摘要：
Whether the stems and leaves of leaf-vegetable sweet potatoes can be listed ahead of schedule is related to the improvement in economic benefits for farmers, and the key to all of this is to implement the safe overwintering of potato seedlings under the premise of saving production costs. Only in this way can we truly seize the "market opportunity" and achieve the goals of cost saving and increasing economic benefit. In this study, the main leaf-vegetable sweet potato variety Fucai 18 was used as the material, and the L9(3(4)) orthogonal experiment was carried out in a simple solar greenhouse environment for two consecutive years from 2021 to 2022 and from 2022 to 2023, respectively. The effects of nine different combinations of factors on the above-ground and underground agronomic traits of overwintering sweet potato seedlings were studied under the conditions of four factors and three levels: planting density (a); different cutting seedlings (b); rooting agent concentration (c); and transplanting time (d). The methods of principal component analysis, membership function method, cluster analysis, grey correlation degree and stepwise regression analysis were used to evaluate the growth of overwintering seedlings, and try to screen out the key indicators that can be used to identify and evaluate the growth of overwintering sweet potato seedlings. Through range analysis, identify the optimal combination of four factors and three levels, and explore the main factors that have a significant impact on the key indicators for evaluating the growth of overwintering potato seedlings. The results indicate the following: (1) The use of simple sunlight greenhouse in Changsha area can achieve the safe overwintering of vegetable sweet potato seedlings. (2) Stem thickness, root length, and root diameter can be used as three key indicators for identifying and evaluating the growth potential of vegetable sweet potato overwintering seedlings. (3) Under four factors and three levels, the best combination was A3B3C1D1 (planting density of 250,000 plants/ha, stem tip core-plucking seedlings, rooting agent concentration of 50 mg/L, the first batch of transplanting time). (4) The transplanting time (D) is the main factor for the two key evaluation indicators of stem diameter and root diameter, while there is no significant difference in the three other factors. (5) Different cutting seedlings (B) are the main influencing factors for the key evaluation index of root length, while the other three factors have the following impact on root length: transplanting time (D) > rooting agent concentration (C) > planting density (A). The results of this study not only contribute to the construction of a safe overwintering cultivation technology system for vegetable sweet potato seedlings, but also provide a certain theoretical basis for the breeding of new cold-leaf-vegetable sweet potato varieties in the future.
摘要：
<jats:p>Rice (Oryza sativa L.) is one of the most important food crops worldwide. However, during direct seeding, rice is extremely vulnerable to flooding stress, which impairs rice’s emergence and seedling growth and results in a significant yield loss. According to our research, chitosan oligosaccharides have the potential to be a chemical seed-soaking agent that greatly increases rice’s resistance to flooding. Chitosan oligosaccharides were able to enhance seed energy supply, osmoregulation, and antioxidant capacity, according to physiological index assessments. Using transcriptome and metabolomic analysis, we discovered that important differential metabolites and genes were involved in the signaling pathway for hormone synthesis and antioxidant capacity. Exogenous chitosan oligosaccharides specifically and significantly inhibit genes linked to auxin, jasmonic acid, and abscisic acid. This suggested that applying chitosan oligosaccharides could stabilize seedling growth and development by controlling associated hormones and reducing flooding stress by enhancing membrane stability and antioxidant capacity. Finally, we verified the effectiveness of exogenous chitosan oligosaccharides imbibed in seeds by field validation, demonstrating that they can enhance rice seedling emergence and growth under flooding stress.</jats:p>
关键词：
fatty acids;abscisic acid;microRNA;seed development
摘要：
Fatty acids are synthesized and stored in seeds during development in Brassica napus. Understanding the molecular mechanism behind fatty acid biosynthesis during seed development is a crucial research objective. In this study, we proved that exogenous application of abscisic acid (ABA) to the siliques can efficiently improve unsaturated fatty acid content in rapeseeds. Then we identified a total of 97 novel microRNAs (miRNAs) and 211 known miRNAs in the seeds of B. napus by high-throughput sequencing. Among them, a total of 23 differentially expressed miRNAs were observed between siliques treated with ABA and the control group. These 23 miRNAs regulated target genes that were involved in lipid metabolism through the integration of gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations. Moreover, we validated selected members from these miRNAs and their predicted targets through quantitative RT-PCR. Among these, miR172a, miR395a, and novel13 were significantly down-regulated after ABA treatment, while novel3 was significantly up-regulated. Notably, the predicted target genes of miR172a and miR395a, namely, KAS I and DGAT, play crucial roles in fatty acid synthesis and exhibit up-regulated expression in response to ABA. Our findings suggest that a variety of miRNAs interact with ABA to regulate fatty acid biosynthesis, highlighting the important roles played by miRNAs in the process of fatty acid biosynthesis during seed development.
关键词：
Paddy fields;Abandonment;Soil aggregates;Soil organic carbon;Soil total nitrogen;Stoichiometric stability
摘要：
Background and Aims Abandonment of paddy fields is a significant threat to soil organic carbon (SOC) stocks owing to the associated shift from anaerobic to aerobic conditions. However, the impact of this transition on the dynamics of soil total nitrogen (TN) and its relationship with SOC in bulk soil and soil aggregates remains unclear. Methods A long-term experiment was conducted to examine abandoned paddy fields with different fertilizer treatments over a 16-year period before abandonment, followed by an 8-year period after abandonment. Results The abandonment of paddy fields led to a significant decrease in TN content by an average of 14.0%, resulting in a mean annual loss rate of 0.08 t N ha-1. The loss of TN was as sensitive as that of SOC, and there was a positive correlation between SOC and TN in both bulk soil and soil aggregates. The loss of SOC and TN was mainly caused by reductions in the middle- and micro-aggregate-associated SOC and TN, which together explained approximately 87.3% of C loss and 81.3% of N loss. The weaker protective capacity of soil aggregates (> 53 mu m) was evidenced by a significant decrease in aggregate-associated C (average of 8.7%) and N (average of 9.1%). Abandonment maintained stoichiometric stability, with bulk soil C:N ratios ranging from 9.4 to 9.6 following abandonment. Conclusions Paddy soil aggregate-associated SOC and TN were sensitive to loss owing to the weaker protective capacity of soil aggregates following the abandonment of paddy fields. The C:N ratios remained relatively consistent after abandonment.
通讯机构：
[Yuzhu Zhang; Zhenxie Yi] A;Authors to whom correspondence should be addressed.<&wdkj&>College of Agronomy, Hunan Agricultural University, Changsha 410128, China<&wdkj&>Authors to whom correspondence should be addressed.<&wdkj&>State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha 410125, China
