Species diversity is the most basic level of biodiversity, which not only reflects the richness of biological species, but also the spatial scope of species evolution and the ecological adaptability to specific environments. Structure is the basis for studying the historical dynamics of plants, and while understanding and clarifying the growth competition relationship between species, it reflects the trend of community succession. Based on the results of 62 plots with a total area of 3.72 hm², the species diversity and structure of tree populations of Dagangshan were analyzed. There were 486 species of plants in the community, belonging to 286 genera of 120 families, of which single species accounted for 66.43% of the total, and China fir were in a dominant position in the community. Dagangshan is located in the subtropical region and has the nature of transition zone. The genus of seed plants included 13 distribution types, and 9 genera with endemic components in China. Shannon-Weiner index, Simpson index and Pielou index were basically the same in the distribution trend of each growth layer. The advantage of shrub layer was obvious. The herbaceous layer was slightly higher than the arbor layer. The overall species diversity index of the community was higher and the species were more abundant. By sample belt, the 2nd sample was the most abundant, and the 1st sample was slightly lower than the others. However, the community similarity was the highest in the 1st and 2nd belts, and the difference in species diversity indices in the 3rd and 4th samples was small, but the community differences were the largest.

In order to explore the pollution level and source of soil heavy metals in Haikou City, taking the agricultural land in Haikou City as the research object, the content of eight kinds of heavy metals such as Cd, Hg, As, Pb, Cr, Cu, Ni and Zn in soil surface samples were collected and determined, and the spatial distribution characteristics of heavy metals were clarified combined with geostatistical analysis method. The single factor pollution index method, geo-accumulation index method and potential ecological risk index method were used to evaluate soil pollution. The source of heavy metals was quantitatively analyzed by the correlation analysis and principal component analysis/absolute principal component fraction (PCA/APCS) receptor model. Six heavy metals such as Cd, Pb, Cr, Cu, Ni and Zn exceeded the risk screening value of agricultural land, and the proportion of exceeding the standard points from high to low was Cr, Ni (31.6%)>Cu (21.1%)>Cd (5.3%)>Pb and Zn (2.6%). The spatial distribution characteristics of Cu, Zn, Ni and Cr contents were basically the same, which were similar to the distribution of basic volcanic rocks in the study area. The evaluation results of heavy metal geo-accumulation index showed that the concentration of Cd in the soil was the highest, and the soil was greatly affected by Cd, followed by Cr, and other heavy metals were less affected. The potential ecological risk levels of soil heavy metal pollution were mainly mild and moderate risk levels, while As, Pb, Cr and Zn were slight ecological risks, and the potential ecological harm was small. The above points of Cd, Hg and Ni intensity ecological risk accounted for 52.6%, 15.8% and 5.3% respectively. The potential ecological risk of soil heavy metals in the study area was mainly caused by Cd and Hg. Eight kinds of heavy metal elements were identified as three sources. Cu, Ni, Cr and Zn were mainly from natural sources, which were mainly affected by the high soil background value of basic volcanic parent rock, Pb, Cd, As and Hg were mainly from industrial sources and traffic sources. As was also affected by agricultural sources. The source of heavy metals in Haikou soil was relatively single. As a result, it is necessary to strengthen the pollution control of Cd, Cr and Hg in the soil, with the focus on the pollution control of Cd.

In this paper, the bibliometrics approach in conjunction with the Research Leadership Index (RLI) was used to compare and assess the scientific research performance and innovation level of the major producing nations of natural rubber on 12 Research Fronts. The Research Fronts of each nation were revealed to enter the innovation excellence position, innovation forefront position, and innovation rank position, as well as the status of innovation catching up position and innovation gap, from three major research areas of agriculture and plant science, ecology and environmental science, chemistry and material science. China has grown to be a significant player in global natural rubber research, with the highest RLI score globally. The United States comes in second with a score roughly 65% of that of China. France, Germany, Thailand, India, and Malaysia are ranked third through seventh, respectively, with France, Germany, and Thailand being in the same active cascade as India and Malaysia. The United States and France are currently in the innovation excellence position in the majority of the Research Fronts (more than 50.00%), while China has entered the position in 100% of the Research Fronts. There is a large Research Front gap between the countries of Germany, Thailand, India, Malaysia and the countries of China, the United States, and France. 16.67% of the Research Front in Germany, Thailand, India, and Malaysia is still in the innovation catching up stage. In all three of these lucrative industries, where China excels at invention, the country has taken the lead. The performance of the other six nations varies in several areas. In the fields of agriculture and plant science, Germany, Thailand and Malaysia, have taken the innovation leadership and ranked positions, respectively, while India is in the innovation catching up position. The United States and France have entered the innovation excellence position. While India lags behind, the United States and France fare better than Germany, Thailand, and Malaysia. The United States and Germany have taken the top spots for innovation and excellence in the field of ecological and environmental science. France, Thailand, India, and Malaysia are still lagging behind in terms of innovation. The performance of the United States and Germany is superior, whereas that of France, Thailand, India, and Malaysia is subpar. In the fields of chemistry and materials science, the innovative excellence position has been attained by 50.00% of the Research Front in the United States and France, 30.00% in Thailand and India, 20.00% in Germany, and 10.00% in Malaysia. In the United States and France, 50.00% of the Research Front has joined the innovation forefront position and the innovation rank position, while India is at 70.00%. At 60.00%, 50.00%, and 80.00%, respectively, Germany, Thailand, and Malaysia are in the innovation forefront position and innovation rank position, but 20.00%, 20.00%, and 10.00% of the Research Front are still in the innovation catching up position. The six nations perform fairly evenly in this regard, but the United States, France, and India outperform Germany, Thailand, and Malaysia by a small margin.

In order to reveal the mechanism of flower development and provide a theoretical basis for solving the problems of flowering in the sugar apple industry, the Auxin Response Factor (ARF) family genes were identified and the expression patterns were analyzed. Based on transcriptome sequencing, 11 AsARF genes were selected and identified. The biological functions of AsARF family genes were preliminarily analyzed by homologous evolution analysis, protein domain analysis, subcellular localization, qRT-PCR, and other techniques. The AsARFs were divided into five classes based on phylogenetic analysis. The proteins had molecular weight varying from 73.85 to 112.51 kDa and isoelectric point from 5.42 to 7.63. All the AsARFs contained two domains of DBD and MR, and, except for AsARF3a, 6a and 6b, they also all contained a CTD domain. Subcellular location prediction results showed that the AsARF members were mainly located in the nucleus. Based on amino acid enrichment in the intermediate region of the protein, AsARF5a, AsARF5b, AsARF6c, AsARF6d, AsARF7 and AsARF16 were speculated to be transcriptional activators, while AsARF2, AsARF3a, AsARF3b, AsARF6a and AsARF6b were presumed to be transcriptional repressors. Three CTD domain-deleted ARF genes were identified and they may have unique biological functions. The results of subcellular location experiments showed that AsARF2, AsARF3a and AsARF6a were localized in the cell nucleus. Real-time quantitative PCR results showed that AsARF3a, AsARF3b, AsARF5a, AsARF5b, AsARF6a and AsARF7 genes were expressed more in the inflorescent meristem. AsARF2 and AsARF6b genes were highly expressed in flower buds. AsARF2, AsARF3a, AsARF5a, AsARF5b, AsARF6b, AsARF6c and AsARF16 genes were predominantly expressed in normal flowers, while the expression of AsARF3b, AsARF6a, AsARF6d and AsARF7 genes in malformed flowers was greater than that in normal flowers. These results suggest that AsARF may play key roles in regulating the flower development in sugar apple. The high expression of AsARF6b and AsARF6c in normal flowers and AsARF6a and AsARF6d in abnormal flowers indicate that they play important roles in the normal development of flowers.

Phalaenopsis is the most popular Spring Festival pot flower in China. In order to accurately regulate the flowering stage and excavate the key flowering gene in the production and cultivation of Phalaenopsis, this paper studied the effects of growth regulators GA₃ and 6-BA on the flowering of Phalaenopsis Big Chilli, and the PhPIF4 gene selected from transcriptome data was cloned, and its bioinformatics analysis and response to growth regulator GA₃ were studied. The results showed that PhPIF4 had a typical conserved domain of the bHLH_SF super family (cl00081) homobox family. PhPIF4 of Big Chilli is closely related to Phalaenopsis equestris, followed by Cymbidium ensifolium, C, sinense and Dendrobium catenatum. The protein encoded by PhPIF4 was localized in non-chloroplast organelles. GA₃ treatment increased stalk length and the maximum stalk length of the treatment group was 200 mg/L GA₃. GA₃ could bring forward flowering 9-11 d. 6-BA significantly increased the number of flowers, and the treatment group with the most flowering amount was 300mg/L 6-BA, but 6-BA had no significant effect on flowering time and stalk length. When the two growth regulators were mixed to spray, the effect on flowering time and flowering time of Phalaenopsis was between the two. PhPIF4 was closely related to the development of flowering, and its expression gradually increased with the development of flowering. After spraying GA₃, the expression of PhPIF4 in flower buds, leaves and roots increased, and the increase was the largest in flower bud stage, suggesting that the expression of PhPIF4 might be affected and regulated by GA₃, and PhPIF4 might participate in the gibberellin flowering pathway. In this paper, the effects of GA₃ and 6-BA on reproductive growth of Phalaenopsis were studied, and the expression of PhPIF4 in response to GA was investigated, which would lay a foundation for revealing the role of PhPIF4 in gibberellin regulation of growth and development regulatory network.

Simple sequence repeats (SSR) and single nucleotide polymorphism (SNP) markers have been confirmed to be high sensitivity and specificity. Development of molecular markers related to different types of fruit quality traits of Canarium album (Lour.) Raeusch. can provide reference for its molecular assisted breeding to a considerable extent. The fully mature fruits of C. album cv. Changying and Huiyuan were collected to use as materials. After total RNA extraction and cDNA library construction, the transcriptome was sequenced on the Illumina Novaseq platform, and the SSR, SNP and InDel loci characteristics of the transcriptome were analyzed by MISA 1.0 and GATK3 software. Results showed that a total of 13 935 SSR loci were identified from 10 124 unigenes of C. album fruit transcriptome, the average 1 kb sequence appeared 0.25 SSR loci, the frequency and average length was 22.98% and 14.34 bp, respectively. Among them, the single base repeat type had the largest number of SSR loci (accounting for 66.80%), with a length of 10-64 bp, and an average length of 12.85 bp, the repeat times of repeat motifs were concentrated in 9-12, and the motif with the highest frequency was A/T (accounting for 66.67%). The number of SSR loci of six base repeat motif type was the least (0.47%), the length was 30-54 bp, which average length was 31.76 bp, the number of motif repeats was concentrated in 5-8 times, and the motif with the highest frequency was AGATGG/ATCTCC (0.04%). A total of 284 992 SNP loci were detected in the transcriptome of C. album fruit, the average 1 kb sequence contained 5.21 SNP loci; Among them, the number of SNP loci of transformation type was 166 162, including C/T and A/G. The number of SNP loci of transversion type was 118 830, including A/T, A/C, T/G and C/G. In addition, 18 548 InDel loci were found in the transcriptome of C. album fruit, the average 1 kb sequence existed 2.95 InDel loci. The number of unigenes containing one InDel locus was the largest. It was predicted that the unigene containing the most InDel loci might be the callose synthase gene. These results showed that SSR and SNP/InDel markers could be effectively developed through RNA-seq. The SSR loci and SNP/InDel loci were widely distributed in C. album fruits with different quality traits. The results would provide a data basis for the development of identification markers of C. album fruit traits.

Erigeron annuus, a member of the Asteraceae family, is widely distributed in tropic, subtropical and temperate regions of China. It is a plant native to North America, which was introduced to China at the end of the nineteenth century as an ornamental plant. E. annuus has great medicinal value. Its whole plant has been used in folk medicine for the treatment of indigestion, enteritis, epidemic hepatitis, lymphadenitis, hematuria, acute inflammation, malaria and obesity. E. annuus could be a phytoremediator for metal- and metalloid-contaminated soils. It can degrade diesel effectively, has strong tolerance and accumulation for uranium, cadmium, zinc, lead, and antimony, and can be distributed in soils with high pollution levels. Hence, In this study, it was to explore the characteristics of chloroplast (cp) genome and its phylogenetic relationship, laying a foundation for the further development of species identification, control and full utilization of E. annuus. The complete cp genome of E. annuus was assembled and sequenced by Illumina Nova Seq 6000 Sequencing platform and SPAdes v3.10. software. Taking the cp genome of E. canadensis (MT806101.1) as a reference, the genome feature and phylogenetic analysis study were investigated. The cp genome of E. annuus was a circular and quadripartite structure with a total length of 153 283 bp. The GC and AT content of the cp genome was 36.77%and 63.23%, respectively. The cp genome of E. annuus had four typical regions, containing a pair of inverted repeats (IRs, 25 019 bp) that were separated by the large single-copy (LSC, 84 833 bp) and small single-copy (SSC, 18 412 bp). In total, 132 genes were predicted, consisting of 88 protein-coding genes, 36 transfer RNA genes, and 8 ribosomal RNA genes. The genes were divided into 4 categories according to the functions, including 45 photosynthesis genes, 73 self-replication genes, 6 other genes and 8 genes of unknown function. SSR site analysis revealed that the cp genome sequence contained 200 SSR loci in total, which were spaced disproportionately through the genome with the largest number of SSRs distributed in the LSC region, followed by the SSC and IR regions. LSC, SSC and IR regions had 126, 40, and 34 SSRs, respectively. The number of SSRs in LSC, SSC and IR regions was accounted with 63%, 20% and 17%, respectively. The SSRs were mononucleotides, especially for A/T. The second most abundant motif type was the trinucleotide type, especially TAA, TAT and TTA. Phylogenetic analysis showed that E. annuus was closely related to the plant of E. canadensis. This study revealed the cp genomic information of E. annuus and would provide essential data for further studies on genetics, phylogeny, utilization and prevention of this species. This study revealed the chloroplast genome information and identified the phylogenetic branches of E. annuus, which would provide molecular theoretical support for further research on population genetics, phylogenetic geography, adaptive mechanism and management of E. annuus.

In this study, 29 new sugarcane lines were evaluated on adaptation by multiple statistics analysis to select new lines with excellent overall trait performance. The variation coefficients of 10 phenotypic traits ranged from 3.52% to 184.52%, the variation coefficients of smut rate was the highest. Correlation analysis showed that the cane yield was extremely significantly positively correlated with plant height and sugar yield, the smut rate was extremely negatively correlated with sucrose content and gravity purity. The results of principal compoment analysis showed that the cumulative contribution rate of 4 principal component factors was 85.019%, among which the first principal component was related to cane yield, quality and diseases, the second principal component was related to sugar yield and cane yield, the third principal component was related to quality and stalk diameter, the fourth principal component was related to fiber cane. Based on cluster analysis, the 31 new sugarcane lines were divided into 5 groups, among which group Ⅰ, including 6 lines, had the highest sucrose content; group Ⅱ, including 10 lines, had the lowest agronomic traits; group Ⅲ, including 5 lines, had the lowest smut rate and the highest cane yield and sugar yield; group Ⅳ, including 4 lines, had the highest smut rate and the lowest sucrose content; group Ⅴ, including 6 lines, had the lowest cane yield and sugar yield. Stepwise discriminant analysis gave every group probability of 100%. GNZ151505, GT17-232, GT13-1154, GT17-929, GT16-151 in group Ⅲ showed good comprehensive features. HT15-5, GT15-1074, GT15-1131, GT13-1004, GT12-284, GT17-910 in group Ⅰhad the highest sucrose content and the lower smut rate, could be used as high sugar content parents and highly resistant smut parents.

In this study, 20 phenotypic traits of 81 Capsicum annuum germplasm resources were analyzed by genetic diversity, correlation, principal component analysis and cluster analysis. The result showed that the genetic diversity index (H´) of the 20 phenotypic traits was 5.91-6.32, Shannon-Wiener diversity index of leaf shape was the highest, and one quantitative trait had the coefficient of variation (CV) of 29.28%, indicating that rich genetic diversity in the phenotypic traits of 81 C. annuum germplasms. The correlation analysis indicated that there were 65 correlation coefficients between traits reaching significant or extremely significant level, indicating that most phenotypic traits influenced and promoted each other. The results of principal component analysis showed that the cumulative contribution rate of the first four principal components was 57.526%, and represented the main information of phenotypic traits of C. annuum, indicating that the four principal components could reflect the basic characteristics of 20 phenotypic traits. Based on the eigenvalue and contribution rate, fruit shape, fruit shoulder shape, leaf shape, nodal position of first flower, spicy taste, fruit color, cotyledon color, main stem color, anther color, hypocotyl color and style color were the main factors causing phenotypic differences of C. annuum germplasms. The cluster analysis results showed that the 81 C. annuum germplasms were divided into 5 groups at a genetic distance of 16.0 which effectively distinguished the germplasm of different genetic relationships. Group Ⅰ contained 21 germplasms that were C. chinense Jacquin, which had light green cotyledon, flat lantern fruit shape and extremely spicy taste. Group Ⅱ contained 38 germplasms which were mainly based on C. annuum var. lgrossum, and the main characteristics were no stem hair, medium branching, lantern fruit shaped and no spicy taste. Group Ⅲ contained 20 germplasms that were mainly based on C. annuum var. longum, which were mainly characterized by no shoulder shape, purple hypocotyl and spicy taste. Group Ⅳ and Group Ⅴ were composed of one germplasm, indicating that the two germplasm (L206 and L508) were far related to other germplasms and could be used for parental selection in C. annuum breeding. The research would provide an important reference for the utilization, innovation of C. annuum germplasm resources and variety breeding.

It is normally difficult to distinguish germplasms of Kadsura coccinea with morphological traits before they bear fruits because the evaluations on the specificity are mainly based on fruit and economic traits. Establishing DNA fingerprinting profile is useful for rapid and accurate identification of K. Coccinea germplasms. SSR analysis for 20 clones of K. coccinea was conducted using 15 pairs of primers, the clones were clustered based on Nei's (1972) genetic distance by UPGMA clustering method, and SSR fingerprinting profile was established through combinations of some markers. 15 pairs of primers produced 75 alleles at 15 loci from 20 clones of K. coccinea, with two to 15 alleles per locus, the Shannon diversity index varied from 0.199 to 2.456, polymorphic information index from 0.095 to 0.894, and genetic similarity coefficient from 0.328 to 0.891. The 20 clones could be divided into two groups by the UPGMA clustering method. All the 15 loci could not distinguish 20 clones separately, among which KCZ023 showed the strongest ability to distinguish. Two-loci combinations of KCZ023 with KCZ135, KCZ100 or KCZ147 as well as 28 three-loci combinations could distinguish all the 20 clones separately. The 20 clones of K. coccinea show abundant genetic diversity, and can be fully distinguished by any of three two-loci combinations or 28 three-loci combinations. The findings would provide evidences for germplasm identification and hybrid parent selection.