Rapid and accurate diagnosis of nitrogen (N) and phosphorus (P) is crucial for Hydrangea macrophylla nursery management. Traditional methods are time-consuming, and existing non-destructive studies rarely target ornamental plants or support joint N-P diagnosis at the early growth stage. A total of 339 RGB images were captured from potted hydrangeas grown under varying N and P levels at the seedling stage, with 65 phenotypic traits (color, texture, and morphology) extracted. Nutritional status (deficient, optimal, and surplus) was categorized with reference to plant nutrition indices. Discriminant models were then developed using four machine learning algorithms: convolutional neural network (CNN), support vector machine (SVM), random forest (RF), and probabilistic neural network (PNN). The model performances were evaluated using overall accuracy, precision, recall, F1-score, and Cohen’s Kappa coefficient (κ). As a result, CNN achieved 82.65% accuracy (κ = 0.7392) for N classification, and SVM reached 83.65% accuracy (κ = 0.7357) for P classification. Color-related traits dominated the top five contributing features, indicating a stronger correlation with N and P status. This work offers a practical solution for real-time, low-cost, and non-destructive nutrient diagnosis, supporting precision fertilization and enhancing environmental sustainability in nursery production.

Eucalyptus urophylla × E. grandis is a major hybrid species of timber plantations. However, our understanding of Eucalyptus mitochondrial genome, especially within the Myrtaceae family, is limited. In this study, we employed hybrid sequencing combining the Illumina and Oxford Nanopore sequencing to assemble and annotate the mitogenome (mtDNA) of E. urophylla × E. grandis. Our results reveal a structure characterized by one circular molecule, with a cumulative length of 483,907 base pairs (bp) and a GC content of 44.96%. The circular molecule collectively harbored 59 annotated genes. Among these, 38 were unique protein-coding genes (PCGs), accompanied by 18 transfer RNA (tRNA) genes and 3 ribosomal RNA (rRNA) genes. Our study also examined repetitive sequences, RNA editing sites, and intracellular sequence transfers within the mtDNA. Furthermore, we conducted a phylogenetic analysis between E. urophylla × E. grandis and 30 closely related species based on genetic affinities. The outcomes furnish a high-quality organelle genome for E. urophylla × E. grandis, thereby explaining basic insights into organelle genome evolution and phylogenetic relationships.

Lignin is a crucial constituent of cell walls and plays a pivotal role in plant growth and development. However, the transcriptional regulatory network governing lignin biosynthesis is not fully understood. In this study, we observed that PpnCCT39 overexpression resulted in greener stems, larger basal diameters, and increased stem dry weight. Additionally, the secondary xylem of lines overexpressing PpnCCT39 was wider, had larger xylem fiber cell areas, and thicker cell walls, compared to those of wild-type plants. Furthermore, PpnCCT39 overexpression led to elevated lignin content and enhanced the rigidity of secondary cell walls. RNA-seq and ChIP-seq association analyses identified 826 potential regulatory target genes of PpnCCT39 that were upregulated and expressed in 1-month-old PpnCCT39 overexpression lines. Gene enrichment analyses revealed enrichment in pathways related to cell wall formation, xylem and phloem development, and the phenylpropanoid pathway. Two genes involved in lignin biosynthesis, PagCOMT1 and PagBGLU18-2, exhibited significantly increased expression in stems of lines overexpressing PpnCCT39, as demonstrated by high FPKM values and RT-qPCR results. Further investigations using yeast one-hybrid, dual-luciferase assays, and electrophoretic mobility shift assays demonstrated that PpnCCT39 directly activates the transcription of PagCOMT1 and PagBGLU18-2, thereby promoting lignin biosynthesis. This study elucidated the transcriptional regulatory mechanism of PpnCCT39 in poplars and revealed its role in activating the expression of key lignin biosynthesis genes. PpnCCT39 facilitates lignin biosynthesis and secondary growth processes, offering a novel theoretical framework for modulating lignin biosynthesis and enhancing timber yield through molecular design.

The GRAS [GRI (Gibberellic Acid Insensitive), RGA (Repressor of GAI-3 mutant), and SCR (Scarecrow)] transcription factors play a pivotal role in the development and stress responses of plants. Eucalyptus is an important fast-growing tree species worldwide, yet its poor cold tolerance limits its cultivation range. This study conducted a bioinformatics analysis of Eucalyptus grandis GRAS family and investigated the expression patterns of GRAS genes in different ploidy Eucalyptus under cold treatment. This study identified 92 EgrGRAS genes, which were divided into eight subfamilies. Interspecies synteny analysis found that E. grandis and Populus trichocarpa have more syntenic GRAS gene pairs. Chromosome localization analysis revealed that 90 EgrGRAS genes were found to be unevenly distributed across 11 chromosomes. Gene structure analysis found similar intron-exon structures in EgrGRAS genes. Protein motif analysis revealed that proteins within the same subfamily have certain structural similarities. The physical and chemical properties of the proteins encoded by EgrGRAS genes vary, but the ranges of amino acid numbers, molecular weights, and isoelectric points (pI) are similar to those of GRAS proteins from other species. Subcellular localization prediction using software found that 56 members of EgrGRAS family are localized in the nucleus, with a few members localized in the cytoplasm, chloroplasts, and mitochondria. Tobacco subcellular localization experiments verified a nuclear-localized GRAS transcription factor. Cis-acting element analysis predicted that EgrGRAS genes are involved in the growth as well as the response to hormones, light induction, and low-temperature stress. Transcriptome data analysis and quantitative real-time PCR (qRT-PCR) experiments in diploid and triploid Eucalyptus urophylla found that some EgrGRAS genes exhibited upregulated expression under different cold treatment durations, with certain genes from the LISCL, PAT1, and DELLA subfamilies significantly upregulated in triploid Eucalyptus. These EgrGRAS transcription factors may play an important role in Eucalyptus response to cold stress. The study lays a molecular foundation for the breeding of cold-resistant Eucalyptus varieties.

is an important species for establishing pulpwood plantations due to its high application value in engineered wood products. However, the lack of a well-established in vitro regeneration system has severely constrained its industrial-scale propagation and the induction of tetraploids. In this study, using the superior A. melanoxylon clone SR3, an in vitro regeneration system using a bud-bearing stem segment was established. A DKW medium supplemented with 0.5 mg/L 6-BA, 0.1 mg/L IAA, and 0.2 mg/L NAA was determined as the optimal differentiation medium. Adding 0.5 mg/L IBA and 0.25 mg/L NAA to the 1/2 MS medium produced a higher rooting percentage and root number. To determine the optimal timing for tetraploid induction in A. melanoxylon, morphological, cytological, and flow cytometric analyses were conducted on the swollen tissue at the base of the bud-bearing stem segment. On the 5th day of preculture, white callus tissue was observed, characterized by vigorous cell division and the highest G2/M-phase cell content in the adventitious bud primordia. After colchicine treatment, the tetraploid induction efficiency on the 5th day of preculture was significantly higher compared to the 4th or 6th day. The highest induction rate of 12.26 ± 0.80

It is known that laccase genes are involved in lignin synthesis. Eucalyptus is an important timber species; functional studies of specific laccase members and their upstream regulatory factors in Eucalyptus are incomplete, and the mechanism of lignin content variation in polyploid plants remains unclear. Therefore, in this study, we investigated the function of EuLAC17 by overexpressing it in tobaccos and the result showed the lignin content in transgenic tobacco increased significantly. Further, yeast one hybrid sequencing was used to identify a series of potential regulatory factors of EuLAC17, among which EuMYB308 showed the most significant correlation with EuLAC17. Yeast one hybrid, dual-luciferase reporter gene assay and electrophoretic mobility shift assay jointly verified that EuMYB308 could directly target the EuLAC17 promoter and repress its expression. In addition, overexpression of EuMYB308 resulted in significant reductions in plant growth, xylem cell lumen area, cell wall thickness and lignin content. Transcriptome sequencing showed that lignin biosynthesis genes including laccase genes were significantly differential expression in transgenic plants compared with wild-type plants. In triploid Eucalyptus urophylla, the expression of EuMYB308 was significantly upregulated, which may enhance the inhibition of EuLAC17 and thus reduce its expression level in triploid, which is one possible reason for the reduced lignin content in triploid E. urophylla. This study provides important insights into transcriptional regulation of lignin biosynthesis in Eucalyptus, and also contributes to revealing the genetic mechanism of lignin content variation in polyploid plants, which are of great significance for promoting the improvement of wood quality in forest trees and polyploid breeding.

Lemierre syndrome (LS) is a rare and life-threatening condition predominantly caused by Fusobacterium necrophorum. Currently, there are no standardized clinical guidelines for LS management. Here, we describe the case of a 40-year-old male with fever, productive cough, and dyspnea but no sore throat. Diagnostic radiological examinations revealed multiple pulmonary cavitary nodules and an internal jugular vein occlusion. Metagenomic Next-Generation Sequencing (mNGS) of the alveolar lavage fluid identified Fusobacterium necrophorum, thereby confirming the diagnosis of LS. Intriguingly, the patient exhibited a delayed clinical response despite receiving the appropriate antibiotic. After integrating tigecycline into the treatment to address potential co-infecting bacteria, we observed a marked improvement in his clinical symptoms. Subsequent follow-up over 12 weeks post-discharge revealed complete alleviation of symptoms, and a chest CT scan showed marked regression of the lung lesions.

BACKGROUND:Lignin is a major restriction factor for the industrial production of biomass resources, such as pulp and bioenergy. Eucalyptus is one of the most important sources of pulp and bioenergy. After polyploidization, the lignin content of forest trees is generally reduced, which is considered a beneficial genetic improvement. However, the differences in the lignin content between triploid and diploid Eucalyptus and the underlying regulatory mechanism are still unclear.RESULTS:We conducted a comprehensive analysis at the phenotypic, transcriptional and metabolite levels between Eucalyptus urophylla triploids and diploids to reveal the effects of polyploidization on the lignin content and lignin metabolic pathway. The results showed that the lignin content of Eucalyptus urophylla triploid stems was significantly lower than that of diploids. Lignin-related metabolites were differentially accumulated between triploids and diploids, among which coniferaldehyde, p-coumaryl alcohol, sinapaldehyde and coniferyl alcohol had significant positive correlations with lignin content, indicating that they might be primarily contributing metabolites. Most lignin biosynthetic genes were significantly downregulated, among which 11 genes were significantly positively correlated with the lignin content and above metabolites. Furthermore, we constructed a co-expression network between lignin biosynthetic genes and transcription factors based on weighted gene co-expression network analysis. The network identified some putative orthologues of secondary cell wall (SCW)-related transcription factors, among which MYB52, MYB42, NAC076, and LBD15 were significantly downregulated in Eucalyptus urophylla triploids. In addition, potential important transcription factors, including HSL1, BEE3, HHO3, and NAC046, also had high degrees of connectivity and high edge weights with lignin biosynthetic genes, indicating that they might also be involved in the variation of lignin accumulation between triploid and diploid Eucalyptus urophylla.CONCLUSIONS:The results demonstrated that some lignin-related metabolites, lignin biosynthetic genes and transcription factors in Eucalyptus urophylla triploids may be relatively sensitive in response to the polyploidization effect, significantly changing their expression levels, which ultimately correlated with the varied lignin content. The analysis of the underlying formation mechanism could provide beneficial information for the development and utilization of polyploid biomass resources, which will be also valuable for genetic improvement in other bioenergy plants.

Abstract Kobresia species are common in meadows on the Qinghai–Tibet Plateau. They are important food resources for local livestock, and serve a critical foundation for ecosystem integration. Genetic resources of Kobresia species are scarce. Here, we generated a chromosome-level genome assembly for K. myosuroides (Cyperaceae), using PacBio long-reads, Illumina short-reads, and Hi–C technology. The final assembly had a total size of 399.9 Mb with a contig N50 value of 11.9 Mb. The Hi–C result supported a 29 pseudomolecules model which was in consistent with cytological results. A total of 185.5 Mb (44.89% of the genome) transposable elements were detected, and 26,748 protein-coding genes were predicted. Comparative analysis revealed that Kobresia plants have experienced recent diversification events during the late Miocene to Pliocene. Karyotypes analysis indicated that the fission and fusion of chromosomes have been a major driver of speciation, which complied with the lack of whole-genome duplication (WGD) in K. myosuroides genome. Generally, this high-quality reference genome provides insights into the evolution of alpine sedges, and may be helpful to endemic forage improvement and alpine ecosystem preservation.

Golden 2-Like ( GLK ) transcription factors play a crucial role in chloroplast development and chlorophyll synthesis in many plant taxa. To date, no systematic analysis of GLK transcription factors in tree species has been conducted. In this study, 40 EgrGLK genes in the Eucalyptus grandis genome were identified and divided into seven groups based on the gene structure and motif composition. The EgrGLK genes were mapped to 11 chromosomes and the distribution of genes on chromosome was uneven. Phylogenetic analysis of GLK proteins between E. grandis and other species provided information for the high evolutionary conservation of GLK genes among different species. Prediction of cis -regulatory elements indicated that the EgrGLK genes were involved in development, light response, and hormone response. Based on the finding that the content of chlorophyll in mature leaves was the highest, and leaf chlorophyll content of triploid Eucalyptus urophylla was higher than that of the diploid control, EgrGLK expression pattern in leaves of triploid and diploid E. urophylla was examined by means of transcriptome analysis. Differential expression of EgrGLK genes in leaves of E. urophylla of different ploidies was consistent with the trend in chlorophyll content. To further explore the relationship between EgrGLK expression and chlorophyll synthesis, co-expression networks were generated, which indicated that EgrGLK genes may have a positive regulatory relationship with chlorophyll synthesis. In addition, three EgrGLK genes that may play an important role in chlorophyll synthesis were identified in the co-expression networks. And the prediction of miRNAs targeting EgrGLK genes showed that miRNAs might play an important role in the regulation of EgrGLK gene expression. This research provides valuable information for further functional characterization of GLK genes in Eucalyptus .

Induction of triploids through sexual polyploidisation requires in-depth understanding of plant reproductive biology. However, the method to identify the developmental stages of the gametes in Eucalyptus is still unclear. In this study, microsporogenesis and megasporogenesis of Eucalyptus pellita were revealed by staining with acetocarmine and paraffin sectioning. Results showed two types of stamens existed in a single flower, and the microsporogenesis in anthers of long stamens were significantly ahead of those in short ones. A temporal relationship between megasporogenesis and microsporogenesis could be found in a single flower where megasporogenesis was consistent with microsporogenesis in the long stamens. Although the flower bud development and meiosis process of a single flower bud at different positions on the branch were asynchronous, those positioned at the upper end of the branch were relatively consistent. From the study report, a simple and accurate method to identify the meiotic period of megasporocytes was proposed based on temporal relationships between megasporogenesis and microsporogenesis. The study not only deepened the understanding of E. pellita reproductive biology, but also provided important theoretical guidance for the genetic improvement of this tree species, especially the triploid breeding by sexual polyploidisation.

GATA transcription factors have been demonstrated to play key regulatory roles in plant growth, development, and hormonal response. However, the knowledge concerning the evolution of GATA genes in Eucalyptus urophylla and their trans-regulatory interaction is indistinct. Phylogenetic analysis and study of conserved motifs, exon structures, and expression patterns resolved the evolutionary relationships of these GATA proteins. Phylogenetic analysis showed that EgrGATAs are broadly distributed in four subfamilies. Cis-element analysis of promoters revealed that EgrGATA genes respond to light and are influenced by multiple hormones and abiotic stresses. Transcriptome analysis revealed distinct temporal and spatial expression patterns of EgrGATA genes in various tissues of E. urophylla S.T.Blake, which was confirmed by real-time quantitative PCR (RT-qPCR). Further research revealed that EurGNC and EurCGA1 were localized in the nucleus, and EurGNC directly binds to the cis-element of the EurGUN5 promoter, implying its potential roles in the regulation of chlorophyll synthesis. This comprehensive study provides new insights into the evolution of GATAs and could help to improve the photosynthetic assimilation and vegetative growth of E. urophylla at the genetic level.

After polyploidization, plants usually undergo some morphological and physiological changes, including the lignin content of polyploids usually becoming lower than that of diploids. However, the regulatory mechanism of the variation of lignin content in polyploid plants remains unclear. Therefore, in this research, we used full-sib poplar triploids and diploids to explore the molecular regulatory basis of lignin content in poplar triploid leaves through the determination of lignin content, the observation of xylem cells, and transcriptome sequencing. The results showed that the lignin content of triploid leaves was significantly lower than that of diploid leaves. The xylem cells of triploid leaves were significantly larger than those of diploids. Transcriptome sequencing data show that most lignin biosynthesis genes were significantly downregulated, and genes related to cell growth were mostly upregulated in triploid leaves compared with diploid leaves. In addition, co-expression network analysis showed that several transcription factors might be involved in the regulation of lignin biosynthesis. Consequently, the altered expression of genes related to lignin might lead to the reduced lignin content in triploids. These results provide a theoretical basis for further exploring the molecular mechanism of the variation of polyploid lignin content and the utilization of polyploid lignocellulosic resources.

Proteins containing Common in Fungal Extracellular Membrane (CFEM) domains uniquely exist in fungi and play significant roles in their whole life history. In this study, a total of 11 MbCFEM proteins were identified from Marssonina brunnea f. sp. multigermtubi (MULT), a hemibiotrophic pathogenic fungus on poplars that causes severe leaf diseases. Phylogenic analysis showed that the 11 proteins (MbCFEM1-11) were divided into three clades based on the trans-membrane domain and the CFEM domain. Sequence alignment and WebLogo analysis of CFEM domains verified the amino acids conservatism therein. All of them possess eight cysteines except MbCFEM4 and MbCFEM11, which lack two cysteines each. Six MbCFEM proteins with a signal peptide and without trans-membrane domain were considered as candidate effectors for further functional analysis. Three-dimensional (3D) models of their CFEM domains presented a helical-basket structure homologous to the crucial virulence factor Csa2 of Candida albicans. Afterward, four (MbCFEM1, 6, 8, and 9) out of six candidate effectors were successfully cloned and a yeast signal sequence trap (YSST) assay confirmed their secretion activity. Pathogen challenge assays demonstrated that the transient expression of four candidate MbCFEM effectors in Nicotiana benthamiana promoted Fusarium proliferatum infection, respectively. In an N. benthamiana heterogeneous expression system, MbCFEM1, MbCFEM6, and MbCFEM9 appeared to suppress both BAX/INF1-triggered PCD, whereas MbCFEM8 could only defeat BAX-triggered PCD. Additionally, subcellular localization analysis indicated that the four candidate MbCFEM effectors accumulate in the cell membrane, nucleus, chloroplast, and cytosolic bodies. These results demonstrate that MbCFEM1, MbCFEM6, MbCFEM8, and MbCFEM9 are effectors of M. brunnea and provide valuable targets for further dissection of the molecular mechanisms underlying the poplar-M. brunnea interaction.

Improvements in plant growth can bring great benefits to the forest industry. Eucalyptus urophylla is an important plantation species worldwide, and given that ploidy increases are often associated with plant phenotype changes, it was reasoned that its polyploidization may have good prospects and great significance toward its cultivation. In this study, the zygotic development period of E. urophylla was observed through paraffin sections, and a correlation between the development time of flower buds after pollination and the zygotic development period was established. On this basis, it was determined that the 25th day after pollination was the appropriate time for a high temperature to induce zygotic chromosome doubling. Then tetraploid E. urophylla was successfully obtained for the first time through zygotic chromosome doubling induced by high temperature, and the appropriate conditions were treating flower branches at 44°C for 6 h. The characterization of tetraploid E. urophylla was performed. Chromosome duplication brought about slower growing trees with thicker leaves, larger cells, higher net photosynthetic rates, and a higher content of certain secondary metabolites. Additionally, the molecular mechanisms for the variation in the tetraploid's characteristics were studied. The qRT-PCR results showed that genes mediating the tetraploid characteristics showed the same change trend as those of the characteristics, which verified that tetraploid trait variation was mainly caused by gene expression changes. Furthermore, although the tetraploid had no growth advantage compared with the diploid, it can provide important germplasm resources for future breeding, especially for the creation of triploids.

Photosynthesis plays vital role in plant growth and development throughout its life, and it is influenced by environmental signals and circadian rhythms. We analyzed the transcriptome landscape of the two poplars progeny with contrasting photosynthesis rates at three times point (ZT4, ZT16, ZT22), constructed gene regulatory network that related to circadian rhythm and photosynthesis. We suggest that the differences in photosynthetic rate between the progenies may originate from plant endogenous circadian oscillators prepare poplar plants for photosynthesis by regulating photosynthesis-associated nuclear genes and carotenoid metabolism genes before dawn, genes associated with plant hormone signal transduction and transcription factor increase leaf size and stomatal movement, the influence of other core regulatory factors on chlorophyll accumulation. Furthermore, overexpression of candidate regulatory gene, AP3 (Potri.007G017000), induced leaf senescence and reduced the content of chlorophyll. These results demonstrated that many potential key regulators are integrated closely with chlorophyll content and photosynthesis.

The tremendous functional, spatial, and temporal diversity of the plant proteome is regulated by multiple factors that continuously modify protein abundance, modifications, interactions, localization, and activity to meet the dynamic needs of plants. Dissecting the proteome complexity and its underlying genetic variation is attracting increasing research attention. Mass spectrometry (MS)-based proteomics has become a powerful approach in the global study of protein functions and their relationships on a systems level. Here, we review recent breakthroughs and strategies adopted to unravel the diversity of the proteome, with a specific focus on the methods used to analyze posttranslational modifications (PTMs), protein localization, and the organization of proteins into functional modules. We also consider PTM crosstalk and multiple PTMs temporally regulating the life cycle of proteins. Finally, we discuss recent quantitative studies using MS to measure protein turnover rates and examine future directions in the study of the plant proteome.

Homologous recombination is an important source of biological genetic variation. Limited by detection methods, there are only a few reports on the homologous recombination in high plants and its product - heteroduplex DNA (hDNA). In the present study, applying the strategy of detecting hDNA by constructing populations from inhibited post-meiotic segregation, two hybrid triploid populations were constructed from two maternal parents inPopulus tomentosa by inhibiting post-meiotic segregation. One hundred and ten simple sequence repeat (SSR) markers were used to study the occurrence and variation of hDNA on nine chromosomes inP. tomentosa with different genotypes. The results showed that the frequencies of hDNA between two female parents inP. tomentosa ranged from 8.5% to 87.2%. The hDNA frequency was positively correlated to the distance from the centromere, but the average hDNA frequency on a chromosome had no correlation with the chromosome length. One to 3 times recombination events were detected on most chromosomes, and only a few four- or five-times recombination events were detected. The overall frequencies of hDNA on the same chromosome in two genotypic individuals were roughly similar, while the hDNA frequencies varied greatly at specific SSR loci. Compared withTacamahaca poplar hybrid,P. pseudo-simonii × P. nigra 'Zheyin3#', detection of homologous recombination times and the frequency and location of hDNA were largely different. This study is the first to describe the characteristics and variations of homologous recombination inP. tomentosa with two different genotypes, which will provide valuable insights for exploring the characteristics and variations of homologous recombination among interspecies and intraspecies in higher plant.

Homologous recombination (HR), the most significant event in meiosis, has important implications for genetic diversity and evolution in organisms. Heteroduplex DNA (hDNA), the product of HR, can be captured by artificially induced chromosome doubling during the development of the embryo sac to inhibit postmeiotic segregation, subsequently, and hDNAs are directly detected using codominant simple sequence repeat (SSR) markers. In the present study, two hybrid triploid populations derived from doubling the chromosomes of the embryo sac induced by high temperature in Populus tomentosa served as starting materials. Eighty-seven, 62, and 79 SSR markers on chromosomes 01, 04, and 19, respectively, that were heterozygous in the maternal parent and different from the paternal parent were screened to detect and characterize the hDNA in P. tomentosa . The results showed that the hDNA frequency patterns on chromosomes changed slightly when the number of SSR primers increased. The highest hDNA frequency occurred at the adjacent terminal on chromosomes, which was slightly higher than those at the terminals in the two genotypic individuals, and the hDNA frequency gradually decreased as the locus-centromere distance decreased. With the increase in the number of SSR markers employed for detection, the number of recombination events (REs) detected significantly increased. In regions with high methylation or long terminal repeat (LTR) retrotransposon enrichment, the frequency of hDNA was low, and high frequencies were observed in regions with low sequence complexity and high gene density. High-frequency recombination occurring at high gene density regions strongly affected the association between molecular markers and quantitative trait loci (QTLs), which was an important factor contributing to the difficulty encountered by MAS in achieving the expected breeding results.

目前自然界仍未发现天然多倍体桉树的存在,建立人工诱导桉树未减数2n花粉技术体系对于推进桉树的多倍体种质创制及遗传改良的意义重大.本研究以粗皮桉为对象,探究其花蕾发育与小孢子母细胞减数分裂进程的特点,并对不同发育阶段花蕾施加秋水仙碱处理,诱导粗皮桉花粉染色体加倍.结果表明,待观察到小孢子母细胞减数分裂开始后48 h,即处于细线期至粗线期的花蕾占比最高时,在靠近花序位置的花枝上切口并导入0.5％浓度的秋水仙碱溶液处理6 h的效果最佳,人工诱导2n花粉的有效诱导率达到31.34％.诱导获得的粗皮桉2n花粉较普通单倍性花粉的形态差异显著.本研究揭示了粗皮桉花蕾发育与小孢子母细胞减数分裂的时序性关系,建立了基于花蕾着生位置和发育时数,即时判别粗皮桉小孢子母细胞减数分裂时期的方法,明确了采用秋水仙碱溶液处理诱导粗皮桉花粉染色体加倍的最佳时机和处理条件,为进一步开展桉树多倍体种质创新工作奠定了重要基础.