Variation of first-order root traits across climatic gradients and evolutionary trends in geological time

Decomposition is a key component of the global carbon (C) cycle, yet current ecosystem C models do not adequately represent the contributions of plant roots and their mycorrhizae to this process. The understanding of decomposition dynamics and their control by traits is particularly limited for the most distal first-order roots. Here we followed decomposition of first-order roots and leaf litter from 35 woody plant species differing in mycorrhizal type over 6 years in a Chinese temperate forest. First-order roots decomposed more slowly (k = 0.11 ± 0.01 years−1) than did leaf litter (0.35 ± 0.02 years−1), losing only 35% of initial mass on average after 6 years of exposure in the field. In contrast to leaf litter, nonlignin root C chemistry (nonstructural carbohydrates, polyphenols) accounted for 82% of the large interspecific variation in first-order root decomposition. Leaf litter from ectomycorrhizal (EM) species decomposed more slowly than that from arbuscular mycorrhizal (AM) species, whereas first-order roots of EM species switched, after 2 years, from having slower to faster decomposition compared with those from AM species. The fundamentally different dynamics and control mechanisms of first-order root decomposition compared with those of leaf litter challenge current ecosystem C models, the recently suggested dichotomy between EM and AM plants, and the idea that common traits can predict decomposition across roots and leaves. Aspects of C chemistry unrelated to lignin or nitrogen, and not presently considered in decomposition models, controlled first-order root decomposition; thus, current paradigms of ecosystem C dynamics and model parameterization require revision.

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Development of Nonferrous Metal Deposits in Geological Time

Canadian Journal of Earth Sciences ◽

10.1139/e73-002 ◽

1973 ◽

Vol 10 (1) ◽

pp. 18-25 ◽

Cited By ~ 15

Author(s):

P. Laznicka

Keyword(s):

Nonferrous Metal ◽

Ore Deposits ◽

Nonferrous Metals ◽

Earth’S Crust ◽

Evolutionary Trends ◽

Geological Time ◽

Earth's Crust

A computer-derived graph of a development of deposits of twelve nonferrous metals in geological time is presented. It is based on a file containing over 5000 ore deposits, districts, and metalliferous areas of the world.The sequence of depositional ages based on ore deposits presently outcropping on the earth's surface is, from the oldest to the youngest, Cr, Ni–Au–Cu, Zn–Pb, Ag–Sn, W, Sb, Mo–Hg. Although this sequence parallels several evolutionary trends involved in the formation of the earth's crust, it is believed and semiquantitatively demonstrated that depth of denudation rather than evolution is the more important factor; in other words, the conditions of preservation have had greater influence on the age relationships of ore deposits outcropping on the present earth's surface than have the conditions of formation and their progressive evolution in the earth's history.

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Genotypic variations in root traits of wheat varieties at phytomer level

Journal of the Bangladesh Agricultural University ◽

10.3329/jbau.v12i1.21238 ◽

2014 ◽

Vol 12 (1) ◽

pp. 45-54 ◽

Cited By ~ 8

Author(s):

AHK Robin ◽

MJ Uddin ◽

S Afrin ◽

PR Paul

Keyword(s):

Root Hair ◽

Significant Variation ◽

Root Traits ◽

Dry Weight ◽

Main Axis ◽

Hair Density ◽

Wheat Varieties ◽

First Order ◽

Root Hair Density ◽

Axis Length

The aims of this study were to investigate genotypic variations in root traits at phytomer level of wheat varieties and for recommending a few root traits as selection parameters in future breeding programs. Two separate experiments were conducted to measure their root traits for hydroponically grown wheat plants. In Experiment 1, main axis length, root hair density and diameter differed from phytomer to phytomer at 60 days after sowing for two varieties, Shotabdi and Sonalika. Density of first order laterals at their axis of origin, dry weights of roots and shoots and root:shoot ratio varied significantly among 8 varieties. In Experiment 2, number of root bearing phytomer, total number of adventitious roots, main axis length at root bearing phytomer 1 and 2 (youngest roots were the reference point and numbered as phytomer 1), length of first order laterals at phytomer 3, root hair density and dry weights of roots and shoots were significantly different among varieties. PC1 (principal component 1) resulted in significant variation among varieties for number of live leaves, new roots appeared, number of root bearing phytomer, total number of adventitious roots, root dry weight and shoot dry weight. PC2 yielded significant difference among varieties for live leaves, main axes length at phytomer 1 & 2, number of new roots, root hair density and diameter. Selection of varieties based on main axes length at the youngest phytomer & root hair density per unit surface area along with dry weights of roots and shoots could be recommended for future breeding program as these four parameters consistently resulted in significant variation among varieties. DOI: http://dx.doi.org/10.3329/jbau.v12i1.21238 J. Bangladesh Agril. Univ. 12(1): 45-54, June 2014

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Variations in the first-order root diameter in 89 woody species in a subtropical evergreen broadleaved forest

Chinese Journal of Plant Ecology ◽

10.17521/cjpe.2019.0189 ◽

2019 ◽

Vol 43 (11) ◽

pp. 969-978

Author(s):

Xue WANG ◽

Guang-Shui CHEN ◽

Xiao-Jun YAN ◽

Ting-Ting CHEN ◽

Qi JIANG ◽

...

Keyword(s):

Woody Species ◽

Root Diameter ◽

Evergreen Broadleaved Forest ◽

First Order ◽

Order Root

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Anatomy of Dianthoveus cremnophilus (Cyclanthaceae)

Canadian Journal of Botany ◽

10.1139/b89-440 ◽

1989 ◽

Vol 67 (12) ◽

pp. 3580-3599 ◽

Cited By ~ 2

Author(s):

George J. Wilder

Keyword(s):

Boundary Layers ◽

Cross Section ◽

Central Cylinder ◽

Vascular Bundles ◽

Monotypic Genus ◽

Ground Tissue ◽

Intercellular Spaces ◽

First Order ◽

Parenchyma Cells ◽

Order Root

Dianthoveus is a monotypic genus of the Cyclanthaceae and in this paper the anatomy of D. cremnophilus is described, including that of the lamina, petiole, peduncle, rhizome and first-order root. The lamina within interridge areas is hypostomatic and the mesophyll between boundary layers exhibits either two main regions according to sizes of intercellular spaces, or three main regions according to wall thickness of ordinary parenchyma cells. Expansion tissue occurs opposite adaxial and abaxial ridges of the lamina and where the median costa and noncostal portions of lamina are joined together. The petiole exhibits three main zones of ground tissue and the median costa has two to three zones. Certain veins of the petiole compose a conspicuous V in cross section. The peduncle has four main zones of ground tissue, including pith. This organ contains simple vascular bundles (commonly, collateral bundles) and bipolar compound vascular bundles. The rhizome has a conspicuous periderm, cortex (including endodermis), and central cylinder. Diverse forms of vascular bundles occur within the central cylinder, e.g., collateral, amphivasal, compound-tetrapolar, and compound-multipolar. In the first-order root the cortex exhibits various regions, including exodermis and endodermis, and the stele contains peripheral and nonperipheral fascicles, each type of fascicle of either xylem or phloem. Styloid sacs and raphide sacs occur in all and some organs studied, respectively, and in the rhizome and interridge areas of the lamina the styloid sacs are randomly oriented and abundant. Mucilage canals occur in the peduncle and petiole. These anatomical data are used to compare Dianthoveus with other cyclanthaceous genera, particularly Evodianthus.

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First-order root development from cuttings of Populus trichocarpa x P. deltoides hybrids

Tree Physiology ◽

10.1093/treephys/14.7-8-9.911 ◽

1994 ◽

Vol 14 (7-8-9) ◽

pp. 911-920 ◽

Cited By ~ 18

Author(s):

P. E. Heilman ◽

G. Ekuan ◽

D. B. Fogle

Keyword(s):

Root Development ◽

Populus Trichocarpa ◽

First Order ◽

Order Root

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Salinity Stress Alters Root Morphology and Root Hair Traits in Brassica napus

Plants ◽

10.3390/plants8070192 ◽

2019 ◽

Vol 8 (7) ◽

pp. 192 ◽

Cited By ~ 9

Author(s):

Mohammad Rashid Arif ◽

M. Thoihidul Islam ◽

Arif Hasan Khan Robin

Keyword(s):

Lateral Roots ◽

Root Hairs ◽

Root Traits ◽

Morphological Plasticity ◽

Root Surface ◽

Root Surface Area ◽

Third Order ◽

Breeding Programs ◽

First Order ◽

Treated Condition

Plant roots show morphological plasticity and play a substantial role in tolerance to various edaphic stresses. The aim of this study was to explore salinity-induced morphogenic responses of root traits and root hairs of two rapeseed varieties, BARI Sarisha-8 and Binasarisha-5, at the reproductive stage and perceive the effects on their reproductive growth. The experiment was conducted in a hydroponic culture. Two treatments, 0 mM NaCl as control and 100 mM NaCl, were imposed 55 d after germination. Plants exposed to 100 mM NaCl for seven days displayed greater damage in the leaves, flowers, and siliquae compared to control. Length of root hairs on first-order and third-order lateral roots, density of root hairs on first-order lateral roots, and length of third-order lateral roots were significantly greater by 91%, 22%, 29%, and 48%, respectively, in the treated condition compared to the control. An increase in estimated root surface area by 20% under salt stress conditions indicated that the spontaneous responses of plants to uptake more water and nutrients allowed a plant to cope with stressful conditions. The results of this study suggest that any future stress breeding programs should consider plasticity of root traits intensively.

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Pleistocene geochronology and palaeothermometry from protein diagenesis in ostrich eggshells: implications for the evolution of modern humans

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.1992.0092 ◽

1992 ◽

Vol 337 (1280) ◽

pp. 149-157 ◽

Cited By ~ 40

Keyword(s):

Effective Means ◽

Modern Human ◽

Peptide Fragments ◽

Geological Time ◽

Modern Humans ◽

Radiocarbon Dates ◽

First Order ◽

Anatomically Modern Humans ◽

Instantaneous Temperature ◽

Sample Age

Proteinaceous residues incorporated within the crystal structure of ostrich eggshells (OES) are retained without loss over geological time exceeding 10 million years. Degradation of the polypeptides, including hydrolysis to smaller peptide fragments and eventual release of free amino acids, decomposition, and racemization and epimerization occur at regular, predictable rates dependent on ambient temperature. The extent of isoleucine epimerization (alle/Ile ratio) in OES follows linear first-order reversible kinetics in controlled-temperature laboratory simulations of time up to an alle/Ile ratio in excess of 1.0. The hydrolysis of leucine also follows a predictable pattern, but deviates from first-order kinetics. A nonlinear mathematical model has been developed that adequately describes the pattern of leucine hydrolysis through a wide temperature range. Arrhenius parameters were derived from laboratory experiments combined with rate constant values found for 14 C-dated OES from stratified caves in southern Africa. These parameters for isoleucine epimerization and leucine hydrolysis differ by ca . 10%, allowing the simultaneous solution of the two equations for temperature, independent of sample age. Although the uncertainty of the simultaneous temperature is relatively high (± 10°C), it provides an effective means of identifying burned samples. If sample age is known, palaeotemperatures (the integrated thermal history experienced by an eggshell as opposed to an ‘instantaneous’ temperature) can be calculated with a precision of better than ± 1°C. The ages of levels at Border Cave, South Africa, from which anatomically modern human skeletal remains have been recovered, are dated by the extent of isoleucine epimerization in associated OES. The reaction is calibrated in the upper levels by a series of concordant radiocarbon dates on charcoal at 38 ka before present (BP). The amino acid dates on deeper levels indicate that the Howiesons Poort stratum at Border Cave is more than 70 ka old, and that anatomically modern humans occupied the site as early as 100 ka ago.

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Relationship between root traits and arbuscular mycorrhizal fungi in three species of weeds with different synanthropy index

Scientia Fungorum ◽

10.33885/sf.2021.51.1360 ◽

2021 ◽

Vol 51 ◽

pp. e1360

Author(s):

Rocío Vega-Frutis ◽

Ana M. Hanan-Alipi

Keyword(s):

Root Length ◽

Mycorrhizal Fungi ◽

Specific Root Length ◽

Root Traits ◽

Arbuscular Mycorrhizal ◽

Mycorrhizal Colonization ◽

Foraging Strategies ◽

Root Branching ◽

Arbuscular Mycorrhizal Colonization ◽

Order Root

Background: Nutrient foraging strategies between thin and thick roots, including mycorrhizal symbionts are resource-costly, and therefore a trade-off could exist. These strategies can vary with the synanthropy index (degree to which a species associates with anthropogenic habitats), thus maximizing the benefits for the acquisition of soil resources. Objectives: To quantify the arbuscular mycorrhizal colonization of Melampodium species with different synanthropy index, and to determine the correlations between arbuscular mycorrhizal colonization and the architectural and morphological root traits. Methods: Roots of Melampodium divaricatum, M. perfoliatum and M. tepicense, with highest to lowest synanthropy index, respectively were collected. The root branching rate (RBR), total root length (TRL), diameter of first-order root, (FOR), root tissue density (RTD), specific root length (SRL), and arbuscular mycorrhizal colonization were quantified. Additionally, soil chemistry analyses were done. Results and conclusion: Melampodium tepicense had lowest FOR, highest SRL and lowest arbuscular mycorrhizal colonization, whereas M. divaricatum and M. perfoliatum had the opposite values. Additionally, M. divaricatum and M. perfoliatum had higher TRL, RTD, and RBR, suggesting that both strategies, arbuscular mycorrhiza and fine roots, are used for acquisition of nutrients, independently of their phylogenetic relationship and soil nutrients.

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