Environmental Sustainability

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Browsing Environmental Sustainability by Subject "3004 Crop and pasture production"

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    Morphological changes of lenticels and their role in gas exchange and sprouting physiology of potato tubers during postharvest storage
    (Frontiers, 2025-06-11) Magwaza, Lembe Samukelo; Bernal, Antonio J. B.; Chope, Gemma A.; Alamar, M. Carmen; Terry, Leon A.
    The application of exogenous gases has been used to suppress sprouting in stored potato tubers. However, their efficacy in extending ecodormancy largely depends on achieving optimal gas exchange between the storage atmosphere and the tuber itself. This study aimed to investigate morphological variations and spatial distribution of lenticels and apical buds and to identify their potential role in tuber respiration rate and sprouting of five potato cultivars (‘Hermes’, ‘Lady Claire’, ‘Lady Rosetta’, ‘Saturna’, and ‘VR808’) during storage. Results revealed a consistent spatial pattern wherein the apical section of potato tubers exhibited significantly higher bud counts compared to lateral and stolon regions. ‘Lady Claire’ stood out as having the highest number of apical buds among the cultivars studied. Digital image analysis showed a seven times higher number of buds surrounding the apical eye and these were generally smaller than those distributed across the skin. ‘Saturna’ displayed double the lenticel density (12 lenticels cm-2) in smaller tubers, suggesting an inverse relationship between tuber size and lenticel density. ‘Lady Claire’ and ‘Saturna’ had respiration rates of 2.75 and 1.9 mL CO2 kg-1 h-1, respectively, and were selected for additional respiration and ethylene efflux analyses. In both cultivars, distinct spatial differences were observed, with the apical section exhibiting a seven-fold increase in lenticel density compared to the lateral and stolon sections. Respiration rate increased five-fold when apical lenticels were blocked, whereas it decreased 30-fold when the apical was the only unblocked section, suggesting differential physiological activity across lenticel locations. The apical sections, with the highest lenticel density, exhibited elevated respiration rates as a stress-induced physiological response upon blockage, compared to the lateral and stolon sections. Lenticels changed their morphology during storage, erupting before bud movement, suggesting lenticel eruption could be used as a pre-symptomatic visual marker of dormancy break. This study highlights the critical role that lenticel morphology and spatial distribution may have in determining potato tuber gas exchange and refining allied storage regimes.
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    Prolonged heat stress in Brassica napus during flowering negatively impacts yield and alters glucosinolate and sugars metabolism
    (Frontiers, 2025-01-01) Kourani, Mariam; Anastasiadi, Maria; Hammond, John P.; Mohareb, Fady R.
    Oilseed rape (Brassica napus), one of the most important sources of vegetable oil worldwide, is adversely impacted by heatwave-induced temperature stress especially during its yield-determining reproductive stages. However, the underlying molecular and biochemical mechanisms are still poorly understood. In this study, we investigated the transcriptomic and metabolomic responses to heat stress in B. napus plants exposed to a gradual increase in temperature reaching 30°C in the day and 24°C at night for a period of 6 days. High-performance liquid chromatography (HPLC) and liquid chromatography–mass spectrometry (LC-MS) was used to quantify the content of carbohydrates and glucosinolates, respectively. Results showed that heat stress reduced yield and altered oil composition. Heat stress also increased the content of carbohydrate (glucose, fructose, and sucrose) and aliphatic glucosinolates (gluconapin and progoitrin) in the leaves but decreased the content of the indolic glucosinolate (glucobrassicin). RNA-Seq analysis of flower buds showed a total of 1,892, 3,253, and 4,553 differentially expressed genes at 0, 1, and 2 days after treatment (DAT) and 4,165 and 1,713 at 1 and 7 days of recovery (DOR), respectively. Heat treatment resulted in downregulation of genes involved in respiratory metabolism, namely, glycolysis, pentose phosphate pathway, citrate cycle, and oxidative phosphorylation especially after 48 h of heat stress. Other downregulated genes mapped to sugar transporters, nitrogen transport and storage, cell wall modification, and methylation. In contrast, upregulated genes mapped to small heat shock proteins (sHSP20) and other heat shock factors that play important roles in thermotolerance. Furthermore, two genes were chosen from the pathways involved in the heat stress response to further examine their expression using real-time RT-qPCR. The global transcriptome profiling, integrated with the metabolic analysis in the study, shed the light on key genes and metabolic pathways impacted and responded to abiotic stresses exhibited as a result of exposure to heat waves during flowering. DEGs and metabolites identified through this study could serve as important biomarkers for breeding programs to select cultivars with stronger resistance to heat. In particular, these biomarkers can form targets for various crop breeding and improvement techniques such as marker-assisted selection.