Modeling in-situ pine root decomposition using data from a 60-year chronosequence

2002 ◽  
Vol 32 (9) ◽  
pp. 1675-1684 ◽  
Author(s):  
Kim H Ludovici ◽  
Stanley J Zarnoch ◽  
Daniel D Richter
Keyword(s):  
Loblolly Pine ◽  
Lateral Root ◽  
Lateral Roots ◽  
Nutrient Release ◽  
Root Systems ◽  
Root Decomposition ◽  
Good Precision ◽  
Clear Cut ◽  
Stump Diameter

Because the root system of a mature pine tree typically accounts for 20–30% of the total tree biomass, decomposition of large lateral roots and taproots following forest harvest and re-establishment potentially impact nutrient supply and carbon sequestration in pine systems over several decades. If the relationship between stump diameter and decomposition of taproot and lateral root material, i.e., wood and bark, can be quantified, a better understanding of rates and patterns of sequestration and nutrient release can also be developed. This study estimated decomposition rates from in-situ root systems using a chronosequence approach. Nine stands of 55- to 70-year-old loblolly pine (Pinus taeda L.) that had been clear-cut 0, 5, 10, 20, 25, 35, 45, 55, and 60 years ago were identified on well-drained Piedmont soils. Taproot and lateral root systems were excavated, measured, and weighed. Although more than 50% of the total root mass decomposed during the first 10 years after harvest, field excavations recovered portions of large lateral roots (>5 cm diameter) and taproots that persisted for more than 35 and 60 years, respectively. Results indicate that decomposition of total root biomass, and its component parts, from mature, clear-cut loblolly pine stands, can be modeled with good precision as a function of groundline stump diameter and years since harvest.

Root mapping of three tropical pasture species using 32P

1969 ◽  
Vol 9 (39) ◽  
pp. 445 ◽  
Author(s):  
RA Bray ◽  
JB Hacker ◽  
DE Byth
Keyword(s):  
Root Growth ◽  
Root Development ◽  
Lateral Root ◽  
Sandy Loam ◽  
Lateral Roots ◽  
Root Systems ◽  
Growth Patterns ◽  
Constant Rate ◽  
Initial Root

Root growth patterns of Glycine javanica, Setaria anceps, and Medicago sativa were studied by uptake of 32P from a sandy loam. Placement of isotope was through permanently positioned PVC conduit on a grid over a 90� quadrant of the root system. Detection of radioactivity was in in situ plant material. Lucerne had strong initial root development but was slow to form lateral roots. Glycine and Setaria had quite similar root systems although Setaria had more rapid vertical root development than Glycine. Both these species had strong lateral root systems. When a regression of minimum root length against time was calculated, lateral root growth was shown to be independent of depth and distance from the plant, suggesting that roots behave as if growing from a point source in random directions at a constant rate. This rate was the same for all species. There were also indications of strong vertical root systems in lucerne and Setaria.

Lateral Root Pruning of Sitka Spruce and Western Hemlock Seedlings

1972 ◽  
Vol 2 (3) ◽  
pp. 223-227 ◽  
Author(s):  
S. Eis ◽  
J. R. Long
Keyword(s):  
Lateral Root ◽  
Lateral Roots ◽  
Root Systems ◽  
Growing Season ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Short Length ◽  
Western Hemlock ◽  
Root Pruning

Roots of Sitka spruce (Picea sitchensis) and western hemlock (Tsugaheterophylla) seedlings were side pruned in nursery beds at semimonthly intervals to produce dense and compact root systems. Root pruning early in the growing season stimulated the growth of existing roots and also initiated new roots. The densest root systems were produced by pruning before the end of June. However, because of the short length of lateral roots on seedlings early in their second growing season, pruning equidistant between rows 18 cm apart was ineffective. The best compromise appeared to be to prune spruce at the beginning of July, and hemlock around the middle of July. Earlier pruning equidistant between rows can be effective on larger seedlings during their third growing season. If early pruning is carried out on 2 + 0 seedlings, a pruning distance of about 6 cm from the row is recommended.

Changes in loblolly pine root growth potential from September to April

1987 ◽  
Vol 17 (7) ◽  
pp. 635-643 ◽  
Author(s):  
Laura E. DeWald ◽  
Peter P. Feret
Keyword(s):  
Root Growth ◽  
Loblolly Pine ◽  
Environmental Changes ◽  
Lateral Roots ◽  
Root Systems ◽  
Shoot Elongation ◽  
Growth Potential ◽  
Late Winter ◽  
Root Growth Potential ◽  
Shoot Phenology

Loblolly pine (Pinustaeda L.) 1 + 0 seedlings were periodically hand lifted from a Virginia nursery to determine how root growth potential (RGP) varied between September and April. Several seedling characteristics, RGP, and shoot phenology were recorded for each lift date in 1983–1984 and 1984–1985. An attempt was made to relate RGP variation to changes in the nursery environment and to shoot phenology. Root growth potential variation was consistent between years and was more closely related to shoot phenological changes than to short-term environmental changes. During the development of dormancy, RGP was low, RGP increased when shoot activity resumed during the RGP tests (late winter, early spring), and declined as active shoot elongation began in the nursery. When RGP was low, elongation of existing lateral roots primarily contributed to the new root systems, but as seedling metabolism increased in the late winter, new root initiation also contributed to new root systems. Absolute differences in RGP between years may be related to the fibrosity of seedling root systems.

Incidence of Resin-Soaked Roots in Subsoiled Loblolly Pine Seed Orchards on Sandy Soils

1982 ◽  
Vol 6 (2) ◽  
pp. 104-107
Author(s):  
R. S. Webb ◽  
S. A. Alexander
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Lateral Roots ◽  
Sandy Soils ◽  
Root Systems ◽  
Seed Orchard ◽  
Heterobasidion Annosum ◽  
Seed Orchards ◽  
Loblolly Pines ◽  
Pinus Taeda L

Abstract The root systems of 70 loblolly pines (Pinus taeda L.) from three subsoiled seed orchards were excavated to determine the association of subsoiling with the incidence of resin-soaked lateral roots. The number of lateral roots and the proportion of resin-soaked and healthy root tissue were recorded. Chips from the resin-soaked margin of lateral roots were incubated for 10 days at 24°C on two general media and two media selective for Heterobasidion annosum (Fr.) Bref. Verticicladiella procera Kend. was isolated from 30 percent of the declining/subsoiled trees at one seed orchard. Monilia spp. were also isolated. Of the lateral roots severed by subsoiling, 60 percent were resin-soaked from 10 to 45 cm in length.

scholarly journals Decomposition and nutrient release from fresh and dried pine roots under two fertilizer regimes

2006 ◽  
Vol 36 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Kim H Ludovici ◽  
Lance W Kress
Keyword(s):  
Mass Loss ◽  
Loblolly Pine ◽  
Fine Roots ◽  
Mass Loss Rate ◽  
Nutrient Release ◽  
Nutrient Content ◽  
Root Decomposition ◽  
Nutrient Concentrations ◽  
Release Rates ◽  
Root Tissues

Root decomposition and nutrient release are typically estimated from dried root tissues; however, it is unlikely that roots dehydrate prior to decomposing. Soil fertility and root diameter may also affect the rate of decomposition. This study monitored mass loss and nutrient concentrations of dried and fresh roots of two size classes (<2 and 2–5 mm) over a 12-month period in fertilized and control plots in a 13-year-old loblolly pine (Pinus taeda L.) plantation. Nutrient content was calculated and used to assess the effects of fertilization, root size, and initial condition (hydration) on nutrient release rates. Roots that grew and decomposed in fertilized plots had higher concentrations and greater total release of N, P, K, and Mg than roots in control plots, but C concentrations and mass loss rate were not significantly different between roots in fertilized plots and those in control plots. Very fine roots (<2 mm) had higher concentrations of N, P, and Ca and faster release rates for C, N, and K than fine roots (2–5 mm), resulting in greater total release of C and N. Roots dried prior to decomposition decayed and released C, K, Ca, and Mg at a faster rate than fresh roots. Results indicate that using dried root tissues will overestimate fine root decomposition and nutrient cycling rates.

A Technique for the Periodic Observation of Root Systems in Situ 1

1962 ◽  
Vol 54 (1) ◽  
pp. 56-56 ◽  
Author(s):  
T. J. Muzik ◽  
J. W. Whitworth
Keyword(s):  
Root Systems

Lateral root formation and nutrients: nitrogen in the spotlight

2021 ◽  
Author(s):  
Pierre-Mathieu Pélissier ◽  
Hans Motte ◽  
Tom Beeckman
Keyword(s):  
Signaling Pathways ◽  
Root System ◽  
Root Development ◽  
Lateral Root ◽  
Molecular Mechanisms ◽  
Root Formation ◽  
Lateral Roots ◽  
Nutrient Use Efficiency ◽  
Lateral Root Formation ◽  
Lateral Root Development

Abstract Lateral roots are important to forage for nutrients due to their ability to increase the uptake area of a root system. Hence, it comes as no surprise that lateral root formation is affected by nutrients or nutrient starvation, and as such contributes to the root system plasticity. Understanding the molecular mechanisms regulating root adaptation dynamics towards nutrient availability is useful to optimize plant nutrient use efficiency. There is at present a profound, though still evolving, knowledge on lateral root pathways. Here, we aimed to review the intersection with nutrient signaling pathways to give an update on the regulation of lateral root development by nutrients, with a particular focus on nitrogen. Remarkably, it is for most nutrients not clear how lateral root formation is controlled. Only for nitrogen, one of the most dominant nutrients in the control of lateral root formation, the crosstalk with multiple key signals determining lateral root development is clearly shown. In this update, we first present a general overview of the current knowledge of how nutrients affect lateral root formation, followed by a deeper discussion on how nitrogen signaling pathways act on different lateral root-mediating mechanisms for which multiple recent studies yield insights.

Formation of lateral root meristems is a two-stage process

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3303-3310 ◽  
Author(s):  
M.J. Laskowski ◽  
M.E. Williams ◽  
H.C. Nusbaum ◽  
I.M. Sussex
Keyword(s):  
Lateral Root ◽  
Lateral Roots ◽  
Initial Period ◽  
Subsequent Stage ◽  
Root Initiation ◽  
Root Meristems ◽  
Lateral Root Initiation ◽  
Cell Layers ◽  
Stage Process ◽  
Pericycle Cells

In both radish and Arabidopsis, lateral root initiation involves a series of rapid divisions in pericycle cells located on the xylem radius of the root. In Arabidopsis, the number of pericycle cells that divide to form a primordium was estimated to be about 11. To determine the stage at which primordia are able to function as root meristems, primordia of different stages were excised and cultured without added hormones. Under these conditions, primordia that consist of 2 cell layers fail to develop while primordia that consist of at least 3–5 cell layers develop as lateral roots. We hypothesize that meristem formation is a two-step process involving an initial period during which a population of rapidly dividing, approximately isodiametric cells that constitutes the primordium is formed, and a subsequent stage during which meristem organization takes place within the primordium.

scholarly journals AT-HOOK MOTIF NUCLEAR LOCALISED PROTEIN 18 as a Novel Modulator of Root System Architecture

2020 ◽  
Author(s):  
Marek Šírl ◽  
Tereza Šnajdrová ◽  
Dolores Gutiérrez-Alanís ◽  
Joseph G. Dubrovsky ◽  
Jean Phillipe Vielle-Calzada ◽  
...  
Keyword(s):  
Root System ◽  
System Architecture ◽  
Lateral Root ◽  
Apical Meristem ◽  
Lateral Roots ◽  
Primary Root ◽  
Root System Architecture ◽  
Root Apical Meristem ◽  
Root Initiation ◽  
Lateral Root Initiation

The AT-HOOK MOTIF NUCLEAR LOCALIZED PROTEIN (AHL) gene family encodes embryophyte-specific nuclear proteins with DNA binding activity. They modulate gene expression and affect various developmental processes in plants. We identify AHL18 (At3G60870) as a developmental modulator of root system architecture and growth. AHL18 regulates the length of the proliferation domain and number of dividing cells in the root apical meristem and thereby, cell production. Both primary root growth and lateral root development respond according to AHL18 transcription level. The ahl18 knock-out plants show reduced root systems due to a shorter primary root and a lower number of lateral roots. This change results from a higher number of arrested and non-developing lateral root primordia (LRP) rather than from decreased initiation. Overexpression of AHL18 results in a more extensive root system, longer primary roots, and increased density of lateral root initiation events. Formation of lateral roots is affected during the initiation of LRP and later development. AHL18 regulate root apical meristem activity, lateral root initiation and emergence, which is in accord with localization of its expression.

scholarly journals Influence of Root Morphology on Ecological Slope Protection

2020 ◽  
Vol 198 ◽  
pp. 04036
Author(s):  
JI Xiaolei ◽  
XU Lanlan ◽  
YANG Guoping
Keyword(s):  
Root Morphology ◽  
Lateral Root ◽  
Lateral Roots ◽  
Soil Mass ◽  
Soil Reinforcement ◽  
Main Root ◽  
Protection Effect ◽  
Included Angle ◽  
Theoretical Support ◽  
Object Based

Ecological slope protection is of great importance for preventing the water and soil loss on bare slopes, improving the ecological environment, and realizing the sustainable ecosystem development. The root-soil composite slope consisting of homogenous soil mass and oleander root system was taken as the study object. Based on the mechanics principle of soil reinforcement by roots in ecological slope protection, the influences of the lateral root quantity of plants and included angle between main root and lateral root on the slope protection were investigated via the finite element (FE) software ABAQUS. The simulation results show that the larger the quantity of lateral roots, the more obvious the displacement reduction of the soil mass on the slope surface will be. The slope protection effect varies with the root morphology, the included angle between main root and lateral root is an important factor influencing the slope protection effect of plants, and the slope protection effect at included angle of 30° is apparently superior to that at 90°. The research results can provide a theoretical support for the plant selection in the ecological slope protection.

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