The leaf functional properties and eco stoichiometric characteristics of seven greening shrubs in the split green belt of University East Road in Nanning were studied to provide a theoretical basis for the selection and allocation of urban road greening plants and the construction of urban ecological engineering in similar environments. The average value of leaf area (LA), specific leaf area (SLA), dry matter content (LDMC), leaf water content (LWC) and chlorophyll content (Chl) of the seven shrubs was 15.68 cm², 136.33 cm²/g, 0.24 g/g, 76.42 % and 9.36 mg/g respectively. The average value of N, P, K, N∶P, N∶K and K∶P in the leaves was 21.23 mg/g, 0.39 mg/g, 9.37 mg/g, 55.48, 2.28 and 25.14 respectively. There were significant differences in leaf functional traits and eco stoichiometry among different shrub species. Correlation analysis showed that N, N∶P and N∶K in the leaves were significantly positively correlated with SLA and CHL, and P in the leaves was significantly positively correlated with LWC. In addition, K in the leaves was significantly positively correlated with LWC. Through redundancy analysis, it was found that the first and second ranking axes jointly explained 93.51% of the total variation of leaf eco stoichiometric characteristics. Among them, SLA, LWC and Chl were the leaf functional trait factors that have a significant impact on leaf eco stoichiometry. Principal component comprehensive analysis showed that the growth status and resource utilization efficiency of Forsythia suspensa, Hibiscus rosasinensis L. and Pittosporum pentandrum var. formosanum were better. In addition, the shrubs have better adaptability to the environment of the study area, so they are suitable to be used as important tree species for urban landscape planning.

Old trees play important roles in maintaining biodiversity, ecological balance and environmental protection. To conserve the old tree community of Taxus wallichiana var. mairei in Liancheng county, Fujian province, the species composition and structure of the community were analyzed using the method of sample survey. There were 74 vascular plants belonging to 66 genera of 41 families, in which most were monotypic genus. Rosaceae, Gramineae, Hamamelidaceae and Lauraceae were the four families with the largest number of species in this community. There were 12 genus areal-types in the community, which was consistent with the location of the community with the ratio of tropical element to temperate element (T/R) 1.03. The important values of T. wallichiana var. mairei, Phyllostachys edulis, and Cunninghamia lanceolata in arbor layer of this community were relatively high, which was 50.76%, 14.33% and 6.61%, respectively, while those of Camellia fraternal, Loropetalum chinense and Photinia davidsoniae in shrub layer were relatively high, which was 4.07%, 3.91% and 3.60%, respectively. In herb layer, Stellaria media, Dicranopteris linearis, and Miscanthus sinensis were the top three with importance values 13.30%, 10.33% and 9.82%, respectively. The vertical structure of this old tree community was clear, and it could be divided into three layers for arbor, shrub, and herb layers within few interlayer plants. T. wallichiana var. mairei was the dominated species in the uppermost layer. The old tree community of T. wallichiana var. mairei in Liancheng had important conservation value; however, young trees and seedlings of T. wallichiana var. mairei were missing in this community due to the constraints of human interference and interspecific competition. It is a feasible strategy to protect this community by constructing a fengshui forest with T. wallichiana var. mairei as the main body based on the scientific management.

Pokkah boeng disease (PBD) caused by Fusarium complex is one of the major diseases in sugarcane with great impact on the sugarcane industry worldwide. F. sacchari is the prevalent species responsible for PBD in Guangxi. Albeit of a long history of study on the disease, the mechanisms underlying the pathogenicity of the pathogen are still far from clear. To tackle this challenge, we generated an insertional mutant library by transformation of the conidial spores from F. sacchari strain FF001 via Agrobacterium tumefaciens-mediated transformation (ATMT). A total of 3018 hygromycin B-resistant transformants were obtained. Among 12 transformants randomly selected, nine out of 12 transformants carried a single copy of T-DNA, as verified by PCR and Southern blot analysis. The mutants were further screened for virulence variation on detached leaves and 30 mutants with obvious changes in virulence were obtained, including 21 mutants with significantly attenuated and 9 mutants with enhanced virulence. The sites of insertion were determined by thermal asymmetric interlaced PCR (TAIL-PCR) and sequence alignment to the genome sequence of F. sacchari. The majority of the insertions were found in coding regions or promotor regions, with a few in terminator or intergenic regions. It was observed that a few insertions were accompanied with genome fragment deletion, resulting in more than one genes being disrupted in a single insertion. Among the 22 mutated genes with annotated functions were those encoding alpha-mannosidase, neutral amino acid permease, oligomeric Golgi complex component 4, oligopeptide transporter 2, acyl-CoA dehydrogenase, acetoacetyl-CoA synthetase, carbonic anhydrase, Bud 10 protein, kinesin-related protein bimC, zinc finger protein ASD 4, transcription initiation factor TFIID, cutinase G-box binding protein, acriflavine sensitivity control protein ACR-2, nuclear VCP-like protein, heat shock protein 30, thioredoxin, type 2C protein phosphatase (PP2C), exoribonuclease, selenoprotein, DNA polymerase eta, survival factor 1, and aldehyde dehydrogenase, several of which, such as zinc finger protein ASD4 in Magnaporthe oryzae, cutinase G-box binding protein in Ustilaginoidea virens, oligopeptide transporter in Colletotrichum gloeosporioides, PP2C in Fusarium oxysporum, have been implicated as pathogenicity genes. The availability of the diversified pathogenic mutants lay a new foundation for further study on the molecular pathogenic mechanisms of F. sacchari.

In order to screen healthy and excellent introduced sugarcane germplasm, enrich sugarcane hybrid parent resources and obtain excellent sugarcane varieties with direct popularization and application value, 41 foreign sugarcane germplasm materials from France, United States, Barbados, Belize, Jamaica, Romania, Guyana and other countries introduced through Visacane, CIRAD, France, responsible for introduction, export and quarantine of sugarcane germplasm from different countries, were planted in quarantine house for two sugarcane growth cycles. During the period, the quarantine disease such as sugarcane white stripe disease, Fiji disease and gummosis disease were monitored. After qualified quarantine, the natural disease occurrence, agronomic traits, cane yield and sugar content were investigated in field experiment. The 41 introduced foreign sugarcane germplasm entries had quarantine diseases and pests. In the field natural disease test, there were nine sugarcane germplasms B03-224, B03-876, FG08-057, FG08-757, FG09-128, FG09-331, FG09-367, FG09-538 and FR89-746 with good disease resistance, which could be used as disease resistant parents. Eight high sugar germplasms with high sugar content, B03-224, BBZ88-343, BJ99-32, BR08-004, CP04-1844, CP05-1526, FG06-691 and FG09-367, were evaluated as 1 grade, which could be used as high sugar parent. Five high-yield germplasms with high yield, BZ93-855, CP00-1446, FG09-124, FG09-346 and FR90-881, were evaluated as grade 1 and could be used as high-yield parents. Eleven germplasms, B03-224, BBZ93-855, BJ99-106, CP00-1446, CP05-1526, FG04-333, FG06-691, FG07-338, FG09-124, FG09-128 and FG09-367, with high-yield and excellent agronomic characters, entered the next round of comparative test to continue screening. In order to select sugarcane germplasms with high yield, high sugar and disease resistance that can adapt to the ecological environment of Guangxi for direct planting, four with excellent comprehensive performance, B03-224, FG09-128, FG09-367 and CP05-1526, were selected for the further variety comparison test. All sugarcane germplasms were kept in Nanning Sugarcane Germplasm Resources Nursery and Sanya Sugarcane Cross Breeding Base of Guangxi Academy of Agricultural Sciences for further evaluation of drought resistance, cold resistance, and subsequent cross utilization. This study could provide reference for the utilization of sugarcane germplasms introduced from abroad.

Single nucleotide polymorphism (SNP) is widely distributed in plant genomes, which is one of the most abundant form of DNA variation. The molecular markers based on single nucleotide polymorphism are considered to be of great application prospect. Penta-primer amplification re-fractory mutation system (PARMS) is a kind of new genotyping system based on single nucleotide polymorphism (SNP) which has the advantages of high throughput, high accuracy, low cost and short time consuming. The establishment of the PARMS system of pineapple is significant in germplasm identification, gene mapping and marker-assisted selection of pineapple. In this study, three germplasms of significant difference in phenotypes were used as the materials. A specific primer SNP31 was designed based on the resequencing data of 130 germplasm resources. The result revealed SNP31 could effectively group the pineapple germplasm resources, and be used for the subsequent optimization of the system. Reaction volume,primer concentration, method of DNA extracting and template DNA amount were optimized. The results showed that reaction volume, primer concentration and template DNA amount could affect the fluorescence signal value of the genotype signal point. The fluorescence signal value of genotypic signal point decreased when the reaction volume was larger or smaller. The optimal reaction volume was 6 μL. When the concentration of primer and template DNA increased, the fluorescence signal value of genotype signal point increased. The optimal concentration of primer and template DNA was 100 μmol/L and 25 ng/μL, respectively. In addition, different methods of genomic DNA extraction could group well the PARMS-SNP for the three germplasms of pineapple. The optimal PARMS reaction system was as follows:total volume 6 μL, containing 1 μL template DNA (25 ng), 3 μL PARMS mix (2×), 0.45 μL primer mix (100 μmol/L) and 1.55 μL ddH₂O. With the optimal PARMS reaction system, high quality results of PARMS-SNP genotyping was produced on sixty-five pineapple germplasm resources, which indicated that the reaction system was accurate and stable. The establishment of the optimized PARMS genotyping system could provide a basis for the genetic diversity analysis, genetic linkage map construction, gene mapping and marker-assisted selection of pineapple in this study.

Codon bias is an important factor affecting gene expression, and it is also one of the key clues to reflect gene evolution. Orchidaceae plants are the "flagship" group in plant protection, and most species have medicinal and ornamental values, but seeds are not easy to germinate. ABI3 (abscisic acid insensitive 3) gene is the central regulator of ABA signal transduction, involved in seed development and dormancy processes, and is the key factor to regulate plant seed germination. Therefore, in-depth study of codon bias of orchid ABI3 gene can lay a foundation for analyzing the function of the gene and optimizing the codon composition. Using Arabidopsis thaliana ABI3 gene as a probe, 45 Orchidaceae ABI3 genes were screened from the public database (NCBI), and the codon use patterns and preferences were analyzed by bioinformatics programs such as CodonW, SPSS and MEGA. The ENC (effective number of codon) value of the genes ranged from 40.84 to 58.46, of which 82.2% was greater than 52. The average value of CAI (codon adaptation index) was 0.203, far less than 1, indicating that the codon usage bias of ABI3 gene was relatively weak. Neutral plot analysis showed that the slope of the regression curve between GC₁₂ and GC₃ was 0.6103, R²=0.7928 (P<0.05), indicating that the base composition has an important influence on codon bias. In ENC plot analysis, the ENC value of all genes was lower than the expected value, but the difference was small, indicating that the codon of orchid ABI3 gene is mainly affected by base mutation and other factors such as selection pressure. Parity preference analysis showed that most genes were distributed in the right region of the plan, and the use frequency of A/T (U) at codon 3 was higher than that of G/C. Through RSCU and ΔRSCU analysis, 26 optimal codons were identified, including 14 codons ending in A/T (U) and 10 codons ending in T (U), indicating that ABI3 gene of orchid plants relatively prefers to use codons ending in A/T (U), especially codons ending in T (U), which is different from that of most monocotyledonous plants. This study may provide a theoretical basis for the phylogenetic and functional elucidation of ABI3 genes in Orchidaceae and for improving ABI3 gene expression efficiency, as well as facilitating codon biology in plants and the improvement of exogenous genes.

Tribe Vandeae belongs to Orchidaceae and is distributed at low altitudes in southern and southeastern Tibet. Due to the limited transportation conditions in the past, understanding of tribe Vandeae species in Tibet was poor. We reporte a less known species of orchids from China: Papilionanthe uniflora (Lindl.) Garay. It was originally only recorded in the Flora of Tibet, but was not included in the Flora of China due to the lack of important features such as flowers. This article provides detailed information about the anatomy of this species for future supplement and revision. The following 12 new recorded species are reported in Tibet: Aerides rosea Lodd. ex Lindl. & Paxton, Cleisostoma aspersum (Rchb. f.) Garay, Cleisostoma linearilobatum (Seidenf. & Smitin.) Garay, Cleisostoma racemiferum (Lindl.) Garay, Cleisostoma simondii (Gagnep.) Seidenf., Gastrochilus affinis (King & Pantl.) Schltr., Gastrochilus prionophyllus H. Jiang, D. P. Ye & Q. Liu, Gastrochilus pseudodistichus (King et Pantl.) Schltr., Phalaenopsis lobbii (Rchb. f.) H. R. Sweet, Taeniophyllum glandulosum Blume, Uncifera obtusifolia Lindl. and Vanda concolor Blume, Uncifera Lindl. is a new recorded genus in Tibet. We providedetailed descriptions of morphological identification and pictures. Mos Vandeae species have important ornamental value, such as Phalaenopsis and Vanda. The findings not only expand orchid resources in Tibet, but also provide basic information for the utilization of ornamental orchids in Tibet.

Macadamia nuts contain abundant source of unsaturated fat acid (UFA), but the molecular mechanism of biosynthesis of UFA remains to be further analyzed. Stearoyl acyl-carrier- protein desaturase catalyses the insertion of a double bond into saturated fatty acid bound in saturated acyl chains bound to ACP in higher plant, which is the key enzyme in unsaturated fatty acid biological synthesis pathway. The Macadamia intergrifolia plant as research object, the full-length gDNA and cDNA of SAD gene encoding stearoyl acyl-carrier- protein desaturase were isolated from M. integrifolia using PCR technique. The structure, function and expression pattern of MiSAD were preliminarily studied. The gDNA of SAD was 6947 bp and contained 3 exons and 2 introns. The open reading frame was 1191 bp and encoded 396 amino acids which was highly consistent with the public MtSAD sequence, and SAD was a water soluble enzyme with a total predicted molecular mass of 45.22 kDa and isoelectric point (pI) 5.93 located in chloroplast or plasmids stroma. The amino acid sequences of SAD involved in active site showed highly conserved and significant difference in N-end and C-end. The highly conserved region contained 2 central motifs of E-X-X-H iron atoms which formed the active site of this enzyme. The α-helix and random curl were predominate in the secondary structure. The helix-turning-helix was found in the prediction of tertiary structure for formation of fatty acyl chain binding site. Derived amino acid sequence showed the highest homology 94.2% with Telopea speciosissima, and the homology is above 80%in other species of SAD, close to Nelumbo nucifera in phylogentic tree. The SAD gene expression trends were basically identical by qRT-PCR. The SAD expression were found in root, stem, leaf, flower and macadamia nut, and the highest level was in nut. The expression of SAD gene increased about 90days after and reached the highest level at 100 days, then declined gradually in the following days during the macadamia nut maturation and presenting a normal distribution trend. This study would build a foundation for elucidating the molecular mechanism of MiSAD in biosynthesis of unsaturated fatty acid in macadamia.

The invasive plant Mexican sunflower has strong allelopathy to weeds and could be used for weed control. However, the allelopathy of Mexican sunflower on Leptochloa chinensis has not been reported. In order to clarify the allelopathy of Mexican sunflower on L. chinensis and find the control technology of L. chinensis, the roots, stems and leaves of L. chinensis were extracted with petroleum ether, ethyl acetate, absolute ethyl alcohol and distilled water. The allelopathy of extracts on the germination and growth of seeds of Mexican sunflower and its effect on the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were evaluated. GC-MS was used to identify the chemical constituents in the extract of Mexican sunflower. The results showed that the effect of extracts from different tissue parts on the germination rate of Mexican sunflower was in the order of leaf > stem > root. Ethyl acetate and absolute ethanol extracts from the roots, stems and leaves of Mexican sunflower had a significant inhibitory effect on the growth of the seedlings. The ethyl acetate extract from the root, stem and leaf, and the absolute ethanol extract from the leaf and root could significantly inhibit the SOD activity; the absolute ethanol extract from the stem could obviously inhibit the CAT activity; the ethyl acetate extracts from stems and roots could significantly inhibit the POD activity. GC-MS detection showed that the extract of Mexican sunflower contained terpenoids, phenols, amides, esters and hydrocarbons, among which terpenoids (α-pinene and phytol) and phenols (2,5-diacetyl-6-hy droxybenzofuran) were higher. The results showed that the extracts from the roots, stems and leaves of Mexican sunflower had strong allelopathic effects on L. chinensis, α-pinene, phytol and 2,5-diacetyl-6-hydroxybenzofuran may be the potential active components of Mexican sunflower for allelopathy, which can be used for the control of L. chinensis.

Dendrobium is a class of ornamental plants native to tropical regions, suitable for cultivation in high temperature and high humidity environment, and susceptible to low temperature stress. To investigate the physiological response and cold tolerance of Dendrobium to low temperature stress, Dendrobium 'Sonia Hiasakul' mature (SH) were treated in temperature 15 ℃, 10 ℃ and 5 ℃ for 1 h, 2 h, 4 h, 8 h, and the physiological indexes and morphological changes of SH were surveyed 1 d, 2 d, 4 d, 8 d and 16 d after. The changes of physiological indexes included soluble protein, soluble sugar, free proline, malondialdehyde (MDA), chlorophyll content, electrical conductivity and the defoliation rate of the treated plants. Based on the relative conductivity of different temperature treatments, a Logistic equation was fitted to calculate the half-lethal temperature (LT₅₀) of SH, and a correlation analysis between the half-lethal temperature at low temperature (LT₅₀) and the physiological indexes of cold resistance was conducted, with the aim to investigate the morphological and physiological response characteristics of SH under different low temperature environment and to understand the pattern of its growth and development. The electrical conductivity, free proline, malondialdehyde (MDA) content and the defoliation rate of SH increased significantly with the extension of the stress time and the soluble protein and soluble sugar content fluctuated continuously, in a state of rising, falling, then rising again. The chlorophyll content decreased gradually, reaching the lowest 0.2534 mg/g treated at 5 ℃ for 16 d. Correlation analysis revealed that the free proline, malondialdehyde (MDA), defoliation rate and semi-lethal temperature were all highly significantly correlated and chlorophyll content and semi-lethal temperature were significantly correlated, and it was speculated that the content of the physiological indicators was related to the cold resistance characteristics of SH. The study would provide a theoretical basis for determining the cold tolerance identification index and dealing with cold damage in SH, and lay a foundation for further research on the resistance of Dendrobium hybrids to low temperature damage.