Does local soil factor drive functional leaf trait variation? A test on Neilingding Island, South China.

Leaf traits were affected by soil factors and displayed varietal differences in forest. However, few examples have been reported on the Island ecosystems. We comprehensively investigated 9 leaf traits (leaf length, leaf width, leaf area, SLA, leaf fresh weight, leaf C content, leaf N content, leaf K content, leaf C:N ratio) of 54 main subtropical woody species and soil parameters (soil pH, total C content, total N content, total K content, available N content, available P content, available K content and soil moisture) in Neilingding Island, Shenzhen, southern China.

Response of leaf functional traits to soil nutrients in the wet and dry seasons in a subtropical forest on an island.

Introduction: Island ecosystems often have a disproportionate number of endemic species and unique and fragile functional characteristics. However, few examples of this type of ecosystem have been reported.

Methods: We conducted a comprehensive field study on Neilingding Island, southern China.

Plant species identity and mycorrhizal type explain the root-associated fungal pathogen community assembly of seedlings based on functional traits in a subtropical forest.

Introduction: As a crucial factor in determining ecosystem functioning, interaction between plants and soil-borne fungal pathogens deserves considerable attention. However, little attention has been paid into the determinants of root-associated fungal pathogens in subtropical seedlings, especially the influence of different mycorrhizal plants.

Methods: Using high-throughput sequencing techniques, we analyzed the root-associated fungal pathogen community for 19 subtropical forest species, including 10 ectomycorrhizal plants and 9 arbuscular mycorrhizal plants.

Host Recognition and Specific Infection of during Early Infection.

Coevolution between the pathogen and host plant drives pathogenic effector diversity. However, the molecular mechanism behind host-specific pathogenesis remains to be explored. Here, we present a 43 Mb whole-genome sequence of strain LS29, a host-specific pathogen of the common subtropical tree .

Negative impacts of sea-level rise on soil microbial involvement in carbon metabolism.

Sea-level rise has been threatening the terrestrial ecosystem functioning of coastal islands, of which the most important component is carbon (C) cycling. However, metagenomic and metabolomic evidence documenting salt intrusion effects on molecular biological processes of C cycling are still lacking. Here, we investigated microbial communities, metagenomic taxonomy and function, and metabolomic profiles in the marine-terrestrial transition zone of low- and high-tide, and low- and high-land areas based on distances of 0 m, 50 m, 100 m, and 200 m, respectively, to the water-land junction of Neilingding Island.

Asexual reproduction and vegetative growth of in response to temperature and photoperiod.

Growth and reproduction are two essential life-history traits for fungi. Understanding life-history strategies provides insight into the environmental adaption of species. Here, we investigated the colonial morphology, vegetative growth, and asexual reproduction of the ascomycete fungus in response to a variety of environmental conditions.

Compatible Mycorrhizal Types Contribute to a Better Design for Mixed Plantations.

Mixed-species forest plantation is a sound option to facilitate ecological restoration, plant diversity and ecosystem functions. Compatible species combinations are conducive to reconstruct plant communities that can persist at a low cost without further management and even develop into natural forest communities. However, our understanding of how the compatibility of mycorrhizal types mediates species coexistence is still limited, especially in a novel agroforestry system.

The effects of density dependence and habitat preference on species coexistence and relative abundance.

In plant communities, some mechanisms maintain differences in species' abundances, while other mechanisms promote coexistence. Asymmetry in conspecific negative density dependence (CNDD) and/or habitat preference is hypothesized to shape relative species abundance, whereas community compensatory trends (CCTs) induced by community-level CNDD and heterospecific facilitation are hypothesized to promote coexistence. We use survey data from three 1-ha permanent dynamic plots in a subtropical forest over the course of a decade to find out which of these processes are important and at which life-history stages (the seedling, sapling, and juvenile stages) they exert their effects.

Light and competition alter leaf stoichiometry of introduced species and native mangrove species.

Ecological stoichiometry is the study of the balance of ecosystem energy and nutrient cycling, especially carbon (C), nitrogen (N), and phosphorus (P). C, N, and P are the key elements for plant growth and metabolism. Systematic research on leaf stoichiometry in mangrove forest ecosystems is still lacking.

Neighboring trees regulate the root-associated pathogenic fungi on the host plant in a subtropical forest.

Root-associated fungi and host-specific pathogens are major determinants of species coexistence in forests. Phylogenetically related neighboring trees can strongly affect the fungal community structure of the host plant, which, in turn, will affect the ecological processes. Unfortunately, our understanding of the factors influencing fungal community composition in forests is still limited.

Soil fungal networks maintain local dominance of ectomycorrhizal trees.

The mechanisms regulating community composition and local dominance of trees in species-rich forests are poorly resolved, but the importance of interactions with soil microbes is increasingly acknowledged. Here, we show that tree seedlings that interact via root-associated fungal hyphae with soils beneath neighbouring adult trees grow faster and have greater survival than seedlings that are isolated from external fungal mycelia, but these effects are observed for species possessing ectomycorrhizas (ECM) and not arbuscular mycorrhizal (AM) fungi. Moreover, survival of naturally-regenerating AM seedlings over ten years is negatively related to the density of surrounding conspecific plants, while survival of ECM tree seedlings displays positive density dependence over this interval, and AM seedling roots contain greater abundance of pathogenic fungi than roots of ECM seedlings.

Linking Aboveground Traits to Root Traits and Local Environment: Implications of the Plant Economics Spectrum.

The plant economics spectrum proposes that ecological traits are functionally coordinated and adapt along environmental gradients. However, empirical evidence is mixed about whether aboveground and root traits are consistently linked and which environmental factors drive functional responses. Here we measure the strength of relationships between aboveground and root traits, and examine whether community-weighted mean trait values are adapted along gradients of light and soil fertility, based on the seedling censuses of 57 species in a subtropical forest.

Soil microbes drive phylogenetic diversity-productivity relationships in a subtropical forest.

The relationship between plant diversity and productivity and the mechanisms underpinning that relationship remain poorly resolved in species-rich forests. We combined extensive field observations and experimental manipulations in a subtropical forest to test how species richness (SR) and phylogenetic diversity (PD) interact with putative root-associated pathogens and how these interactions mediate diversity-productivity relationships. We show that (i) both SR and PD were positively correlated with biomass for both adult trees and seedlings across multiple spatial scales, but productivity was best predicted by PD; (ii) significant positive relationships between PD and productivity were observed in nonsterile soil only; and (iii) root fungal diversity was positively correlated with plant PD and SR, while the relative abundance of putative pathogens was negatively related to plant PD.

Effect of root exudates of Eucalyptus urophylla and Acacia mearnsii on soil microbes under simulated warming climate conditions.

Background: Recent studies demonstrated that warming and elevated carbon dioxide (CO) indirectly affect the soil microbial community structure via plant root exudates. However, there is no direct evidence for how the root exudates affect soil microbes and how the compositions of root exudates respond to climate change.

Results: The results showed that warming directly decreased biomass of soil-borne bacteria and fungi for Acacia mearnsii De Willd but it did not impact soil microbial community for Eucalyptus urophylla S.

Effects of neighborhood trait composition on tree survival differ between drought and postdrought periods.

Although direct tree demographic responses to drought are widely recognized, studies of drought-mediated changes in tree interactions are rare. We hypothesize that drought exacerbates soil-water limitation and intensifies competition for water, but reduces light limitation and competition for light. We predict that competition would be stronger for trees (1) consuming more water or more susceptible to water deficits during drought and (2) intercepting more light or more susceptible to shade during postdrought periods.

Habitat effects on intra-species variation in functional morphology: Evidence from freshwater fish.

Biotic-environment interactions have long been considered an important factor in functional phenotype differentiation in organisms. The differentiation processes determining functional phenotypes can reveal important mechanisms yielding differences in specific functions of animal traits in the ecosystem. In the present study, we examined functional morphological variations in relation to increasing geographic altitude.

Development of polymorphic EST-SSR markers in (Iteaceae) and cross-amplification in related species.

Premise Of The Study: We isolated and characterized 16 expressed sequence tag-simple sequence repeat (EST-SSR) markers in (Iteaceae), a common evergreen broadleaf tree, for future studies on the genetic diversity and spatial genetic structure of the species.

Methods And Results: Based on transcriptome data of , a total of 36 primer pairs were initially designed and tested. Of these, 16 were successfully amplified and showed clear polymorphism.

Abundance-dependent effects of neighbourhood dissimilarity and growth rank reversal in a neotropical forest.

Why tropical forests harbour an exceptional number of species with striking differences in abundances remains an open question. We propose a theoretical framework to address this question in which rare species may have different extirpation risks depending on species ranks in tree growth and sensitivities to neighbourhood interactions. To evaluate the framework, we studied tree growth and its responses to neighbourhood dissimilarity (ND) in traits and phylogeny for 146 species in a neotropical forest.

Development of microsatellite markers for (Theaceae).

Premise Of The Study: Sixteen microsatellite markers were developed to study the fine-scale spatial genetic structure of , a dioecious tree species of Theaceae endemic to southern China.

Methods And Results: A total of 30 primer pairs were initially designed and tested on the basis of the transcriptome data of , of which 16 were successfully amplified and showed clear polymorphism. For these microsatellites, one to 17 alleles per locus were identified.

Inorganic phosphorus fertilizer ameliorates maize growth by reducing metal uptake, improving soil enzyme activity and microbial community structure.

Recently, several studies have showed that both organic and inorganic fertilizers are effective in immobilizing heavy metals at low cost, in comparison to other remediation strategies for heavy metal-contaminated farmlands. A pot trial was conducted in this study to examine the effects of inorganic P fertilizer and organic fertilizer, in single application or in combination, on growth of maize, heavy metal availabilities, enzyme activities, and microbial community structure in metal-contaminated soils from an electronic waste recycling region. Results showed that biomass of maize shoot and root from the inorganic P fertilizer treatments were respectively 17.

Ecological effects of soil properties and metal concentrations on the composition and diversity of microbial communities associated with land use patterns in an electronic waste recycling region.

Soil microbes play vital roles in ecosystem functions, and soil microbial communities may be strongly structured by land use patterns associated with electronic waste (e-waste) recycling activities, which can increase the heavy metal concentration in soils. In this study, a suite of soils from five land use types (paddy field, vegetable field, dry field, forest field, and e-waste recycling site) were collected in Longtang Town, Guangdong Province, South China. Soil physicochemical properties and heavy metal concentrations were measured, and the indigenous microbial assemblages were profiled using 16S rRNA high-throughput sequencing and clone library analyses.

Adult trees cause density-dependent mortality in conspecific seedlings by regulating the frequency of pathogenic soil fungi.

Negative density-dependent seedling mortality has been widely detected in tropical, subtropical and temperate forests, with soil pathogens as a major driver. Here we investigated how host density affects the composition of soil pathogen communities and consequently influences the strength of plant-soil feedbacks. In field censuses of six 1-ha permanent plots, we found that survival was much lower for newly germinated seedlings that were surrounded by more conspecific adults.