Project description:The seasonal rainforests distributed across the tropical karst hills of south China are of high biodiversity conservation value and serve many important ecosystem functions. However, knowledge surrounding distribution patterns of woody plants in tropical karst hills remains limited. In this study, we surveyed the distribution of families, genera and species of woody flora at four slope positions (depression, lower slope, middle slope, and upper slope), and analyzed the influence of topographic and soil variables on the distribution of woody plants in the tropical karst hills of south China. Forty forest plots (each 20 m × 20 m) contained 306 species of woody plants with a diameter at breast height (DBH) ≥1 cm, representing 187 genera and 66 families. As slope increased, the number of families increased slowly, and the number of genera and species followed a concave-shaped trend, with the lowest number of genera and species in the lower slope position. Differences in species composition were significantly stronger between slope positions than within slope positions. The topographic and soil variables explained 22.4% and 19.6%, respectively, of the distribution of woody plants, with slope position, slope degree, soil potassium and soil water content as the most significant variables. The results of generalized linear mixed model analysis showed that total R2 of fixed effects on variation of woody species richness was 0.498, and rock outcrop rate and soil total phosphorus were the best fitting effects. Our results help to explain the community assembly mechanism and to inform management and protection strategies for species-rich seasonal rainforests in the karst area.
Project description:Harsh habitats dominated by invasive species are difficult to restore. Invasive grasses in arid environments slow succession toward more desired composition, yet grass removal exacerbates high light and temperature, making the use of "nurse plants" an appealing strategy. In this study of degraded subtropical woodlands dominated by alien grasses in Hawai'i, we evaluated whether individuals of two native (Dodonaea viscosa, Leptocophylla tameiameia) and one non-native (Morella faya) woody species (1) act as natural nodes of recruitment for native woody species and (2) can be used to enhance survivorship of outplanted native woody species. To address these questions, we quantified the presence and persistence of seedlings naturally recruiting beneath adult nurse shrubs and compared survival and growth of experimentally outplanted seedlings of seven native woody species under the nurse species compared to intact and cleared alien-grass plots. We found that the two native nurse shrubs recruit their own offspring, but do not act as establishment nodes for other species. Morella faya recruited even fewer seedlings than native shrubs. Thus, outplanting will be necessary to increase abundance and diversity of native woody species. Outplant survival was the highest under shrubs compared to away from them with few differences between nurse species. The worst habitat for native seedling survival and growth was within the unmanaged invasive grass matrix. Although the two native nurse species did not differentially affect outplant survival, D. viscosa is the most widespread and easily propagated and is thus more likely to be useful as an initial nurse species. The outplanted species showed variable responses to nurse habitats that we attribute to resource requirements resulting from their typical successional stage and nitrogen fixation capability.
Project description:Genome-wide transcriptome analysis was performed to understand the expression pattern of transcriptomes in tolerant and susceptible subtropical maize genotypes under water deficit stress condition.<br><br>
Project description:The morphology, ecology, and phylogenetic relationships of specimens of the family Boletaceae from subtropical and tropical China were investigated. Four species, Butyriboletushuangnianlaii, Lanmaoamacrocarpa, Neoboletusmultipunctatus, and Sutoriussubrufus, are new to science. Chalciporusradiatus and Caloboletusxiangtoushanensis are redescribed. Caloboletusguanyui is proposed to replace Boletusquercinus Hongo, an illegitimate later homonym. The recently described Tylopiluscallainus is synonymized with the Japanese Boletusvirescens, and the new combination T.virescens (Har. Takah. & Taneyama) N.K. Zeng et al. is proposed. Moreover, Neoboletus is treated as an independent genus based on evidence from morphology and molecular phylogenetic data in the present study, and many previously described taxa of Sutorius are recombined into Neoboletus: N.ferrugineus (G. Wu et al.) N.K. Zeng et al., N.flavidus (G. Wu & Zhu L. Yang) N.K. Zeng et al., N.hainanensis (T.H. Li & M. Zang) N.K. Zeng et al., N.obscureumbrinus (Hongo) N.K. Zeng et al., N.rubriporus (G. Wu & Zhu L. Yang) N.K. Zeng et al., N.sanguineoides (G. Wu & Zhu L. Yang) N.K. Zeng et al. , N.sanguineus (G. Wu & Zhu L. Yang) N.K. Zeng et al., and N.tomentulosus (M. Zang et al.) N.K. Zeng et al.
Project description:This study aimed to use pan-viral detection microarrays to identify viruses in serum from cases of acute pediatric febrile illness in a tropical setting. Patient clinical data and serum samples were collected between 2005 and 2009 as part of an ongoing pediatric dengue virus study at the Hospital Infantil Manuel de Jesús Rivera in Managua, Nicaragua. This study focused on patients who presented with dengue-like illness but who tested negative for dengue-virus infection. We hypothesized that non-dengue viruses or previously uncharacterized viruses might be causing these illnesses. The Virochip microarray is capable of detecting known viruses and discovering novel viruses. This series includes 153 arrays corresponding to 148 cases and 5 HeLa controls. Keywords: viral detection, tropical febrile illness, dengue virus, Nicaragua, Virochip From each serum sample, total nucleic acid was extracted and used to prepare a randomly-primed dsDNA library. These libraries were fluorescently labeled and hybrized to Virochip arrays.
Project description:Genome-wide transcriptome analysis was performed to understand the expression pattern of transcriptomes in tolerant and susceptible subtropical maize genotypes under waterlogging stress condition. Waterlogging stress causes yield reduction in maize (Zea mays). It is important to dissect the genetic circuits that underlie the plant responses to waterlogging. So, the experiment was designed with the following objectives: to understand the expression pattern of transcriptomes in the tolerant and the susceptible genotypes under waterlogging stress; to identify DEGs functioning in important pathways underlying adaptive traits; to co-map bin locations of the transcriptomes with already known QTLs for waterlogging and find synteny with other species; and to generate gene co-expression networks to study cohorts of genes expressed together in modules and functional cluster, while comparing the two genotypes. Two tropical maize (Zea mays L.) inbred lines, HKI1105 (tolerant) and V-372 (susceptible), were used for our experiment. The genotypes were sown in plastic pots filled with loam soil with sandy texture. The plants were watered daily to soil capacity until the application of stress at 28 days after sowing. To impose waterlogging condition, the perforation in the bottom of the pots (35 cm in height) was sealed and the stress treatment was given by watering the pots (5 cm standing water) for seven continuous days. To allow for recovery from stress, the perforations of the pots were unsealed for proper drainage of excess water. The root samples from both genotypes were collected on the 28th, 32nd, 35th and 42nd day after sowing, which represented control, moderate stress, severe stress and post-stress recovery stages, respectively. Two biological replications were used for each comparison.