Fine roots of plants play an important role in terrestrial ecosystems. There is a close association between the anatomical characteristics and physiological and ecological functions of plants, but we ...still have a very limited knowledge of anatomical traits. For example, (1) we do not know if herbs and grasses have anatomical patterns similar to those of woody plants, and (2) the variation among different woody plants in the same ecosystem is unclear. In the present study, we analysed the anatomical structures of the fine root systems of various groups of vascular plants (ferns, eudicot herbs, monocots and woody plants) from the same ecosystem (a natural secondary forest on Mao'er Mountain, Heilongjiang, China) to answer the following questions: (1) How does the anatomy of the fine roots change with root order in various plant groups in the same ecosystem? (2) What is the pattern of variation within group? The results show that anatomical traits can be divided into 3 categories: traits that indicate the root capacity to transport resource along the root (stele diameter, xylem cell diameter and xylem cell area); traits that indicate absorptive capacity cortical thickness, (the number of cortical cell layers and the diameter of cortical cells); and traits that are integrated indicators (diameter and the stele to root diameter ratio). The traits indicate the root capacity to transport resource along the root order is generally similar among groups, but absorptive capacity is very different. The shift in function is the main factor influencing the fine root anatomy. Some traits show large variation within groups, but the variations in other traits are small. The traits indicate that the lower-order roots (absorbing roots) in distinct groups are of the first one or two root order in ferns, the first two or three orders in eudicot herbs, the first (only two root orders) or first two orders (more than three root orders) in monocots and the first four or five root orders in woody plants and the other roots are higher-order roots (transport roots). The result will helpful to understand the similarities and differences among groups and the physiological and ecological functions of plant roots.
Aims
Absorptive and transport roots (diameter ≤ 2 mm) are closely related to soil resource uptake for plant growth, carbon budget and nutrient cycling in forest ecosystems, but how and why the ...relative share of root biomass or root length for both root functional types changes with tree species is not well understood. Our aims were to examine the inter-specific variations of root biomass and length per unit area of absorptive and transport roots, and their relationships with stand structure and soil characteristics, root morphological and architectural traits.
Methods
We measured root biomass and length per unit area, diameter, specific root length (SRL), root tissue density (RTD), and branching ratio of the first five order roots, stand and soil characteristics in seven forests consisting of different tree species at a common site. The first order roots were classified as absorptive roots and the other orders as transport roots based on our earlier work.
Results
Biomass ratios of absorptive to transport roots varied from 1:5.56 to 1:1.12 among species, and length ratios ranged from 1:1.56 to 1:0.29. Root biomass was not influenced by root morphology or architecture, nor by stand or soil characteristics. Absorptive root length was significantly correlated with SRL, RTD, and branching ratio of the first to second order roots among species, whereas transport root length was significantly correlated with stem density.
Conclusions
The relative share of biomass and length for absorptive and transport roots differed among tree species, which may influence belowground carbon allocation and resource competition.
Despite extensive research on the seasonal dynamics of non-structural carbohydrate (NSC) and nitrogen (N) concentrations, the size and relative contributions of NSC and N pools across different tree ...organs are not well understood. We have measured the changes in NSC and N concentrations in leaves, branches, stems and all root branch orders at monthly intervals in control and girdled trees of larch (Larix gmelinii) and ash (Fraxinus mandshurica). The biomass of each plant compartment was also determined to calculate the size of the NSC and N pools. In both species, 13–37 % of the NSC and N pools were mobilized at the beginning of the growing season. Among the mobilized pools, stems and non-absorptive roots (branch orders 4–9) acted as the largest NSC sources in larch and ash, respectively, while branches served as the largest N source in both species. After stem girdling, 22 and 50 % of the root NSC stores in larch and ash, respectively, were mobilized to maintain root activities during the growing season. Tree mortality was observed 1 year after girdling, at which time there was still an abundant NSC pool in the roots. We conclude that (1) different storage organs differ in their contribution to new tissue growth at the beginning of the growing season and that those storage organs holding higher fractions of the NSC or N pool are not necessarily those which mobilize more NSC or N; (2) tree growth may not be limited by carbon (C) availability; (3) C storage in non-absorptive roots plays an important role in maintaining tree survival after the termination of photosynthate flow from aboveground sources.
The study aimed to explore the influencing factors on critical coronavirus disease 2019 (COVID-19) patients' prognosis and to construct a nomogram model to predict the mortality risk. We ...retrospectively analyzed the demographic data and corresponding laboratory biomarkers of 102 critical COVID-19 patients with a residence time ≥ 24 h and divided patients into survival and death groups according to their prognosis. Multiple logistic regression analysis was performed to assess risk factors for critical COVID-19 patients and a nomogram was constructed based on the screened risk factors. Logistic regression analysis showed that advanced age, high peripheral white blood cell count (WBC), low lymphocyte count (L), low platelet count (PLT), and high-sensitivity C-reactive protein (hs-CRP) were associated with critical COVID-19 patients mortality risk (p < 0.05) and these were integrated into the nomogram model. Nomogram analysis showed that the total factor score ranged from 179 to 270 while the corresponding mortality risk ranged from 0.05 to 0.95. Findings from this study suggest advanced age, high WBC, high hs-CRP, low L, and low PLT are risk factors for death in critical COVID-19 patients. The Nomogram model is helpful for timely intervention to reduce mortality in critical COVID-19 patients.
The management of forest pests has become a significant challenge, particularly for wood borers, because they spend most of the time in the trunks or cones. The coneworm, Dioryctria abietella, is a ...representative of cone borers as its larvae feed on the cones of Pinaceae plants. The molecular mechanisms underlying the interactions between this species and host plants or habitats can assist in developing strategies for pest control. In this study, we extended the expression profiles of 32 odorant binding proteins (OBPs) in the reproductive tissues of D. abietella, revealing the detectable transcription of 29 genes. Using two DabiOBPs highly expressed in antennae (DabiOBP5 and DabiOBP14) as targets, six compounds with high affinities (dissociation constants < 13 μM) were identified through a reverse chemical ecology strategy, including insecticides widely used for the control of lepidopteran pests. Of these compounds, a floral volatile β-ionone and a pear-produced ester ethyl-(2E,4Z)-decadienoate may serve as behaviorally active compounds in D. abietella. The strong binding of DabiOBPs to insecticides suggested their involvement in insecticide resistance, reflecting sophisticated detoxification mechanisms of this moth. In the molecular simulations, DabiOBP14 possessed stronger interactions with the six ligands compared to DabiOBP5, in which a few key residues within the binding pockets were involved in the formation of hydrogen bonds. This study provides some valuable reference active compounds for the development of lures or repellents in D. abietella and unravels the putative roles of two antenna-dominant DabiOBPs in the perception of plant-derived odorants and insecticides.
Absorptive and transport fine roots (diameter ≤ 2 mm) differ greatly in anatomy, morphology, and physiology, as well as their responses to environmental changes. However, it is still not well ...understood how their functional traits and biomass repartition respond to resource variability associated with increasing soil depth. Herein, we sampled the first five order roots of three hardwoods, i.e., Juglans mandshurica Maxim., Fraxinus mandshurica Rupr., and Phellodendron amurense Rupr. at surface (0–10 cm) and subsurface (20–30 cm) soil layers, respectively, and measured root biomass, anatomy, morphology, chemistry, and physiology at the branch-order level. Based on the anatomical characteristics, absorptive and transport fine roots were identified within each order, and their amounts and functional trait plasticity to soil depth were examined. The results showed that across soil layers, the first three order roots were mainly absorptive roots, while the fourth- and fifth-order roots were transport ones. From surface to subsurface soil layers, both the number and biomass proportion of absorptive fine roots decreased but those of transport fine roots increased. Transport fine root traits were more plastic to soil depth than absorptive ones, especially for the conduit-related traits. Absorptive fine roots in surface soil generally had stronger potential for resource acquisition than those in deeper soil, as indicated by their longer specific root length and greater root branching density. In comparison, transport fine roots in deeper soil were generally enhanced in their transportation function, with wider stele and higher hydraulic conductivity. Our findings suggest that functional specialization via multi-trait plasticity and coordination in both absorptive and transport fine roots along the soil depth would benefit the efficient soil resource exploitation of trees in forest ecosystems.
Optimized Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) pretreatment methods for determination of six polychlorinated biphenyls (PCBs) residues in fish and aquatic invertebrates samples ...were investigated. Large volume injection (LVI) coupled gas chromatography tandem mass spectrometry (GC-MS/MS) with selected reaction monitoring (SRM) was used to provide a very sensitive and selective means of analyzing PCBs via internal calibration. Three analytical processes were validated and compared, and the florisil Celite®545 pretreatment method was selected. Performance characteristics, such as linearity, limit of detection (LOD), limit of quantization (LOQ), recovery and precision (relative standard deviation, RSD) were studied. The method was applied to 233 samples obtained from local markets, which was useful and thus suggested that the method could serve as a screening model for PCB residues analysis.
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•Rapid disinfection of water containing E. coli is obtained by a pilot-scale ARHCR.•The ARHCR can cause serious cleavage and surface damages to E. coli.•Proposed disinfection ...mechanism includes hydrodynamical and sonochemical effects.
Hydrodynamic cavitation is a promising technique for water disinfection. In the present paper, the disinfection characteristics of an advanced hydrodynamic cavitation reactor (ARHCR) in pilot scale were studied. The effects of various flow rates (1.4–2.6 m3/h) and rotational speeds (2600–4200 rpm) on the removal of Escherichia coli (E. coli) were revealed and analyzed. The variation regularities of the log reduction and reaction rate constant at various cavitation numbers were established. A disinfection rate of 100% was achieved in only 4 min for 15 L of simulated effluent under 4200 rpm and 1.4 m3/h, with energy efficiency at 0.0499 kWh/L. A comprehensive comparison with previously introduced HCRs demonstrates the superior performance of the presented ARHCR system. The morphological changes in E. coli were studied by scanning electron microscopy. The results indicate that the ARHCR can lead to serious cleavage and surface damages to E. coli, which cannot be obtained by conventional HCRs. Finally, a possible damage mechanism of the ARHCR, including both the hydrodynamical and sonochemical effects, was proposed. The findings of the present study can provide strong support to the fundamental understanding and applications of ARHCRs for water disinfection.
Abstract
Adherent macrofouling in marine environments caused complex corrosion of steel surfaces, resulting in localized corrosion at the oyster/steel interface and uniform corrosion at the ...ascidian/steel interface. Sulfate-reducing bacteria (SRB) have been implicated in the microbiologically influenced corrosion (MIC) process at macrofouling-covered interfaces. To better understand the role of marine biofilms as key mediators in the MIC process, metagenomic techniques were used to study microbial communities and their response to macrofouling’s coverage. Compared to ascidians, the formed local anaerobic zone at oyster/steel interface stimulated the growth of SRBs, leading to higher FeS content and severe localized corrosion. SRB
Desulfovibrio
and
Desulfobulbus
, along with the SRB-related functional gene
dsr
, were found to increase, while oxygen-related function genes
coxC
,
ccoN
,
ccoO
,
ccoP
, and
ccoQ
decreased. In contrast, steel surfaces without macrofouling coverage had the richest microbial communities, yet experienced less severe MIC, suggesting no direct connection between microbial abundance/diversity and steel corrosion promotion.
The response of belowground biological processes to soil N availability in Larix gmelinii (larch) and Fraxinus mandshurica (ash) plantations was studied. Soil and root respiration were measured with ...Li-Cor 6400 and gas-phase O₂ electrodes, respectively. Compared with the control, N fertilization induced the decreases of fine root biomass by 52% and 25%, and soil respiration by 30% and 24% in larch and ash plantations, respectively. The average soil microbial biomass C and N were decreased by 29% and 42% under larch stand and 39% and 47% under ash stand, respectively. While the fine root tissue N concentration under fertilized plots was higher 26% and 12% than that under control plots, respectively, the average fine root respiration rates were increased by 10% and 13% in larch and ash stands under fertilized plot, respectively. Soil respiration rates showed significantly positive exponential relationships with soil temperature, and a seasonal dynamic. These findings suggest that N fertilization can suppress fine root biomass at five branch orders (<2 mm in diameter), soil respiration, and soil microbial biomass C and N, and alter soil microbial communities in L. gmelinii and F. mandshurica plantations.
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