Abstract:To further understand the molecular adaptation linked to fern radiation, evolutionary patterns of the rbcL sequences in the family Pteridaceae were examined using random-site and branch-site models along with the estimated time-scale of pteridaceous phylogeny. By comparing Models M1a/M2a and M7/M8 under random-site models, six amino acid sites (149I, 251M, 255V, 282F, 359S and 375F) were found to be positively selected. The site 282F plays an important role in maintaining Rubisco function. Under branch-site models, no adaptive site was identified in the epiphytic clade, whereas two sites(230A and 247C) were detected in the ceratopteridoid clade. In comparison with shade conditions, aquatic habitats may have imposed stronger selection on the pteridaceous RbcL subunits. Moreover, the phylogenetic tree reconstructed with uncorrelated lognormal distributed relaxed clock model shows that the pteridaceous fern radiations occurred during the Oligocene, suggesting possible roles played by the Paleocene-Eocene Thermal Maximum. These results provide new insights into how leptosporangiate ferns response to the terrestrial ecosystem changes caused by the rise of angiosperms.

Abstract:The resources allocation and reproductive success were compared between Liriodendron chinense and L. tulipifera based on mating design trial and floral characteristics. Six adult trees, 3 from L. chinense and 3 from L. tulipifera, were chosen as mating parents. By comparing the floral characteristics between Liriodendron chinense and L. tulipifera, we found that there was a significant interspecies difference existing in both reproductive strategy and reproductive success. To ensure their reproductive success, L. chinense seems to pursue the strategy of augment to the number of reproductive organ, while L. tulipifera takes the way of improvement for the reproductive efficiency. Overall, the male reproductive success of L. chinense was higher than that of L. tulipifera, while its female reproductive success was lower than L. tulipifera.

Abstract:The changes of Cynodon dactylon propagules under flooding were studied in morphology and biomass. Results showed that the stem length increased with increasing of flooding depth, whereas leaf number decreased obviously. Flooding duration had significant effects on leaf number, stem diameter, and ratio of stem length to root depth, but not on branch number, stem length, root depth, stem node number. The aboveground biomass and total biomass of plants decreased significantly with the prolongation of flooding time, but the underground biomass of plants changed little. Plants of all the treatments could survive and recovered after flooding. However, stem length, root depth, branch number, stem diameter, leaf number, leaf length, leaf width and ratio of leaf length to leaf width all decreased significantly with the increase of flooding duration during recovery, so did the stem, leaf, root biomass and total biomass. But node number and leaf number of plants showed no significant difference among treatments. It suggested that Cynodon dactylon had strong toleration to flooding by prolonging stem, changing leaf shape and reducing biomass.

Abstract:Water-soluble pectin (WSP) and acid-soluble pectin (ASP) polysaccharides were isolated from pulp of banana at different mature stages, and then the effects of pH, temperatures and metal ions on the degradation of WSP and ASP caused by endopolygalcturonase (endo-PG) were studied. The results showed that the optimum pH of endo-PG was from 3.7 to 4.6. At the same pH, the degradation of WSP by endo-PG increased with banana maturity, but that of ASP decreased. The degradation of WSP and ASP by endo-PG increased with the temperature from 20℃ to 40℃. Moreover, Ca2+, Cu2+, Mg2+and Fe3+ inhibited significantly the degradation of WSP and ASP, but Fe2+and Mn2+ enhanced significantly. It was suggested that pH, temperatures and metal ions could cooperate the degradation of pectin polysaccharides of banana.

Abstract:The changes in activity and isozyme of ascorbate peroxidase (APX) in pomelo (Citrus grandis ‘Guanximiyou’) juicy sac were studied at different development stages. The results showed that APX activity increased gradually with juicy sac development and decreased rapidly at aging and rotting stages. The APX isozyme also changed during juicy sac development stages. A new APX isozyme was identified with mobility of 0.66 on 150 days after anthesis, and its expression enhanced with maturity of juicy sac. On 242 days after anthesis, most of APX isozyme disappeared. The APX activity in normal juicy sac was lower than that in granulated juicy sac. It suggested that APX could scavenge active oxygen free radicals and prevent the oxidative damage during pumelo juicy sac granulation stage.

Abstract:Qiyunshan Nature Reserve lies in the southwest of Jiangxi, 113°55′~114°38′E，25°24~25°55N，with a land area of 17 105 hm2. Based on the field surveys and microscopic identification of 534 collections, 191 species in 98 genera and 52 families have been found in Qiyunshan. Among them, 47 liverworts belong to 27 genera and 22 families，144 mosses belong to 71 genera and 30 families. In Qiyuanshan bryoflora, 3 families (Haplomitriaceae, Makinoaceae and Pallaviciniaceae), 5 genera (Haplomitrium, Makinoa, Pallavicinia, Phaeoceros and Kurzia), and 24 liverworts are new to Jiangxi.

Abstract:Echinacanthus longipes H. S. Lo & D. Fang (Acanthaceae), a species previously known only from Guangxi, China, has been found to occur also in Yunnan Province, China, and Vietnam. This represents the first record of the genus Echinacanthus Nees from Vietnam.

Abstract:Manglietia lucida (Magnoliaceae) is newly recorded from Vietnam, occurring in a secondary forest in the Hoang Lien National Park, Sapa, Lao Cai Province. These specimens are preserved in Herbaria of South China Botanical Garden, the Chinese Academy of Sciences (IBSC) and Vietnam Forestry University (FUV).

Abstract:Crassocephalum rubens (Juss. ex Jacq.) S. Moore is common weed from Africa. It is found naturalized in Yunnan in recent years and is a new record species in China.

Abstract:The chromosome number and karyotype of a cultivar in the Asteraceae, Solidago canadensis var. gilvocanescens Rydb., cultivated in Foshan City, Guangdong Province, China, were reported. The chromosomes were counted to be 2n=18, and one pair of them had satellites on their short arms. The karyotype was formulated as 2n=2x=18=14m+4sm (2SAT), and belonged to Stebbins’ 2A type.

Abstract:The spores of Phanerophlebiopsis blinii (Lévl.) Ching were cultured in humus soil of pro-habitat. The spore germination and the gametophyte development were observed under microscope. The spores are dark-brown, monolete, elliptical in polar view and hemicyclic in equatorial view. The spores germinate about one week after sowing. The type of germination is Vittaria-type, and that of gametophyte development is Aspidium-type. Germ filament is consisted of 4 to 12 cells. Prothallial plate is usually lopsided with 9-cell width. Mature prothallus are cordate-thalloid with unicellular papillate hairs on the margin as well as the dorsal and ventral parts. More advanced characteristics, such as rhizoids usually are bifurcated and enlarged on the apex with granular stored substances, and antheridium is consisted of three wall cells. However, short and vertical neck of archegonia is a rather primitive character. The gametophyte development of Phanerophlebiopsis blinii is asynchronous, the development and maturation of antheridia is earlier than that of archegonia. From the view of characteristics of gametophyte development, the possible reasons of restricted distribution of P. blinii in the field environment were discussed.

Abstract:We analyzed the floristic composition, structure, physiognomy and species diversity of a Schima remotiserrata + Fokienia hodginsii community in Nanling National Nature Reserve, Guangdong, by field investigation of a 1 600 m2 plot at the altitude of 1 400 m. Results showed that there were 113 vascular species, belonging to 75 genera and 45 families. Pantropic elements were the dominant (20.59%), followed by Tropical and Temperate elements which showed obviously transitional characteristic. The community was mainly dominated by Schima remotiserrata, Fokienia hodginsii, and Ilex hanceana, and of complex structure. However, the dominant components scatteredly distributed and were not obviously enough. The vertical structure of the community was composed of arbor, shrub and herb-liana layers, and dominated by evergreen plants in Microphanerophytes (30.97%) and Mesophanerophytes (27.43%). According to the Raunkiaer Frequency Law, species in 1-20% occurrence frequency dominated the community, accounting for 55.75% of the total species. Saplings and young trees comprised the F. hodginsii population, indicating the population was in pioneer stage and with growing status. The diversity indices, such as Margalef richness index, Simpson dominance index, Shannon-Wiener index and Pielou evenness index showed similar trend, with shrub layer>arbor layer>herb-liana layer in the community.

Abstract:To understand the natural regeneration of Cyclobananopsis chungii nature forest, seed rain and soil seed bank of a C. chungii forest in Minqing C. chungii Forest Nature Reserve were investigated. The results showed that seed rain continued about two months with an average of 12.44 seeds m-2 and peaked at late November to early December. There’s significant difference among the proportions of perfect, worm-eaten, abortive, decayed and germinated seeds in the process of seed rain, in which the proportion of the worm-eaten was 19.44 times as great as the geminated. In the soil seed bank, the proportion of the worm-eaten seed was 53.79%. Compared with the seed rain, the quantities of the perfect and geminated seed were less 2.15 seeds m-2 and 0.20 seeds m-2 respectively. Seed survival rate and the proportion of seed damaged by animals were 13.51% and 45.90%, respectively, which showed that animal damage was the main cause of seed loss. In total, 69 species of seeds were recorded in the soil seed bank, with a very low density of germinable seeds and most of them were buried in 2~5 cm in soil. Seedling density of C. chungii was very low in the nature forest, which was closely related to the seed characteristics and habitat. Due to the animal invasion, rotten, abortion, and so on, it’s difficult for C. chungii mature seed to long-term preserve in the soil, and the natural regeneration of C. chungii forest was blocked seriously.

Abstract:Growth status of reproductive individuals of Betula alnoides were investigated in an ecological ectone of two types of soils originated from limestone (site L) and granite (site G), respectively, at Jingxi County, Guangxi, and the relationships between reproductive modules and their allocation patterns in crown layer were discussed. The results showed that the diameter at breast height (DBH) in site L were remarkably smaller than that in site G, when plants started flowering and fruit setting. The number of flower buds, total number of inflorescences and ratio of male inflorescences were not significantly correlated with DBH and plant height (P>0.05). The number of male inflorescences increased with increment of total number of inflorescences by logarithm curve, and the trees trended to develop male inflorescences under lower reproductive investment, while mainly develop female inflorescences under larger reproductive investment. There were remarkable differences in characteristics of reproductive module between both sites, the number of male buds and number of inflorescences developed from each male bud at site L was significantly lower than that in site G (P<0.05), the ratio of the plants with male inflorescences less than female ones was much higher than that at site G, and the ratio of reproductive branches was also significantly lower than that at site G (P<0.05). Although the number of male inflorescences, female inflorescences, total inflorescences and ratio of male inflorescences at site L were smaller than those at site G, and ratio of female inflorescences at site L was larger than that at site G, there were no significant difference between them (P>0.05) due to high level of variation among individuals at each site. The majority of inflorescences were on upper and middle layers of crown, and above 90% of reproductive branches occupied on the surface of crown at both sites.

Abstract:Nine compounds, such as tetracosanoic acid (1), 7,8-dimethylalloxazine (2), (2S,3S,4R,10E)-2-[(2′R)-2′-hydroxylignoceroylamino]-10-octadecene-1,3,4-triol (3), uracil (4), butanedioic acid (5), adenosine (6), mannitol (7), β-sitosterol (8), and β-daucosterol (9), were isolated from the pulps of Dimocarpus longan Lour. The compounds 1~3, 5 and 7 were reported from D. longan for the first time.

Abstract:Essential oils were extracted from Michelia alba Dc. at perianth development stages by SPME and its chemical constituents were identified by GC-MS, their relative contents were determined by peak area normalization method. The results showed that chemical constituents at 5 perianth development stages were different，and 30, 29, 28, 30 and 27 constituents were identified, respectively. The main components were terpenoid, alkanes, ester, acid and alcohol compounds. Sixteen compounds were identified at more than 3 stages, in which 14 terpenoid compunds, 1 aromatic compound and 1 amine compound. There were 7 compositions only presented at IV stage, so it was considered to be the best stage to scent tea and extract essential oil. But if it couldn’t scent tea and extract essential oils in time or the transport distance was very far, the best harvesting stage is Ⅲ stage.

Abstract:Twelve nitrogen-containing heterocycles were isolated from the solid cultures of Metarhizium sp. SC0924. On the basis of spectral data, they were identified as cyclo-(Ala-Pro) (1), cyclo-(Pro-Tyr) (2), cyclo-(Val-Leu) (3), cyclo-(Leu-Ile) (4), adenine (5), adenosine (6), uracil (7), thymine (8), thymidine (9), 4-acetyl-aminoimidazole (10), n-butyl pyroglumate (11), and lumichrome (12). Compounds 2 and 3 showed weak antifungal activities against Peronophythora litchii by the agar diffusion method with paper disks.

Abstract:Five flavones were isolated from the ethanol extraction of the stem of Aquilaria sinensis. On the basis of spectral analysis, their structures were elucidated as: apigenin-7,4′-dimethylethers (1), 5-hydroxyl-7,3′,4′-trimethoxyflavone (2), 7,4′-dimethyl -luteolin (3), genkwanin (4) and 4′,5-dihydroxy-3′,7-dimethoxyflavone (5). All the compounds were isolated from the stem of this species for the first time.

Abstract:The research progresses in the invasion mechanisms of Mikania micrantha H. B. K. were summarized, including its distribution and damage, the invasiveness of this weed and the invasibility of native community. It was not pay attention to some areas in previous studies, such as the integrated research of its invasion process, analysis of influencing factors of the invasive spread, the effects of spatial scales, and the defects of analytical methods and technical means. Therefore, in the future, it should focus on the reconstruction of the invasion process and prediction of the potential regional spread, the influence of landscape structure in the invasion, as well as the improvement of the monitoring network and risk assessment system.