Total Glomalin-related Soil Protein Research Articles

Integrated reclamation of saline soil nitrogen transformation in the hyphosphere by earthworms and arbuscular mycorrhizal fungus

Soil salinization greatly alters nitrogen cycling and threatens the sustainable productivity of food production areas worldwide. A two-compartment microcosm was used to investigate the integrated effects of arbuscular mycorrhizal fungi (AMF) hyphae and earthworms on nitrogen transformation at different incubation times in saline soil. The treatments were designed with or without hyphae and with or without earthworms harvested at day 40 or 60 in the hyphal compartments (HC). Salt concentration, soil aggregate-size distribution, soil organic carbon, hyphal length density (HLD), total glomalin-related soil protein (TGRSP), inorganic nitrogen concentrations, microbial biomass nitrogen (MBN) and the N-functional marker genes were determined in the HC. The results showed that earthworms and AMF hyphae decreased the soil salt concentration, while increased the soil NO3−-N, NH4+-N, MBN and the abundance of nifH and AOB amoA genes. Earthworms and AMF hyphae could independently or cooperatively affect soil macroaggregates. Earthworms and AMF hyphae affected soil NH4+-N and NO3−N by increasing the soil macroaggregates and MBN. At day 60, earthworms affected soil NO3−N by regulating the abundance of nifH and AOB amoA genes, while AMF hyphae increased soil NH4+-N by regulating the HLD and TGRSP. In conclusion, earthworms and AMF hyphae cooperatively affected soil NO3−-N and NH4+-N by regulating the soil macroaggregates, microbial biomass nitrogen and N-cycling bacteriain saline soil. The results would be useful in reclamation programmes undertaken to rehabilitate land sources that suffer from problems associated with soil salinization.

Effect of tea plantation age on the distribution of glomalin-related soil protein in soil water-stable aggregates in southwestern China.

Glomalin-related soil protein (GRSP) is crucial for the accumulation of soil organic carbon (SOC), and contributes to the formation of soil aggregates. However, it remains unclear whether GRSP is involved in altering the stability of soil aggregates in the long-term tea planting process. The relationship between the distribution of GRSP and soil aggregates in tea plantations is poorly studied. We compared the distribution of SOC and GRSP in aggregates in tea plantations of different ages (18, 25, 33, and 55years) and those in an abandoned land and investigated their potential contribution to the soil aggregate stability. Tea plantation was found to be beneficial for the accumulation of SOC and GRSP compared to the abandoned land. The content of SOC significantly increased after tea plantation, especially in surface soil (0-20cm), and the increase range was 21.79%-46.51%, due to the centralized management of tea plantations. The content of total glomalin-related soil protein (T-GRSP) and easily extractable glomalin-related soil protein (EE-GRSP) varied with the increasing tea plantation age. The T-GRSP content was higher in 25-year-old tea plantation, while EE-GRSP was gradually decreased with the increasing age of the tea plantation, and T-GRSP had better correlation with SOC than EE-GRSP. Long-term tea plantation (after 33years) was not conducive to the preservation of GRSP. The distribution of GRSP in the tea plantation soils differed greatly among the aggregates, with the 0.25-1-mm aggregate having less GRSP, which might be related to the distribution of soil fungi in the aggregates. There was a significant correlation between T-GRSP and mean weight diameter (MWD; P < 0.05) in the whole soil, whereas EE-GRSP had no correlation with the MWD of the aggregates. The T-GRSP content was correlated closely with the stability of soil aggregates in the tea plantations, and their relationship was dependent on the aggregate scale. Our results show that the T-GRSP content in the tea plantation soils has important effects on the formation and stability of aggregates in this region, which was one of the factors affecting the structure and quality of tea plantation soil. Improving GRSP is an effective way for the both SOC sequestration and soil health after long-term tea plantation.

Effect of different inoculation treatments on AM fungal communities and the sustainability of soil remediation in Daliuta coal mining subsidence area in northwest China

Artificial ecological engineering plays an important role in promoting the restoration of mining subsidence areas. To investigate the effects of field inoculation on soil remediation, field studies were conducted in Shendong Daliuta mining area in Yulin, northwest China. Amorpha fruticose plants were treated with under five different inoculations, Funneliformis mosseae (F. m), Rhizophagus intraradices (R. i), F. mosseae and R. intraradices (F. m + R. i), Pantoea sp. (CA), F. mosseae and Pantoea sp. (F. m + CA), as well as no inoculation (CK) as control. The diversity and structure of arbuscular mycorrhizal (AM) fungal communities, glomalin, and soil organic carbon (SOC), available phosphorus, available nitrogen, soil pH were investigated. Based on pyro-sequencing on small subunit ribosomal RNA genes (SSUs), 63 AM fungal operational taxonomic units (OTUs) were identified, which belonged to six genera and two families. F. m + CA inoculation exhibited the highest available phosphorus, the lowest N/P ratio, and higher the ratio between total glomalin-related soil protein (T-GRSP) fractions and soil organic carbon (SOC). Fungal community diversity indices, including Shannon-Wiener, Simpson, and pielou, in F. m inoculation were significantly lower than others, and the phylogenetic index in F. m + CA inoculation was the highest (P < 0.05). In addition, Permutational multivariate analysis of variance (PerMANOVA) and non-metric multidimensional scaling (NMDS) analyses showed that the distribution of AM fungal communities without F. m inoculation were not significantly different from CK. These results demonstrated that the diversities and structures of AM fungal communities were sensitive indicators for monitoring the environmental changes in subsidence area. Furthermore, structural equation model (SEM) showed that AM fungal diversity had direct effects on T-GSRP. In summary, field inoculation of Amorpha fruticose plants had a valid effect on soil remediation, and F. m + CA inoculation is the befitting combination for soil restoration in the experimental field.

Towards meaningful quantification of glomalin‐related soil protein (GRSP) taking account of interference in the Coomassie Blue (Bradford) assay

Glomalin‐related soil protein (GRSP), an operationally defined fraction of soil organic matter containing protein and various other components, is usually quantified using the colorimetric nonspecific Bradford method. This method is limited by a short working range, a nonlinear response and interference from co‐extracted compounds. These limitations hinder the exact quantification of the protein component. The aim of this study was to investigate the source of interference in the Bradford quantification of GRSP and propose several methodological improvements based on identified interferences. The easily extractable and total GRSP in five topsoils with contrasting texture, organic carbon content and land use were compared. Results showed that: (a) the extent of interference varied between different soils, (b) the standard addition method overestimated the extent of inhibition, (c) absorbance should be corrected for colour, (d) use of the ratio of absorbances at 595 and 465 nm, A595/A465, is not recommended because it is sensitive to pH and dilution‐dependent absorbance at 465 nm, (e) although a quadratic fit to the protein calibration curve was better than the linear fit, it was not possible for the dilution method, and (f) estimation of protein content from the dilution curve of the soil extract appeared to be suitable as it integrates the often observed, and hitherto unexplained, effect of dilution on the calculated protein content of soil extracts and avoids artefacts because of the choice of protein spike and dilution.Highlights Soil protein colorimetric quantification is hampered by co‐extracted compounds. Variants of Bradford assay of glomalin‐related soil protein are tested for five contrasting soils. Direct assay underestimates soil protein, but standard addition may overestimate. Controlled sample dilution with colour correction might give the best estimate of soil protein.

Effects of freeze-thaw cycles on aggregate-associated organic carbon and glomalin-related soil protein in natural-succession grassland and Chinese pine forest on the Loess Plateau

Glomalin-related soil protein (GRSP) is a hydrophobic glycoprotein that can protect soil organic carbon (SOC) from decomposition by promoting the formation of soil aggregates. Few studies, however, have evaluated the response of aggregate-associated SOC and GRSP to freeze-thaw cycles (FTs) under different patterns of vegetation restoration. Soil samples were collected from three typical natural-succession grasslands (dominated by Artemisia capillaris, A. sacrorum, and Bothriochloa ischaemum) and a Chinese pine (Pinus tabuliformis) forest before and after natural FTs during a winter-spring season on the Loess Plateau in China. The soil aggregate stability and concentrations of SOC, easily extractable GRSP (EE-GRSP) and total GRSP (T-GRSP) in different aggregate fractions were measured. The FTs decreased the proportion of >5.0 mm wet-sieved fractions, increased the proportion of <0.25 mm wet-sieved fractions, and decreased the mean weight diameters by 8.7, 9.5, 2.9, and 9.4% in the soils of A. capillaris, A. sacrorum, B. ischaemum, and P. tabuliformis, respectively. The SOC, T-GRSP, and EE-GRSP concentrations in each aggregate fraction generally decreased after FTs in the four vegetation types. The SOC, T-GRSP, and EE-GRSP concentrations did not differ significantly in the larger aggregate fractions before the FTs in the soils for B. ischaemum and P. tabuliformis, but their concentrations were significantly higher for B. ischaemum than P. tabuliformis after FTs. The SOC and GRSP concentrations were significantly and linearly correlated in most aggregate fractions both before and after the FTs. These results indicated that the FTs decreased SOC by decreasing the GRSP concentration in each aggregate fraction and that SOC was more sensitive to FTs in forest than in natural-succession grassland.

Glomalin-related soil protein influences the accumulation of polycyclic aromatic hydrocarbons by plant roots

Studies have demonstrated that the inoculation of soil with arbuscular mycorrhizal fungi (AMF) enhances the content of glomalin-related soil protein (GRSP), which in turn elevates the availability of polycyclic aromatic hydrocarbons (PAHs) in soil. However, few studies have examined the influence of GRSP on PAH accumulation by plants and their tissues. Understanding of this issue would provide new perspectives on the role of GRSP in PAH uptake by plants at contaminated sites. This investigation was the first observational study of the GRSP-influenced PAH accumulation in roots of ryegrass (Lolium multiflorum Lam.). GRSP (0–120 mg/L) enhanced the root PAH accumulation in a GRSP-concentration-dependent manner, based on the observed root concentrations and root concentration factors (RCFs). The greatest enhancement of ΣPAH accumulation appeared at 40 mg/L of the total GRSP (T-GRSP) and 80 mg/L of the easily extracted GRSP (EE-GRSP), respectively. The weakly and strongly adsorbed fractions accounted for 88.8–94.4%, while the absorbed fraction contributed no >11.2% of total PAH accumulation in roots. The capacity of PAH adsorption on roots was enlarged in the presence of GRSP (0–120 mg/L). As the adsorbed fraction dominated the total PAH contents in roots overwhelmingly, the GRSP-induced changes in root PAH accumulation were ascribed to GRSP-affected PAH sorption by roots.

Nitrogen addition increases the contents of glomalin-related soil protein and soil organic carbon but retains aggregate stability in a Pinus tabulaeformis forest.

BackgroundGlomalin-related soil protein (GRSP) and soil organic carbon (SOC) contribute to the formation and stability of soil aggregates, but the mechanism by which global atmospheric nitrogen (N) deposition changes soil aggregate stability by altering the distribution of GRSP and SOC in different aggregate fractions remains unknown.MethodsWe used a gradient N addition (0–9 g N m−2 y−1) in Pinus tabulaeformis forest for two years in northeast China and then examined the changes in SOC contents, total GRSP (T-GRSP), and easily extractable GRSP (EE-GRSP) contents in three soil aggregate fractions (macro-aggregate: >250 μm, micro-aggregate: 250–53 μm, and fine material: <53 μm) and their relationship with aggregate stability.Results(1) The soil was dominated by macro-aggregates. Short term N addition had no significant effect on mean weight diameter (MWD) and geometric mean diameter (GMD). (2) GRSP varied among aggregate fractions, and N addition had different effects on the distribution of GRSP in aggregate fractions. The EE-GRSP content in the macro-aggregates increased initially and then decreased with increasing N addition levels, having a peak value of 0.480 mg g−1 at 6 g N m−2 y−1. The micro-aggregates had the lowest EE-GRSP content (0.148 mg g−1) at 6 g N m−2 y−1. Furthermore, the T-GRSP content significantly increased in the aggregate fractions with the N addition levels. (3) The macro-aggregate had the highest SOC content, followed by the micro-aggregate and the fine material had the lowest SOC content. N addition significantly increased the SOC content in all the aggregate fractions. (4) GRSP and SOC contents were not significantly correlated with MWD.ConclusionGlomalin-related soil protein and SOC contents increased by N addition, but this increase did not enhance aggregate stability in short term, and the improvement of stability might depend on binding agents and incubation time.

Tensile strength of mollisols of contrasting texture under influence of plant growth and crop residues addition

Tensile strength (TS) of soil aggregates is considered a sensitive and important indicator of the effects of the management practices on soil structure quality, which affects the seed germination and the initial crop growth. However, the influence of plant growth, crop residues addition and the produced aggregating agents on TS has not been widely studied. The objectives of this study were: i) to determine the specific effects of plant growth and different types, rates and location of crop residues in the aggregates tensile strength, and ii) to assess the relationship between the aggregating agents produced by plant growth and crop residues addition and the aggregate tensile strength of soils of contrasting texture. A greenhouse experiment was carried out in pots with a loamy soil (Typic Hapludoll, Santa Isabel series) and a silty-loamy soil (Typic Argiudoll, Esperanza series) under controlled conditions for 112 days. For each soil the following treatments were set up in triplicate: (i) soil type, (ii) with or without plant growth of wheat (Triticum aestivum L.), (iii) with or without residues addition, (iv) location of residues (surface vs. incorporated), (v) wheat vs. soybean (Glycine max L.) residues, and (vi) residue rates (6.3 and 15.7 g of dry matter per pot for wheat, and 6.3 and 18.8 g of dry matter per pot for soybean). Pots were exposed to wetting and drying (W/D) cycles. TS values and aggregating agent's content, i.e., total organic carbon (TOC), particulate organic carbon (POC), hot water extractable carbohydrates (HWEC), dilute acid extractable carbohydrates (DAC), total carbohydrates (TC), total glomalin-related soil protein (T-GRSP), and easily extractable glomalin-related soil protein (EE-GRSP) were measured. TS were significantly lower in the Typic Hapludoll (TS = 39.9 kPa) than in the Typic Argiudoll (TS = 61.6 kPa). TS values were significantly higher in the treatments with plants of wheat than in treatments without plants (49.5 vs. 30.3 kPa in the Hapludoll and 71.2 vs. 50.9 kPa in the Argiudoll). Plant growth increased TS through physical mechanisms, i.e. a greater number of drying-wetting cycles. Also, plant growth increased TS by producing aggregating agents. TS values were not directly affected by the addition of different types, rates and locations of crop residues. However, they increased the content of aggregating agents. Multiple regression analysis showed that TS was significantly related to soil type, TC and T-GRSP. TS increased with increasing TC and T-GRSP. These two variables explained 87% of the model variation. The obtained model provides a basis for understanding which are the most important aggregating agents and, consequently, which are the better management systems to improve o recover the structure quality of soils with different textures.

Glomalin‐related soil protein in the rhizosphere of Robinia pseudoacacia L. seedlings under higher air temperature combined with Cd‐contaminated soil

SummaryGlomalin‐related soil protein (GRSP) can bind heavy metals and plays an important role in soil carbon sequestration. The GRSP contains glycoproteins produced by arbuscular mycorrhizal fungi (AMF), as well as lipids, humic materials and non‐mycorrhizal‐related heat‐stable proteins, which might be affected by environmental conditions. Current and predicted changes in global climate make it important to understand how GRSP might be affected by higher atmospheric temperatures and heavy metal contamination of soil. Here, we investigated the response of GRSP to higher temperature in the rhizosphere of Robinia pseudoacacia L. seedlings in cadmium (Cd)‐contaminated soil. Easily extractable (EE) and total (T) GRSP concentrations increased significantly (P &lt; 0.05) under Cd pollution alone. Compared with ambient temperature, a higher temperature (2.7°C) alone significantly (P &lt; 0.05) increased EE‐ and T‐GRSP concentrations, the EE‐GRSP:T‐GRSP ratio and the GRSP:soil organic carbon (SOC) ratio, but significantly (P &lt; 0.05) decreased SOC content in the rhizosphere. Higher temperature significantly (P &lt; 0.05) increased EE‐ and T‐GRSP concentrations, the EE‐GRSP:T‐GRSP ratio and the GRSP:SOC ratio, but decreased SOC content under Cd pollution. Under higher temperature, the amount of Cd bound to GRSP increased significantly (P &lt; 0.05), and available Cd content decreased significantly (P &lt; 0.05). Glomalin‐related soil protein contributed more carbon to the rhizosphere SOC pool under higher temperature + Cd than under Cd alone, and the higher temperature led to a significant (P &lt; 0.05) decrease in available Cd. Under the higher temperature, T‐GRSP contributed more to the decrease in available Cd than did EE‐GRSP. Increases in GRSP resulting from higher temperatures could increase Cd binding in contaminated soil.HighlightsHigher temperature increased GRSP in the rhizosphere of R. pseudoacacia seedlings. The amount of Cd bound to GRSP increased under higher temperature. Available Cd in rhizosphere soil decreased under higher temperature. Higher temperature could contribute to chelation of Cd‐contaminated soil.

Glomalin-related soil protein deposition and carbon sequestration in the Old Yellow River delta

Glomalin-related soil protein (GRSP), a particular terrigenous-derived carbon (C), is transported to the coastal oceans, where it accumulates in sediments. We hypothesized that terrigenous C (GRSP) accumulation could enhance marine C sequestration, and sediment fertility would increase the C stock in the marine ecosystem. In this study, we tested GRSP contribution to marine sediment C, nitrogen (N) and iron (Fe), and explored whether GRSP deposition varied with sediment fertility levels in the Old Yellow River delta. The mean concentration of total GRSP was 1.10±0.04mgg−1 (0.24MgCha−1), accounting for 6.41±0.17% of total organic C and 3.75±0.13% of total N in the 0–10cm marine sediments, indicating that the coastal marine system is an important sink of GRSP. GRSP also contained 1.46±0.06% Fe (20.7kgFeha−1), accounting for 0.058±0.003% of total Fe in marine sediments. Meanwhile, Fe-content in GRSP significantly decreased with distance from the shore, indicating that Fe was released with GRSP transfer and thus GRSP was a new natural Fe fertilization in marine environment. Furthermore, GRSP enhanced marine C sequestration by its rapid deposition and Fe contribution. Combined indicators of sediment fertility (factor 1) were significantly positively correlated with GRSP concentrations by Principal Component Analysis. Co-deposited with nutrient elements, GRSP fractions were accumulated more in more fertile sediments but less in less fertile sediments. GRSP, a mixture of co-existent multiple elements, can be used as a nutrient controlled-release agent in the marine ecosystem. GRSP fractions were responsive to marine sediment fertility levels and the understanding of their function in sediment C sequestration will provide new insights into the importance of terrestrial-marine linkages.

Is glomalin an appropriate indicator of forest soil reactive nitrogen status?

AbstractIn this paper we address total glomalin‐related soil protein (T‐GRSP) as a possible indicator of differences in forest soils related to reactive nitrogen and forest composition. We focused especially on the relationship between T‐GRSP (g kg−1), soil organic carbon (SOC), and reactive nitrogen (Nr) availability among different categories of temperate forests and different horizons. Our study included 105 sampling sites divided into 5 categories, which vary in elevation and tree species composition (coniferous, deciduous, mixed). We detected significantly higher T‐GRSP and SOC in the F+H horizon under conifers. We assume that this observation might be attributed to suppression of decomposition of T‐GRSP and SOC by nature of coniferous litter. The lack of significant differences in T‐GRSP/SOC among the categories and the positive correlations between T‐GRSP and SOC in most of the categories confirmed the strong relationship of T‐GRSP with SOC. We found a significantly higher content of T‐GRSP in the F+H horizon for all studied forest categories. However, the contribution of T‐GRSP to SOC is significantly higher in the A horizon, which might be caused by stabilization of glomalin by mineral fraction, including clay minerals or by the belowground origin of glomalin. We found the increase of SOC with increasing Nr in the A horizon for most categories of forest. T‐GRSP follows this trend in the case of deciduous forests (decid), mixed forest (mixed), and mountain forests (mount). On the other hand, we detected a decrease of T‐GRSP with increasing Nr in the F+H horizon of coniferous forests (conif). Moreover the T‐GRSP/SOC decreases with the increase of Nr in the A horizon of conif, mixed and mount, which points to the higher sensitivity of forest with prevalence of coniferous trees. Our observations have confirmed an ecosystem‐specific relationship between T‐GRSP, SOC and Nr. We concluded that T‐GRSP in combination with T‐GRSP/SOC has the potential to reveal qualitative changes in soil organic matter (SOM) connected with increasing Nr.

Glomalin contributed more to carbon, nutrients in deeper soils, and differently associated with climates and soil properties in vertical profiles

Despite vital importance in soil conditioning and a proxy for arbuscular mycorrhizal (AMF), glomalin-related soil protein (GRSP) contribution to soil carbon and nutrients at vertical soil profiles and underlying mechanism were not well-defined yet. Thus, 360 soil samples were collected from 72 farmland 1-m soil profiles in northeastern China, and soil physiochemical properties, nutrients, glomalin characteristics, local climates were determined. Linear decreases of glomalin amounts were observed from the top to deep soils, and glomalin/SOC (glomalin ratio to total SOC) in the 80–100 cm soil (EEG, easily-extracted GRSP, 2.2%; TG, total GRSP, 19%) was 1.34–1.5-fold higher than did in the 0–20 cm soil. Different statistical analyses crosschecked that the lower pH and higher SOC usually accompanied with the higher EEG and TG, while EEG was more sensitive to climates; Moreover, glomalin was more physiochemical-regulated in the deep soils, but more nutrient-regulation was found in the surface soils. Structure Equation Model showed that soil depths and climates indirectly affected TG and EEG features through soil properties, except significant direct effects on EEG. In future, glomalin assessment should fully consider these for identifying the AMF importance in the whole 1-m profile, and our findings also favor degrade soil improvement from glomalin rehabilitation.

Spatial distribution of glomalin-related soil protein and its relationship with sediment carbon sequestration across a mangrove forest

Arbuscular mycorrhizal (AM) fungi produce a recalcitrant glycoprotein, (glomalin-related soil protein (GRSP)), which can contribute to soil carbon sequestration. Here we made a first study to characterize the spatial distribution of GRSP fractions in a mangrove forest at Zhangjiang Estuary, Southeastern China and to explore potential contributions of GRSP to sediment organic carbon (SOC) in this forest. We identified GRSP fractions in surface sediments, as well as those at a depth of 50 cm. The contents of easily extractable GRSP (EE-GRSP), total GRSP (T-GRSP), GRSP in particulate organic matter (POM-GRSP) and GRSP in pore water (PW-GRSP) ranged between 1.20–2.22mgg−1, 1.38–2.61mgg−1, 1.45–10.78mgg−1 and 10.35–39.65mgL−1 respectively, and these four GRSPs are significantly affected by sample sites and sediment layers. Carbon in GRSP accounted for 2.8–5.9% of SOC and its contributions can far exceed that of microbial biomass carbon (0.21–0.73%) in the 0–50cm sediment layers. Our data indicate that GRSP could be transported by pore water and accumulated in sediment profiles. The non-linear regression analysis revealed that as SOC and particulate organic carbon (POC) contents decrease, GRSP proportions increase, indicating the increase of the recalcitrant carbon offsetting the effects of mangrove carbon loss, especially labile C. Regression and ordination analyses indicated that GRSP fractions were mainly positively correlated with sediment carbon fractions and spore density but were negatively correlated with sand, pH. Strikingly, the unfavorable environmental factors for microbial organisms, especially AM fungi, prove to be able to promote the production or accumulation of GRSP. We propose that there are two different pathways for affecting the pool size of GRSP in mangrove ecosystems: (i) directly via indigenous AM fungi propagules; (ii) or via the GRSP transport and deposition by pore water and tides.

Inoculation with arbuscular mycorrhizal fungi increases glomalin-related soil protein content and PAH removal in soils planted with Medicago sativa L.

This was the first observation of the enhancement of glomalin-related soil protein (GRSP) content by the arbuscular mycorrhizal fungi (AMF) inoculation of soils contaminated with pyrene as a representative polycyclic aromatic hydrocarbon (PAH), and GRSP content was significantly positively correlated with PAH removal in mycorrhizal soils. Both total GRSP and easily extractable GRSP promoted the release of pyrene from soil solids into solution, consequently assisting the microbial biodegradation of pyrene in soil. The results provide insight into the role of GRSP in AMF-aided rhizoremediation and will be beneficial for improving remediation efficiency at PAH-contaminated sites.

Intensive management decreases soil aggregation and changes the abundance and community compositions of arbuscular mycorrhizal fungi in Moso bamboo (Phyllostachys pubescens) forests

Intensive management practices, such as inorganic fertilization, soil tillage and understory removal, have been widely used to increase bamboo products and economic return in Moso bamboo (Phyllostachys pubescens) forests. Arbuscular mycorrhizal fungi (AMF) play a critical role in soil aggregation and carbon cycling. However, little is known about the effects of such long-term soil disturbance on soil AMF community composition and abundance, and their linkage to aggregation in Moso bamboo forests. We investigated soil chemical properties, water-stable soil aggregates, glomalin-related soil protein (GRSP), AMF community composition and biomass across a chronosequence of long-term intensively managed Moso bamboo forests (0, 10, 15, 20 and 25years of intensive management) in a subtropical region of China. Our results showed that intensive management resulted in significant decreases in soil pH and high accumulations of soil available N, P and K contents. Both soil AMF biomass (indicated by neutral lipid fatty acid) and total GRSP content were significantly decreased with increasing duration under intensive management. High-throughput sequencing showed that intensive management greatly altered soil AMF community composition, and soil available N, P and K were important driving factors shaping it. Soil macroaggregate (>250μm) proportion decreased by 20–29% in bamboo forest soils after 15years of intensive management. Soil macroaggregate proportion and organic C content were found significantly and positively correlated with AMF biomass and total GRSP content, respectively, indicating a high risk of soil erosion and organic C depletion when AMF biomass was reduced in long-term intensively managed bamboo forests. In conclusion, our study suggests that long-term intensive management induced alterations in abundance and community composition of AMF are responsible for the decrease in soil aggregation in the Moso bamboo forests. Alternative management practices, such as reduced tillage and organic amendments, are urgently needed to improve AMF community in order to enhance soil aggregation and C sequestration in Moso bamboo forests.

Dynamics of arbuscular mycorrhizal fungi and glomalin under Psammochloa villosa along a typical dune in desert, North China

The temporal and spatial dynamics of AM fungi and glomalin were investigated in Saibei sandland, North China. The soil samples in the rhizosphere of Psammochloa villosa were collected from the three sites (the top-dune, mid-dune, and foot-dune) along one typical dune in June, August, and October 2013 and 2014. The results demonstrated that P. villosa could form symbiotic relationships with AM fungi. The AM fungal status and glomalin significantly differed among the three studied plots and six sampling times. Correlation coefficient analysis revealed that spore density was significantly and positively correlated with soil moisture, soil organic carbon (SOC), available K, and phosphatase activities. Furthermore, the total infection level was significantly and positively correlated with soil edaphic factors. The two glomalin-related soil proteins (total glomalin-related soil proteins and easily extractable glomalin-related soil proteins) were also significantly and positively correlated with soil edaphic factors. The means of total glomalin-related soil proteins (T-GRSP,TG) and easily extractable glomalin-related soil proteins (EE-GRSP,EEG) were 3.03 and 0.68 mg·g−1, respectively. The GRSP levels in Saibei sandland were lower than those in grassland soils, but the GRSP:SOC ratios were higher than those noted in grassland and some desert soils. Thus, the dynamics of AM fungi and glomalin exhibited highly temporal and spatial patterns, which were influenced by soil factors in Saibei sandland. Moreover, AM fungal infections and glomalin may be useful to monitor desertification and soil degradation.

Contribution of glomalin to dissolve organic carbon under different land uses and seasonality in dry tropics

Glomalin related soil protein (GRSP) is a hydrophobic glycoprotein that is significant for soil organic carbon (SOC) persistence and sequestration, owing to its large contribution to SOC pool and long turnover time. However, the contribution of GRSP to dissolve OC (DOC) leach from soil is not yet comprehensively explored, though it could have implication in understanding SOC dynamics. We, therefore, aim to measure the contribution of GRSP to DOC, in a range of land uses and climatic seasons in the dry tropical ecosystem. Our results demonstrated that a significant proportion of GRSP (water soluble GRSP; WS-GRSP) leached with DOC (7.9–21.9 mg kg-1), which accounts for 0.2–0.23% of soils total GRSP (T-GRSP). Forest exhibited significantly higher WS-GRSP and DOC leaching than fallow and agriculture. WS-GRSP and DOC accumulations were higher in the dry season (summer and winter) than in rainy. The extent of seasonal variations was higher in forest than in other two land uses, indicating the role of vegetation and biological activity in soil dissolve organic matter (DOM) dynamics. The regression analysis among WS-GRSP, T-GRSP, DOC and SOC prove that the accumulations and leaching of GRSP and other soil OM (SOM) depend on similar factors. The ratio of WS-GRSP-C to DOC was higher in agriculture soil than in forest and fallow, likely a consequence of altered soil chemistry, and organic matter quantity and quality due to soil management practices. Multivariate analysis reflects a strong linkage among GRSP and SOC storage and leaching, soil nutrients (nitrogen and phosphorus) and other important soil properties (pH and bulk density), suggesting that improving GRSP and other SOM status is an urgent need for the both SOC sequestration and soil health in dry tropical agro-ecosystems.

Effects of soil salinity on the content, composition, and ion binding capacity of glomalin-related soil protein (GRSP).

Soil aggregation, an ecosystem function correlated with the concentration of glomalin-related soil protein (GRSP), is highly disturbed in saline soil. However, few studies have focused on differences in amount, composition, and ion binding capacity of GRSP in typical sodic-saline soils. In this study, a field study was performed in Songnen Plain. Combined indicators of soil salinity (Q value) were significant negatively correlated with GRSP concentration by Principal Component Analysis. Multiple linear regression models showed that soil salinity might account for 46%, 25% and 44% variation in total GRSP (T-GRSP), easily-extractable GRSP (EE-GRSP) and difficultly-extractable GRSP (DE-GRSP), respectively. Soil bulk density had most important impact on GRSP concentration, followed by the pH, soil EC had the weak influence. Comparative analysis was carried out between low-salinity and high-salinity soil. Purified T-GRSP of high-saline soil contained higher N content (13.13%), lower C content (43.41%) and lower functional groups relative content (e.g. CO and SiOSi). Purified T-GRSP of high-salinity soil had a greater binding capacity with calcium and phosphorus, the binding capacity could compensate the GRSP loss about 29.8% and 14.1%, respectively. Our findings suggested that sodic salinization of the soil led to a decrease in GRSP concentration and a change in the component percentages. This change in composition might be related to adaptation of fungi-plant systems to varied environments. The calcium and phosphorus binding capacity had a positive dependent of soil salinization, which was possible to develop ecological management or recovery technology in the future.

落叶松、水曲柳、樟子松和农田土壤指标差异及其综合比较

PDF HTML阅读 XML下载 导出引用 引用提醒 落叶松、水曲柳、樟子松和农田土壤指标差异及其综合比较 DOI: 10.5846/stxb201603080412 作者: 作者单位: 东北林业大学，森林植物生态学教育部重点实验室,东北林业大学，森林植物生态学教育部重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家"十三五"重点研发项目（2016YFA0600802）；黑龙江省杰出青年基金（JC201401）；中央高校创新团队与重大项目培育资金项目（2572014EA01）；国家自然基金资助项目（41373075） Larch, ash, Scots pine, and farmland-induced differences on 17 soil parameters and their comprehensive analyses Author: Affiliation: Key Laboratory of Forest Plant Ecology Ministry of Education, Northeast Forestry University,Key Laboratory of Forest Plant Ecology Ministry of Education, Northeast Forestry University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:东北地区以大森林和大农业为主要特色，主要造林树种落叶松、水曲柳、樟子松及农田对土壤肥力、物理指标、盐碱度、碳截获等的影响差异是本文研究目的。选择秀水林场和帽儿山林场的4种植被类型进行0-60cm分层土壤采样，对根系密度、土壤pH、电导率、全氮、全磷、全钾、碱解氮、速效磷、速效钾、土壤真菌代谢产物（球囊霉素相关蛋白易提取球囊霉素EEG、总提取球囊霉素TG）、容重、比重、孔隙度、比表面积、SOC、有机碳矿化速率等17个指标进行研究。主要结论如下：植被类型间的差异在不同土层之间表现一致的指标所占比例很大，其中秀水林场13个指标，帽儿山林场全部17个指标。尽管不同地点间土壤差异较大，但也存在树种差异一致性。土壤物理性质（容重、比重、孔隙度、比表面积）维持方面，两个林场均显示水曲柳综合得分最高，说明其具有更好的土壤物理性质维持能力，且多通过土壤容重下降来实现。土壤固碳能力得分最高的也是水曲柳，并且两个研究地点结果类似，主要与其高根系密度有关。综合土壤肥力维持能力（N、P、K及其有效态及真菌代谢产物球囊霉素相关蛋白），不同地点间植被类型差异排序不同。降低土壤盐碱能力（pH和电导率）方面，樟子松得分最高，尽管不同地点不尽一致。不同植被类型对土壤影响尽管不同地点、不同土壤深度多不相同，但总体上存在规律性，特别是土壤物理性质维持和土壤固碳能力方面。进行造林绿化时应该根据造林目的进行树种选择，提升土壤物理性质应该考虑种植更能够维持良好土壤物理性质的树种（如水曲柳、樟子松等），而提升土壤碳截获则要考虑根系密度大的树种（如水曲柳）。相关研究结果对国家重大生态工程（三北防护林、退耕还林）工程生态功能评价以及后续管理、树种选择具有支撑作用。 Abstract:The main characteristics of Northeast China are large forests and agriculture. The effect of the primary afforestation species (larch: Larix gmelinii, ash: Fraxinus mandschurica, Scots pine: Pinus sylvestris var. mongolica) and farmland on soil fertility, physical properties, salinity, and carbon sequestration were analyzed. In the present study, four vegetation types were selected from Xiushui Forest and Maoershan Forest Farms, and samples from 0–60 cm soils were collected for measuring 17 parameters, including root density, soil pH, electrical conductance(EC), alkali-hydrolyzed nitrogen(AN), total nitrogen(TN), available phosphorus(AP), total phosphorus(TP), available potassium(AK), total potassium(TK), glomalin related soil protein (GRSP) (including easily extracted GRSP (EEG) and total GRSP (TG)), soil bulk density, soil specific gravity, soil porosity, soil specific surface area, soil organic carbon(SOC), and organic carbon mineralization rate. The main conclusions were as follows: inter-species differences between most of the measured indicators were consistent in different soil layers, including 13 indicators in the Xiushui Forest Farm and all 17 indicators in the Maoershan Forest Farm samples. Although there were considerable differences in soil between different locations, the inter-species differences were consistent. Through comprehensive analyses, standardized comprehensive scores of two forest farm-related indicators showed that ash had the highest scores regarding its ability to maintain the physical properties of soil. Therefore, ash had the greatest ability of all the trees and farmland to maintain the physical properties of soil, and depended primarily on decreased soil bulk density. Ash also showed the highest scores for soil carbon sequestration, with similar results at both locations, mainly related to its higher root density. The comprehensive soil fertility (N, P, K, and its effective state, and fungal metabolic product GRSP) indicated inter-species differences between the different locations. Scots pine had the highest scores for reducing the soil salinity (pH and EC). The effects of different vegetation types on the soil were not the same in different locations and soil depths, but there was a general regularity, especially regarding the soil physical properties and carbon sequestration. Therefore, the selection of tree species for afforestation should be planned depending on the particular purpose of afforestation. To improve the physical properties of soil, plant species with the ability to maintain the physical properties effectively (e.g.,ash, Scots pine) should be considered; and to enhance soil carbon sequestration, plant species with large root densities (e.g., ash) should be considered. The findings in this paper will enhance the evaluation of the national ecological projects of the Three-North Shelterbelt Project and Returning Farmland to Forest Project, and forest management including tree species selections. 参考文献 相似文献 引证文献

Systematicness of glomalin in roots and mycorrhizosphere of a split-root trifoliate orange

Understanding the behavior of mycorrhiza-originated glomalin, either of plant or soil origin, is anticipated to facilitate better opportunities of modulating antioxidants and carbon distribution in plants. In this study, trifoliate orange seedlings with half of roots were colonized by Acaulospora scrobiculata and Funneliformis mosseae in a split-root rootbox. Mycorrhizal inoculation showed a significantly higher plant biomass of trifoliate orange, regardless of mycorrhizal species. Glomalin-related root protein showed a systematic increase in non-mycorrhiza-inoculated chamber under inoculation with A. scrobiculata and F. mosseae than under non-mycorrhizal inoculation. Similar increase was also observed in easily extractable glomalin-related soil protein and total glomalin-related soil protein as a result of F. mosseae colonization only. Mean weight diameter and soil organic carbon were significantly higher under mycorrhization than non-mycorrhization, irrespective of mycorrhized or non-mycorrhized chamber. Mycorrhizal inoculation stimulated an increase in soil protease activity in the mycorrhized chamber, without any distinctive change in the non-mycorrhized chamber. These results, hence, suggested that mycorrhization conferred a systematic increase in glomalin synthesis in roots and soils, collectively, aiding in better aggregate stability and soil carbon sequestration.