Transpiration integrated model for root ion absorption under salinized condition

Biologia ◽  
2013 ◽  
Vol 68 (6) ◽  
Author(s):  
Ryosuke Nomiyama ◽  
Daisuke Yasutake ◽  
Yuki Sago ◽  
Masaharu Kitano
Keyword(s):  
Integrated Model ◽  
Model Parameters ◽  
Crop Fields ◽  
Root Absorption ◽  
Ion Absorption ◽  
Maize Roots ◽  
Dependent Model ◽  
Flow Through ◽  
Maize Plants ◽  
Intact Root

AbstractSalinization of crop fields is a pressing matter for sustainable agriculture under desertification and is largely attributed to root absorptive functions of the major crops such as maize. The rates of water and ion absorption of intact root system of maize plants were measured under the salinized condition, and the salt absorptive function of maize roots was analyzed by applying different two kinetic models of root ion absorption (i.e. the concentration dependent model and the transpiration integrated model). The absorption rates for salinization ions (Na+, Cl−, Ca2+ and Mg2+) were found to depend on ion mass flow through roots driven by the transpiration, and therefore the transpiration integrated model represented more accurately rates of root ion absorption. The root absorption of salinization ions was characterized quantitatively by two model parameters of Q′max and K′M involved in the transpiration integrated model, which are considered to relate to the potential absorbing power and the ion affinity of transport proteins on root cell membranes, respectively.

Turing and Benjamin–Feir instability mechanisms in non-autonomous systems

2020 ◽  
Vol 476 (2238) ◽  
pp. 20200003 ◽  
Author(s):  
Robert A. Van Gorder
Keyword(s):  
Autonomous Systems ◽  
Reaction Diffusion ◽  
Reaction Rates ◽  
Time Dependent ◽  
Model Parameters ◽  
Time Varying ◽  
Reaction Diffusion Systems ◽  
Diffusion Systems ◽  
Dependent Model ◽  
Spatio Temporal

The Turing and Benjamin–Feir instabilities are two of the primary instability mechanisms useful for studying the transition from homogeneous states to heterogeneous spatial or spatio-temporal states in reaction–diffusion systems. We consider the case when the underlying reaction–diffusion system is non-autonomous or has a base state which varies in time, as in this case standard approaches, which rely on temporal eigenvalues, break down. We are able to establish respective criteria for the onset of each instability using comparison principles, obtaining inequalities which involve the in general time-dependent model parameters and their time derivatives. In the autonomous limit where the base state is constant in time, our results exactly recover the respective Turing and Benjamin–Feir conditions known in the literature. Our results make the Turing and Benjamin–Feir analysis amenable for a wide collection of applications, and allow one to better understand instabilities emergent due to a variety of non-autonomous mechanisms, including time-varying diffusion coefficients, time-varying reaction rates, time-dependent transitions between reaction kinetics and base states which change in time (such as heteroclinic connections between unique steady states, or limit cycles), to name a few examples.

scholarly journals Application of Transpiration Integrated Model to Simulation of Dynamics of Ion Absorption by Tomato Roots Growing in Soil-less Culture

2017 ◽  
Vol 55 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Ryosuke NOMIYAMA ◽  
Daisuke YASUTAKE ◽  
Yuki SAGO ◽  
Masaharu KITANO
Keyword(s):  
Integrated Model ◽  
Ion Absorption ◽  
Tomato Roots

Modeling study of solid-particle erosion with consideration of particle velocity dependent model parameters

2016 ◽  
Vol 07 (03) ◽  
pp. 1650026 ◽  
Author(s):  
Shijie Qian ◽  
Kuiying Chen ◽  
Rong Liu ◽  
Ming Liang
Keyword(s):  
Experimental Data ◽  
Solid Particle ◽  
Particle Velocity ◽  
Target Material ◽  
Model Parameters ◽  
Particle Impact ◽  
Erosion Rates ◽  
Proposed Model ◽  
Dependent Model ◽  
Predicted Model

An advanced erosion model that correlates two model parameters—the energies required to remove unit mass of target material during cutting wear and deformation wear, respectively, with particle velocity, particle size and density, as well as target material properties, is proposed. This model is capable of predicting the erosion rates for a material under solid-particle impact over a specific range of particle velocity at the impingement angle between [Formula: see text] and [Formula: see text], provided that the experimental data of erosion rate for the material at a particle velocity within this range and at impingement angles between [Formula: see text] and [Formula: see text] are available. The proposed model is applied on three distinct types of materials: aluminum, perspex and graphite, to investigate the dependence behavior of the model parameters on particle velocity for ductile and brittle materials. The predicted model parameters obtained from the model are validated by the experimental data of aluminum plate under Al2O3 particle impact. The significance and limitation of the model are discussed; possible improvements on the model are suggested.

EFFECT OF ASSET VALUE CORRELATION ON CREDIT-LINKED NOTE VALUES

2002 ◽  
Vol 05 (05) ◽  
pp. 455-478 ◽  
Author(s):  
C. H. HUI ◽  
C. F. LO
Keyword(s):  
Interest Rate ◽  
Credit Risk ◽  
Structural Model ◽  
Credit Spreads ◽  
Model Parameters ◽  
Risk Premiums ◽  
Closed Form Solutions ◽  
Asset Values ◽  
Dependent Model ◽  
Payoff Condition

This paper develops a simple model to study the credit risk premiums of credit-linked notes using the structural model. Closed-form solutions of credit risk premiums of the credit-linked notes derived from the model as functions of firm values and the short-term interest rate, with time-dependent model parameters governing the dynamics of the firm values and interest rate. The numerical results show that the credit spreads of a credit-linked note increase non-linearly with the decrease in the correlation between the asset values of the note issuer and the reference obligor when the final payoff condition depends on the asset values of the note issuer and the reference obligor. When the final payoff condition depends on the recovery rate of the note issuer upon default, the credit spreads could increase with the correlation. In addition, the term structures of model parameters and the correlations involving interest rate are clearly the important factors in determining the credit spreads of the notes.

scholarly journals A Ratio-Dependent Model of Replicator-Genetic Parasite Coevolution Demonstrates Instability of the Parasite-Free State

2021 ◽  
Author(s):  
Faina Berezovskaya ◽  
Georgy P. Karev ◽  
Eugene V. Koonin
Keyword(s):  
Mortality Rate ◽  
Carrying Capacity ◽  
Biological Evolution ◽  
Type Model ◽  
Model Parameters ◽  
Volterra Type ◽  
Dependent Model ◽  
Ratio Dependent ◽  
Host Parasite ◽  
Intrinsic Feature

AbstractNearly all organisms on earth are hosts to diverse genetic parasites including viruses and various types of mobile genetic elements. The emergence and persistence of genetic parasites was hypothesized to be an intrinsic feature of biological evolution. Here we examine this proposition by analysis of a ratio-dependent Lotka-Volterra type model of replicator(host)-parasite coevolution where the evolutionary outcome depends on the ratio of the host and parasite numbers. In a large, unbounded domain of the space of the model parameters, which include the replicator carrying capacity, the damage inflicted by the parasite, the replicative advantage of the parasites, and its mortality rate, the parasite-free equilibrium takes the form of a saddle and accordingly is unstable. Therefore, the evolutionary outcome is either the stable coexistence of the replicator and the parasite or extinction of both. Thus, the results of ratio-dependent model analysis are compatible with the hypothesis that genetic parasites are inherent to life.

scholarly journals Spatio-temporal modelling of the duration of the cotton cycle in the State Of Goiás, Brazil

2011 ◽  
Vol 31 (4) ◽  
pp. 652-662
Author(s):  
Jorge C. dos A. Antonini ◽  
Euzebio M. da Silva ◽  
Nori P. Griebeler ◽  
Edson E. Sano
Keyword(s):  
Pearson Correlation ◽  
The State ◽  
Coefficient Of Determination ◽  
Maximum Temperature ◽  
Model Parameters ◽  
Crop Fields ◽  
Time Space ◽  
Spatio Temporal ◽  
Temperature Records ◽  
Comparative Results

The objective of this work was to develop and validate a mathematical model to estimate the duration of cotton (Gossypium hirsutum L. r. latifolium hutch) cycle in the State of Goiás, Brazil, by applying the method of growing degree-days (GD), and considering, simultaneously, its time-space variation. The model was developed as a linear combination of elevation, latitude, longitude, and Fourier series of time variation. The model parameters were adjusted by using multiple-linear regression to the observed GD accumulated with air temperature in the range of 15°C to 40°C. The minimum and maximum temperature records used to calculate the GD were obtained from 21 meteorological stations, considering data varying from 8 to 20 years of observation. The coefficient of determination, resulting from the comparison between the estimated and calculated GD along the year was 0.84. Model validation was done by comparing estimated and measured crop cycle in the period from cotton germination to the stage when 90 percent of bolls were opened in commercial crop fields. Comparative results showed that the model performed very well, as indicated by the Pearson correlation coefficient of 0.90 and Willmott agreement index of 0.94, resulting in a performance index of 0.85.

Isolation and characterisation of sulfur-oxidising bacteria, including strains of Rhizobium, from calcareous sandy soils and their effects on nutrient uptake and growth of maize (Zea mays L.)

2006 ◽  
Vol 57 (1) ◽  
pp. 101 ◽  
Author(s):  
Khaled A. El-Tarabily ◽  
Abdou A. Soaud ◽  
Maher E. Saleh ◽  
Satoshi Matsumoto
Keyword(s):  
Growth Inhibition ◽  
United Arab Emirates ◽  
Sandy Soils ◽  
First Record ◽  
Rhizobium Strain ◽  
Maize Roots ◽  
Zn And Cu In ◽  
Maize Plants ◽  
S Oxidation

Four sulfur-oxidising bacteria were selected among 427 bacterial isolates from calcareous sandy soils in the United Arab Emirates (UAE). These isolates were selected based on their strong ability to oxidise elemental sulfur (S°) in vitro and were identified as Paracoccus versutus CBS 114155, Paracoccus pantotrophus CBS 114154, and 2 strains as Rhizobium spp. NCCB 100053 and NCCB 100054. This is the first published report of a Rhizobium species capable of S° oxidation and also the first record of sulfur-oxidising bacteria from UAE soils. These isolates were tested in a greenhouse in the presence and absence of S° to study their effects on maize growth. Best growth was observed in the treatment with P. versutus application combined with S°, which significantly reduced soil pH, increased soil SO4 level and the uptake of N, S, Fe, Mn, and Zn in maize roots and shoots. The P and Cu uptake in the shoots of maize plants was not significant compared with the treatment that received the application of S° alone. There was no response in plant growth to treatments that included the application of S° combined with P. pantotrophus or Rhizobium strain NCCB 100053 compared with the treatment that received the application of S° alone. There was significant growth inhibition of maize plants in the treatment receiving Rhizobium strain NCCB 100054 with or without the application of S° compared with the treatment that included the application of S° alone. This growth inhibition was associated with a significant decrease in the levels of N, P, S, Fe, Mn, Zn, and Cu in roots and shoots in the absence of S°. Rhizobium strain NCCB 100054 applied with S° significantly decreased the levels of N, S, and Fe in the roots and the levels of N, P, S, Fe, Mn, and Cu in the shoots of maize, with no significant differences in the levels of P and Mn in the roots and in the levels of Zn in the shoots, compared with the treatment with S° alone. These results indicate that the treatment P. versutus combined with S° can be effective as a soil conditioner for horticultural production in calcareous sandy soils.

scholarly journals Bioturbation by endogeic earthworms facilitates entomopathogenic nematode movement toward herbivore-damaged maize roots

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sandrine Fattore ◽  
Zhenggao Xiao ◽  
Adrienne L. Godschalx ◽  
Gregory Röder ◽  
Ted C. J. Turlings ◽  
...  
Keyword(s):  
Biological Control ◽  
Cropping Systems ◽  
Entomopathogenic Nematode ◽  
Agricultural Practices ◽  
Crop Fields ◽  
Diabrotica Balteata ◽  
Maize Roots ◽  
Biocontrol Potential ◽  
Root Feeding ◽  
Endogeic Earthworms

AbstractEntomopathogenic nematodes (EPNs) have been extensively studied as potential biological control agents against root-feeding crop pests. Maize roots under rootworm attack have been shown to release volatile organic compounds, such as (E)-β-caryophyllene (Eβc) that guide EPNs toward the damaging larvae. As yet, it is unknown how belowground ecosystems engineers, such as earthworms, affect the biological control capacity of EPNs by altering the root Eβc-mediated tritrophic interactions. We here asked whether and how, the presence of endogeic earthworms affects the ability of EPNs to find root-feeding larvae of the beetle Diabrotica balteata. First, we performed a field mesocosm experiment with two diverse cropping systems, and revealed that the presence of earthworms increased the EPN infection potential of larvae near maize roots. Subsequently, using climate-controlled, olfactometer-based bioassays, we confirmed that EPNs response to Eβc alone (released from dispensers) was two-fold higher in earthworm-worked soil than in earthworm-free soil. Together our results indicate that endogeic earthworms, through burrowing and casting activities, not only change soil properties in a way that improves soil fertility but may also enhance the biocontrol potential of EPNs against root feeding pests. For an ecologically-sound pest reduction in crop fields, we advocate agricultural practices that favour earthworm community structure and diversity.

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