p>
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<p>Nitrate concentration of the different culture days of the C1 and C2 consortia. The error bars represent the standard deviation determined with independent replicates (n = 3). Asterisks (*) represent significant differences (Student’s test, <span class="html-italic">p</span> ≤ 0.05) between C1 and C2.</p>
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14 pages, 278 KiB  
Article
Maternal Supplementation with Dietary Betaine during Late Gestation Increased Ewe Plasma Creatine and Lamb Thermoregulation under Field Conditions
by Billie-Jaye Brougham, Alice C. Weaver, Alyce M. Swinbourne, Megan R. Tscharke, Amy L. Munn, Jennifer M. Kelly, David O. Kleemann and William H. E. J. van Wettere
Animals 2024, 14(17), 2605; https://doi.org/10.3390/ani14172605 - 7 Sep 2024
Viewed by 736
Abstract
Twin lamb mortality is a significant economic problem impacting the Australian sheep industry. Maternal betaine supplementation improved lamb vigour and early post-natal survival when ewes and lambs were housed indoors, suggesting that betaine may be beneficial to feed under extensive pasture systems. This [...] Read more.
Twin lamb mortality is a significant economic problem impacting the Australian sheep industry. Maternal betaine supplementation improved lamb vigour and early post-natal survival when ewes and lambs were housed indoors, suggesting that betaine may be beneficial to feed under extensive pasture systems. This study investigated whether maternal betaine supplementation during late gestation would improve Merino twin lamb live weight, thermoregulation, vigour and survival to weaning under field conditions. Ewes received dietary betaine at either 0 g/day (CTL; n = 115) or 4 g/day from day 110 of gestation (dG 110) until ~49 days post-partum (pp) (BET; n = 115). Measures indicative of lamb viability and survival were collected within 4–24 h of birth and at ~49 days pp and ~93 days pp. BET ewes had higher creatine and creatinine concentrations at dG 130 than CTL ewes (p < 0.05). BET lambs had a higher rectal temperature within 4–24 h following birth than CTL lambs (p < 0.05). CTL lambs were heavier at ~49 days pp and grew faster from birth to ~49 days pp than BET lambs (both p < 0.05). The time taken after release from the researcher to first suckling was quicker in the CTL lambs than BET lambs (p < 0.05). This study demonstrated that supplementing betaine increased creatine concentration in twin-bearing ewes and thermoregulatory capacity in neonatal lambs under extensive grazing systems. Full article
15 pages, 2858 KiB  
Article
Rupture Test: A New Method for Evaluating Maize (Zea mays) Seed Vigour
by Heqin Li, Haiwang Yue, Miaomiao Lu, Ru Jia and Xuwen Jiang
Plants 2024, 13(13), 1847; https://doi.org/10.3390/plants13131847 - 4 Jul 2024
Cited by 1 | Viewed by 1073
Abstract
To explore the application of seed germination biomechanical event(s) in seed vigour tests, a new procedure for the evaluation of maize seed vigour tests based on pericarp–testa rupture (PR) and coleorhiza rupture (CR) during seed germination was developed. Twenty–four lots of hybrid maize [...] Read more.
To explore the application of seed germination biomechanical event(s) in seed vigour tests, a new procedure for the evaluation of maize seed vigour tests based on pericarp–testa rupture (PR) and coleorhiza rupture (CR) during seed germination was developed. Twenty–four lots of hybrid maize were used to determine the feasibility of the rupture test (RT) as a seed vigour test in Zea mays. The results showed that the physiological quality pattern of 24 maize seed lots assessed through RT was similar to that obtained through analysis with other seed test methods. Correlation and regression analyses revealed that the percentage of CR and percentage of PR + CR at “15 ± 0.5 °C for 120 h ± 1 h” and “20 ± 0.5 °C for 72 h ± 15 min” exhibited positive correlations with the field seedling emergence data (p < 0.01). Hence, the proposed method (the rupture test) is cogent and effective, thus providing an important reference for more crops to select for seed germination event(s) and establishing corresponding new methods for seed vigour tests in the future. Full article
(This article belongs to the Section Crop Physiology and Crop Production)
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<p>Rupture test for <span class="html-italic">Zea mays</span>. (<b>a</b>) Schematic diagram of the rupture test. (<b>b</b>) Pericarp–testa rupture and coleorhiza rupture. (<b>c</b>) Field seedling emergence test.</p>
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<p>Comparative analysis of the germination first count (GFC) and germination percentage (GP) of different maize cultivars. (<b>a</b>) GFC of samples in 2023. (<b>b</b>) GP of samples in 2023. (<b>c</b>) GFC of samples in 2022. (<b>d</b>) GP of samples in 2022. (<b>e</b>) GFC of samples in 2021. (<b>f</b>) GP of samples in 2021. Different lowercase letters mean a significant difference (<span class="html-italic">p</span> &lt; 0.05), and different capital letters mean an extremely significant difference (<span class="html-italic">p</span> &lt; 0.01). The red dashed boxes represent the representative Chinese hybrid maize cultivar ZD958 and the representative American hybrid maize cultivar XY335.</p>
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<p>Selection and determination of the evaluation indices for the rupture test. (<b>a</b>) The principle of selecting indices for evaluating seed vigour by rupture test. (<b>b</b>) Relationships between the seed lot vigour indices in the rupture test and FSEs (FSE–J, FSE–L, and FSE–S). For the complete list of abbreviations, go to “<a href="#app1-plants-13-01847" class="html-app">Figure S1</a>”. ** indicates significance at <span class="html-italic">p</span> &lt; 0.01.</p>
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<p>The physical features of seeds from ZD958 (ZhengDan958) and XY335 (XianYu335) are compared. The seed morphology is compared in (<b>a</b>); the pericarp–testa water absorption characteristics are compared in (<b>b</b>); the pericarp–testa covering embryo (PCE) thickness is compared in (<b>c</b>); the PCE puncture force is compared in (<b>d</b>); and the puncture force measurement characteristic curve is compared in (<b>e</b>).</p>
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18 pages, 2080 KiB  
Review
Medullary Thyroid Cancer: Molecular Drivers and Immune Cellular Milieu of the Tumour Microenvironment—Implications for Systemic Treatment
by Alexander J. Papachristos, Hazel Serrao-Brown, Anthony J. Gill, Roderick Clifton-Bligh and Stanley B. Sidhu
Cancers 2024, 16(13), 2296; https://doi.org/10.3390/cancers16132296 - 22 Jun 2024
Viewed by 1527
Abstract
In this review, we explore the underlying molecular biology of medullary thyroid carcinoma (MTC) and its interplay with the host immune system. MTC is consistently driven by a small number of specific pathogenic variants, beyond which few additional genetic events are required for [...] Read more.
In this review, we explore the underlying molecular biology of medullary thyroid carcinoma (MTC) and its interplay with the host immune system. MTC is consistently driven by a small number of specific pathogenic variants, beyond which few additional genetic events are required for tumorigenesis. This explains the exceedingly low tumour mutational burden seen in most MTC, in contrast to other cancers. However, because of the low tumour mutational burden (TMB), there is a correspondingly low level of tumour-associated neoantigens that are presented to the host immune system. This reduces tumour visibility and vigour of the anti-tumour immune response and suggests the efficacy of immunotherapy in MTC is likely to be poor, acknowledging this inference is largely based on the extrapolation of data from other tumour types. The dominance of specific RET (REarranged during Transfection) pathogenic variants in MTC tumorigenesis rationalizes the observed efficacy of the targeted RET-specific tyrosine kinase inhibitors (TKIs) in comparison to multi-kinase inhibitors (MKIs). Therapeutic durability of pathway inhibitors is an ongoing research focus. It may be limited by the selection pressure TKI treatment creates, promoting survival of resistant tumour cell clones that can escape pathway inhibition through binding-site mutations, activation of alternate pathways, and modulation of the cellular and cytokine milieu of the tumour microenvironment (TME). Full article
(This article belongs to the Special Issue Molecular Biology, Diagnosis and Management of Thyroid Cancer)
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<p>Canonical RET signalling. RET activation occurs upon fulfilment of multiple steps. Binding of GDNF-family ligands (GFLs), to co-receptor GFRα1-4, concurrently with binding of calcium ions to the calcium binding domain, induces recruitment of RET, forming RET-GFRα complex. Formation of RET-GFRα complex brings two RET monomers in close proximity to induce homodimerization and cross phosphorylation of key RET tyrosine residues that recruit adaptor proteins important for propagation of RET signalling, such as PI3K/AKT, MAPK, and RAS/RAF/ERK. Thus, activation of RET signalling ultimately promotes cell proliferation, growth, and survival through activation of multiple downstream signalling cascades. CRD, cysteine-rich domain; TMD, transmembrane domain; TK, tyrosine kinase domain. Adapted from [<a href="#B12-cancers-16-02296" class="html-bibr">12</a>]. Published under a Creative Commons Attribution (CC BY) License.</p>
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<p>The variety of surface tyrosine kinase receptors that play an important role in the maintenance of cellular homeostasis, through regulation of intracellular signalling pathways. The final effector pathways can be activated by several surface receptors, as well as by other intracellular activation pathways, highlighting the inherent difficulty in achieving sustained therapeutic efficacy through the blockade of a particular tyrosine kinase receptor. Adapted from [<a href="#B118-cancers-16-02296" class="html-bibr">118</a>]. Published under a Creative Commons Attribution (CC BY) License.</p>
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<p>Mechanisms of MKI resistance. RET tyrosine kinase transmembrane receptor has constitutive activation due to RET point mutations leading to downstream pathway activation. (A) Resistance mechanisms are described. (B) On target: the RET receptor kinase domain catalytic cleft is activated when ATP causes phosphorylation. MKIs (vandetanib, cabozantinib) can hinder the ATP binding when there is no V804M/L mutation with bulky hydrophobic side chains: steric inhibition. Acquired solvent front mutations RET G810R, G810S, G810C hinder this binding rendering selpercatinib ineffective. (C) Off Target mutations are shown with multiple tumour clones existing at baseline, reduction in RET, and subsequent increase in KRAS (or MET) allelic frequency. Adapted from [<a href="#B121-cancers-16-02296" class="html-bibr">121</a>]. Published under a Creative Commons Attribution (CC BY) License.</p>
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21 pages, 5735 KiB  
Article
Drought-Stressed Apple Tree Grafted onto Different Rootstocks in a Coastal Sandy Soil: Link between Fast Chlorophyll a Fluorescence and Production Yield
by Andrea Colpo, Sara Demaria, Marzio Zaccarini, Alessandro Forlani, Antonia Senatore, Elena Marrocchino, Angela Martina and Lorenzo Ferroni
Agronomy 2024, 14(6), 1304; https://doi.org/10.3390/agronomy14061304 - 16 Jun 2024
Viewed by 3101
Abstract
Domesticated apple is a drought-sensitive species that spread from continental to Mediterranean temperate regions, where it can particularly experience prolonged water stress. One strategy to improve drought resistance in apple is engrafting on selected rootstocks. This study explores the potential of fast chlorophyll [...] Read more.
Domesticated apple is a drought-sensitive species that spread from continental to Mediterranean temperate regions, where it can particularly experience prolonged water stress. One strategy to improve drought resistance in apple is engrafting on selected rootstocks. This study explores the potential of fast chlorophyll a fluorescence for the comparison of rootstock sensitivity to drought, looking for significant correlations with fruit productivity. The experiment was conducted in a field located in the coastal Po River Plain, Northern Italy, characterized by a loamy sandy soil, particularly prone to drought (86% sand). Mature plants of apple cv. Superchief® Sandidge engrafted on three different rootstocks (CIVP21pbr, MM106, M26) were monitored throughout the summer of 2021 and compared between irrigated and non-irrigated parcels, and at the end of the season, fruit production was evaluated. Despite soil water tension only reaching −13 kPa, the non-irrigated plants experienced a small but consistent loss of Photosystem II (PSII) activity and a lesser capacity of light energy conservation in the photosynthetic electron transport chain. The fruit weight correlated with PSII photochemical indexes recorded during early drought, particularly FV/FM and PIABS; a correlation emerged between fruit number per plant and median values of electron transport parameters, including PITOT. Although all rootstocks underwent a 40% loss of productivity, the fluorescence parameters revealed a graded susceptibility to drought, M26 > CIVP21pbr > MM106, which matched well with the plant vigour. The least drought-sensitive MM106 produced less numerous but heavier fruits than the other two rootstocks. Full article
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<p>(<b>a</b>) Classification of the soil in the experimental field according to the USDA-NRCS Soil Texture Classes (<span class="html-italic">N</span> = 17 samples). (<b>b</b>) Soil water tension in the non-irrigated parcel during the monitoring season and comparative volumetric water content at a depth of 30 cm in irrigated and non-irrigated parcels.</p>
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<p>Examples of chlorophyll <span class="html-italic">a</span> fluorescence induction curves in Superchief<sup>®</sup> Sandidge apple trees engrafted on rootstocks CIVP21<sup>pbr</sup>, MM106, M26, either irrigated or not (drought). (<b>a</b>) Average curves from data recorded on the 30th of June 2021 (21 days without irrigation in the treated parcel). Position of <span class="html-italic">F</span><sub>0</sub> and <span class="html-italic">F<sub>M</sub></span> are indicated. (<b>b</b>) The same curves as in (<b>a</b>) after double normalization between <span class="html-italic">F</span><sub>0</sub> and <span class="html-italic">F<sub>M</sub></span>. The noticeable steps of the fluorescence induction are indicated.</p>
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<p>Variation of chlorophyll <span class="html-italic">a</span> fluorescence parameters related to PSII activity in non-irrigated Superchief<sup>®</sup> Sandidge apple trees engrafted on rootstocks CIVP21<sup>pbr</sup>, MM106, M26. Relative variations in parameters are shown compared to the irrigated control, which was assigned the value 1. (<b>a</b>) Minimum fluorescence <span class="html-italic">F</span><sub>0</sub>. (<b>b</b>) Maximum fluorescence <span class="html-italic">F<sub>M</sub></span>. (<b>c</b>) PSII photochemistry index <span class="html-italic">F<sub>V</sub></span>/<span class="html-italic">F<sub>M</sub></span><b>.</b> (<b>d</b>) PSII photochemistry index <span class="html-italic">F<sub>V</sub></span>/<span class="html-italic">F</span><sub>0</sub>. (<b>e</b>) PSII donor side integrity parameter <span class="html-italic">V<sub>K</sub></span>/<span class="html-italic">V<sub>J</sub></span>. (<b>f</b>) Absorption flux per PSII reaction centre ABS/RC. Means of <span class="html-italic">N</span> = 15–45 leaves per rootstock with standard deviations represented as coloured bands. <span class="html-italic">p</span> values were obtained from one-sample Student’s <span class="html-italic">t</span> test, with <span class="html-italic">H</span><sub>0</sub> stating that the parameter was not different from 1 value assigned to the irrigated controls.</p>
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<p>Variations of chlorophyll <span class="html-italic">a</span> fluorescence parameters related to the light energy conservation in the photosynthetic electron transport chain in non-irrigated Superchief<sup>®</sup> Sandidge apple trees engrafted on rootstocks CIVP21<sup>pbr</sup>, MM106, M26. Relative variations in parameters are shown compared to the irrigated control, which was assigned the value 1. (<b>a</b>) Complement to relative fluorescence at step J, 1 − <span class="html-italic">V<sub>J</sub></span>. (<b>b</b>) Complement to relative fluorescence at step I, 1 − <span class="html-italic">V<sub>I</sub></span>. (<b>c</b>) (1 − <span class="html-italic">V<sub>I</sub></span>)/(1 − <span class="html-italic">V<sub>J</sub></span>) ratio. (<b>d</b>) Normalized area <span class="html-italic">Sm</span> between the OJIP transient and <span class="html-italic">F<sub>M</sub></span>. (<b>e</b>) Performance index on absorption basis, PI<sub>ABS</sub>. (<b>f</b>) Total performance index on absorption basis, PI<sub>TOT</sub>. Means of <span class="html-italic">N</span> = 15–45 leaves per rootstock with standard deviations represented as coloured bands. <span class="html-italic">p</span> values were obtained from one-sample Student’s <span class="html-italic">t</span> test, with <span class="html-italic">H</span><sub>0</sub> stating that the parameter was not different from 1 value assigned to the irrigated controls.</p>
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<p>Principal components analysis of chlorophyll <span class="html-italic">a</span> fluorescence and productive parameters of Superchief<sup>®</sup> Sandidge apple engrafted on the three rootstocks CIVP21<sup>pbr</sup>, MM106, M26 under two watering regimes (w, irrigation; d, drought stress). (<b>a</b>) Biplot built using the median fluorescence parameters measured during the entire season. (<b>b</b>) Biplot built using the fluorescence parameters measured during the 14th after the interruption of irrigation. The vectors of the fluorescence or productive parameters are coloured in blue or purple for fluorescence or productive parameters, respectively.</p>
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<p>Precipitation (bars) and average daily air temperature (line) during the monitoring season (June–August 2021).</p>
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<p>Correlation matrixes with chlorophyll <span class="html-italic">a</span> fluorescence and productivity parameters. For the former, the medians obtained with the entire dataset or the values on the 14th day after watering interruption are shown in (<b>a</b>) and (<b>b</b>), respectively. The graded colour scales are based on Pearson’s <span class="html-italic">r</span>. Asterisks mark significant correlations with <span class="html-italic">p</span> &lt; 0.05. Parameter definitions are given in the main text.</p>
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7 pages, 869 KiB  
Communication
Inheritance and Response to Selection for Seed Weight Using the Large Seeded Landrace Oman 2 of Lucerne
by John A. G. Irwin and Michael J. Havey
Seeds 2024, 3(2), 269-275; https://doi.org/10.3390/seeds3020020 - 31 May 2024
Viewed by 691
Abstract
Seed weight in lucerne (Medicago sativa) may affect subsequent seedling vigour and stand establishment. A landrace of lucerne (Oman 2) from Oman has a 100-seed weight over 60% larger than the largest seeded parent used in previous studies. Crosses were made [...] Read more.
Seed weight in lucerne (Medicago sativa) may affect subsequent seedling vigour and stand establishment. A landrace of lucerne (Oman 2) from Oman has a 100-seed weight over 60% larger than the largest seeded parent used in previous studies. Crosses were made between Oman 2 and the smaller-seeded cultivar Titan 9, and segregating families were produced for genetic analysis and measurement of response to selection for seed size. There were significant differences in 100-seed weights between the parents (Oman 2 and Titan 9) and subsequent families. Regression of 100-seed weights of F2 families versus F1 parents was highly significant (p < 0.001), as well as 100-seed weights of the F3 families versus F1 parents. Analysis of diallel crossing among large and small-seeded F1 plants revealed highly significant general (GCAs) and specific (SCAs) combining abilities, as well as highly significant reciprocals. The GCA effect was much greater than the SCA effect with a GCA/SCA ratio of 15.9. This large ratio agrees with the significant regression coefficients and indicates that 100-seed weight in lucerne has high heritability. The significance of reciprocals was due to a large maternal effect in which large-seeded maternal parents produced progenies with significantly larger seeds relative to small-seeded parents. These results indicate that large-seeded plants should be used as the maternal parents in crosses and for recurrent selection to increase the seed size of progenies. Full article
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<p>Mating scheme for genetic analyses of seed weights in lucerne.</p>
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<p>Boxplots of 100-seed weights of parents (Oman 2 and Titan 9) and families generated after crossing Oman 2 with Titan 9.</p>
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15 pages, 9886 KiB  
Article
Assessing the Effectiveness of Pruning in an Olive Orchard Using a Drone and a Multispectral Camera: A Three-Year Study
by Eliseo Roma, Pietro Catania, Mariangela Vallone and Santo Orlando
Agronomy 2024, 14(5), 1023; https://doi.org/10.3390/agronomy14051023 - 11 May 2024
Viewed by 1097
Abstract
The uses of precision oliviculture have increased in recent years to improve the quality and quantity of extra virgin olive oil. In traditional and intensive systems, biennial pruning is often applied to balance and maintain plant vigour, aiming at reducing management costs. This [...] Read more.
The uses of precision oliviculture have increased in recent years to improve the quality and quantity of extra virgin olive oil. In traditional and intensive systems, biennial pruning is often applied to balance and maintain plant vigour, aiming at reducing management costs. This study presents the results of a three-year experiment with the objective of quantifying the effects of biennial pruning on the vegetative vigour of olive trees, investigating the geometric and spectral characteristics of each canopy determined with multispectral images acquired by UAV. The experiment was carried out in an olive orchard located in western Sicily (Italy). Multispectral images were acquired using a UAV in automatic flight configuration at an altitude of 70 m a.g.l. The segmentation and classification of the images were performed using Object-Based Image Analysis (OBIA) based on the Digital Elevation Model (DEM) and orthomosaic to extract the canopy area, height, volume and NDVI for each plant. This study showed that the technology and image analysis processing used were able to estimate vigour parameters at different canopy densities, compared to field measurements (R2 = 0.97 and 0.96 for canopy area and volume, respectively). Furthermore, it was possible to determine the amount of removed biomass for each plant and vigour level. Biennial pruning decreased the number of plants initially classified as LV (low-vigour) and maintained a vegetative balance for MV (medium-vigour) and HV (high-vigour) plants, reducing the spatial variability in the field. Full article
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<p>Experimental site location in the Mediterranean area and on the island of Sicily, Italy. Mean olive oil production calculated using FAOSTAT (2022) [<a href="#B3-agronomy-14-01023" class="html-bibr">3</a>] data from 2018 to 2022.</p>
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<p>Schedule of flights based on the BBCH stage of olive trees during this experimental study.</p>
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<p>Ground Control Points (GCP) in the experimental plot.</p>
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<p>Workflow of photogrammetry data processing.</p>
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<p>Schematic representation of data processing input and output.</p>
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<p>Representation of canopies in RGB visualisation for the three vigour groups.</p>
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<p>Canopy height (CH) measurement on the sample plants and indication of the two main axes of the canopy (green and yellow colour represent vegetation and axes, respectively).</p>
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<p>Comparison between the observed and predicted values of canopy area (CA, m<sup>2</sup>) before (<b>a</b>) and after (<b>b</b>) pruning, canopy volume (CV, m<sup>3</sup>) before (<b>c</b>) and after (<b>d</b>) pruning and canopy height (CH, m) before (<b>e</b>) and after (<b>f</b>) pruning. The red line is the line interpolating the data. Green and yellow triangles represent the values obtained during the pre and post-pruning operation respectively for each plant.</p>
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<p>Comparison between the observed and predicted values of canopy area (CA, m<sup>2</sup>) before (<b>a</b>) and after (<b>b</b>) pruning, canopy volume (CV, m<sup>3</sup>) before (<b>c</b>) and after (<b>d</b>) pruning and canopy height (CH, m) before (<b>e</b>) and after (<b>f</b>) pruning. The red line is the line interpolating the data. Green and yellow triangles represent the values obtained during the pre and post-pruning operation respectively for each plant.</p>
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<p>Geometric variation of the canopy plant of a sample tree due to pruning in 3D and 2D view.</p>
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<p>(<b>a</b>) Biomass removed with pruning in the three vigour levels. (<b>b</b>) Correlation between volume and canopy area variation. The different bars colours represent the three vigour levels of the plants. Letters ‘a’, ‘b’, and ‘c’ indicate statistically significant differences among the groups, while red line is the line interpolating the data.</p>
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<p>(<b>a</b>) Correlation between volume before and after pruning in the 17 selected plants. (<b>b</b>) Correlation between ΔCV and pruning weight (kg). The red line is the line interpolating the data.</p>
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<p>(<b>a</b>) Biomass pruning density removed in the three vigour levels. (<b>b</b>) Correlation between pruning biomass and pruning density in the 17 selected plants. The different colours of the triangles and bars represent the three vigour levels of the plants. Letters ‘a’, ‘b’, and ‘c’ indicate statistically significant differences among the groups, while the red line is the line interpolating the data.</p>
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<p>Distribution of all plants in the three levels of vigour over the three-year experimental period, evaluated at the BBCH74 phenological stage.</p>
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<p>Vigour levels percentage distribution observed over the three years (HV, MV, LV). Internal pie charts show percentage changes between one level of vigour and the others.</p>
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17 pages, 3744 KiB  
Article
Zn Oxide Nanoparticles and Fine Particles: Synthesis, Characterization and Evaluation of the Toxic Effect on Germination and Vigour of Solanum licopersicum L.
by Marina de Francisco, Sara Mira, Luisa Durães, Andreia Romeiro, Silvia Álvarez-Torrellas and Patricia Almendros
Agronomy 2024, 14(5), 980; https://doi.org/10.3390/agronomy14050980 - 7 May 2024
Cited by 3 | Viewed by 1074
Abstract
The micronutrient Zinc (Zn) is essential for the proper growth and development of crops. Zinc oxide nanoparticles (NPs) and fine particles are presented as an emerging alternative to more traditional fertilizers. In this study, the possible toxic effect of four laboratory-synthesized ZnO NPs [...] Read more.
The micronutrient Zinc (Zn) is essential for the proper growth and development of crops. Zinc oxide nanoparticles (NPs) and fine particles are presented as an emerging alternative to more traditional fertilizers. In this study, the possible toxic effect of four laboratory-synthesized ZnO NPs and fine particles with different characteristics on tomato seed germination and vigor parameters was examined in comparison to bulk ZnO. Different metal precursors were used for the chemical synthesis of the particles: Zn(NO3)2 and ZnSO4, for particles named NIT-. and SUL-., respectively. In addition, the synthesis process was modified to obtain coated particles (denoted as UW-, NIT-UW and SUL-UW) and washed particles (denoted as W-, NIT-W and SUL-W). These particles were applied at different toxic doses (0, 1.4, 2.8, 5.6 and 11.2 g L−1). The results indicated that although the constant contact time between the ZnO particles did not affect the germination capacity of the seeds, it affected the growth of roots and hypocotyls, with a higher impact on the roots’ development. This toxicity was more evident from the lowest particle dose used, although it did not prevent radicle and hypocotyl elongation during the development period studied (14 days). The synthesized coated particles (NIT-UW, SUL-UW) generated high toxicity on radicle and hypocotyl development, and this effect was observed from the first days of contact with the particles. The observed toxic effects on radicle length were minimized by the application of bulk ZnO particles. In the case of hypocotyl growth, these minor toxic effects were observed by using NIT-W particles and bulk ZnO. The possibility of positive effects on seed germination and development (radicle and hypocotyl length) when in continuous contact with ZnO, whether in fine particles, nanoparticles, or bulk sizes, was excluded. Furthermore, no benefits on germination parameters were observed by suppressing the final washing step in the particle’s synthesis process, suggesting that particle coating did not provide any advantage for seed germination under these continuous contact conditions. Full article
(This article belongs to the Section Farming Sustainability)
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Figure 1

Figure 1
<p>SEM micrographs of the synthesized ZnO NPs.</p>
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<p>TGA curves: (<b>a</b>) NIT-UW sample; (<b>b</b>) NIT-W sample; (<b>c</b>) SUL-UW sample; (<b>d</b>) SUL-W sample.</p>
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<p>Bi-plot graph of the two principal parameters in the Principal Component Analysis (PCA) of the germination parameters studied (percentage of germinated seeds, radicle and hypocotyl lengths) and characteristics of the particles used: (<b>A</b>) Zeta potential; %N; %C; %H; %S; V<sub>Mic</sub> (micropores volume); V<sub>Total</sub> (total pores volume); mass loss at 30–150 °C, and at 160–450 °C; (<b>B</b>) S<sub>BET</sub> (specific surface area); V<sub>Meso</sub> (mesopores volume); pore size. The variance values measured for the 2 components were 89.92% (<b>A</b>) and 83.12% (<b>B</b>).</p>
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39 pages, 454 KiB  
Review
Ill Fares the Land: Confronting Unsustainability in the U.K. Food System through Political Agroecology and Degrowth
by Mark Tilzey
Land 2024, 13(5), 594; https://doi.org/10.3390/land13050594 - 29 Apr 2024
Viewed by 1235
Abstract
The U.K. food system exhibits strong unsustainability indicators across multiple dimensions, both in terms of food and nutritional insecurity and in terms of adverse climate change, biodiversity, and physical resource impacts. These indices of an unsustainable and inequitable social metabolism are the result [...] Read more.
The U.K. food system exhibits strong unsustainability indicators across multiple dimensions, both in terms of food and nutritional insecurity and in terms of adverse climate change, biodiversity, and physical resource impacts. These indices of an unsustainable and inequitable social metabolism are the result of capitalist agriculture and society in general and, more specifically, of neoliberal and austerity policies adopted with vigour since the global financial crisis. The causal, capitalistic, and, latterly, more neoliberal bases of the U.K. food system are delineated in the first section of the paper. These bases are then detailed in terms of their impacts in exacerbating climate change, biodiversity (and resource) decline and loss, and food and nutritional insecurity. The political narratives and policy frameworks available to dissemble, mitigate, or, more rarely, to address (resolve) these impacts are then delineated. It is argued that the only policy framework available that strongly integrates food security (social equity) with ecological sustainability is political agroecology and an accompanying degrowth strategy. The final section of the paper details what political agroecology and degrowth might entail for the U.K. food system. Full article
(This article belongs to the Special Issue Feature Papers for Land Systems and Global Change Section)
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