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Introduction: Persian walnut (Juglans regia) is an economically important nut fruit species cultivated worldwide for its nutritious kernel and timber quality wood. Walnut trees are mostly hetero-dichogamous and, depending on the genotype, some cultivars are protogynous, while others are protandrous. Although selfing is possible when male and female blooms overlap, the dichogamy of the species promotes outcrossing. In addition to sexual reproduction, some reports indicate that elements of apomixis may occur in commercial orchards of walnut varieties and in the last two decades, nut production by apomixis has been reported in walnut. However, there are no reliable studies on the occurrence of apomictic reproduction based on cytoembryological observations and/or molecular marker-progeny tests. This study addresses the combined use of molecular and cytological analyses to gain new insights into the population genetics and reproduction systems of J. regia. Methods: We systematically analyzed the reproductive origin of individual progeny plants from 8 different cultivated walnut genotypes using microsatellite genotyping and carried out cytohistological investigations of 5 cultivated walnut genotypes arising seed sets from isolated flowers, to shed light on the mode of reproduction. Results and discussion: These cytometric and genotyping analyses did not support any asexual mode of reproduction or asexual propagation by seed and all individuals studied were identified as zygotic plants produced by crossing. Likewise, the cytological findings did not confirm completely the first component of apomixis, namely apomeiosis. On the other hand, according to histological evidence, adventitious embryony seems to take place at low frequency. Overall, our findings suggest that the occurrence of gametophytic apomixis is unlikely in J. regia, but sporophytic apomixis cannot be completely ruled out. [ABSTRACT FROM AUTHOR]

Introduction: Persian walnut (Juglans regia) is an economically important nut fruit species cultivated worldwide for its nutritious kernel and timber quality wood. Walnut trees are mostly hetero-dichogamous and, depending on the genotype, some cultivars are protogynous, while others are protandrous. Although selfing is possible when male and female blooms overlap, the dichogamy of the species promotes outcrossing. In addition to sexual reproduction, some reports indicate that elements of apomixis may occur in commercial orchards of walnut varieties and in the last two decades, nut production by apomixis has been reported in walnut. However, there are no reliable studies on the occurrence of apomictic reproduction based on cytoembryological observations and/or molecular marker-progeny tests. This study addresses the combined use of molecular and cytological analyses to gain new insights into the population genetics and reproduction systems of J. regia. Methods: We systematically analyzed the reproductive origin of individual progeny plants from 8 different cultivated walnut genotypes using microsatellite genotyping and carried out cytohistological investigations of 5 cultivated walnut genotypes arising seed sets from isolated flowers, to shed light on the mode of reproduction. Results and discussion: These cytometric and genotyping analyses did not support any asexual mode of reproduction or asexual propagation by seed and all individuals studied were identified as zygotic plants produced by crossing. Likewise, the cytological findings did not confirm completely the first component of apomixis, namely apomeiosis. On the other hand, according to histological evidence, adventitious embryony seems to take place at low frequency. Overall, our findings suggest that the occurrence of gametophytic apomixis is unlikely in J. regia, but sporophytic apomixis cannot be completely ruled out. [ABSTRACT FROM AUTHOR]

Background: The outbreak of Covid-19 virus has affected many issues, including the students' education. Distancing from face-to-face educational environment, the disruption of leisure and social activities, and the separation from friends are some of the quarantine consequences, which can affect issues such as students' academic satisfaction and motivation. Therefore, this study aimed was to examine the level of academic satisfaction and motivation during Covid-19 quarantine among rehabilitation students of Ahwaz University of Medical Sciences. Methods: This cross-sectional analytical study was performed on 180 Ahvaz Jundishapur University of Medical Sciences rehabilitation students with a convenient sampling method from 2020 August to July 2021. To evaluate the level of academic motivation, the Persian version of Harter's academic motivation questionnaire was electronically used, and to assess the level of academic satisfaction, the questionnaire by Shakornia et al. (2014) was electronically used. To investigate the association between academic motivation and academic satisfaction, the chi-square independence test (or Fisher's exact test in case of the sparsity of contingency table) was used. Data analysis was performed using SPSS 22 software at a significant level of 0.05. Results: The results showed that there is a significant correlation between academic satisfaction and intrinsic motivation (P=0.047), but there is no significant correlation between the academic satisfaction and extrinsic motivation (P=0.165) and academic satisfaction score and overall academic motivation (P=0.752). The correlation between academic satisfaction and field of study is significant (P=0.004). Conclusion: This study showed that despite the prevalence of Covid-19 and changes in educational methods during this period, the rate of academic motivation and academic satisfaction is almost high in most rehabilitation students of Ahvaz Jundishapur University of Medical Sciences. To investigate the strengths and weaknesses of education and the factors affecting the use of online education, students' learning, and their academic motivation and satisfaction, it is recommended to examine the level of students' academic motivation and satisfaction in different universities during the Covid-19 pandemic. [ABSTRACT FROM AUTHOR]

BACKGROUND: Oxalic acid is a common antinutrient in the human diet, found in large quantities in spinach. However, spinach is highly regarded by vegetable producers because of its nutritional content and economic value. One of the primary purposes of spinach‐breeding programs is to improve the nutritional value of spinach by adjusting oxalate accumulation. Knowledge of the biosynthetic patterns of oxalic acid, and its different forms, is important for a better understanding of this process. RESULTS: We found three biosynthetic patterns of accumulation and concentration of oxalates. Two of them are related to the maximum type and one is related to the minimum type. We also developed a general model of variations in these compounds in the genotypes that were studied. CONCLUSION: This study introduced a unique type of spinach with high oxalate accumulation, which could be particularly suitable for consumption. This had the highest ratio of insoluble oxalate to soluble oxalate. It also accumulated more ascorbic acid (AA) than other types. Our findings in this study also indicate a small role for AA as a precursor to oxalate production in spinach, possibly confirming the significant role of glyoxylate as the most critical precursor in this plant. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]