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.

The supply and demand of feed resources in China appear the phenomenon of lack of concentrate feed, protein feed, green feed and insufficient total resources, especially the serious shortage of protein feed. Cnidoscolus aconitifolius and hybrid Broussonetia papyrifera, as two new and high quality woody protein feed resources, have high potential for feed production. In this study, C. aconitifolius and hybrid B. papyrifera were taken as the experimental objects to determine the conventional nutrutional components, mineral elements and amino acid components. The comparison results were performed by t test and the feeding values of the two woody fodder plants were evaluated combined with relative feed value (RFV). The results of analysis showed that the crude protein (CP) content of C. aconitifolius and hybrid B. papyrifera was more than 20%, the crude fiber (CF) content was less than 15%, the mineral element content such as Ca, P, K, Mg, Fe and Zn was high. Among them, the Ca/P ratio of C. aconitifolius was 1.82∶1, which met the requirement of Ca/P ratio in general feed, while the Ca/P ratio of hybrid B. papyrifera was 8∶1, which was far greater than that in general feed. The essential amino acids (EAA)/non-essential amino acids (NEAA) and essential amino acids (EAA)/total amino acids (TAA) in both C. aconitifolius and hybrid B. papyrifera was above 60% and 40%, respectively. The variety of limiting amino acid (LAA) and sulfur-containing amino acids was comprehensive and rich in content. The evaluation results of C. aconitifolius and hybrid B. papyrifera combined with the relative feed value (RFV) showed that C. aconitifolius was super grade forage material and hybrid B. papyrifera was senior grade forage material, both had good overall effect and high feeding value. The results of comparative analysis on nutritional value of C. aconitifolius and hybrid B. papyrifera showed that both belonged to high-quality woody feed raw materials rich in protein, minerals and amino acids, had high feeding value and development potential in livestock diets. In particular, C. aconitifolius had higher CP content, lower CF content, lower NDF content and more reasonable proportion of calcium-phosphorus ratio, which had better feeding value compared with hybrid B. papyrifera.

In order to improve the technological process of industrial tissue culture speed propagation of Curcuma alismatifolia 'Majeo Impress Red', and provide a reference for the large-scale production, we used different organs as the explants to study the bud multiplication, proliferation, rooting culture and transplanting. Six different explants including corm, storage root, corm shoot, lateral bud, flower bud and tender leaves were employed in this study. Based on the MS medium with different concentration of 6-BA and NAA, the process of tissue culture speed propagation was optimized. The best explants were corm shoot and lateral bud. The best medium for induction culture was MS + 6-BA 3 mg/L +NAA 0.1 mg/L + sucrose 30 g/L + carrageenans 7 g/L. The best medium for proliferation was MS + 6-BA 3 mg/L +NAA 0.1 mg/L + sucrose 30 g/L + carrageenans 7 g/L. The best medium for rooting was 1/2 MS + NAA 0.1 mg/L +sucrose 20 g/L + carrageenans 7 g/L. When the seedlings were pluged in tray and transplanted in flowerpot, the optimum medium was tiny peat∶tiny coco coir = 1∶1 and the survival rate was over 95%. Eight EST-SSR markers were employed to amplified the maternal parent and 20 randomly selected tissue culture seedlings, which supported the obsence of DNA-level variations. We screened the most appropriate explants and culture medium for C. alismatifolia 'Majeo Impress Red', optimized the technological process and set up a technical system of industrial tissue culture speed propagation.

Exocarpium Citrus Grandis (ECG) is a medicinal plant of Citrus in Rutaceae. It is a medicine that has great effects. To distinguish the 'Zhengmao' and 'Non-zhengmao' germlplasms, 13ECG germplasms were selected, including 'Zhengmao' germplasms ('Dahe huangrong', 'Dahe miye', 'Pingding huangrong', 'Pingding miye', 'Pingding hongrou', 'Shanche zhengmao' and 'Shiwan zhengmao') and 'Non Zhengmao' germplasms ('Shanche fengwei', 'Shanche fumao', 'Shanche jiaxiyang', 'Shanche guangqing', 'Pingding jinqiandu', 'Pingding shishengli'). The botanical morphological traits were measured, active substances were analyzed, and molecular markers were carried by the ISSR and SRAP for distinguishing analysis. There were significant differences in length of leaf, leaf shape index, L^*, a^* and b^*. The leaves of 'Zhengmao' germplasms were slenderer than those of 'Non-zhengmao', the whole leaf was whiter, greener and yellower. There were significant differences in fruit shape and the fruit shape index between 'Zhengmao' germplasms and 'Non-Zhengmao' germplasms. The content of rhubarb glycoside in most 'Zhengmao' germplasms was higher than that of 'Non-zhengmao' samples, except the 'Shanche fumao'. The content of alcohol soluble extract was also significantly different between the germplasms. The clustering results of ISSR and SRAP showed that when the genetic distance of the two molecular markers was 15 cM, the 13 germplasms could be divided into one 'Zhengmao' and three 'Non Zhengmao' groups. The correlation analysis between germplasm botany and medicinal components showed that, when P<0.05, only the fruit shape and fruit shape index were significantly correlated with the content of wild rhubarb glycoside and naringin, the water-soluble extract was significantly positively correlated with L^*. To conclude, when combined with the three identification results, the molecular marker is the most reliable to distinguish the germplasm of ECG, the plant morphology (petal length, fruit shape and fruit shape index) or medicinal components (content of wild rhubarb glycoside and alcohol extract) can also distinguish these germplasm to a certain extent.

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.

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.

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.

In order to assess the breeding value of HoCP series sugarcane germplasms introduced from USA, 12 HoCP sugarcane clones (HoCP00-1142, HoCP01-517, HoCP01-564, HoCP02-610, HoCP02-623, HoCP03-704, HoCP03-708, HoCP03-716, HoCP05-902, HoCP07-613, HoCP07-617 and HoCP92-648) were used as core parents in 73 sugarcane cross combinations. The effect on combining ability, economic breeding values of height, diameter, effective stem number, sugar content and cane yield for the 11 HoCP sugarcane parents and 73 F₁ population were estimated using the family test method. Significant differences were found for height among HoCP males and cross combinations, whereas no significant differences were detected for height among HoCP females, suggesting that the plant height was affected by only male and cross combination. For the stem diameter, effective stem number, sugar content and cane yield, there were significant differences existed among different HoCP female, male and cross combination, indicating that the four characters were affected by female, male and cross combination. Among the 12 clones, the highest general combining ability for height, diameter, effective stem number, sugar content and cane yield appeared in HoCP03-704, HoCP02-623, HoCP02-610, HoCP07-617, and HoCP92-648 as female, respectively, while HoCP03-704, HoCP02-623, HoCP07-617, HoCP03-708 and HoCP02-623 as male possessed the highest general combining ability for height, diameter, effective stem number, sugar content and cane yield, respectively. The better economy breeding value (EBV) and general combining ability (GCA) in cane yield and sugar content were detected in HoCP02-623, HoCP03-708 and HoCP92-648 as the female, and HoCP01-517and HoCP07-617 as the male, which indicated that the clones could be used as excellent female and male with high-yield and hight-sugar, respectively. Among the 73 cross combinations, the highest special combining ability for height, diameter, effective stem number, sugar content and cane yield appeared in HoCP03-704×'Neijiang 03-218', 'Yuetang 00-236'×HoCP00-1142, 'Yacheng 07-71'×HoCP05-902, 'Yuetang 00-236'×HoCP03-708, HoCP01-564×'Guitang 92-66', respectively. A total of 38 cross combinations showed possitive EBV. The combinations 'Yuetang 94-128'×HoCP01-517, HoCP01-564×'Guitang 92-66', 'Guitang 02-467'×HoCP01-564 had better special combining ability in cane yield, sugar content and EBV than the others, which could be considered as the most important productive families in future breeding program. However, HoCP03-716×'Funong 02-6404', 'Yuetang 99-66'×HoCP01-564 and 'Yuenong 73-204'×HoCP01-564 showed lower special combining ability in five characters and lower EBV than other combinations, suggesting that the combinations did not suit for using as productive families in future breeding program. Therefore, the results would provide helpful information for using HoCP sugarcane parents in cross combination.

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.

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.