Abstract:To understand the function of phosphoenolpyruvate carboxylase (PEPC) in peanut, PEPC sequences of the diploid progenitor Arachis duranensis genome database were analyzed. Nine gene family members were found, and their sequence lengths ranged from 3 584 to 12 956 bp with 702-3 168 bp open reading frame (ORF), distributed in the 3, 5, 7, 8, 9, and 10th chromosomes. In the amino acid sequences of AdPEPC proteins, there were conserved domains, such as HCO₃^- binding sites and PEP binding sites, et al. According to the sequence characteristics, AdPEPC proteins could be divided into 3 groups as plant type, bacterium type and short sequence type. Protein homologies of the same type were high, and the number of intron and exon in gene structures was similar. Gene expression analysis showed that the expressions of most members were high in flowers or stems. AdPEPC1;2 and AdPEPC4;2 had the highest expression in stem. Other family members, especially AdPEPC2, AdPEPC1;5 and AdPEPC1;3, expressions were significantly higher in flower than other tissues. AdPEPC1;5 expression was not detected in leaf. No expression of AdPEPC3 was detected in root, stem, leaf and flower, and it was presumed to be pseudogenes based on its gene structure. These would lay a foundation for further study on the functions of AdPEPC family genes.

Abstract:In order to precise identification Eucalyptus germplasms, twenty-eight germplasms of Eucalyptus were classified by using 4 SSR loci with complete conservation sequence. According to the multiplicity of microsatellite and the specific bases in associated flanking region (FR) sequences, the identification barcodes among the 28 species of Eucalyptus were constructed, and 9 species of Eucalyptus were precisely identified. Therefore, these would provide the biological basis for hybrid breeding of Eucalyptus.

Abstract:Gynura bicolor is rich in anthocyanidin. In order to identify the transcription factors involved in anthocynidin biosynthesis pathway in G. bicolor, the transcriptome of this plant was sequenced by Illumina HiSeq 2500 platform. By searching of 3 databases, including Pfam, SwissProt and Nr, 138 MBW-related unigenes were obtained, which containing 42 MYBs, 67 bHLHs, 15 bHLH-MYBs and 14 WD40s. Among these MBWs, 11 MYBs, 33 bHLHs, 6 bHLH-MYBs and 3 WD40s involved in anthocynidin biosynthesis pathway were annotated in other plant species, including Vitis vinifera, Dahlia pinnata, Gerbera, Catharanthus roseus, Prunus persica etc. The obtaining of the 138 unigenes related to MBWs from Gynura bicolor provides a good basis for further research in gene cloning and the regulation of anthocyanin synthesis.

Abstract:In order to evaluate the effects of critical environmental factors on growth of Cylindrospermopsis raciborskii, the growth of two strains isolated from Zhenhai Reservoir in Guangdong Province was studied under combining temperature from 12℃ to 32℃ and irradiance (from 30 to 120 µmol m^-2s^-1) and three nitrogen sources (nitrate-N, ammonium-N and urea-N). The result showed that the growth of N1 and N8 strains of C. raciborskii increased with temperature under three light conditions and their growth rate was the biggest at 28℃ with high irradiance. Cylindrospermopsis raciborskii N1 strain was not able to grow at both 12℃ and 16℃, while N8 strain only could not be at 12℃. These suggested that the strain N8 had higher tolerance to low temperature than N1. The strains N1 and N8 grew well under nitrate-N (2-247 mg L^-1), but only at a low level of ammonium-N and urea-N. Moreover, the growth of both strains completely inhibited under high ammonium-N and urea-N (128-247 mg L^-1). The specific growth rates of N1 strain under three nitrogen sources were always higher than those of N8 strain, which indicated that the capability for strain N1 to utilize nitrogen was stronger than strain N8. In conclusion, Cylindrospermopsis raciborskii isolated from Guangdong Province has high strain diversity and adapt to high temperatures and a wide range of light intensities, and is able to use multisource of nitrogen. This may be the reason for frequent occurrence of C. raciborskii in the studied region.

Abstract:In order to reveal the light response mechanism of Davallia mariesii, the growth, photosynthetic characters and chlorophyll fluorescence parameters were measured under five shading treatments, including 0, 25%, 50%, 70% and 90% shading. The results showed that the leaf type became large and leaf color deepened with the increment of shading. Under 70% shading, the growth vigor of D. mariesii was good with hard glossy leaves, low sporulation rate, and spore maturation delay. The contents of chlorophyll a, chlorophyll b and Chlorophyll a+b increased with increment of shading, but decreased under 90% shading, the chlorophyll a/b, the changes in light saturation point, light compensation point and dark respiration rate were opposite, there was significant difference in light saturation point between deep shading and nature light. Among five shading levels, the chlorophyll fluorescence parameters, such as Fm, φ_Po, ψ_O, φ_Eo, TR_O/RC, ABS/RC, and ET_O/RC, reached up to the maximum under 70% shading. Therefore, D. mariesii had the smallest light inhibition, the largest light energy utilization, and the strongest photosynthetic capacity under 70% shading, so that it was helpful for the growth of D. mariesii.

Abstract:In order to understand the effect of light intensity on seedling growth of Dracaena cambodian, the changes in morphological, physiological and biomass allocation characteristics were studied under four kinds of light intensity, including 100%, 37.3%, 15.5%, and 4.2% nature sunlight. The results showed that there were significant differences in morphological, physiological and biomass allocation indexes among different light intensities. The PI (plasticity indices) of all indexes ranged from 0.08 to 0.86, in which PI of biomass was generally higher (0.67-0.86) than that of the others, indicating that the seedlings had better adaptability to illumination conditions by adjusting the allocation of biomass. With the decrease of light intensity, the specific leaf area (SLA) and leaf area to root mass ratio (LARM) significantly increased, which indicated that the seedling could increase the leaf area and the area of photosynthesis to effectively adjust biomass allocation. In conclusion, the seedling growth of D. cambodiana would be the best under 37.3% NS (L2). Because the existing habitat of D. cambodiana was damaged, and the seedlings lacked shading, it was unfavorable to the growth of seedling root system during the dry season. So, this may be one of important reasons for the failure of the natural regeneration of D. cambodiana.

Abstract:In order to understand the biodiversity characteristics of shrub communities in the middle of Guangxi, the species composition, floral, life-form and species biodiversity of seven typical shrub communities were investigated and analyzed. The results showed that there were 85 shrubs belonging to 37 families and 68 genera, and 74 herbs belonging to 35 families and 61 genera in the seven shrub communities. The shrub species were dominant by Euphorbiaceae and Leguminosae, which contained 10 and 9 species, accounting for 11.76% and 10.59% of the total shrub species, respectively. The herb species were dominant by Gramineae and Asteraceae, which contained 13 and 11 species, accounting for 17.57% and 14.87% of the total herb species, respectively. Among the seven shrub communities, Bauhinia championii community had the highest species richness, Shannon-Weiner, Simpson and Pielou indexes, followed by Mimosa sepiaria, Pterolobium punctatum, Rhodomyrtus tomentosa communities. The areal-type was dominant by Pantropical element accounting for 43.94%, and the phanerophytes was dominant in the life form accounting for 37.50%. Therefore, it was suggested that the tropical floral and life-form of shrub communities in middle Guangxi was stronger than temperate, and closed to the vegetation in southern subtropics.

Abstract:In order to selection of excellent provenance of Excentrodendron hsienmu, the monthly changes in photosynthetic and growth characteristic were studied by using a completely random zone experiment design. The results showed that the photosynthetic and growth characteristics of E. hsienmu had significantly differences among different months and different provenances. The net photosynthetic rate, stomata conductance, transpiration rate and water use efficiency (WUE) changed with the month, indicated the adaptability to climate changes. The net photosynthetic rate, stomata conductance and transpiration rate of different provenances were the highest in August, but low in April and December. However, the WUE were the lowest in August, and high in April and December. The seedling height had significant positive correlation with ground diameter and net photosynthetic rate and seedling height, as well as the net photosynthetic rate and ground diameter. The net photosynthetic rate could be used as indicative monitoring indicators in the growth process of E. hsienmu. The provenances of Daxin, Wuming and Long'an had high net photosynthetic rate and growth increment and low transpiration rate during whole growing season. Therefore, the three provenances of Daxin, Wuming and Long'an were more suitable to introduction planting in Nanning area.

Abstract:The flowering habit of Pleioblastus yixingensis was observed at first, and the inflorescence morphological structure was described. Genus Pleioblastus has 3 stamens according to the Flora Reipublicae Popularis Sinicae, but the number of stamens with 3, 4, 5 or 6 were observed during field investigation, of which 3 was the majority. These enriched the data of Pleioblastus. The boron was not necessary element during pollen germination. The pollen was stained aborted with germination rate only 5.11%, which was an important reason of low setting of P. yixingensis. Pleioblastus yixingensis in Henan, Jiangsu, Zhejiang, Anhui was synchronized flowering in 2017 with fruiting rate less than 10%.

Abstract:In order to understand the chemical constituents of Osmanthus fragrans leaves, thirteen compounds were isolated from the 95% ethanol extract. On the basis of spectral data, their structures were identified as aromadendrin (1), genistein (2), lupinalbin A (3), methy oleanolate (4), 3-ketooleanolic acid (5), fouquierol (6), 19α-hydroxyl acetylursolic acid (7), betulin (8), stigmasta-3,5-dien-7-one (9), ciwujiatone (10), p-hydroxyaceto-phenone (11), entkaurane-3,16α-diol (12), and trigoflavidone A (13). All of compounds are isolated from the leaves of O. fragrans for the first time. The compounds 2, 3, 10 showed significant antitumor activities, and their activity determination to 4 kinds of tumor cells was reported for the first time.

Abstract:To clarify the chemical constituents in the aerial parts of Isodon serra (Maxim.) Kudo, nine compounds were isolated from the ethanol extract. Basis on the spectral data, their structures were identified as methyl rosmarinate (1), 3,3'-bis(3,4-dihydro-4-hydroxy-6,8-dimethoxy-2H-1-benzopyran) (2), 7-megastigmene-3,5,6,9-tetrol (3), 7-megastigmene-3,5,6,9-tetrol 9-O-β-d-glucopyranoside (4), 5,6-epoxy-7-megastigmene-3,9-diol (5), (−)-loliolide (6), 3-formylindole (7), ethyl α-l-arabinofuranoside (8), and ethyl β-d-xylopyranoside (9). Compounds 1 and 2 belong to phenylpropanoids, 3-6 are megastigmanes, 7 is an alkaloid, 8 and 9 are alkyl glycosides. Compounds 2-9 were reported from this species for the first time.

Abstract:In order to search the chemical constituents of Artabotrys hexapetalus, twelve alkaloid compounds were isolated from the stems of A. hexapetalus. On the basis of spectal data, they were identified as stepholidine (1), tetrahydrocolumbamine (2), tetrahydrojatrorrhizine (3), pronuciferine (4), glaziovina (5), sinoacutine (6), pallidine (7), stepharine (8), artacinatine (9), lanuginolide (10), isoscoulerine (11) and N-methylasimilobine (12). The alkaloids 1-7 were isolated from the genus Artabotrys for the first time. Compound 10 showed potent antibacterial effects on Staphylococcus albus and Bacillus cereus, with MIC of 20 and 10 μg mL^-1, respectively.

Abstract:In order to understand the bioactivity constituents from Aristolochia tuberosa O. F. Liang et S. M. Huang, four compounds were isolated from methanol extract of A. tuberosa fruits by using silica gel column chromatography, Sephadex LH-20 gel column chromatography, precipitation and recrystallization methods. On the basis of spectral data, their structures were identified as aristololactam W (1), 8-epidiosbulbin e acetate (2), diosbulbin B (3) and β-sitosterol (4). Furthermore, nematicidal activity of four compounds against the second stage juvenile (J2) of Meloidogyne javanica were analyzed. The compounds 1-3 exhibited obviously toxic effects on J2 of M. javanica in vitro, especially for aristololactam W with the LC₅₀ values of 119.94 μg mL^-1 after 96 h. So, Aristolochia species have the potential value of developing new plant source to control root nematodes.

Abstract:To understand the chemical constituents from Dasymaschalon rostratum, eight compounds were obtained from its roots by multiple chromatographic separation techniques. On the basis of spectral data, their structures were identified as (+)-taxifolin (1), catechin (2), calycosin (3), (-)-syringaresinol (4), (-)-medioresinol (5), lirioresinol A (6), N-trans-cinnamoyltyramine (7), and hydroxytyrosol (8). All of the compounds were isolated from this plant for the first time. Compounds 1-8 showed no obvious antibacterial activites.

Abstract:In order to protect Carpinus insularis, an endemic species to Hong Kong, the community characteristics of C. insularis were investigated by using typical plot method. The results showed that there were sixty-eight species vascular plants, belonging to 66 genera, 37 families within a quadrat of 225 m². Carpinus insularis is the constructive species with the maximum height to 3 m, but its average height in this community is 0.92 m. The C. insularis community in Hong Kong Island showed recession with very few young individuals. Therefore, it was suggested that the managements of in situ and ex-situ conservation would help to re-establish populations.

Abstract:Thrixspermum longipedicellatum (Orchidaceae) is reported as a new record from China. The detailed morphological descriptions and photos are also provided. It could be identified from other related species in the genus by having iridiform leaves, lateral inflorescence, and a lip sac at base, with the midlobe cordiform and a long column foot.