Using nanoparticles (NPs) to effectively mitigate the negative effects of abiotic stressors on plant growth and development will help to achieve sustainable agriculture. Although there have been some prior reviews in this area, bibliometrics is still lacking. In this study, the most productive nations or regions, journals, publishers, and scholars in this field were identified using an objective bibliometric examination of the pertinent material published in the Web of Science core database. To dig deeper for information, the keywords co-occurrence, collaboration network of countries/regions and authors, and network map of highly cited papers citation are used to characterize present advances and forecast potential future trends. The results show a growing interest in using nanoparticles to alleviate abiotic stressors. There has been an exponential increase in the number of relevant papers and citations. Moreover, Asian countries are the most active in this subject, even if the USA generates papers with the best overall quality. The most common publishers and journals in this area are Elsevier and Environmental Science-Nano, while Wu HH is currently the most active author. Even though many researchers have formed close partnerships, there is not yet a large collaborative group of researchers in this field. Gaps in the current scientific literature are highlighted, such as the lack of use of omics, especially multi-omics, to provide a more in-depth and comprehensive explanation of the molecular mechanisms by which NPs enhance plant resistance to abiotic stresses. This bibliometric study will provide a valuable reference for studying the evolution of the field and identifying research frontiers.

Melia azedarach Linn. is a deciduous tree of the Melia genus in the Meliaceae family that is native to China. To study the mechanism of drought resistance in Melia azedarach and evaluate the drought resistance capacity of each provenance, we selected eight provenances (Shandong Kenli, Jiangsu Pizhou, Hubei Shayang, Jiangsu Xuanwu, Jiangxi Xihu, Jiangsu Jurong, Guangdong Luogang, and Henan Shihe) as the research subjects and set four levels of drought stress treatment (CK: 75% of field capacity, mild drought: 60% of field capacity, moderate drought: 45% of field capacity, and severe drought: 30% of field capacity). The results showed that the growth in the seedling height and the ground diameter, the leaf relative water content, transpiration rate (Tr), net photosynthetic rate (Pn), stomatal conductance (Gs), and the content of chlorophyll (Chl) decreased with the increasing stress levels, while the root–shoot ratio, water saturation deficit, and the contents of malondialdehyde (MDA) increased. The SOD in most provenances initially increased and then decreased, reaching a peak during moderate drought. At the late stage of treatment, the magnitude of the changes in the photosynthetic indicators was more pronounced than in the physiological indicators. Principal component analysis showed that the contribution of all four principal components under the three drought stresses was above 85%, which represented the majority of the original data. Combined with the affiliation function method and weights, the comprehensive evaluation value (D value) of the drought resistance was calculated for the eight provenances. Then, we obtained the order of drought resistance of the test materials under the three drought stresses, respectively. The combined results revealed that the drought resistance of Henan Shihe and Jiangxi Xihu was stronger, while the drought resistance of Guangdong Luogang and Hubei Shayang was weaker. Based on the above findings, we can select provenances with strong and weak drought resistance for transcriptome sequencing to screen drought-resistant genes for an in-depth study at the molecular level.

Styrax tonkinensis, whose seeds are rich in unsaturated fatty acids (UFAs), is a high oil value tree species, and the seed oil has perfect biodiesel properties. Therefore, the elucidation of the effect of 24-epibrassinolide (EBL) on fatty acid (FA) concentration and the expression of FA biosynthesis-related genes is critical for deeply studying the seed oil in S. tonkinensis. In this study, we aimed to investigate the changing trend of FA concentration and composition and identify candidate genes involved in FA biosynthesis under EBL treatment using transcriptome sequencing and GC-MS. The results showed that 5 μmol/L of EBL (EBL5) boosted the accumulation of FA and had the hugest effect on FA concentration at 70 days after flowering (DAF). A total of 20 FAs were identified; among them, palmitic acid, oleic acid, linoleic acid, and linolenic acid were the main components. In total, 117,904 unigenes were detected, and the average length was 1120 bp. Among them, 1205 unigenes were assigned to ‘lipid translations and metabolism’ in COG categories, while 290 unigenes were assigned to ‘biosynthesis of unsaturated fatty acid’ in KEGG categories. Twelve important genes related to FA biosynthesis were identified, and their expression levels were confirmed by quantitative real-time PCR. KAR, KASIII, and accA, encoding FA biosynthesis-related enzymes, all expressed the highest at 70 DAF, which was coincident with a rapid rise in FA concentration during seed development. FAD2 and FATB conduced to UFA and saturated fatty acids (SFA) accumulation, respectively. EBL5 induced the expression of FA biosynthesis-related genes. The concentration of FA was increased after EBL5 application, and EBL5 also enhanced the enzyme activity by promoting the expression of genes related to FA biosynthesis. Our research could provide a reference for understanding the FA biosynthesis of S. tonkinensis seeds at physiological and molecular levels.

Liquidambar formosana Hance has a highly ornamental value as an important urban greening tree species with bright and beautiful leaf color. To gain insights into the physiological and molecular mechanisms of L. formosana leaf color change, the leaves of three different clones were sampled every ten days from October 13, 2019, five times in total, which are S1, S2, S3, S4 and S5. Transcriptome sequencing was performed at S1 and S4. The chlorophyll content of the three clones decreased significantly, while the anthocyanins content of the three clones increased significantly in the coloring stage. The anthocyanins content of clone 2 was far more than that of the other two clones throughout the period of leaf color change. The transcriptome analysis showed that six DEGs related to anthocyanins biosynthesis, including CHS (chalcone synthase), CHI (chalcone isomerase), F3′H (flavonoid 3′-hydroxylase), DFR (dihydroflavonol 4-reductase), ANS (anthocyanidin synthase) and FLS (flavonol synthase), were found in three clones. Clone 2 has another three DEGs related to anthocyanins biosynthesis, including PAL (Phenylalanine ammonia-lyase), F3′5′H (flavonoid 3′,5′-hydroxylase) and UFGT (flavonoid 3-O-glucosyltransferase). We lay a foundation for understanding the molecular regulation mechanism of the formation of leaf color by exploring valuable genes, which is helpful for L. formosana breeding.

As the germ of a highly productive oil tree species, Styrax tonkinensis seeds have great potential to produce biodiesel and they have marvelous fatty acid (FA) composition. In order to explore the molecular regulatory mechanism of FA biosynthesis in S. tonkinensis seeds after methyl jasmonate (MJ) application, transcriptomic and metabolomic techniques were adopted so as to dissect the genes that are related to FA biosynthesis and their expression levels, as well as to discover the major FA concentration and composition. The results revealed that 200 μmol/L of MJ (MJ200) increased the crude fat (CF) mass fraction and generated the greatest impact on CF accumulation at 70 days after flowering. Twenty FAs were identified, among which palmitic acid, oleic acid, linoleic acid and linolenic acid were the major FAs, and the presence of MJ200 affected their concentrations variously. MJ200 could enhance FA accumulation through elevating the activity of enzymes that are related to FA synthesis. The number of differentially expressed genes increased with the seeds’ development in general. Fatty acid biosynthesis, the biosynthesis of unsaturated fatty acid, fatty acid elongation and glycerolipid metabolism were the main lipid metabolism pathways that were found to be involved. The changes in the expression levels of EAR, KAR, accA, accB and SAD2 were consistent with the changes in the CF mass fraction, indicating that they are important genes in the FA biosynthesis of S. tonkinensis seeds and that MJ200 promoted their expression levels. In addition, bZIP (which was screened by weighted correlation network analysis) also created significant impacts on FA biosynthesis. Our research has provided a basis for further studies on FA biosynthesis that is regulated by MJ200 at the molecular level and has helped to clarify the functions of key genes in the FA metabolic pathway in S. tonkinensis seeds.

This study investigated the physiological and biochemical responses of Styrax japonica Sieb. et Zucc. seedlings to normal water and nutrient management (control group, CK), waterlogging (root submerged, T1), and partial submergence (partial stem submergence, T2) over a period of 25 days. Measurements of root activity, malondialdehyde (MDA) content, hydrogen peroxide (H₂O₂) content, antioxidant enzyme (SOD, POD, and CAT), and anaerobic respiratory enzyme (LDH, ADH, and PDC) activities were conducted every 5 days. The results showed the following: the seedlings of the control group maintained high root activity and low oxidative damage levels throughout the experiment; under T1 treatment, root activity initially increased but declined, while MDA and H₂O₂ content gradually increased; T2 seedlings showed little change initially, but root activity briefly increased at Day 20 before rapidly declining. Regarding the antioxidant system, the control group had the highest SOD activity, while seedlings under T1 and T2 treatments exhibited compensatory upregulation of CAT and POD activities (from Day 15 to 20). Additionally, under waterlogging stress, LDH and ADH activities significantly increased, reflecting the activation of anaerobic metabolic pathways, while PDC content continuously decreased, indicating that low-oxygen stress induced the accumulation of LDH and ADH but reduced ethanol fermentation. PCA revealed that the first two principal components explained 61.53% of the total variation, with PC1 (45.76%) reflecting the contrasting relationship between the activation of anaerobic metabolism (increased ADH and LDH activity) and decreased root activity under waterlogging stress, while PC2 (15.77%) primarily captured the responses of oxidative damage (increased MDA) and corresponding antioxidant defense (upregulated CAT and POD activities). Overall, S. japonica seedlings adapt to short-term waterlogging stress by regulating anaerobic respiration and antioxidant systems, but prolonged stress leads to a continued increase in H₂O₂ and a decline in antioxidant enzyme activities. This study provides experimental evidence and theoretical support for understanding the waterlogging tolerance mechanisms of S. japonica. This experiment provides important information on the adaptive mechanisms of plants under waterlogging stress.