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 order to clarify the effects of tropical organic materials on the physicochemical properties and microbial community structure of latosol, pineapple leaves, banana stems, coconut husk and organic fertilizer were selected as the test materials in this study and carried out organic materials-soil mixture incubation experiment with 90-day. After that, the effects of organic materials on soil pH, available phosphorus, aggregate, microbial community structure change and enzyme activity were compared with those of CK. The results showed that banana stems and organic fertilizer could increase soil pH value and available phosphorus content, and pineapple leaf aggravated soil acidification in the short term. Pineapple leaves and banana stems were helpful to promoting the formation of diameter > 0.25 mm aggregates. Pineapple leaves, banana stems and organic fertilizer increased the activities of soil xylanase, cellulase and leucine aminopeptidase, as well as the G⁺ strains, G^- strains, eukaryotes and fungi in soil. The average proportion of G⁺ strains in banana stems and pineapple leaves was 27.8% higher than that in CK (21.4%). Compared with CK, the proportion of fungi in banana stalk, pineapple leaf, coconut bran and organic fertilizer increased by 300.2%, 232.1%, 165.0% and 51.9%, respectively. The application of organic fertilizer significantly increased the proportion of AM fungi, while pineapple leaves and banana stems helped to increase the number of eukaryotic organisms in soil.

In order to research the biological characteristics of the pathogen and fungicide screening for Sedum morganianum of Corynespora cassiicola, the effects of temperature, pH, light condition and different carbon and nitrogen sources on mycelial growth were studied with the mycelial growth rate method, and the toxicity measurement of six fungicides to C. cassiicola was determined. The results showed that the optimum temperature for the mycelial growth of the pathogen was 30 ℃, the optimum pH for mycelial growth was 7, light was conducive to mycelial growth, the optimum carbon was glucose and nitrogen source was peptone. Toxicity measurement results showed that the six fungicides had different toxicity on the pathogen of C. cassiicola. Among them, the toxicity of mefentrifluconazole was the best, with EC₅₀ 0.0129 mg/L, followed prochloraz, with EC₅₀ 0.0135 mg/L. The toxicity of difenoconazole and fludioxonil were strong, with EC₅₀ 0.0273 mg/L and 0.0296 mg/L respectively. The toxicity of pyraclostrobin was mild, with EC₅0 0.0768 mg/L. The toxicity of carbendazim was the weakest, with EC₅₀ 0.9353 mg/L. The study could provide a theoretical basis and guidance for the cultivation of succulent plants and the comprehensive management of black rot.

Hirschmanniella spp. are migratory endoparasitic nematodes which are parasitic in the root of rice. They are widely distributed in different types of fields and have become serious parasitic nematodes to rice. The plant-parasitic nematode Hirschmanniella mucronate is one of the most serious rice nematodes in Jiangxi, China. At present, breeding and planting other disease-resistant varieties is the most economical and effective measure to control the disease. The significant up-regulated OsECH1 gene was screened by transcriptome analysis of healthy susceptible rice 'Bawangbian' root tissues and susceptible rice 'Bawangbian' root tissues infected by H. mucronata. Phylogenetic analysis of OsECH1 and its homologous proteins showed that OsECH1 and other homologous proteins had the same structure, including the same conserved domain PLN02874. And OsECH1 belonged to the ECH protein family. Besides, five homologous genes were found in the genome of 'Nipponbare' group and OsECH1 was located in Chr1. The full length of OsECH1 was cloned and the recombinant expression vector was constructed by homologous recombination technique. Meanwhile, the transgenic rice was transformed by GV1301. RT-qPCR was used to analyze the effect of OsECH1 gene expression level on the infection of H. mucronate in rice. The results showed that overexpressing OsECH1 in rice could reduce the infection of H. mucronata, while silencing OsECH1 in rice could significantly increase the infection of H. mucronata. The results of subcellular localization of OsECH1 showed that the protein was expressed in nucleus. And the results of His-tag pull down demonstrated that the protein may interacted with five defence-related proteins. The five defense-related proteins belonged to vATP-synt_E protein family, Ricin-B protein family, catalase and B_lectin protein family respectively. Meanwhile, RT-qPCR results showed that OsECH1 had regulatory effects on the five proteins. The results would provide a basis for further understanding the function of OsECH1 gene, and for understanding the molecular mechanism of OsECH1.

Identification of heterozygote is a key step in the cross breeding of Lentinula edodes. A new ISSR technique (N-ISSR) was designed in this study based on discrimination between the two nucleus of the donor strain to identify quickly and accurately the authenticity of hybrid strains of L. edodes. The new ISSR was used to identify 40 hybrid strains which were from the Di-mon mating between dikaryon wild strain YX7 and spore monokaryons of cultivated strain 808, as well as microscopy observation combined with antagonistic test (MOCAT) and the traditional ISSR technique (T-ISSR) as the control. N-ISSR results showed 27 strains were confirmed to be true heterozygote as they possessed specific DNA bands from one of the nucleus of donor strain YX7, and the other 13 strains were confirmed to not be heterozygote. Among them, 11 strains were strain YX7 itself as they possessed both specific DNA bands from the two nucleus of strain YX7, and 2 strains were spore monocaryons of strain 808 as they had no any specific DNA bands of donor strain YX7. Compared with MOCAT, N-ISSR could thorough identify all the 27 heterozygote strains, which included the 19 strains identified as heterozygote, the 6 strains unable to be identified and 2 strains incorrectly identified as non-heterozygote by MOCAT. N-ISSR could identify all the 27 heterozyote stains and 13 non-heterozyote stains with simple primer, and could classify the heterozygote strains into two groups according to the type of nucleus received from the donor. On contrast, T-ISSR needed 4 primers to identify all the 27 heterozygote strains, and was unable to con firm the other 13 stains as non-heterozygote stains, and was unable to classify the heterozygote strains into two groups. In conclusion, N-ISSR was an effective tool to be used for fast, extensive and accurate identification of heterozygote and non-heterozygote strains of L. edodes, and would be a technical support for further study on the cross breeding and genetic analysis of L. edodes.

The analysis of the genetic diversity of aromatic rice varieties and clarification of the genetic relationship of aromatic rice varieties can provide references for breeding high-quality aromatic rice varieties. 24 conventional aromatic rice varieties approved in Guangxi was used in the study. The genetic diversity of the varieties was analyzed by SSR fluorescence labeled capillary electrophoresis in this study. The results showed that a total of 170 alleles were detected by 48 SSR primers. The number of alleles (Na) varied from 1 to 9, with an average of 3.54. The range of effective allele number (Ne) ranged from 1 to 4.5534, with an average of 2.0736. The highest effective allele number was RM21, followed by RM481, RM493 and RM258. Four pairs of primers had high detection efficiency. Shannon's index (I) ranged from 0 to 1.7942 with an average of 0.7726. The variation range of polymorphic information content (PIC) ranged from 0 to 0.7541 with an average value of 0.3732, indicating that the 24 varieties had certain genetic variation. The genetic similarity coefficient of the 24 varieties ranged from 0.3299 to 0.9600, among which the genetic similarity coefficient of 'Sanxiang 628' and 'Nongxiang 32' was the lowest, indicating that the genetic basis difference of the two varieties was the greatest and the genetic relationship was the furthest. The genetic similarity coefficient of 'Wanxiang 696' and 'Guangliangxiang 2' was the greatest, indicating that the genetic basis difference of the two varieties was small and the genetic relationship was close. Cluster analysis showed that the 24 cultivars could be divided into three large groups and four subgroups at the similarity coefficient of 0.504. There were two varieties in theⅠcategory, 19 varieties in theⅡcategory and 3 varieties in theⅢcategory. CategoryⅡcould be divided into 4 subclasses at the similarity coefficient of 0.624, including 1 variety in Subclassⅰ, 14 varieties in subclass ⅱ, 3 varieties in subclass ⅲ, and 1 variety in subclass ⅳ. The results showed that there was a certain genetic diversity in the 24 varieties, but it was not rich enough. The DNA fingerprints of the 24 varieties were constructed in the form of digital coding. The results could provide references for breeding and identification of conventional aromatic rice varieties in Guangxi.

As one of the characteristic spice crops in tropical areas of China, the content of aroma components is the key index to identify the quality of Pandanus amaryllifolius Roxb. (Pa). Pa is suitable for planting under shade of Hevea brasiliensisr (Hb) forest in Hainan Island, China. However, the effect of Hb and Pa intercropping on the aroma component of the leaves of Pa has not been explored. Pot experiments were set up to compare the differences of soil physical and chemical properties and the types and content of aromatic composition in Pa leaves under intercropping and monoculture treatments. The intercropping mode significantly increased the soil bulk density by 13.63%, the content of soil alkali hydrolyzed nitrogen by 59.71%, the content of soil available phosphorus by 193.03%, the content of soil available potassium by 9.78% and the soil pH reduced by 1.00 (P<0.05). A total of 10 categories and 68 aroma components were detected in the intercropping and monocropping treatments. Compared with monocropping treatment, intercropping significantly decreased the number of ketones by 56.52%, furans by 14.29%, furanones by 33.33%, hydrocarbons by 20.00% and phenols by 28.57% (P<0.05). Although furans significantly reduced the content of aroma components by 65.28%, hydrocarbons by 20.88% and ketones by 69.00%, they significantly increased the content of alcohol by 31.50%, pyrrole by 597.56%, esters by 122.78% and furanone by 96.89% (P<0.05). The decrease of soil pH was the main reason for the reduction of ketones, furans, furanones, hydrocarbons and phenols. Intercropping indirectly increased the content of alcohols, pyrroles and esters and reduced the content of furans and hydrocarbons by reducing pH, while increasing soil available phosphorus and alkali hydrolyzable nitrogen. Pyrrole compounds were the main aroma components of Pa, thus the intercropping mode could significantly promote the quality of Pa. The results of this study would have a positive effect on the optimization and promotion of the Hb intercropping Pa mode, and also conducive to promoting the income increase of farmers and the sustainable development of related industries.

In order to promote the application of digital image processing technology in forest nutrition diagnosis and realize real-time monitoring of forest growth status and nutrient content, three prediction models of the total nitrogen content of young Aquilaria sinensis Lignum Resinatum based on image color and shape characteristics were constructed in this study, which provided a theoretical basis for nutrition diagnosis of young forest tree. Firstly, the optimal K value is determined according to the boundary distance and the size of the setting error, and the improved K-Means algorithm is used to extract the foreground image. Then, separate the three channels of R, G, and B of the foreground image and calculate the average value respectively. Then, the R, G, and B three channels of the foreground image are separated and the mean values are calculated respectively. According to the image color space conversion formula, the image is converted to HIS and Lab color space respectively, and the hue (H), saturation (S), brightness (I), brightness (L), red to green channel (a), yellow to blue channel (b), and a total of 9 color features are obtained. Find the minimum circumscribed rectangle of the foreground image, calculate the area (CA) of the foreground image, the area (RA), perimeter (RC), and rectangularity (RD) of the minimum circumscribed rectangle of the foreground image, and obtain four shape features in total. Finally, principal component analysis was performed on the color features, shape features, and color features + shape features, and the obtained three types of principal components were used as independent variables to construct a prediction model for the total nitrogen content of young A. sinensis, and the accuracy of the three models constructed was tested. Finally, the principal component analysis of color feature, shape feature, and color feature +shape feature was carried out respectively, and the three principal components obtained were used as independent variables to construct the prediction model of the total nitrogen content of young A. sinensis, and the accuracy of the three models was teste. The results show that improving the K value selection method can reduce the uncertainty of the K-Means clustering segmentation algorithm, enhance the segmentation efficiency of the algorithm, and achieve accurate segmentation of A. sinensis visible light images. The three models of the total nitrogen content of young agarwood constructed in this study had good prediction ability. The model accuracy based on single image parameters was basically the same, but the model based on shape features used fewer parameters and had higher relative modeling efficiency. The two-image parameter model uses more parameters than the single-image parameter model, but the fitting degree is better and the accuracy is higher. In practical applications, it can be selected according to different needs. In this study, different image features were used to build a total nitrogen model, which better realized the non-destructive estimation of the total nitrogen content of young trees, and provided a certain reference for precision forestry.

C2H2 zinc finger protein is one of the most common zinc finger proteins and widely found in eukaryotes. It plays an important role in plant growth and development, abiotic stress response to salt, low temperature and drought stress. In this study, the C2H2 amino acid sequence of Arabidopsis thaliana were used to blast with local BLASTP in the oil palm genome database and to predict the conservative domains, and to screen the C2H2 zinc finger protein family of oil palm. The physical and chemical properties, evolutionary relationships, chromosomal location, gene structure, conservative motif and promoter cis-elements were analyzed through bioinformatics softwares, the expression of EgC2H2 gene was analyzed by the transcriptome data and real-time fluorescence quantitative PCR under low temperature stress. A total of 73 C2H2 type zinc finger protein family members were identified from the genome of oil palm. The number of amino acids in EgC2H2 family was between 128 and 556, The molecular weight was between 14 176.73 and 58 983.30 Da, the isoelectric point was between 4.99 and 9.62, the instability index was between 38.84 and 86.01, and the gravy was between -1.154 and -0.226. Subcellular localization showed that the C2H2 gene family were localized in the nucleus. Phylogenetic tree analysis showed that EgC2H2 family members were divided into four subfamilies, most members of EgC2H2 family were classified into subfamily Ⅰ and subfamily Ⅱ, and the domains of the same subfamily members were highly consistent. Chromosome location results showed that EgC2H2 family members were unevenly distributed on the 16 chromosomes of oil palm. Analysis of promoter cis-elements showed that the EgC2H2 family contained many promoter cis-elements related to light response elements, plant hormones response elements and stress response elements. Transcriptome analysis showed that most EgC2H2 genes responded to low temperature stress, and most EgC2H2 genes were highly expressed in cold-tolerant materials and low expressed in cold-sensitive materials. qRT-PCR analysis showed that the expression level of EgC2H2-23, EgC2H2-11, EgC2H2-19, EgC2H2-17 and EgC2H2-21 was significantly up-regulated, and the expression level of cold-tolerant materials was significantly higher than that of cold-sensitive materials. It was speculated that the genes would play a key role in oil palm response to low temperature stress, and can be used as candidate genes for further study. This study would provide theoretical reference for further study on the functional analysis of C2H2 gene family in oil palm.

In this study, 27 phenotypic traits of the floral organs of 135 Phalaenopsis varieties were observed and analyzed to provide a theoretical basis for the utilization of Phalaenopsis germplasm resources and the directional breeding of new varieties. 135 Phalaenopsis germplasm resources collected and preserved in the Fuzhou Branch of the New Plant Variety Testing Center of the Ministry of Agriculture and Rural Affairs were used as the test materials to collect data on 27 phenotypic traits of Phalaenopsis orchid organs and analyze the flower phenotypic traits. The distribution frequency, coefficient of variation, Simpson index and Shannon-Wiener index, and correlation, principal component and cluster analysis of quantitative traits were studied. The majority of butterfly orchid organs were violet petals, racemes, separated petals and no fragrance, which accounted for 31.85%, 60.74%, 79.26% and 84.44% of the corresponding description distribution frequencies respectively. The Simpson index and Shannon-Wiener index of the lobes in the lip were the highest, 0.992 and 7.047, respectively, and the diversity was the most abundant. The variation coefficient of quantitative traits ranged from 19.79% to 52.72%, of which the coefficient of variation of the number of inflorescences was the largest, which was 52.72%. Most of the main quantitative traits had extremely significant positive correlations. Principal component analysis extracted 3 quantitative traits as the representative traits for evaluating Phalaenopsis phenotypic traits, and calculated comprehensive scores. The top 3 were 'JB2312', 'Wanhuayanhuo' and 'Dongfanghong' respectively. The R-type cluster analysis showed that the 16 quantitative traits of Phalaenopsis could be divided into 4 categories, and the Q-type cluster analysis showed that the 135 Phalaenopsis varieties were divided into 5 major species groups. Our research indicates that the flower phenotypes of 135 Phalaenopsis varieties have rich genetic diversity.