Kinetics of metal toxicity in plant roots and its effects on root morphology

The effect of metal mixtures on the biomass production rates of natural assemblages of copepods was predicted by assuming that metal-induced increases in the inverse of the growth rate (i.e. the growth time) are additive. The average observed growth time increase, ΔGTobs in 14 binary mixtures of the metals Cd, Cu, Hg, Pb, Zn, and As was 17% larger than the average calculated growth time increases, ΔGTcal (assuming additivity), indicating a slight but statistically significant synergism. Synergism in multimetal mixtures appears to be cumulative, since the average ΔGTobs was 53% greater than the average ΔGTcal in mixtures containing five metals simultaneously. One of the 15 possible binary mixtures (Zn:As) of the six metals tested demonstrated a large divergence between ΔGTobs and ΔGTcal. For all other metal mixtures studied, most of the toxicity is accounted for by the summation of noninteractive, single, metal effects.Key words: copepods, metal toxicity, metal interactions, biomass production, cadmium, copper, mercury, lead, zinc, arsenic

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Impact of Plant Root Morphology on Rooted-Soil Shear Resistance Using Triaxial Testing

Advances in Civil Engineering ◽

10.1155/2020/8825828 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Suyun Meng ◽

Guoqing Zhao ◽

Yuyou Yang

Keyword(s):

Internal Friction ◽

Root System ◽

Root Morphology ◽

Root Length ◽

Friction Angle ◽

Plant Roots ◽

Distribution Characteristics ◽

Soil Cohesion ◽

Shearing Strength ◽

Individual Root

Mechanical reinforcement by plant roots increases the soil shearing strength. The geometric and distribution characteristics of plant roots affect the soil shearing strength. Current research on the shear strength of rooted-soil is mostly based on direct shear tests with a fixed shear surface and thus cannot reflect the actual failure state of the rooted-soil. In this study, Golden Vicary Privet was used to create a rooted-soil, and a triaxial test method was used for soil mechanical property analysis. The influence of the root geometry (root diameter and individual root length) and distribution characteristics (root density and root distribution angle) on the rooted-soil shearing strength was studied by controlling the root morphology in the specimens. According to the results, both the root geometry and distribution characteristics affect the rooted-soil shearing strength. For a fixed total length of the roots, the longer the individual root length is, the better the soil shearing strength is. In addition, the reinforcement effect of the root system increases as the angle between the root and the potential failure surface increases. The results also show that the root system significantly enhances the soil cohesion while only minimally affecting the internal friction angle. The maximum rooted-soil cohesion is 2.39 times that of the plain soil cohesion, and the maximum internal friction angle of rooted-soil is 1.24 times that of plain soil. This paper provides an approach for the determination of the rooted-soil strength and a rationale for vegetation selection in ecological slope reinforcement applications.

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ROOT MORPHOLOGY AND NUTRIENT UPTAKE KINETICS BY AUSTRALIAN CEDAR CLONES

Revista Caatinga ◽

10.1590/1983-21252016v29n118rc ◽

2016 ◽

Vol 29 (1) ◽

pp. 153-162 ◽

Cited By ~ 7

Author(s):

RAQUEL OLIVEIRA BATISTA ◽

ANTONIO EDUARDO FURTINI NETO ◽

SOAMI FERNANDA CAIO DECCETTI ◽

CASSIANO SILVA VIANA

Keyword(s):

Nutrient Uptake ◽

Root Morphology ◽

System Development ◽

Morphological Characteristics ◽

Average Diameter ◽

Uptake Efficiency ◽

Root System Development ◽

Randomized Design ◽

Kinetics Of

ABSTRACT: Evaluation of root morphology and kinetic parameters assist in the characterization of genotypes in nutrient uptake efficiency. This study characterized Australian cedar clones concerning their nutrient uptake capacity at the seedling stage through root morphology and the kinetics of P, K, Ca, and Mg uptake. The experiment was conducted using a nutrient solution in a greenhouse and growth chamber. Four Australian cedar clones (HE, XF, XD, and XE), provided by Bela Forest View (Empresa Florestal Bela Vista), were tested using a completely randomized design with five repetitions, totaling 20 experimental plots. The length, volume, surface area, average diameter, and root length per diameter class, as well as the uptake parameters Vmax, Km, Cmin, and the estimated inflow of P, K, Ca, and Mg, were determined. The root morphological characteristics varied between Australian cedar clones; clone XD exhibited the largest root system development. The uptake efficiency of P, K, Ca, and Mg varied between cedar Australian clones. When availability differed, clones XE and XF exhibited greater plasticity in the uptake of P and K respectively, and similar results were found for clone HE in the uptake of Ca and Mg.

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