Abstract:The aim was to understand the leaf function of ferns grown under different habitats. The leaf characters of six ferns, such as specific leaf area, gas exchange rates, leaf nutrients, construction cost, and carbon isotope ratio, in monsoon evergreen broad-leaved forest in Dinghushan Mountain were measured, and their adaption to environment were studied. The results showed that two epiphytic ferns (Microsorum fortune and Pseudodrynaria coronans) had low specific leaf area (SLA) and photosynthetic rates (A_area), but high leaf construction cost (CC_area) and carbon isotope ratio (δ¹³C). In contrast, two terrestrial ferns (Adiantum flabellulatum and Alsophila spinulosa) showed high A_area and relative low δ¹³C. Hicriopteris chinensis growing on bared rocks at forest edge had the lowest leaf phosphorus contents, and the highest photosynthetic phosphorus use efficiency among the six fern species, while Selaginella delicatula growing in streamside had the highest SLA, and the lowest CC_area and δ¹³C. Therefore, it was suggested that there were close relationship between leaf traits of ferns and environment. In addition, because of high energy investment and low photosynthetic rate, epiphytic ferns have low adaption ability to environment, their survive might be under great pressure.

Abstract:Triadica rotundifolia is a common species of secondary forest in limestone region. In order to understand the dynamic changes of T. rotundifolia community in limestone region, the species diversity and population structure of T. rotundifolia community in Qingxin and Yangshan Counties, Guangdong Province, were studied by plot method. The results showed that there were 140 vascular plants in two plots with a total area of 4800 m², belonging to 65 families and 118 genera. The dominant families were Euphorbiaceae, Rubiaceae, Rutaceae, Moraceae and Oleaceae. Among them, the tropical distribution elements at genus level were dominate accounting for 79.6%, and then 18.3% for temperate distribution elements. The species richness, species diversity and evenness of T. rotundifolia community in Qingxin were higher than those in Yangshan, except for evenness of herbal layer. T. rotundifolia population in Qingxin is unstable owing to lack seedlings and small individuals, while T. rotundifolia population in Yangshan is young comparatively with abundant small trees. With succession of the community, the dominance of T. rotundifolia in community would be replaced by other shade-tolerant species.

Abstract:In order to understand facility effects on field control experiments for ecological studies, based on introduction of a relatively large field controlled precipitation pattern change experiment for forest ecosystem, the facility effects on soil chemical properties and net nitrogen transformation rates were analyzed. The results showed that soil organic carbon (SOC), total nitrogen (TN), nitrate nitrogen, ammonium nitrogen, microbial biomass carbon (MBC), net N mineralization rate (NMR) and net N nitrification rate (NNR) all varied spatially in a 0.7 hm² sampling area from May to September, 2012. The facility effects on SOC, TN, nitrate-N, ammonium-N, MBC, and NMR were not statistically significant. In contrast, the facility effects on NNR were statistically significant (P<0.05) after the installation of experimental facilities. But such facility effects on NNR became insignificant statistically after restoration for three months, although some differences still existed among treatment types. These implicate that facility effects and slope position influences need be paid attention while analyzing the precipitation change effects on NNR in experiment.

Abstract:In order to understand the changes in soil respiration of sloping-land with purple soils in Hengyang, the soil basal respiration (SBR), metabolic quotient (qCO₂) were studied by using the space series to replace time series, and the relationships between SBR, qCO₂ and soil properties were analyzed. The results showed that SBR and qCO₂ had significant difference at different re-vegetation stages. From bare land stage (Ⅰ), herb community stage (Ⅱ), shrub community stage (Ⅲ) to tree community stage (Ⅳ), SBR significantly increased (P<0.05), while qCO₂ significantly decreased (P<0.05). At every re-vegetation stage, SBR significantly decreased (P<0.05) along 0-20 cm, 20-40 cm, and 40-60 cm soil layers, while qCO₂ significantly increased (P<0.05). From Ⅱ, Ⅲ to Ⅳ stages, SBR of rhizosphere (R) and non-rhizosphere (S) significantly increased (P<0.05), and R/S of SBR significantly decreased (P<0.05), while qCO₂ of R and S gradually decreased (P>0.05), and R/S of qCO₂ gradually increased (P>0.05). SBR and qCO₂ in rhizosphere were bigger than those in non-rhizosphere. Correlation analysis showed that SBR had significantly positive correlation with soil microbial biomass carbon (SMBC) and soil temperature (ST) (P<0.01), and significantly negative with soil bulk density (SBD) (P<0.05). qCO₂ had significantly negative correlation with SMBC (P<0.01) and ST (P<0.05), but significantly positive with SBD and pH value (P<0.05). These would have a theoretical and practical significance for building vegetation restoration technique system.

Abstract:In order to understand the changes in secondary metabolite of Eucalyptus demaged by Leptocybe invasa, the contents of flavonoid and tannin in 24 strains of Eucalyptus invasived by L. invasa were studied. The results showed that flavonoid content in Eucalyptus leaves increased significantly after damaged by L. invasa, and the flavonoid content in high sensitive strains was significantly lower than that in other strains. The tannin content in high-resistant strains was significantly higher than that in high-sensitive strains before damaged by L. invasa. The tannin content in high-resistant strains declined at first, and then increased after infected by L. invasa. Therefore, tannin and flavonoid contents in Eucalyptus leaves could be used as indexes to detect whether Eucalyptus damaged by Leptocybe invasa or not.

Abstract:In order to understand the biomass dynamic changes in tropical montane rainforest with selective harvesting at different altitudes, fifty permanent plots of 10 m×10 m were established to investigate the biomass of forest communities in Yinggeling montane rainforest at each area of high (1063 m), middle (899 m) and low (473 m) altitudes. The results showed that the biomass of above-ground and tree layer in Yinggeling montane rainforest was only 152.6 t hm^-2 and 142.6 t hm^-2, respectively, which was far less than that in natural forests of other areas in Hainan Island. The tree layer biomass of sample plots at high altitude was higher than that at middle and low altitude, amounting to 197.6 t hm^-2, 112.2 t hm^-2 and 117.8 t hm^-2, respectively. The ratio of biomass allocation was in the order of tree layer (94.22%) > snags & fallen log (2.9%) > litter (2.88%), while that of tree layer was in descending order: trunks (72.63%) > branches (15.35%) > barks (9.23%) > leaves (2.79%). Due to selective harvesting, number of large and extra large diameter trees was small, therefore, the ratio of biomass allocation in small diameter trees (5-19.9 cm), middle diameter trees (20-35.9 cm), large diameter trees (36-47.9 cm) and extra large diameter trees (≥ 48 cm) was accounting for 35.89%, 26.24%, 16.01% and 21.86%, respectively. After over 30 year's natural restoration, Yinggeling montane rainforest was still in the midsuccessional stage, which indicated that it would have a great potential on forest carbon sequestration in the future.

Abstract:We synonymize three names of the genus Ligularia from China, including L. brassicoides Hand.-Mazz., L. ianthochaeta C. C. Chang, and L. paradoxa Hand.-Mazz. var. palmatifida S. W. Liu & T. N. Ho.

Abstract:Ardisia crenata complex include A. crenata Sims, A. crenata var. bicolor (E. Walker) C. Y. Wu & C. Chen, and A. linangensis C. M. Hu. They are taxonomically perplexing. By means of conventional taxonomic methods, it is difficult to discriminate them from one another. Nine characters are analysed for the 135 specimens of this complex from 14 provinces of China by means of pictorialized scatter diagram and histogram. The results support the idea of merging A. crenata var. bicolor (E. Walker) C. Y. Wu & C. Chen into A. crenata Sims, but do not support treating A. linangensis C. M. Hu as the synonym of A. crenata Sims.

Abstract:Ninety taxa of the genus Ardisia (Primulaceae s.l.) was cladistically analyzed based on 42 morphological characters. One hundred equally most parsimonious trees were generated from parsimonious analysis. Fifty percent majority rule consensus tree of those trees is basically consistent with the tribal classifications of Walker and Chen. However, the Consistency Index, Retention Index and the bootstrap values are all very low except the bootstrap values between species and varieties or species and subspecies. The out-group members of genus Embelia, Myrsine, Rapanea are all clustered into a most basal clade, genus Ardisia is a monophyletic group. The subgenus Tinus, Akosmos, Pimelandra and Acrardisia are in the basal clades of Ardisia, and they are the relatively primitive taxa in Ardisia. The subgenus Crispardisia and Bladhia compose a big clade. They are very close related groups in phylogeny and the evolutionary taxa in Ardisia. In order to provide the basis for taxonomic revision, the phylogenetic relationship within the genus was discussed.

Abstract:In order to understand the function of COBL similar protein in bamboo, BoCOBL, a COBL homologous gene, was clonned from Bambusa oldhamii by RT-PCR and RACE methods. The full-length cDNA of BoCOBL was 1743 bp (GenBank accession No.: EU247930). Sequence analysis showed that BoCOBL encoded 451 amino acids with a transmembrane helical structure at the N-terminal and a glycosylphosphatidylinositolanchored protein signal sequence at the C-terminal, which indicated that it was a membrane protein, belonging to glycosylphosphatidyl inositol-anchored protein family. The expression vector of BoCOBL::GFP was constructed and transformed into suspension cells of tobacco. The BoCOBL::GFP proteins were mainly located on the cytoplasmic membrane, while the control of GFP proteins was non-specific in the transformed cells. So, it was confirmed that the protein encoded by BoCOBL was a membrane protein. The analysis of tissue specific expression indicated that the expression of BoCOBL was constitutive, with similar level in root, leaf and sheath, while slightly low in stem. These results would be helpful for further study on the function of BoCOBL in bamboo.

Abstract:In order to understand the mechanism of 1-methylcyclopropene (1-MCP) delaying softening of harvested Averrhoa carambola fruits, the effect of 0.6 μL L^-1 1-MCP on softening and cell wall metabolism of harvested A. carambola ‘Xiangmi’ fruits during storage at (15±1)℃ and 90% relative humidity were studied. The results showed that, compared with the control fruits, 1-MCP treatment could keep high fruit firmness, obviously inhibit activities of cell wall-degrading enzymes, such as pectinesterase (PE), polygalacturonase (PG) and cellulase, retard the decrease of contents of protopectin, cellulose and hemicellulose, and meanwhile delay the increase of water soluble pectin content. Therefore, it could be concluded that 0.6 μL L^-1 1-MCP treatment could effectively control fruit softening process of harvested A. carambola ‘Xiangmi’ fruits, and prolong fruit storage life.

Abstract:To study the chemical constituents of Eurya chinensis R. Brown, eight compounds were isolated from the 95% ethanol extract of its stems. They were identified by comparison of their spectroscopic data with those reported in the literature and elucidated as: erythrodiol (1), betulinic acid (2), friedelin (3), lupeol (4), β-sitosterol (5), stigmasterol (6), salicylic aldehyde (7), nonacosanol (8). All the compounds were obtained from Eurya chinensis for the first time.

Abstract:Organ size is an important morphological trail in plants, and shows significant differences among species. Organ growth is influenced by environmental factors, such as light and nutrients; however, it is determined by the intrinsic information of cell number and cell size. A large number of genes involved in regulation of cell proliferation and/or cell expansion have been identified, and their up-regulated or down-regulated expression change organ size and accelerate organ growth by means of transcription regulation, protein synthesis and modification, hormonal regulation and cell-wall loosening, and so on. In spite of this, these genes act through relative independent pathways, making it difficult to demonstrate an integrated regulation network in plants. Further challenges will be the regulation pattern and molecular changes in different plant species. Several genes participated in organ growth have been used in crop breeding, and produced significantly large crops. Similarly, characterization of the genes involved in organ size control of Chinese herbs to artificially promote organ size and morphology at the molecular level will contribute to overcome the shortage and endangerment of medicinal plants.