scholarly journals Effects of sulfuric, nitric, and mixed acid rain on the decomposition of fine root litter in Southern China

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Xin Liu ◽  
Miaojing Meng ◽  
Yong Zhang ◽  
Chong Li ◽  
Shilin Ma ◽  
...  
Keyword(s):  
Acid Rain ◽  
Soil Ph ◽  
Decomposition Rate ◽  
Enzyme Activities ◽  
Fine Roots ◽  
Forest Ecosystems ◽  
Fine Root ◽  
Total Carbon ◽  
Root Litter ◽  
Soil Urease

Abstract Background China has been increasingly subject to significant acid rain, which has negative impacts on forest ecosystems. Recently, the concentrations of NO3− in acid rain have increased in conjunction with the rapid rise of nitrogen deposition, which makes it difficult to precisely quantify the impacts of acid rain on forest ecosystems. Methods For this study, mesocosm experiments employed a random block design, comprised of ten treatments involving 120 discrete plots (0.6 m × 2.0 m). The decomposition of fine roots and dynamics of nutrient loss were evaluated under the stress of three acid rain analogues (e.g., sulfuric (SO42−/NO3− 5:1), nitric (1:5), and mixed (1:1)). Furthermore, the influences of soil properties (e.g., soil pH, soil total carbon, nitrogen, C/N ratio, available phosphorus, available potassium, and enzyme activity) on the decomposition of fine roots were analyzed. Results The soil pH and decomposition rate of fine root litter decreased when exposed to simulated acid rain with lower pH levels and higher NO3− concentrations. The activities of soil enzymes were significantly reduced when subjected to acid rain with higher acidity. The activities of soil urease were more sensitive to the effects of the SO42−/NO3− (S/N) ratio of acid rain than other soil enzyme activities over four decomposition time periods. Furthermore, the acid rain pH significantly influenced the total carbon (TC) of fine roots during decomposition. However, the S/N ratio of acid rain had significant impacts on the total nitrogen (TN). In addition, the pH and S/N ratio of the acid rain had greater impacts on the metal elements (K, Ca, and Al) of fine roots than did TC, TN, and total phosphorus. Structural equation modeling results revealed that the acid rain pH had a stronger indirect impact (0.757) on the decomposition rate of fine roots (via altered soil pH and enzyme activities) than direct effects. However, the indirect effects of the acid rain S/N ratio (0.265) on the fine root decomposition rate through changes in soil urease activities and the content of litter elements were lower than the pH of acid rain. Conclusions Our results suggested that the acid rain S/N ratio exacerbates the inhibitory effects of acid rain pH on the decomposition of fine root litter.

scholarly journals Decomposition and Temperature Sensitivity of Fine Root and Leaf Litter of 43 Mediterranean Species

2021 ◽  
Author(s):  
Giuliano Bonanomi ◽  
Mohamed Idbella ◽  
Maurizio Zotti ◽  
Lucia Santorufo ◽  
Riccardo Motti ◽  
...  
Keyword(s):  
Decay Rate ◽  
Leaf Litter ◽  
Temperature Sensitivity ◽  
Decomposition Rate ◽  
Fine Roots ◽  
Fine Root ◽  
Mediterranean Species ◽  
Lignin Concentration ◽  
N Concentration ◽  
Root Litter

Abstract Aims: Data on the decomposition of fine roots are scarce for the Mediterranean basin. This work aims to compare chemical traits, decomposition rate, and temperature sensitivity (Q10) for root and leaf litter of 43 Mediterranean species. Methods: We carried out a two-years litterbag decomposition experiment using 43 fine roots litter and leaf litter types incubated in laboratory conditions at three different temperatures, i.e. 4°C, 14°C, and 24°C. Litter was characterized for carbon (C), nitrogen (N), lignin and cellulose concentration, C/N, and lignin/N ratios. Results: Fine root litter had lower N content but higher lignin concentration, lignin/N, and C/N ratios compared to leaf litter. The decay rate of fine root litter was slower than leaf litter. For both tissues, the decay rate was negatively associated with lignin concentration, lignin/N, and C/N ratios but positively with N concentration. Q10 was higher for fine root than leaf litter, with a positive correlation with lignin while negative with N concentration. Conclusions: Our findings demonstrate a higher Q10 accompanied by a slower decomposition rate of fine root litter compared to leaf litter in Mediterranean ecosystems. These results must be considered in modeling organic C at the ecosystem scale.

scholarly journals Decomposition and temperature sensitivity of fine root and leaf litter of 43 mediterranean species

2021 ◽  
Author(s):  
Giuliano Bonanomi ◽  
Mohamed Idbella ◽  
Maurizio Zotti ◽  
Lucia Santorufo ◽  
Riccardo Motti ◽  
...  
Keyword(s):  
Decay Rate ◽  
Leaf Litter ◽  
Temperature Sensitivity ◽  
Decomposition Rate ◽  
Fine Roots ◽  
Fine Root ◽  
Mediterranean Species ◽  
Lignin Concentration ◽  
N Concentration ◽  
Root Litter

Abstract Aims Data on the decomposition of fine roots are scarce for the Mediterranean basin. This work aims to compare chemical traits, decomposition rate, and temperature sensitivity (Q10) for root and leaf litter of 43 Mediterranean species. Methods We carried out a two-years litterbag decomposition experiment using 43 fine roots litter and leaf litter types incubated in laboratory conditions at three different temperatures, i.e. 4 °C, 14 °C, and 24 °C. Litter was characterized for carbon (C), nitrogen (N), lignin and cellulose concentration, C/N, and lignin/N ratios. Results Fine root litter had lower N content but higher lignin concentration, lignin/N, and C/N ratios compared to leaf litter. The decay rate of fine root litter was slower than leaf litter. For both tissues, the decay rate was negatively associated with lignin concentration, lignin/N, and C/N ratios but positively with N concentration. Q10 was higher for fine root than leaf litter, with a positive correlation with lignin while negative with N concentration. Conclusions Our findings demonstrate a higher Q10 accompanied by a slower decomposition rate of fine root litter compared to leaf litter in Mediterranean ecosystems. These results must be considered in modeling organic C at the ecosystem scale.

scholarly journals Leaf and Root Litter Species Identity Influences Bacterial Community Composition in Short-Term Litter Decomposition

2020 ◽  
Author(s):  
Ying Lu ◽  
Kun Li ◽  
Ruiqiang Ni ◽  
Rongchu Han ◽  
Chuanrong Li ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Leaf Litter ◽  
Community Composition ◽  
Fine Roots ◽  
Bacterial Community Structure ◽  
Fine Root ◽  
Bacterial Community Composition ◽  
Litter Type ◽  
Opposite Result ◽  
Root Litter

Abstract Background: Microorganisms play a crucial role in litter decomposition in terrestrial ecosystems. However, it remains unclear, which effects of leaf litter and root species on bacterial community composition and diversity after one year's decomposition. Methods: The leaf and fine roots litters of Robinia pseudoacacia , Quercus acutissima , Pinus tabulaeformis and Pinus densiflora , which are the dominant afforestation species in Mount Tai, were analysed using the Nylon litterbag method and Illumina Miseq high-throughput sequencing for the amplification of bacterial 16S rRNA V4-V5. We measured the remaining litter mass and the bacterial community composition and assessed the effects of leaf and root litter species on the bacterial community after one-year decomposition periods.Results: (1) The remaining masses of leaf and fine roots litters of the four plant species were significantly influenced by organ type and species. The remaining mass of fine root litter was smaller than that of leaf litter for broad-leaved species, and the opposite result was found for coniferous species. (2) The observed species Chao1 and phylogenetic diversity values were significantly lower for leaf litters than for fine root litter. The community richness index was positively correlated with the C content, C:N and lignin content and negatively correlated with N:P, N content and P content. The bacterial community structure differed significantly among leaf and root litter decomposition for the four species ( p <0.05). The bacterial community structure in leaf litter was most highly correlated with the initial N content and N:P. The bacterial community structure in fine roots was most highly correlated with the lignin content. (3) The bacterial phyla Bacteroidetes , Acidobacteria and Gemmatimonadetes were significantly affected by litter and species type, and the relative abundances of Firmicutes and Chloroflexi were only affected by litter type. The relative abundances of Acidobacteria , Firmicutes and Chloroflexi in fine root litter were higher than those in leaf litter, while the opposite result was found for Bacteroidetes . The bacterial genera Burkholderia-Paraburkholderia , Sphingomonas and Mucilaginibacter were affected by litter type ( p <0.05). The relative abundance of Burkholderia-Paraburkholderia in fine root litter was higher than that in leaf litter, while the opposite result was found for Bradyrhizobium , Sphingomonas and Mucilaginibacter . Pearson correlation analysis showed that the average relative abundance of the dominant phyla and genera was affected by the initial litter properties, especially for Bacteroides , Acidobacteria , Burkholderia , and Sphingomonas . Conclusions: Litter type, interaction between litter type and species were important than species in shaping the bacterial diversity and community composition in decomposing litter. And this were affected by initial chemical properties of the litter.

scholarly journals Seasonal patterns of fine-root productivity and turnover in a tropical savanna of northern Australia

2004 ◽  
Vol 20 (2) ◽  
pp. 221-224 ◽  
Author(s):  
Xiaoyong Chen ◽  
Derek Eamus ◽  
Lindsay B. Hutley
Keyword(s):  
Fine Roots ◽  
Forest Ecosystems ◽  
Net Primary Productivity ◽  
Fine Root ◽  
Root Production ◽  
Seasonal Patterns ◽  
Tropical Savanna ◽  
Coarse Roots ◽  
Ecosystem Production ◽  
Below Ground

Fine roots and their turnover represent a dynamic aspect of below-ground biomass (BGB) and nutrient capital in forest ecosystems, and account for a significant fraction of net primary productivity (NPP) (Cuevas 1995, Vogt et al. 1990). On a weight basis, coarse roots contribute more to total ecosystem biomass than fine roots, but they account for only a small portion of annual root production (Eamus et al. 2002). Despite the fact that fine roots may compose less than 2% of total ecosystem biomass, they may contribute up to 40% of total ecosystem production (Vogt et al. 1990). Therefore, estimates of root production, like estimates of root biomass, should differentiate between coarse- and fine-root production.

Response of carbon utilization and enzymatic activities to nitrogen deposition in three forests of subtropical China

2015 ◽  
Vol 45 (4) ◽  
pp. 394-401 ◽  
Author(s):  
Yong-Sheng Wang ◽  
Shu-Lan Cheng ◽  
Gui-Rui Yu ◽  
Hua-Jun Fang ◽  
Jiang-Ming Mo ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Ph ◽  
Enzyme Activities ◽  
Southern China ◽  
Soil Enzyme ◽  
Total Carbon ◽  
N Addition ◽  
Soil Enzyme Activities ◽  
Microbial Biomass Nitrogen ◽  
Soil Microbial

Nitrogen (N) deposition has been shown to affect soil carbon (C) and N cycling in subtropical forests; however, the underlying microbial mechanisms are poorly understood. We used patterns of community-level physiological profiles and enzyme activities to assess the relative effects of the addition of four N levels (0, 50, 100, and 150 kg·ha−1·year−1) on the soil microbial community in three forest stands (pine, mixed, and broadleaf forests) in southern China, where the forests have been experimentally manipulated for over 8 years. In pine forests, N50 addition significantly increased microbial biomass carbon (MBC) concentration but decreased soil pH levels. N100 addition significantly increased soil peroxidase activity but decreased soil β-1,4-glucosidase activity. In broadleaf forests, N addition increased soil dissolved organic carbon (DOC) concentration and polyphenol oxidase activity but decreased soil MBC concentration and soil pH levels. N addition also significantly increased soil microbial metabolism activity (expressed as average well color development) in pine forest and broadleaf forest soils. However, the mixed forests responded slowly to N additions and exhibited no significant response of C-utilization profiles and soil enzyme activities. Principal component analysis of C-utilization data separated microbial communities with respect to N addition and forest successional stage. In addition, microbial C utilization was driven by soil pH levels. Although enzyme activities were correlated with soil MBC and microbial biomass nitrogen concentrations, stepwise regression results indicated that soil total carbon contents that were integrated with soil pH levels were key integrators of soil enzyme activities. Our results suggest that soil acidification due to N addition increased soil bacterial C utilization and enzyme activities.

Above- and below-ground litter production in three tropical montane forests in southern Ecuador

2005 ◽  
Vol 21 (5) ◽  
pp. 483-492 ◽  
Author(s):  
Marina Röderstein ◽  
Dietrich Hertel ◽  
Christoph Leuschner
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
Fine Root ◽  
Fine Root Biomass ◽  
Litter Production ◽  
Montane Forests ◽  
Tropical Montane Forests ◽  
Root Litter ◽  
Southern Ecuador ◽  
Below Ground

Litter production from above-ground (leaves, twigs, fruits, flowers) and below-ground (roots) plant organs is an important component of the cycling of carbon and nutrients in forests. Tropical montane forests possess comparatively large quantities of fine-root biomass, suggesting that litter production by dying fine roots may represent a major component of total litter production. In a comparative study in three tropical montane forests of southern Ecuador at 1890, 2380 and 3060 m elevation, we measured leaf-fall by litter trapping and fine-root litter production by sequential soil coring and fine-root biomass and necromass analysis for about 1 y with the objectives (1) to quantify annual above- and below-ground litter production, and (2) to investigate elevational differences in litter production. Leaf litter mass decreased to less than a third (862 to 263 g m−2 y−1) with increasing elevation (1890 m to 3060 m), whereas fine-root litter production increased by a factor of about four (506 to 2084 g m−2 y−1). Thus, the ratio of leaf to fine-root litter shifted by an order of magnitude in favour of fine-root litter production between 1890 to 3060 m. Fine-root litter production was not synchronized with leaf litterfall and was seasonal only at 3060 m with mortality peaks in the drier and the wetter periods. We conclude that dying fine roots represent a very important fraction of total litterfall in tropical montane forests that can exceed the quantity of leaf litter. At 3060 m, the largest part of the organic material on top of the soil must originate from dying fine roots but not from fallen leaves.

Fine root exudation rate increases in drier soils, but tree level carbon exudation does not change under drought in mature Fagus sylvatica - Picea abies trees

2021 ◽  
Author(s):  
Benjamin D. Hafner ◽  
Melanie Brunn ◽  
Marie J. Zwetsloot ◽  
Kyohsuke Hikino ◽  
Karin Pritsch ◽  
...  
Keyword(s):  
Picea Abies ◽  
Fagus Sylvatica ◽  
Forest Ecosystems ◽  
Fine Root ◽  
Carbon Allocation ◽  
Root Exudation ◽  
Total Carbon ◽  
Tree Level ◽  
Root Abundance ◽  
Exudation Rate

&lt;div&gt;&lt;span&gt;Drought is a severe natural risk that increases drying-rewetting frequencies of soils. Yet, it remains largely unknown how forest ecosystems respond to dry-wet cycles, hampering our ability to evaluate the overall sink and source functionality for this large carbon pool. Recent investigations suggest that the release of soluble carbon via root exudation increases under drought, influencing soil carbon stabilization and mineralization. However, an integration of root exudation into the carbon allocation dynamics of drought stressed trees is missing. We hypothesized that roots in dry soil layers have a higher exudation rate than roots in more moist layers across different soil depths. Further, we tested if higher exudation rates under drought are attenuated by reduced root abundance in dry soils and if the fraction of root exudation from total carbon allocation increases with decreasing photosynthesis rates under drought. At the KROOF experimental site in southern Germany, where mature beech (&lt;em&gt;Fagus sylvatica &lt;/em&gt;L.) and spruce (&lt;em&gt;Picea abies &lt;/em&gt;(L.) Karst.) trees were exposed to artificial drought stress for five consecutive growing seasons, we show that at the root level root exudation rate increases in drier soils. Especially roots in the upper soil profile and roots of spruce trees increased root exudation under drought. When scaled to whole tree level, we did not find differences in total exudation between drought stressed and control trees, indicating sustained root exudation at the tree level under drought. As photosynthesis rates and therefore total carbon assimilation was substantially reduced under drought (by 50&amp;#160;% in beech and almost 70&amp;#160;% in spruce), the fraction of root exudation from total assimilation slightly increased for drought stressed trees. Our results demonstrate that stimulation of root exudation rates with drought exists in natural temperate forest ecosystems but might be mitigated by reduced fine root abundance under drought. Nevertheless, increased exudation per root surface area will have localized impacts on rhizosphere microbial composition and activity especially in the topsoil exposed to more extreme dry-wet cycles. Finally, also the exudate composition can help to determine how priming of soil organic matter relates to belowground carbon allocation dynamics and to disclose processes of complementary species interaction and should be emphasised in future studies. &lt;/span&gt;&lt;/div&gt;

Influence of Pruning and Irrigation on Root Longevity of `Concord' Vines

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 511a-511
Author(s):  
L.H. Comas ◽  
D.M. Eissenstat ◽  
A.N. Lakso ◽  
R. Dunst
Keyword(s):  
Fine Roots ◽  
Fine Root ◽  
Cultural Practices ◽  
Growing Season ◽  
Root Production ◽  
Root Dynamics ◽  
Supplemental Irrigation ◽  
Root Longevity ◽  
Root Lifespan ◽  
Median Lifespan

Improved cultural practices in grape require a better understanding of root growth and physiology. Seasonal root dynamics were examined in mature `Concord' vines with balanced or minimal-pruning, and with or without supplemental irrigation in Fredonia, N.Y. Fine roots were continuously produced during the growing season starting in mid-June around time of bloom. Roots began to die in September at verasion. Minimal-pruned vines produced more roots than balanced-pruned vines, with the minimal-pruned/unirrigated vines producing the most roots. Irrigation and pruning delayed fine root production at the beginning of the growing season. Peak fine root flush was 16 June to 21 July 1997 for the minimal-pruned/unirrigated treatment, while peak flush was 7 July to 2 Sept. 1997 for balanced-pruned/irrigated treatment. In minimal-pruned vines, many roots were observed down to depths of 120 cm. In contrast, balanced-pruned vines had very few fine roots deeper than 40 cm. From initial observations, median lifespan of fine roots was 5 to 9.5 weeks, depending on treatment and depth in soil. Fine roots lived longer in the top 15-cm than in the 16- to 30-cm layer of soil in all treatments. Both minimal pruning and irrigation increased root lifespan. Fine roots had the shortest lifespan in the balanced-pruned/unirrigated treatment and the longest lifespan in the minimal-pruned/irrigated treatment.

scholarly journals Observations on early fungal infections with relevance for replant disease in fine roots of the rose rootstock Rosa corymbifera 'Laxa'

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
G. Grunewaldt-Stöcker ◽  
C. Popp ◽  
A. Baumann ◽  
S. Fricke ◽  
M. Menssen ◽  
...  
Keyword(s):  
Fine Roots ◽  
Woody Plant ◽  
Fine Root ◽  
Fungal Infections ◽  
Thin Sections ◽  
Replant Disease ◽  
Pot Trials ◽  
Worldwide Phenomenon ◽  
First Time ◽  
The Rose

AbstractReplant disease is a worldwide phenomenon affecting various woody plant genera and species, especially within the Rosaceae. Compared to decades of intensive studies regarding replant disease of apple (ARD), the replant disease of roses (RRD) has hardly been investigated. The etiology of RRD is also still unclear and a remedy desperately needed. In greenhouse pot trials with seedlings of the RRD-sensitive rootstock Rosa corymbifera ‘Laxa’ cultured in replant disease affected soils from two different locations, early RRD symptom development was studied in fine roots. In microscopic analyses we found similarities to ARD symptoms with regards to structural damages, impairment in the root hair status, and necroses and blackening in the cortex tissue. Examinations of both whole mounts and thin sections of fine root segments revealed frequent conspicuous fungal infections in association with the cellular disorders. Particularly striking were fungal intracellular structures with pathogenic characteristics that are described for the first time. Isolated fungi from these tissue areas were identified by means of ITS primers, and many of them were members of the Nectriaceae. In a next step, 35 of these isolates were subjected to a multi-locus sequence analysis and the results revealed that several genera and species were involved in the development of RRD within a single rose plant. Inoculations with selected single isolates (Rugonectria rugulosa and Ilyonectria robusta) in a Perlite assay confirmed their pathogenic relationship to early necrotic host plant reactions, and symptoms were similar to those exhibited in ARD.

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