The role of fine‐root mass, specific root length and life span in tree performance: A whole‐tree exploration

Root length and root mass were studied in two different forest stands: an oak-beech and an ash stand, both in the 'Aelmoeseneie' experimental forest at Gontrode, Belgium. In the oak-beech stand, the length of the finest roots < 1 mm) was significantly higher than the length of the other diameter classes (1-2 and 2-5 mm) in the upper 60 cm of the mineral soil. Because of large variances, this significance could not be found in the ash forest. In this ash forest type, the length of the finest roots in the upper mineral soil layer (0-15 cm) was higher than all the other lengths, both considering the vertical root length distribution within the ash plot, and comparing the ash plot to the oak-beech stand. For the root mass, only the amount of roots with a diameter between 2 and 5 mm in the upper mineral soil layer of the ash plot was significantly higher than the others. SpecifiC root length (m root/g D.M.) is calculated for both the oak-beech and the ash plot. These values can be used to convert biomass data into root length data, which gives a better indication of the water uptake capacity of the forest stand.

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The morphological and chemical properties of fine roots respond to nitrogen addition in a temperate Schrenk’s spruce (Picea schrenkiana) forest

Scientific Reports ◽

10.1038/s41598-021-83151-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Haiqiang Zhu ◽

Jingjing Zhao ◽

Lu Gong

Keyword(s):

Nitrogen Deposition ◽

Root Length ◽

Fine Roots ◽

Fine Root ◽

Specific Root Length ◽

Nitrogen Addition ◽

Nonstructural Carbohydrates ◽

High Nitrogen ◽

Picea Schrenkiana ◽

Nitrogen Treatment

AbstractFine roots (< 2 mm in diameter) play an important role in belowground ecosystem processes, and their physiological ecology is easily altered by nitrogen deposition. To better understand the response of physiological and ecological processes of fine roots to nitrogen deposition, a manipulation experiment was conducted to investigate the effects of exogenous nitrogen addition (control (0 kg ha−1 a−1), low (5 kg ha−1 a−1), moderate (10 kg ha−1 a−1), and high nitrogen (20 kg ha−1 a−1)) on the biomass, morphological characteristics, chemical elements and nonstructural carbohydrates of fine roots in a Picea schrenkiana forest. We found that most fine roots were located in the 0–20 cm of soil layer across all nitrogen treatment groups (42.81–52.09% of the total biomass). Compared with the control, the biomass, specific root length and specific root area of the fine roots increased in the medium nitrogen treatment, whereas the fine roots biomass was lower in the high nitrogen treatment than in the other treatments. In fine roots, nitrogen addition promotes the absorption of nitrogen and phosphorus and their stoichiometric ratio, while reducing the content of nonstructural carbohydrates. The content of nonstructural carbohydrates in the small-diameter roots (< 1 mm in diamter) in each nitrogen treatment group was lower than that in the large-diameter roots. Correlation analysis showed that soil carbon and nitrogen were positively correlated with fine root biomass and specific root length and negatively correlated with the nonstructural carbohydrates. Our findings demonstrate that medium nitrogen addition is conducive to the development of fine root morphology, while excessive nitrogen can suppress the growth of root systems.

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Fine roots of pedunculate oak (Quercus robur L.) in the Netherlands seven years after liming

Netherlands Journal of Agricultural Science ◽

10.18174/njas.v46i2.491 ◽

1998 ◽

Vol 46 (2) ◽

pp. 209-222 ◽

Cited By ~ 1

Author(s):

M.R. Bakker

Keyword(s):

Root Length ◽

Fine Root ◽

Specific Root Length ◽

Sandy Soils ◽

Nutrient Status ◽

Fine Root Biomass ◽

Pedunculate Oak ◽

Young Stand ◽

Top Soil ◽

Fine Root Length

A liming experiment was initiated in 1988 in which an equivalent dose of 1.6 t/ha CaO was applied to a young and an old stand of Q. robur (planted in 1980 and 19953, respectively), growing on acidic sandy soils in southeast Netherlands. Seven years after the liming treatments, the effects on soil and roots were intensively studied. Prior to liming, the young stand suffered from a deficiency in N, P, Mg, Zn and Fe, whereas the older stand had a deficiency in Mg and Zn. The results indicated that, 7 years after the application of lime, cation availability and soil pH were increased. Liming increased specific root length and number of apices with mycorrhizas per cm of fine root length in most of the profile in the young stand, but stimulated fine root biomass and length only in the top soil of the old stand. The leaf nutrient status was improved the most in the youngest stand, where lime had greatest impact on the area of soil exploited by the root and mycorrhizas system.

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(324) Irrigation Effects on Fine Root Dynamics in Peach (Prunus persica)

HortScience ◽

10.21273/hortsci.40.4.1038d ◽

2005 ◽

Vol 40 (4) ◽

pp. 1038D-1038

Author(s):

Christina Wells ◽

Desmond Layne

Keyword(s):

Soil Temperature ◽

Life Span ◽

Root Length ◽

Fine Roots ◽

Fine Root ◽

Root Dynamics ◽

Fine Root Dynamics ◽

Tree Phenology ◽

Peach Trees ◽

Root Life Span

We are using a minirhizotron camera system to observe fine root dynamics beneath irrigated and nonirrigated peach trees. Our long term goals are: 1) to relate the timing of fine root production to tree phenology, soil water content, and soil temperature; and 2) to determine how fine root architecture and demography differ between trees with and without supplemental irrigation. In early 2002, minirhizotrons were constructed and installed beneath each of 72 open-center, 4-year-old `Redglobe' peach trees at the Musser Fruit Research Farm near Clemson University. Beginning in May 2002, videotaped images from each minirhizotron were collected at 2-week intervals; notes on tree phenology were also recorded biweekly. Videotapes were digitized in the lab, and information on root length, diameter, appearance and longevity was extracted from the images. Soil temperature and volumetric water content were measured in the orchard throughout the growing season. In the 2 years following minirhizotron installation, irrigated trees allocated a significantly greater percentage of their fine root length to the upper soil layers and exhibited less root branching than nonirrigated trees. Fine roots produced by irrigated trees lived significantly longer: irrigated trees had a median root life span of 165 days, while nonirrigated trees had a median root life span of only 115 days (P< 0.001; proportional hazards regression). Fine roots from irrigated trees remained in the physiologically active “white” state for an average of 10 days longer than roots from nonirrigated trees (P< 0.001). Data from 2002–03 indicate that the trees produce new root flushes at least three times during the year, with a significant flush occurring immediately after harvest.

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A Genotyping-by-sequencing Single Nucleotide Polymorphism–based Map and Genetic Analysis of Root Traits in an Interspecific Tomato Population

Journal of the American Society for Horticultural Science ◽

10.21273/jashs04565-19 ◽

2019 ◽

Vol 144 (6) ◽

pp. 394-404 ◽

Cited By ~ 1

Author(s):

Limeng Xie ◽

Patricia Klein ◽

Kevin Crosby ◽

John Jifon

Keyword(s):

Single Nucleotide Polymorphism ◽

Root Length ◽

Specific Root Length ◽

Genotyping By Sequencing ◽

Root Traits ◽

Root Mass ◽

Nucleotide Polymorphism ◽

Single Nucleotide ◽

Shoot Mass ◽

Root And Shoot Traits

Roots impact plants’ capacity to absorb water and nutrients and thus play a vital role in tolerance to drought, salinity, and nutrient stress. In tomato (Solanum lycopersicum) breeding programs, wild tomato species have been commonly used to increase disease resistance and fruit quality and yield. However, tomato has seldom been bred for water/nutrient use efficiency or resilience to abiotic stress. Meanwhile, little knowledge of the genetic control of root traits in tomato is available. In this study, a mapping population consisting of 181 F2 progenies derived from a cross between an advanced breeding line RvT1 (S. lycopersicum) and a wild species Lche4 (Solanum cheesmaniae) was evaluated for root and shoot traits in the greenhouse. Root phenotypes were studied for the early seedling stage. Heritability estimates show that root traits are moderately or highly heritable. Root mass was highly correlated with root size (length, surface area, and volume). Shoot mass and chlorophyll content (SPAD) were moderately correlated with root mass and size. Genotyping-by-sequencing was applied to discover single nucleotide polymorphism (SNP) markers. Seven hundred and forty-two SNPs were successfully mapped, and a medium-dense linkage map was created that covered 1319.47 centimorgans (cM) with an average distance of 1.78 cM between adjacent markers. Using composite interval mapping, multiple quantitative trait loci (QTL) mapping and nonparametric mapping, 29 QTLs were identified for 12 root and shoot traits on eight chromosomes. Those QTLs of major and minor effect were involved in the differences among the F2 population. Two QTL hotspot regions associated with root mass, size, shoot mass and SPAD were identified on chromosomes 1 and 4, which was consistent with the correlation among traits. Five QTLs for shoot length and eight QTLs for SPAD were accounting for 40.01% and 55.53% of the phenotypic variation. Two QTLs were associated with 18.26% of the total variation for specific root length. The wild parent Lche4 has been characterized as a potential genetic donor of higher specific root length and might be a good parent to modify the root system of cultivated tomato.

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Estimating the mass density of fine roots of trees for minirhizotron-based estimates of productivity

Canadian Journal of Forest Research ◽

10.1139/x05-099 ◽

2005 ◽

Vol 35 (7) ◽

pp. 1708-1713 ◽

Cited By ~ 10

Author(s):

Pierre Y Bernier ◽

Gilles Robitaille ◽

Danny Rioux

Keyword(s):

Cross Sections ◽

Root Length ◽

Cell Walls ◽

Fine Roots ◽

Fine Root ◽

Mass Density ◽

Specific Root Length ◽

Root Diameter ◽

Soil Cores ◽

Species Mixture

Allocation of carbon for the production of fine roots is a significant component of the carbon budget within trees. Transformation of fine-root volumes or lengths as seen with minirhizotrons into fine-root mass per unit of horizontal area requires an estimate of the mass density or specific root length of fine roots for the species of interest. We obtained values of mass density of fine roots using three different sampling strategies on temperate and boreal forested sites. The strategies examined were (1) the use of bulk root samples from soil cores, (2) the use of individual roots from seedlings, and (3) the use of individual roots from soil cores. Our results show that the mass density of fine roots taken from seedlings is strongly dependent on root diameter, as shown by the strong drop in mass density with a decrease in diameter in all species examined. However, the dependency of mass density of individual fine roots extracted from soil cores on root diameter varies with the species mixture. Examination of thin cross-sections of roots using microscopy reveals that the proportion of xylem cell walls as a percentage of total cell walls also decreases strongly as root diameter diminishes for seedling fine roots, but that this relationship is not as clear in fine roots obtained from soil cores. We conclude that using the mass density from core fine roots may yield the best estimate of fine-root productivity when deriving such a value from the analysis of minirhizotron images. We also discuss some of the problems associated with the use of specific root length.

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Root Distribution and Tiller Densities of Creeping Bentgrass Cultivars and Greens-type Annual Bluegrass Cultivars in a Putting Green

HortScience ◽

10.21273/hortsci.46.10.1411 ◽

2011 ◽

Vol 46 (10) ◽

pp. 1411-1417 ◽

Cited By ~ 7

Author(s):

Eric M. Lyons ◽

Peter J. Landschoot ◽

David R. Huff

Keyword(s):

Root Length ◽

Root Distribution ◽

Root Zone ◽

Specific Root Length ◽

Creeping Bentgrass ◽

Root Mass ◽

Annual Bluegrass ◽

Putting Green ◽

Second Year ◽

N Rates

Little knowledge exists regarding root distribution of creeping bentgrass (Agrostis stolonifera) and annual bluegrass (Poa annua) in root zones of golf course putting greens. To compare root distribution between these species, three experimental cultivars of greens-type annual bluegrass and two commercial cultivars of creeping bentgrass (‘Penncross’ and ‘Penn A-4’) were established on an experimental golf green and managed under two nitrogen (N) fertility levels (195 and 65 kg N/ha/year) over a 2-year period. Creeping bentgrass had two and three times the total root mass compared with annual bluegrass during the first and second years of the experiment, respectively. At soil depths of 3–12 cm and below 12 cm, creeping bentgrass had three to four times the root mass compared with annual bluegrass at various times during the experiment. During the first year of the experiment, both species exhibited greater than 50% decrease in total root mass from June to August. During the second year, creeping bentgrass total root mass decreased 10% to 15% and annual bluegrass total root mass decreased 25% to 30% over the same period. Of the two bentgrasses, ‘Penn A-4’ creeping bentgrass exhibited greater total root mass only in the second year; however, ‘Penn A-4’ exhibited greater root mass than ‘Penncross’ below 12 cm in both years. Creeping bentgrass cultivars showed greater root mass below 12 cm at 65 kg N/ha/year compared with 195 kg N/ha/year on some sampling dates in both years. Annual bluegrass cultivars showed no change in any root mass parameters in response to N rates (data not shown), but specific root length (SRL) of annual bluegrass increased under the 65 kg N/ha/year rate compared with the 195 kg N/ha/year rate, whereas SRL of creeping bentgrass was similar at both N rates. Tiller densities of both species increased under the 195 kg N/ha/year rate. ‘Penn A-4’ exhibited higher tiller densities than ‘Penncross’ throughout the experiment and at times was equivalent to the tiller densities of the annual bluegrass cultivars. These results suggest that although creeping bentgrass increases root mass deeper in a putting green root zone mix at lower N rates (65 kg N/ha/year), annual bluegrass exhibits plasticity in specific root length in response to different N rates.

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Experimentally altered rainfall regimes and host root traits affect grassland arbuscular mycorrhizal fungal communities

10.32942/osf.io/cu4jh ◽

2019 ◽

Author(s):

Coline Deveautour ◽

Suzanne Donn ◽

Sally Power ◽

Kirk Barnett ◽

Jeff Powell

Keyword(s):

Fungal Community ◽

Community Assembly ◽

Root Length ◽

Specific Root Length ◽

Root Traits ◽

Arbuscular Mycorrhizal ◽

Fungal Communities ◽

Rainfall Regime ◽

Precipitation Regimes ◽

Rainfall Regimes

Future climate scenarios predict changes in rainfall regimes. These changes are expected to affect plants via effects on the expression of root traits associated with water and nutrient uptake. Associated microorganisms may also respond to these new precipitation regimes, either directly in response to changes in the soil environment or indirectly in response to altered root trait expression. We characterised arbuscular mycorrhizal (AM) fungal communities in an Australian grassland exposed to experimentally altered rainfall regimes. We used Illumina sequencing to assess the responses of AM fungal communities associated with four plant species sampled in different watering treatments and evaluated the extent to which shifts were associated with changes in root traits. We observed that altered rainfall regimes affected the composition but not the richness of the AM fungal communities, and we found distinctive communities in the increased rainfall treatment. We found no evidence of altered rainfall regime effects via changes in host physiology because none of the studied traits were affected by changes in rainfall. However, specific root length was observed to correlate with AM fungal richness, while concentrations of phosphorus and calcium in root tissue and the proportion of root length allocated to fine roots were correlated to community composition. Our study provides evidence that climate change and its effects on rainfall may influence AM fungal community assembly, as do plant traits related to plant nutrition and water uptake. We did not find evidence that host responses to altered rainfall drive AM fungal community assembly in this grassland ecosystem.

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