scholarly journals How grow-and-switch gravitropism generates root coiling and root waving growth responses in Medicago truncatula

2015 ◽  
Vol 112 (42) ◽  
pp. 12938-12943 ◽  
Author(s):  
Tzer Han Tan ◽  
Jesse L. Silverberg ◽  
Daniela S. Floss ◽  
Maria J. Harrison ◽  
Christopher L. Henley ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Growth Medium ◽  
Plant Root ◽  
Experimental Studies ◽  
Optimal Strategies ◽  
Growth Responses ◽  
Inclined Plane ◽  
Rigid Barrier ◽  
Primary Roots ◽  
Root Waving

Experimental studies show that plant root morphologies can vary widely from straight gravity-aligned primary roots to fractal-like root architectures. However, the opaqueness of soil makes it difficult to observe how environmental factors modulate these patterns. Here, we combine a transparent hydrogel growth medium with a custom built 3D laser scanner to directly image the morphology of Medicago truncatula primary roots. In our experiments, root growth is obstructed by an inclined plane in the growth medium. As the tilt of this rigid barrier is varied, we find Medicago transitions between randomly directed root coiling, sinusoidal root waving, and normal gravity-aligned morphologies. Although these root phenotypes appear morphologically distinct, our analysis demonstrates the divisions are less well defined, and instead, can be viewed as a 2D biased random walk that seeks the path of steepest decent along the inclined plane. Features of this growth response are remarkably similar to the widely known run-and-tumble chemotactic behavior of Escherichia coli bacteria, where biased random walks are used as optimal strategies for nutrient uptake.

scholarly journals Structural Pounding Detection by Using Wavelet Scalogram

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Shutao Xing ◽  
Marvin W. Halling ◽  
Qingli Meng
Keyword(s):  
Experimental Studies ◽  
Shake Table Tests ◽  
Rigid Barrier ◽  
Single Degree Of Freedom ◽  
Structural Pounding ◽  
Numerical Studies ◽  
Bridge Model ◽  
On Line ◽  
Potential Damage ◽  
Bridge Responses

Structural pounding can cause considerable damage and even lead to collapse of structures. Most research focuses on modeling, parameter investigation, and mitigation approaches. With the development of structural health monitoring, the on-line detection of pounding becomes possible. The detection of pounding can provide useful information of potential damage of structures. This paper proposed using wavelet scalograms of dynamic response to detect pounding and examined the feasibility of this method. Numerical investigations were performed on a pounding system that consisted of a damped single-degree-of-freedom (SDOF) structure and a rigid barrier. Hertz contact model was used to simulate pounding behavior. The responses and pounding forces of the system under harmonic and earthquake excitations were numerically solved. The wavelet scalograms of acceleration responses were used to identify poundings. It was found that the scalograms can indicate the occurrence of pounding and occurrence time very well. The severity of the poundings was also approximately estimated. Experimental studies were carried out, in which shake table tests were conducted on a bridge model that underwent pounding between its different components during ground motion excitation. The wavelet scalograms of the bridge responses indicated pounding occurrence quite well. Hence the conclusions from the numerical studies were verified experimentally.

scholarly journals Root cap size and shape influence responses to the physical strength of the growth medium in Arabidopsis thaliana primary roots

2019 ◽  
Author(s):  
J Roué ◽  
H Chauvet ◽  
N Brunel-Michac ◽  
F Bizet ◽  
B Moulia ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Growth Medium ◽  
Root Cap ◽  
Arabidopsis Mutants ◽  
Physical Strength ◽  
Size And Shape ◽  
Primary Roots ◽  
Root Responses ◽  
Shape Influence

Analysis of the growth and orientation of roots of Arabidopsis mutants with differing root cap sizes and shapes indicates that the form of the cap affects root responses to variations in the strength of the growth medium.

scholarly journals Expression Studies on AUX1-like Genes in Medicago truncatula Suggest That Auxin Is Required at Two Steps in Early Nodule Development

2001 ◽  
Vol 14 (3) ◽  
pp. 267-277 ◽  
Author(s):  
Françoise de Billy ◽  
Cathy Grosjean ◽  
Sean May ◽  
Malcolm Bennett ◽  
Julie V. Cullimore
Keyword(s):  
Medicago Truncatula ◽  
Lateral Root ◽  
Sequence Similarity ◽  
Lateral Roots ◽  
Peripheral Region ◽  
Nodule Development ◽  
Central Position ◽  
Root Tips ◽  
High Sequence Similarity ◽  
Primary Roots

Medicago truncatula contains a family of at least five genes related to AUX1 of Arabidopsis thaliana (termed MtLAX genes for Medicago truncatula-like AUX1 genes). The high sequence similarity between the encoded proteins and AUX1 implies that the MtLAX genes encode auxin import carriers. The MtLAX genes are expressed in roots and other organs, suggesting that they play pleiotropic roles related to auxin uptake. In primary roots, the MtLAX genes are expressed preferentially in the root tips, particularly in the provascular bundles and root caps. During lateral root and nodule development, the genes are expressed in the primordia, particularly in cells that were probably derived from the pericycle. At slightly later stages, the genes are expressed in the regions of the developing organs where the vasculature arises (central position for lateral roots and peripheral region for nodules). These results are consistent with MtLAX being involved in local auxin transport and suggest that auxin is required at two common stages of lateral root and nodule development: development of the primordia and differentiation of the vasculature.

scholarly journals Tissue growth constrains root organ outlines into an isometrically scalable shape

Development ◽  
2021 ◽  
Vol 148 (4) ◽  
pp. dev196253
Author(s):  
Motohiro Fujiwara ◽  
Tatsuaki Goh ◽  
Satoru Tsugawa ◽  
Keiji Nakajima ◽  
Hidehiro Fukaki ◽  
...  
Keyword(s):  
Plant Root ◽  
Lateral Roots ◽  
Time Lapse ◽  
Tissue Growth ◽  
Root Tip ◽  
Root Tips ◽  
Developmental Constraints ◽  
Primary Roots ◽  
Catenary Curve ◽  
Expansion Force

ABSTRACTOrgan morphologies are diverse but also conserved under shared developmental constraints among species. Any geometrical similarities in the shape behind diversity and the underlying developmental constraints remain unclear. Plant root tip outlines commonly exhibit a dome shape, which likely performs physiological functions, despite the diversity in size and cellular organization among distinct root classes and/or species. We carried out morphometric analysis of the primary roots of ten angiosperm species and of the lateral roots (LRs) of Arabidopsis, and found that each root outline was isometrically scaled onto a parameter-free catenary curve, a stable structure adopted for arch bridges. Using the physical model for bridges, we analogized that localized and spatially uniform occurrence of oriented cell division and expansion force the LR primordia (LRP) tip to form a catenary curve. These growth rules for the catenary curve were verified by tissue growth simulation of developing LRP development based on time-lapse imaging. Consistently, LRP outlines of mutants compromised in these rules were found to deviate from catenary curves. Our analyses demonstrate that physics-inspired growth rules constrain plant root tips to form isometrically scalable catenary curves.

scholarly journals Growth Medium and Soil Amendment Influence on Seedling Growth Responses of African Star Apple (Chrysophyllum albidum)

2020 ◽  
Vol 1 (3) ◽  
Author(s):  
Olubode Olusegun Olufemi ◽  
Yisau Oluwaseun Peter ◽  
Olubode Adebanke Ayooluwa ◽  
Oyegoke Clara Olabisi
Keyword(s):  
Growth Medium ◽  
Soil Amendment ◽  
Starch Content ◽  
Sugar Content ◽  
Poultry Manure ◽  
Soil Types ◽  
Clayey Soils ◽  
Growth Responses ◽  
Randomized Design ◽  
African Star Apple

African Star Apple (Chrysophyllum albidum) classified as a forest food tree with economic potentials requires domestication attention for improved productivity. A study conducted in Abeokuta, Nigeria in 2017 using one year old C. albidum seedlings determined the plant’s growth responses when cultivated using different growth medium and soil amendment methods. The 3 x 9 factorial experiment was arranged in a Completely Randomized Design (CRD) at three replications. Three textural soil types (sandy, loamy and clayey soils) were evaluated using nine soil amendment methods (5, 10, 15t/ha poultry manure (PM) and 150, 250 and 500kg/ha NPK, and integrated amendment methods using 5t/ha PM+150kg/ha NPK and 10t/ha PM+150kg/ha NPK), and the un-amended plot as control. The results showed that plants in loamy and clayey soils had more leaves compared to those in sandy soil only at 74WAS. C. albidum had most numerous leaves with 150 kg/ha, taller plant and wider canopy with 250 kg/ha, and thicker girth with all NPK rates compared to control, manure rates and integrated fertilizers. The plants with loamy soil had highest CPC, Ash C, FC, starch and sugar. Plants with inorganic fertilizers and integrated fertilizers had higher FW and DW compared to manure rates. The 5 t/ha manure rate and the 250 kg/ha NPK produced plants with high sugar content and were lowest in starch content compared to other applied rates. In conclusion, C. albidum from juvenile to vegetative stage with proper management can be grown on the different soil types while the 150 kg/ha NPK fertilizer rate appeared as optimum for the plant growth.

scholarly journals Arbuscular mycorrhizal fungi increase Pb uptake of colonized and non-colonized Medicago truncatula root and deliver extra Pb to colonized root

2021 ◽  
Author(s):  
Haoqiang Zhang ◽  
Wei Ren ◽  
Yaru Zheng ◽  
Fei Zhao ◽  
Ming Tang
Keyword(s):  
Medicago Truncatula ◽  
Mycorrhizal Fungi ◽  
Plant Root ◽  
Biomass Accumulation ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Shoot Biomass ◽  
Terrestrial Plants ◽  
Split Root ◽  
Split Root System

Abstract Aims Arbuscular mycorrhizal (AM) fungi form symbiosis with terrestrial plants and improve lead (Pb) tolerance of host plants. The AM plants accumulate more Pb in root than their non-mycorrhizal counterparts. However, the direct contribution of the mycorrhizal pathway to host plant Pb uptake was less reported. Methods In this study, the AM fungi colonized and non-colonized root of Medicago truncatula was separated by a split-root system, and their differences in responding to Pb application was compared. Results Inoculation of Rhizophagus irregularis increased shoot biomass accumulation and transpiration, and decreased both colonized and non-colonized root biomass accumulation. Application of Pb in the non-colonized root compartment increased the colonization rate of R. irregularis and up-regulated the relative expressions of MtPT4 and MtBCP1 in the colonized root compartment. Inoculation of R. irregularis increased the Pb uptake in both colonized and non-colonized plant root, while R. irregularis transferred Pb to the colonized root. The Pb transferred through the mycorrhizal pathway had low mobility move from root to shoot, and might be sequestrated and compartmented by R. irregularis. Conclusions The Pb uptake of plant root might follow water flow that facilitated by the aquaporin MtPIP2. The quantification of Pb transfer via mycorrhizal pathway and the involvement of MtPIP2 deserve further study.

scholarly journals Industrial Hemp (Cannabis sativa L.) Varieties and Seed Pre-Treatments Affect Seed Germination and Early Growth of Seedlings

Agronomy ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 6
Author(s):  
Mohammad Moinul Islam ◽  
Zed Rengel ◽  
Paul Storer ◽  
Kadambot H. M. Siddique ◽  
Zakaria M. Solaiman
Keyword(s):  
Seed Germination ◽  
Growth Medium ◽  
Seedling Growth ◽  
Chlorine Dioxide ◽  
Cannabis Sativa ◽  
Early Growth ◽  
Growth Responses ◽  
Hemp Seed ◽  
Industrial Hemp ◽  
Growth Of Seedlings

Seed germination and seedling growth are two essential early determinants of subsequent crop yield and quality. A high germination percentage of industrial hemp (Cannabis sativa L.) seed is required to import into Australia. The viability of hemp seed can decline rapidly depending on storage and other factors; hence, the quality of imported seed is not always reliable. Here, we aimed to investigate germination and early seedling growth responses of 14 industrial hemp varieties after being imported from various countries. Germination trials were conducted with 100 seeds of 14 varieties using a soil-less Petri dish assay and a compost growth medium under glasshouse conditions. We also assessed the effect of seed pre-treatments such as gibberellic acid (500 and 1000 mg·L−1), chlorine dioxide (500 and 1000 mg·L−1) and cold temperature (4 °C for 72 h) using 300 seeds of each of the three selected varieties in compost growth medium. Hemp varieties imported from China had higher germination and better seedling growth indices than those imported from Europe. All seed pre-treatments were associated with a decreasing trend in germination, but a positive effect on early growth responses was observed. Our findings indicate that the hemp variety Han FNQ performed better than many other varieties did regarding seed germination and seedling growth. Hemp seeds sanitising with 500 mg·L−1 of chlorine dioxide might improve the germination and early growth of seedlings.

scholarly journals Distinct genetic bases for plant root responses to lipo-chitooligosaccharide signal molecules from distinct microbial origins

2020 ◽  
Author(s):  
Maxime Bonhomme ◽  
Sandra Bensmihen ◽  
Olivier André ◽  
Emilie Amblard ◽  
Magali Garcia ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Molecular Mechanisms ◽  
Genome Wide Association Study ◽  
Plant Root ◽  
Pathogenic Fungi ◽  
Signal Molecules ◽  
List Type ◽  
Root Branching ◽  
A Genome ◽  
Root Response

SummaryLipo-chitooligosaccharides (LCOs) were originally found as symbiotic signals called Nod Factors (Nod-LCOs) controlling nodulation of legumes by rhizobia. More recently LCOs were also found in symbiotic fungi and, more surprisingly, very widely in the kingdom fungi including in saprophytic and pathogenic fungi. The LCO-V(C18:1, Fuc/MeFuc), hereafter called Fung-LCOs, are the LCO structures most commonly found in fungi. This raises the question of how legume plants, such as Medicago truncatula, can perceive and discriminate between Nod-LCOs and these Fung-LCOs.To address this question, we performed a Genome Wide Association Study on 173 natural accessions of Medicago truncatula, using a root branching phenotype and a newly developed local score approach.Both Nod- and Fung-LCOs stimulated root branching in most accessions but there was very little correlation in the ability to respond to these types of LCO molecules. Moreover, heritability of root response was higher for Nod-LCOs than for Fung-LCOs. We identified 123 loci for Nod-LCO and 71 for Fung-LCO responses, but only one was common.This suggests that Nod- and Fung-LCOs both control root branching but use different molecular mechanisms. The tighter genetic constraint of the root response to Fung-LCOs possibly reflects the ancestral origin of the biological activity of these molecules.

scholarly journals Choosing a servicing company’s strategy while interacting with freight owners at the road transport market

2021 ◽  
pp. 204-210
Author(s):  
G. Nugymanova ◽  
M. Nurgaliyeva ◽  
Zh. Zhanbirov ◽  
V. Naumov ◽  
I. Taran
Keyword(s):  
Optimal Strategy ◽  
Experimental Studies ◽  
Optimal Strategies ◽  
Road Transport ◽  
Payoff Matrix ◽  
Payoff Function ◽  
The Road ◽  
Transport Services ◽  
Game Theoretical Approach ◽  
Freight Forwarding

Purpose. To develop the methodology for choosing the strategies of freight forwarding companies in the situation of interaction with freight owners as customers of forwarding services. Methodology. The game-theoretical approach is used to formalize the conflict situation between a freight forwarding company and a cargo owner. A set of services proposed by forwarders is used as the base in order to represent possible strategies of a forwarder as the vector of probabilities that the respective services are provided for a client. The strategies of the cargo owner are represented as a binary variable that shows whether the client uses the provided services or not. The payoff function for a forwarder is defined as the companys profit and the clients payoff function as fee paid for forwarding services. To determine the influence of the demand parameters on the forwarders optimal strategies, the demand for transport services is represented as a flow of requests characterized by two numeric parameters delivery distance and consignment weight. Findings. The conducted experimental studies have shown that as a result of the use of the proposed methodology, the optimal strategy of a forwarding company can always be determined from the payoff matrix. The performed simulation experiment allowed us to state that in most cases the forwarders optimal strategy is mixed (the technological and commercial services should be provided with the given probability while servicing the flow of requests from freight owners). Originality. The studies on the influence of the request flow parameters on the probabilities of choosing the elementary strategies are carried in the paper for the first time. Practical value. The proposed methodology can be used as the basic tool for supporting decisions of freight forwarders while servicing the cargo owners at the market of road freight transportation.

Sign in / Sign up

Export Citation Format

Share Document