Prunus tomentosa is a fruit tree native to China, with a broad distribution and high conservation value from ornamental, economic, and ecological perspectives. The germplasm resource is valuable for developing new cherry cultivars due to its high adaptability to almost all soil types and climatic conditions. However, little is known about the genetic diversity, phylogeographic structure and historical events, with its abundant genetic information. Here, we clarified the phylogeography of P. tomentosa based on chloroplast DNA (cpDNA) fragments and nuclear ribosomal internal transcribed spacer (ITS) across 779 individuals from 42 populations. We found 26 unique chloroplast haplotypes and 23 unique ITS haplotypes. Haplotype diversity was high based on cpDNA (Hd = 0.689) and ITS (Hd = 0.877) haplotypes. We observed a significant difference in the genetic differentiation based on Wright’s fixation index (cpDNA: Fst = 0.6077; ITS: Fst = 0.3447). Comparing two genetic differentiation indices, Nst and Gst, it was inferred that the P. tomentosa populations have a phylogeographical structure. Combination of network map, phylogenetic tree, population distribution, and population structure of P. tomentosa haplotype revealed two phylogeographic groups—eastern phylogeographic group (EG) and western phylogeographic group (WG). The divergence time of EG and WG occurred about 12.31 Ma and the common ancestor of P. tomentosa may have emerged during the Miocene period, and a significant correlation was observed between genetic distance and geographical distance of the populations. Signals from cpDNA and ITS data indicate that P. tomentosa has undergone recombination and population expansion. The expansion time was about 5.74 Ka based on the chloroplast data. Our findings illuminated the genetic diversity, species divergence and phylogeographical history of P. tomentosa and provided robust genetic evidence to support that Xiaolong Mountains, Hua Mountains, and Qian Mountains might be the glacial refuges of P. tomentosa. Our findings will not only guide conservation and utilization strategies for P. tomentosa but also contribute to the development of germplasm for breeding novel cherry cultivars.

Sweet cherry (Prunus avium L.) undergoes rapid deterioration after harvest, resulting in severe losses in quality and marketability. Polyvinyl alcohol (PVA) is a biodegradable polymer with favorable film-forming and barrier properties used as an edible coating. Additionally, PVA composites have been explored to enhance coating properties, including antimicrobial and film-strength improvements. This study aimed to develop a PVA–natamycin composite coating and evaluate its potential to preserve the postharvest quality of sweet cherries during cold storage. In this study, PVA coatings at different concentrations (0.5%, 1.0%, and 1.5%) were evaluated, and 1.0% PVA was identified as the optimal formulation. Based on this concentration, a PVA–natamycin composite coating was applied to evaluate its effects on fruit quality during 60 days of cold storage. Compared with the control, the composite coating reduced decay incidence by 47.2% and maintained higher firmness, total soluble solids, titratable acidity, and color attributes, while suppressing respiration rate. Moreover, the composite coating exhibited improved oxidative stability compared with single treatments, as reflected by lower malondialdehyde accumulation, higher antioxidant enzyme activities, and greater retention of phenolic compounds. Overall, the PVA–natamycin composite coating represents a sustainable postharvest treatment for sweet cherries.

Sweet cherry (Prunus avium L.) is a high-value fruit crop whose production is threatened worldwide by bacterial canker, a disease with major economic impacts for which sustainable control strategies are urgently needed. While 24-epibrassinolide (EBR) is recognized as a key regulator of plant immunity, its role and mode of action in woody fruit species, particularly against bacterial pathogens, remain poorly understood. This study investigated the effects and underlying mechanisms of EBR against bacterial canker in two commercially important sweet cherry cultivars, 'Rainier' and 'Sunburst'. Treatment with 0.5 mu M EBR significantly reduced disease symptoms and alleviated oxidative stress, as reflected by decreased accumulation of O2-, H2O2, and malondialdehyde (MDA), together with enhanced activities of key antioxidant enzymes (SOD, CAT, POD, APX, PPO, and PAL) and upregulation of their corresponding genes (PavSOD, PavCAT, PavPOD, PavAPX, PavPPO, and PavPAL). In vitro assays further confirmed that EBR does not directly inhibit Pseudomonas syringae pv. syringae, suggesting that the observed resistance is associated with activation of host defense responses. Collectively, these results suggest that EBR enhances disease resistance in sweet cherry by strengthening host antioxidant defense capacity. These findings support the potential of EBR as an eco-friendly regulator for sustainable management of bacterial canker and related diseases in perennial fruit crops, offering a broadly applicable strategy for fruit tree production under different agroecological conditions.

Mangroves grow in high-salinity environments with low soil water potential (Ψs), where high light intensity and strong winds increase the vapor pressure deficit (VPD), causing physiological drought and high transpiration demand (Δw), which limits carbon dioxide (carbon gain) for photosynthesis. This study explored how mangroves optimize their carbon-gain-to-water-loss ratio (water-use strategies) to maximize carbon gain during both dry and rainy seasons. We also calculated the relative costs of key leaf traits and compared them with those of terrestrial forests under the carbon gain optimization model. The results revealed that (1) with increasing Δw, terrestrial forests primarily adjusted leaf hydraulic conductance (Kleaf), while mangroves altered the difference in water potential (ΔΨ); (2) as Ψs decreased, πtlp of both terrestrial forests and mangroves increased; (3) terrestrial forests developed a more balanced distribution of leaf trait costs between osmotic pressure (46.7 ± 0.2%) and stomata (43.3 ± 1.2%), whereas mangroves had the highest cost in osmotic pressure (49.04 ± 0.03%) and the lowest cost in stomata (11.08 ± 3.00%) during the rainy season; and (4) although mangroves showed differences in trait values between dry and rainy seasons, their responses to drought stress remained consistent. These findings provided new theoretical insights into how mangroves maintain high carbon gain and water-use efficiency under extreme environmental conditions, which is important to improve mangrove conservation efforts and contribute to climate mitigation policies.

The purpose of this study was to establish the relationship between the chilling resistance of rubber trees and the bark-bleeding characteristics caused by chilling stress, considering physiological indicators in rubber tree bark, cell wall chemical components, fiber morphologies, and tensile properties. This offered a unique perspective for examining the underlying mechanisms of latex bleeding and chilling stress in Hevea brasiliensis. One-year-old seedlings and two-year-old twig segments in five- and twenty-one-year-old rubber trees (5YB and 21YB) were used to compare the age-mediation differences in their various parameters. Meanwhile, the LT50 values were calculated with Logistic regression analysis of relative electrical conductivity (REC) data under gradient low temperatures. Subsequently, changes in corresponding parameters of 1-year-old seedling stem bark at different ages were determined, and the bark-bleeding characteristics of seedlings and twig segments were analyzed under artificially simulated chilling stress, respectively. A correlation analysis between semi-lethal temperature (LT50) values, relative water content (RWC) values, bark-bleeding characteristics, cell-wall chemical component contents, fiber dimensions, and tensile property parameters was implemented to estimate interrelationships among them. The LT50 values ranged from −2.0387 °C to −0.8695 °C. The results showed that the chilling resistance order of rubber trees at different ages was as follows: 21YB (2-year-old twig bark from 21-year-old rubber trees) > 5YB (2-year-old twig bark from 5-year-old rubber trees) > SLB (semi-lignification bark in 1-year-old seedlings) > GB (green bark in 1-year-old seedlings). The chilling resistance of seedlings and twig segments in rubber trees was highly positively (p < 0.001) related to fiber morphologies. Chilling-induced bark-bleeding characteristics were significantly correlated (p < 0.001) with fiber morphologies, bark tensile properties, and cell-wall components. The analysis data in this study contribute towards building a comprehensive understanding of the mechanisms of chilling-induced bark bleeding needed not only in rubber tree cultivation but also in sustainable rubber production.

Different tree shapes (TSs) directly influence canopy structure, light interception, and photosynthetic activity, impacting fruit quality and yield. This study investigated the effects of light interception efficiency (LIE) on the quality and yield of "Jimei" sweet cherry fruits by comparing two tree shapes: the Yangling inclined trellis arm TS (YLL-TS) and the Super slender spindle TS (SSS-TS). Using three-dimensional digitization techniques, we analyzed the growth relationships between branches and leaves, constructed virtual canopy models, and examined branch composition, leaf area, and spatial distribution. The present study indicated varying correlation coefficients for growth relationships between branches and leaves in the two TSs. For YLL-TS, the smallest correlation coefficient was between the length of nutrient-bearing branches and leaf petiole length (r² = 0.206), while the largest was between the length of short fruit-bearing branches and the number of branches and leaves (r² = 0.851). For SSS-TS, the smallest was between the length of medium fruit-bearing branches and leaf petiole length (r² = 0.211), and the largest was between the length of nutrient-bearing branches and leaf area (r² = 0.827). The LIE for YLL-TS (0.53 STAR value) was significantly higher than SSS-TS (0.20 STAR value). Although YLL-TS had fewer branches and leaf area, it showed increases in LIE by 48%, 42%, and 27% for overall canopy, fruit-bearing branches, and nutrient-bearing branches, respectively. The photosynthetic parameters (Pn, Tr, Gs, and Ci) were higher in SSS-TS. YLL-TS exhibited a higher economic yield (4.075 kg/ m2) and is more suitable for dense planting, facilitating widespread cultivation.

Prunus tomentosa Thunb, a fruit tree native to China, is an important and excellent plant material. It exhibits high adaptability to almost all soil types and climatic conditions. The germplasm resources are found in the six geographical regions of China, covering a vast expanse, and comprise a variety of ecological types. However, little is known about genetic diversity and population structure, with its abundant genetic information. Nuclear simple sequence repeat markers, with biparentally inherited characteristics, is powerful for evaluating the genetic diversity of population. Therefore, this research assessed the genetic diversity and population structure of P. tomentosa by collecting extensive samples. The finding will contribute to not only proposing scientific conservation strategies of P. tomentosa but also developing the germplasm to breed novel cherry cultivar. A total of 822 germplasms from 40 populations were used for assessing. The indicators of genetic diversity showed high values, including observable heterozygosity (0.546), expected heterozygosity (0.819), Shannon’s information index (I = 1.951), polymorphism information content (0.799). The populations displaying the greatest diversity—Gan-XlM, Shaan-HM, and Gan-ZhC. In addition, extensive genetic differentiation was detected. The genetic differentiation coefficient (FST) values calculated from heterozygosity and analysis of molecular variance were greater than 0.15. Gene flow was relatively stable (number of migrants [Nm] = 1.065). Mantel test analysis showed that there was a significant correlation (R2 = 0.065, P < 0.05) between the genetic distance and the geographical distance of the populations. Integrated cluster, structure, and principal component analysis indicated that the 40 populations were clustered into a Northwest Group and a Northeast Group. However, the Chuan-Aba, Xin-TKS, and Xin-ALR populations were clearly differentiated. The P. tomentosa populations showed high or moderate polymorphism. The genetic differentiation within each population was higher than that between populations. There was a significant correlation between the genetic distance and the geographical distance. Based on genetic diversity and population differentiation levers, the most diverse populations—Gan-XlM, Shaan-HS, and Gan-PL from Gansu and Shaanxi provinces, should first be protected and applied to the innovation of cherry germplasm, followed by significantly differentiated populations, including Chuan-Aba, Ning-HlM, and Gan-PL.

The NAC (NAM, ATAF1/2, and CUC2) family is one of the largest plant-specific transcription factor families, playing a crucial role in adaptation to abiotic stresses. However, the NAC gene family in sweet cherry (Prunus avium L.) remains poorly understood. In this study, we identified 130 NAC genes (PaNAC) from the sweet cherry genome, which were unevenly distributed across eight chromosomes. Phylogenetic analysis classified the PaNACs into 21 distinct groups, including 2 sweet cherry-specific groups. Comparative analysis revealed significant variations in gene proportions, exon–intron structures, and motif compositions among different groups. Furthermore, cis-element analysis suggested the potential roles of PaNACs in regulating plant growth, development, hormone signaling, and stress responses. Transcriptomic data revealed tissue-specific expression patterns for several PaNAC genes. qRT-PCR further confirmed that eight selected PaNACs were responsive to various abiotic stresses in Gisela 6, a widely used hybrid rootstock in sweet cherry production that shares high sequence similarity in NAC genes with P. avium. These findings provide valuable insights for future research on the functional characteristics of the PaNAC genes in the growth, development, and responses to abiotic stress in sweet cherry.

Accurate mapping of rubber plantations in Southeast Asia is critical for sustainable plantation management and ecological and environmental impact assessment. Despite extensive research on rubber plantation mapping, studies have largely been confined to provincial scales, with the few country-scale assessments showing significant disagreement in both spatial distribution and area estimates. These discrepancies primarily stem from persistent cloud cover in tropical regions and limited temporal resolution of datasets that inadequately capture the full phenological cycles of rubber trees. To address these issues, we propose the Full Time Series Satellite Imagery and Full-Cycle Monitoring (FTSI-FCM) algorithm for mapping spatial distribution and establishment year of rubber plantations in Vietnam, a country experienced significant rubber expansion over the past decades. The FTSI-FCM algorithm initially employs the LandTrendr approach-an established forest disturbance detection algorithm-to identify the land use changes during the plantation establishment phase. We enhance this process through a spatiotemporal correction scheme to accurately determine the establishment years and maturity phases of the plantations. Subsequently, the algorithm identifies rubber plantations through a random forest algorithm by integrating features from three temporal phases: canopy transitions from rubber seedlings to mature plantations, phenological changes during mature stages, and phenological-spectral characteristic during the mapping year. This approach leverages an extensive time series of Landsat images dating back to the late 1980s, complemented by Sentinel-2 images since 2015. For the mapping year, these data are further enhanced by the inclusion of PALSAR-2 L-band Synthetic-Aperture Radar (SAR) and very high-resolution Planet optical imagery. When applied in Vietnam-a leading rubber producer with complex cultivation conditions- the FTSIFCM algorithm yielded highly reliable maps of rubber distribution (Overall Accuracy, OA = 93.75%, F1score = 0.93) and establishment years (R2 = 0.99, RMSE = 0.25 years) for 2022 (referred to as FTSI-FCM_2022). These results outperformed previous mappings, such as WangR_2021 (OA = 75.00%, F1-score = 0.71), in both spatial distribution and area estimates. The FTSI-FCM_2022 map revealed a total rubber plantation area of 754,482 ha, closely matching reported statistics of 727,900 ha and showing strong correlation provincial statistics (R2 = 0.99). Spatial analysis indicated that over 90% of rubber plantations are located within 15 degrees N latitude, below 600 m in elevation, on slopes under 15 degrees, and were established after 2000. Notably, there has been no significant expansion of rubber plantations into higher elevations or steeper slopes since 1990s, suggesting the effectiveness of sustainable rubber cultivation management practices in Vietnam. The FTSI-FCM algorithm demonstrates substantial potential for mapping rubber plantations in major producing areas such as Southeast Asia, thereby supporting sustainable development decision-making in the natural rubber industry.

The Camellia nitidissima C.W. Chi, a globally endangered species, is classified as a first-class protected plant in China. Given the potential impact of climate change on the distribution of species on a larger scale, it is crucial to understand the responses of C. nitidissima to this phenomenon for resource protection and sustainable utilization. Based on the existing records of C. nitidissima and multi-source remote sensing data, the optimal MaxEnt model was used to predict the potential habitat of C. nitidissima in both current and future periods. The results indicate that November average maximum temperature(Tx11) is the dominant factor. Under current climate conditions, the potential habitat of C. nitidissima is primarily located in the humid and hot coastal areas of southern China. Under future climate scenarios, the distribution range of C. nitidissima will initially increase, then decrease and finally increase again in correlation with radiation intensity. Comprehensive analysis reveals that under the background of global climate change, there remain significant challenges for the survival and reproduction of C. nitidissima in China. Appropriate protection and utilization measures can be implemented based on its migration trends to ensure the continuity of C. nitidissima habitats.

Rubber trees (Hevea brasiliensis) serve as the primary source of natural rubber. Their native habitat is characterized by warm and humid conditions, so they are particularly sensitive to low temperatures. Under such stress, latex burst can cause severe damage to rubber trees, which is due to the uniqueness of their economically productive parts. In order to establish a correlation between young and mature rubber trees and provide a novel prospective for investigating the mechanisms of latex burst and chilling resistance in rubber trees, the chlorophyll contents, photosynthesis, and chlorophyll fluorescence parameters in four varieties of one-year-old rubber tree seedlings were analyzed under artificially simulated chilling stress. The latex burst characteristics were subsequently recorded. A comprehensive statistical analysis of the chilling-resistance rank was conducted using the membership function method and the combination weighting method. Meanwhile, chemical compositions and tensile properties of barks from two-year-old twigs of mature rubber trees were ascertained. A correlation analysis between chilling resistance, chemical compositions, and tensile properties was performed to identify any interrelationships among them. The results showed that the number and the total area of latex-burst positions in variety Reken628 seedlings were greater than those in other varieties, and the lowest number and total area of latex-burst positions were observed in variety RRIM600 and variety PR107, respectively. With the exception of variety GT1, nectar secretion was noted in all other varieties of rubber tree seedlings under chilling stress. The chilling resistance of the four varieties decreased in the following order: variety GT1 > variety RRIM600 > variety PR107 > variety Reken628. The chilling resistance was strongly (p < 0.001) negatively correlated with cellulose content and acid-insoluble lignin content, respectively. The total area of latex burst was significantly (p < 0.001) and positively correlated with holocellulose content and maximum load, respectively. Furthermore, this study also provides new insights into the mechanism of nectar secretion induced by low temperatures and its association with the chilling resistance of rubber trees.

The rubber elongation factor (REF) is the most abundant protein in the latex of Hevea brasiliensis, which is closely related to natural rubber biosynthesis. In order to gain a deeper understanding of the transcriptional regulation mechanism of HbREF1, a 1758 bp genomic DNA fragment of the HbREF1 promoter was isolated. Promoter sequence analysis revealed several transcription factor binding sites in the HbREF1 promoter, such as bZIP, bHLH, EIL, AP2/ERF, MYB, and Trihelix. To assess the promoter activity, a series of HbREF1 promoter deletion derivatives were created and fused with firefly luciferase (LUC). The LUC image demonstrated that all of the HbREF1 promoters exhibited transcriptional activity. Furthermore, the assay revealed the presence of multiple regulatory elements within the promoter region that negatively regulate the transcriptional activity. Subsequent analysis of the transcriptional activity following treatment with phytohormones identified an ABA-responsive element located between −583 bp and −200 bp, an ET-responsive element between −718 bp and −583 bp, a JA-responsive element between −1758 bp and −1300 bp, and a SA-responsive element between −1300 bp and −718 bp. These results were largely consistent with the predictions of cis-acting elements. This study has established significant groundwork for future investigations into the regulatory mechanism of HbREF1.

Aluminum (Al) toxicity severely restricts crop growth and productivity in acidic soils. The rubber tree is one of the most economically important crops in tropical regions, which is tolerant to high concentrations of Al in sand or hydroponic culture conditions compared with other plants that have been reported. However, the mechanisms of Al tolerance in rubber trees remain unknown. In this study, we conducted a transcriptome and metabolome analysis for rubber tree sapling roots treated with 200 mM Al for 0 (CK), 2 or 5 days, respectively. Compared with the CK, a total of 9534 differentially expressed genes (DEGs) and 3821 differentially expressed metabolites (DEMs) were identified in 2 d of Al treatment. There were 10,373 DEGs and 4636 DEMs after 5 d of Al treatment, and 1626 DEGs and 1674 DEMs between 2 and 5 d of Al treatment. The DEGs mainly concentrated in transporters, transcription factors (TFs), cell wall biosynthesis and antioxidant systems, and the DEMs were mainly focused on lipids and lipid-like molecules, organic acids and derivatives, organic oxygen compounds, phenylpropanoids and polyketides. The combined transcriptome and metabolome analysis indicated DEGs and DEMs involved in ABC transporters, glutathione metabolism, flavonoid biosynthesis and phenylalanine metabolic pathways were identified to be closely associated with the Al tolerance of rubber trees. Our study elucidated the mechanism of rubber trees’ tolerance to Al at the transcriptional and metabolic levels, which provides a theoretical basis for the study of Al tolerance both for rubber trees and other woody plants.

The Pyrabactin resistance 1-like proteins (PYR/PYL/RCAR) are components of the ABA signaling pathway, playing a key role in how plants respond to abiotic stresses. Although PYL genes have been identified in a variety of plants, the evolution and structural characteristics of these genes in sweet cherry (Prunus avium L.) trees are largely unknown. In this study, 11 PaPYL genes were identified at genome-wide level in sweet cherry and were mapped to six chromosomes. According to the phylogenetic analysis, this gene family consisted of four subgroups; genes in the same subgroup had similar conserved motifs and the same number of exons, as revealed by analyzing gene structure. The intra-species collinearity analysis did not find any tandem duplication events in this gene family, and thus fragment duplication may be the primary reason for the generation of some PaPYL genes. Additionally, the inter-species collinearity analysis uncovered a potential evolutionary relationship between them. The expression analysis indicated that some PaPYL genes are specifically expressed in tissues, suggesting they may have unique functions. We also explored the expression of this gene family under different abiotic stress treatments (cold, salinity, drought). The qRT-PCR results showed that the expression levels of most genes were up-regulated under abiotic stress treatments, consistent with the results for their analyzed promoter cis-acting elements. This study provides a basis for further elucidating the function and expression patterning of the PYL gene family in sweet cherry, and helps to further analyze its regulatory mechanism under various abiotic stress factors.

The plant-specific RWP-RK transcription factor family plays a central role in the regulation of nitrogen response and gametophyte development. However, little information is available regarding the evolutionary relationships and characteristics of the RWP-RK family genes in cassava, an important tropical crop. Herein, 13 RWP-RK proteins identified in cassava were unevenly distributed across 9 of the 18 chromosomes (Chr), and these proteins were divided into two clusters based on their phylogenetic distance. The NLP subfamily contained seven cassava proteins including GAF, RWP-RK, and PB1 domains; the RKD subfamily contained six cassava proteins including the RWP-RK domain. Genes of the NLP subfamily had a longer sequence and more introns than the RKD subfamily. A large number of hormone- and stress-related cis-acting elements were found in the analysis of RWP-RK promoters. Real-time quantitative PCR revealed that all MeNLP1-7 and MeRKD1/3/5 genes responded to different abiotic stressors (water deficit, cold temperature, mannitol, polyethylene glycol, NaCl, and H2O2), hormonal treatments (abscisic acid and methyl jasmonate), and nitrogen starvation. MeNLP3/4/5/6/7 and MeRKD3/5, which can quickly and efficiently respond to different stresses, were found to be important candidate genes for further functional assays in cassava. The MeRKD5 and MeNLP6 proteins were localized to the cell nucleus in tobacco leaf. Five and one candidate proteins interacting with MeRKD5 and MeNLP6, respectively, were screened from the cassava nitrogen starvation library, including agamous-like mads-box protein AGL14, metallothionein 2, Zine finger FYVE domain containing protein, glyceraldehyde-3-phosphate dehydrogenase, E3 Ubiquitin-protein ligase HUWE1, and PPR repeat family protein. These results provided a solid basis to understand abiotic stress responses and signal transduction mediated by RWP-RK genes in cassava.

为探索不同品种橡胶树幼龄树耐寒性与成龄树枝条韧皮部纤维形态、树皮抗拉伸性能之间的关系,分析不同品种橡胶树耐寒性与其相应生理、生物力学指标的相关性,从而比较不同品种橡胶树耐寒性的差异,以期建立不同品种橡胶树幼龄树茎段与成龄树枝条树皮相应指标之间的联系,并从细胞结构及树皮生物力学角度研究橡胶树耐寒性机理.以热研7-33-97、PB86、IAN873、大丰95、云研77-2等5个橡胶树品种1年生芽接苗茎段及相应品种成龄树2年生枝条树皮为材料,测定低温梯度下茎段韧皮部电导率及枝条韧皮部纤维形态、树皮抗拉伸性能指标,利用Logistic方程确定其低温半致死温度(LT50)的大小,得出不同品种耐寒性,并采用Spearman相关性分析法,得出LT50与韧皮部纤维形态指标、树皮抗拉伸性能之间的相关性.结果表明,5个橡胶树品种韧皮部相对电导率呈"S"形曲线变化,相对电导率与胁迫温度之间呈极显著负相关,5个品种LT50分别为-2.075℃、-2.240℃、-1.923℃、-1.900℃、-2.186℃;5个品种纤维长度在2921.013～4799.438μm,宽度在21.717～23.908μm,双壁厚度分别为11.504、10.271、10.873、12.715、10.401μm,腔直径分别为0.900、1.423、0.922、1.298、0.915μm,PB86的纤维双壁厚最小,腔直径最大;5个品种树皮厚度分别为0.709、0.564、0.886、0.935、0.774 mm,PB86的树皮厚度与其他品种的差异达到了显著水平(P<0.05),5个品种拉伸破坏荷载在4.935～11.064 N,PB86的抗拉伸强度与最大拉伸位移均为5个品种最大,分别为3.629 MPa、1.360 mm;1年生茎段韧皮部LT50与成龄树2年生枝条韧皮部纤维双壁厚呈显著性正相关,与2年生树皮厚度、抗拉强度分别呈显著性正相关和显著性负相关.从细胞尺度与组织生物力学角度研究橡胶树耐寒性,以此搭建橡胶树幼龄树与成龄树联系的纽带,是橡胶树耐寒机理研究的有效途径.

Secretion and efflux of oxalic acid from roots is an important aluminum detoxification mechanism for various plants; however, how this process is completed remains unclear. In this study, the candidate oxalate transporter gene AtOT, encoding 287 amino acids, was cloned and identified from Arabidopsis thaliana. AtOT was upregulated in response to aluminum stress at the transcriptional level, which was closely related to aluminum treatment concentration and time. The root growth of Arabidopsis was inhibited after knocking out AtOT, and this effect was amplified by aluminum stress. Yeast cells expressing AtOT enhanced oxalic acid resistance and aluminum tolerance, which was closely correlated with the secretion of oxalic acid by membrane vesicle transport. Collectively, these results underline an external exclusion mechanism of oxalate involving AtOT to enhance oxalic acid resistance and aluminum tolerance.

为探究拟南芥种子进行 1/2MS培养基筛选的最适潮霉素浓度,将野生型拟南芥种子灭菌后,点播在含 0,20,30,40,50 mg/L潮霉素的 1/2MS培养基上进行培养(分别记为 M0、M1、M2、M3、M4),观察潮霉素对种子萌发、幼苗生长形态变化的影响,统计种子萌发率、第 3 天萌发势、第 13 天幼苗失绿死亡率,测定第 7 天幼苗鲜重、干重、相对含水率、主根长度,结合逆向思维的变异系数-熵权组合赋权的TOPSIS方法得出不同浓度潮霉素处理效果的综合排序.结果表明,潮霉素对拟南芥种子萌发和幼苗生长均有明显的抑制作用;变异系数-熵权组合赋权的 TOPSIS方法得出不同处理对拟南芥种子萌发和幼苗生长抑制效果的排序为:M4>M3>M2>M1>M0,M2 的接近度为 0.531 5,约为 0.5,最接近抑制效果的 50％;综合实验结果可知,拟南芥种子进行 1/2MS 培养基筛选的适宜潮霉素浓度为 30 mg/L,种子点播的第 7～10天为幼苗移栽的适宜时期.

The subgenus Cerasus , one of the most important groups in the genus Prunus sensu lato , comprises over 100 species; however, the taxonomic classification and phylogenetic relationships of Cerasus remain controversial. Therefore, it is necessary to reconstruct the phylogenetic tree for known Cerasus species. Here, we report the chloroplast (cp) genome sequences of 11 Cerasus species to provide insight into evolution of the plastome. The cp genomes of the 11 Cerasus species (157,571–158,830 bp) displayed a typical quadripartite circular structure. The plastomes contain 115 unique genes, including 80 protein-coding genes, four ribosomal RNAs, and 31 transfer RNAs. Twenty genes were found to be duplicated in inverted repeats as well as at the boundary. The conserved non-coding sequences showed significant divergence compared with the coding regions. We found 12 genes and 14 intergenic regions with higher nucleotide diversity and more polymorphic sites, including matK , rps16 , rbcL , rps16 - trnQ , petN - psbM , and trnL - trnF . During cp plastome evolution, the codon profile has been strongly biased toward the use of A/T at the third base, and leucine and isoleucine codons appear the most frequently. We identified strong purifying selection on the rpoA , cemA , atpA , and petB genes; whereas ccsA , rps19 , matK , rpoC2 , ycf2 and ndhI showed a signature of possible positive selection during the course of Cerasus evolution. In addition, we further analyzed the phylogenetic relationships of these species with 57 other congenic related species.Through reconstructing the Cerasus phylogeny tree, we found that true cherry is similar to the flora of China forming a distinct group, from which P. mahaleb was separated as an independent subclade. Microcerasus was genetically closer to Amygdalus , Armeniaca , and Prunus ( sensu stricto ) than to members of true cherry, whereas P. japonica and P. tomentosa were most closely related to P. triloba and P. pedunculata . However, P. tianshanica formed a clade with P. cerasus , P. fruticosa , P. cerasus × P. canescens ‘Gisela 6’, and P. avium as a true cherry group. These results provide new insights into the plastome evolution of Cerasus , along with potential molecular markers and candidate DNA barcodes for further phylogenetic and phylogeographic analyses of Cerasus species.

根系分泌物是植物自毒物质的重要来源之一,研究表明邻苯二甲酸是一种公认的自毒物质,也是橡胶树根系分泌物中含量较高的物质之一.为探究邻苯二甲酸对橡胶树自身是否具有自毒作用,考察不同浓度(0.05、0.50、1.00、2.00 mmol/L)邻苯二甲酸溶液对橡胶树RRIM600 种子萌发、幼苗生长的影响.结果表明:(1)不同浓度邻苯二甲酸均推迟橡胶树种子的初始萌发时间,对种子发芽率、发芽速率和萌发整齐度均存在抑制作用,且浓度越高抑制作用越强,与对照相比,2.00 mmol/L邻苯二甲酸处理的发芽率、发芽指数、发芽速率、发芽势分别下降了 23.60%、42.75%、37.18%、58.69%.(2)不同浓度邻苯二甲酸均抑制橡胶树芽长、芽粗、根粗的生长,减少了幼苗生物量的积累;在 0.05～2.00 mmol/L浓度范围内,芽长、芽粗、根粗、芽重和根重分别下降了 12.91%～40.70%、20.05%～21.59%、7.89%～34.13%、16.18%～26.47%、20.00%～36.00%.(3)随邻苯二甲酸浓度增加,橡胶树幼苗细胞膜脂过氧化程度逐渐加重,丙二醛(malonaldehyde,MDA)含量逐渐增加;游离脯氨酸和可溶性糖含量也逐渐增加.(4)橡胶树幼苗色素含量和过氧化氢酶(catalase,CAT)活性随邻苯二甲酸浓度增加呈现先增加后减少的趋势,而超氧化物歧化酶(superoxide dismutase,SOD)和过氧化物酶(peroxidase,POD)活性随邻苯二甲酸浓度增加而逐渐减少;0.05 mmol/L 的邻苯二甲酸促进幼苗叶绿素b的积累,降低了叶绿素a含量,并提高CAT活性,降低了POD和SOD活性;当浓度达到 0.50 mmol/L时,叶绿素a、叶绿素总量和类胡萝卜素含量积累至最大,POD和SOD活性持续下降;在 2.00 mmol/L时,所有色素含量和 3 种抗氧化酶活性均降至最低.综上,邻苯二甲酸推迟了橡胶树RRIM600 种子初始萌发时间,降低种子萌发率和萌发速率,导致橡胶树幼苗生理功能紊乱,并抑制生长发育.该研究结果可为客观评价邻苯二甲酸对橡胶树自毒作用提供基础数据支撑.