Activity and expression of ADP-glucose pyrophosphorylase during rhizome formation in lotus (Nelumbo nucifera Gaertn.)

Additional file 7: Figure S6. Comparison of NnAGPS against AGPS of other species

Porous Ru/RuO_x/LDH as highly active heterogeneous catalysts for the aerobic oxidation of alcohols

Porous LDH supported Ru/RuOx nanocatalysts exhibited much better catalytic activity and stability than conventional Ru-based catalysts for alcohol oxidation.</p

NnARF17 and NnARF18 from lotus promote root formation and modulate stress tolerance in transgenic Arabidopsis thaliana

Abstract Auxin response factors (ARFs) play a crucial role in regulating gene expression within the auxin signal transduction pathway, particularly during adventitious root (AR) formation. In this investigation, we identified full-length sequences for ARF17 and ARF18, encompassing 1,800 and 2,055 bp, encoding 599 and 684 amino acid residues, respectively. Despite exhibiting low sequence homology, the ARF17- and ARF18-encoded proteins displayed significant structural similarity and shared identical motifs. Phylogenetic analysis revealed close relationships between NnARF17 and VvARF17, as well as NnARF18 and BvARF18. Both ARF17 and ARF18 demonstrated responsiveness to exogenous indole-3-acetic acid (IAA), ethephon, and sucrose, exhibiting organ-specific expression patterns. Beyond their role in promoting root development, these ARFs enhanced stem growth and conferred drought tolerance while mitigating waterlogging stress in transgenic Arabidopsis plants. RNA sequencing data indicated upregulation of 51 and 75 genes in ARF17 and ARF18 transgenic plants, respectively, including five and three genes associated with hormone metabolism and responses. Further analysis of transgenic plants revealed a significant decrease in IAA content, accompanied by a marked increase in abscisic acid content under normal growth conditions. Additionally, lotus seedlings treated with IAA exhibited elevated levels of polyphenol oxidase, IAA oxidase, and peroxidase. The consistent modulation of IAA content in both lotus and transgenic plants highlights the pivotal role of IAA in AR formation in lotus seedlings

Lignin Synthesis, Affected by Sucrose in Lotus (Nelumbo nucifera) Seedlings, Was Involved in Regulation of Root Formation in the Arabidopsis thanliana

Adventitious roots (ARs) have an unmatched status in plant growth and metabolism due to the degeneration of primary roots in lotuses. In the present study, we sought to assess the effect of sucrose on ARs formation and observed that lignin synthesis was involved in ARs development. We found that the lignification degree of the ARs primordium was weaker in plants treated with 20 g/L sucrose than in 50 g/L sucrose treatment and control plants. The contents of lignin were lower in plants treated with 20 g/L sucrose and higher in plants treated with 50 g/L sucrose. The precursors of monomer lignin, including p-coumaric acid, caffeate, sinapinal aldehyde, and ferulic acid, were lower in the GL50 library than in the GL20 library. Further analysis revealed that the gene expression of these four metabolites had no novel difference in the GL50/GL20 libraries. However, a laccase17 gene (NnLAC17), involved in polymer lignin synthesis, had a higher expression in the GL50 library than in the GL20 library. Therefore, NnLAC17 was cloned and the overexpression of NnLAC17 was found to directly result in a decrease in the root number in transgenic Arabidopsis plants. These findings suggest that lignin synthesis is probably involved in ARs formation in lotus seedlings

Comparative transcriptome analysis revealed the cooperative regulation of sucrose and IAA on adventitious root formation in lotus (Nelumbo nucifera Gaertn)

Abstract Background In China, lotus is an important cultivated crop with multiple applications in ornaments, food, and environmental purification. Adventitious roots (ARs), a secondary root is necessary for the uptake of nutrition and water as the lotus principle root is underdeveloped. To investigate the regulatory pathway during ARs formation, we analyzed the expression of genes and miRNAs upon treatment with differential concentrations of sucrose, and a crosstalk between sucrose and IAA was also identified. Results We observed that the lotus ARs formation was significantly affected by sucrose treatment. Notably, 20 mg/L sucrose promoted the ARs development, whereas 60 mg/L sucrose inhibited the formation of ARs. The expression of genes and miRNAs was evaluated by high-throughput tag-sequencing. We observed that the expression of 5438, 5184, and 5345 genes was enhanced in the GL20/CK0, GL60/CK0, and CK1/CK0 libraries, respectively. Further, the expression of 73, 78, and 71 miRNAs was upregulated in the ZT20/MCK0, ZT60/MCK0, and MCK1/MCK0 libraries, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that most of the differentially expressed genes and miRNAs in the GL20/GL60 and ZT20/ZT60 libraries were involved in signal transduction. A large number of these genes (29) and miRNAs (53) were associated with plant hormone metabolism. We observed an association between five miRNAs (miR160, miR156a-5p, miR397-5p_1, miR396a and miR167d) and nine genes (auxin response factor, protein brassinosteroid insensitive 1, laccase, and peroxidase 27) in the ZT20/ ZT60 libraries during ARs formation. Quantitative polymerase chain reaction (qPCR) was used to validate the high-throughput tag-sequencing data. Conclusions We found that the expression of many critical genes involved in IAA synthesis and IAA transport was changed after treatment with various concentration of sucrose. Based on the change of these genes expression, IAA and sucrose content, we concluded that sucrose and IAA cooperatively regulated ARs formation. Sucrose affected ARs formation by improving IAA content at induction stage, and increased sucrose content might be also required for ARs development according to the changes tendency after application of exogenous IAA.</jats:p

Lignin Synthesis, Affected by Sucrose in Lotus (Nelumbo nucifera) Seedlings, Was Involved in Regulation of Root Formation in the Arabidopsis thanliana

Adventitious roots (ARs) have an unmatched status in plant growth and metabolism due to the degeneration of primary roots in lotuses. In the present study, we sought to assess the effect of sucrose on ARs formation and observed that lignin synthesis was involved in ARs development. We found that the lignification degree of the ARs primordium was weaker in plants treated with 20 g/L sucrose than in 50 g/L sucrose treatment and control plants. The contents of lignin were lower in plants treated with 20 g/L sucrose and higher in plants treated with 50 g/L sucrose. The precursors of monomer lignin, including p-coumaric acid, caffeate, sinapinal aldehyde, and ferulic acid, were lower in the GL50 library than in the GL20 library. Further analysis revealed that the gene expression of these four metabolites had no novel difference in the GL50/GL20 libraries. However, a laccase17 gene (NnLAC17), involved in polymer lignin synthesis, had a higher expression in the GL50 library than in the GL20 library. Therefore, NnLAC17 was cloned and the overexpression of NnLAC17 was found to directly result in a decrease in the root number in transgenic Arabidopsis plants. These findings suggest that lignin synthesis is probably involved in ARs formation in lotus seedlings.</jats:p

Explosive fracturing simulation experiment for low permeability reservoirs and fractal characteristics of cracks produced

Based on the explosive fracturing simulation experiment for low permeability reservoir, growths of the cracks produced by the explosive fracturing in the samples were analyzed. And associated with fractal geometry theory, the cracks fractal characteristics were studied and the influences of explosive quantity and confining pressure on the cracks fractal dimension were analyzed. Different explosive quantities and confining pressures under which the simulation experiment was carried out were designed. After the experiment, the fractal dimension of the cracks produced by explosive fracturing in different samples was got by the box dimension calculation method. The results show that: With the increase of explosive quantity, the amount, length and width of the cracks on the surface of the sample produced by explosive fracturing simulation experiment under the same confining pressure increase. The amount and length of the cracks produced by explosive fracturing under the same explosive quantity decrease with the increase of confining pressure. Under the same confining pressure, the cracks fractal dimension increases with the increase of explosive quantity, and the relationship between them is approximately linear when the confining pressure is relatively low and approximately nonlinear when the confining pressure is relatively high. Under the same explosive quantity, the cracks fractal dimension decreases with the increase of confining pressure. It is suggested that site operation should match the explosive quantity with the confining pressure, and the charge pattern of axial coupling and radial uncoupling should be applied. Key words: low permeability reservoir, explosive fracturing, fractal dimension, explosive quantity, confining pressur