Bioassay and Anatomical Study of Bas 517 Using Etiolated Crop Seedlings

Weed Science ◽  
1993 ◽  
Vol 41 (3) ◽  
pp. 490-496
Author(s):  
Hwei-Yiing Li ◽  
Chester L. Foy
Keyword(s):  
Root Growth ◽  
Growth Inhibition ◽  
Incubation Time ◽  
Inhibitory Activity ◽  
Laboratory Experiments ◽  
Anatomical Study ◽  
High Sensitivity ◽  
Root Tip ◽  
Root Tips ◽  
Soybean Seedlings

Laboratory experiments were conducted to determine the selectivity and inhibitory activity of BAS 517 using whole seedlings or root tips of corn and soybean. Effects of BAS 517 on the morphology of corn root tips were examined as well. Etiolated corn seedlings showed high sensitivity to BAS 517; soybean seedlings were not affected. Growth inhibition of corn varied with concentrations of BAS 517 and incubation time. Radicles of corn were more sensitive than mesocotyls and coleoptiles. Root meristems were the first to show symptoms (reddening tissue followed by cessation of root growth). Results using root tips were similar to those using whole seedlings. However, root tips appeared to be more sensitive than whole seedlings. Concentrations of 0.1 and 10 μM of BAS 517 caused severe vacuolization of cells in the 0.2-cm root tip of corn. A pattern of decreasing injury from epidermal cells toward the centers of roots was observed.

Proteomic Analyses of Soybean Root Tips During Germination

2014 ◽  
Vol 21 (12) ◽  
pp. 1308-1319
Author(s):  
Setsuko Komatsu ◽  
Myeong W. Oh ◽  
Hee Y. Jang ◽  
Soo J. Kwon ◽  
Hye R. Kim ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Proteomic Analysis ◽  
Plant Root ◽  
Root Tip ◽  
Root Tips ◽  
Form Complex ◽  
Molecular Weights ◽  
Soybean Seedlings ◽  
2D Gel ◽  
Proteomic Techniques

Plant root systems form complex networks with the surrounding soil environment and are controlled by both internal and external factors. To better understand the function of root tips of soybean during germination, three proteomic techniques were used to analyze the protein profiles of root tip cells. Proteins were extracted from the root tips of 4-dayold soybean seedlings and analyzed using two-dimensional (2D) gel electrophoresis-based proteomics, SDS-gel based proteomics, and gel-free proteomics techniques. A total of 121, 862, and 341 proteins were identified in root tips using the 2D gel-based, SDS gel-based, and gel-free proteomic techniques, respectively. The proteins identified by 2D gel-based proteomic analysis were predominantly localized in the cytoplasm, whereas nuclear-localized proteins were most commonly identified by the SDS gel-based and gel-free proteomics techniques. Of the 862 proteins identified in the SDS gelbased proteomic analysis, 190 were protein synthesis-related proteins. Furthermore, 24 proteins identified using the 2Dgel based proteomic technique shifted between acidic and basic isoelectric points, and 2 proteins, heat shock protein 70.2 and AAA-type ATPase, displayed two different molecular weights at the same isoelectric point. Taken together, these results suggest that a number of proteins related to protein synthesis and modification are activated in the root tips of soybean seedlings during germination.

Nitrate and glutamate sensing by plant roots

2005 ◽  
Vol 33 (1) ◽  
pp. 283-286 ◽  
Author(s):  
S. Filleur ◽  
P. Walch-Liu ◽  
Y. Gan ◽  
B.G. Forde
Keyword(s):  
Root Growth ◽  
Lateral Root ◽  
Lateral Roots ◽  
Primary Root ◽  
Root Tip ◽  
Root Tips ◽  
Environmental Signals ◽  
Specific Effects ◽  
Large Numbers ◽  
Low Concentrations

The architecture of a root system plays a major role in determining how efficiently a plant can capture water and nutrients from the soil. Growth occurs at the root tips and the process of exploring the soil volume depends on the behaviour of large numbers of individual root tips at different orders of branching. Each root tip is equipped with a battery of sensory mechanisms that enable it to respond to a range of environmental signals, including nutrients, water potential, light, gravity and touch. We have previously identified a MADS (MCM1, agamous, deficiens and SRF) box gene (ANR1) in Arabidopsis thaliana that is involved in modulating the rate of lateral root growth in response to changes in the external NO3− supply. Transgenic plants have been generated in which a constitutively expressed ANR1 protein can be post-translationally activated by treatment with dexamethasone (DEX). When roots of these lines are treated with DEX, lateral root growth is markedly stimulated but there is no effect on primary root growth, suggesting that one or more components of the regulatory pathway that operate in conjunction with ANR1 in lateral roots may be absent in the primary root tip. We have recently observed some very specific effects of low concentrations of glutamate on root growth, resulting in significant changes in root architecture. Experimental evidence suggests that this response involves the sensing of extracellular glutamate by root tip cells. We are currently investigating the possible role of plant ionotropic glutamate receptors in this sensory mechanism.

scholarly journals Impact of cadmium and hydrogen peroxide on ascorbate-glutathione recycling enzymes in barley root

2013 ◽  
Vol 59 (No. 2) ◽  
pp. 62-67 ◽  
Author(s):  
V. Zelinová ◽  
B. Bočová ◽  
J. Huttová ◽  
I. Mistrík ◽  
L. Tamás
Keyword(s):  
Root Growth ◽  
Growth Inhibition ◽  
Reductase Activity ◽  
Barley Root ◽  
Dehydroascorbate Reductase ◽  
Monodehydroascorbate Reductase ◽  
Root Tip ◽  
Root Growth Inhibition ◽  
Short Term ◽  
Short Term Exposure

We analyse the effect of Cd and H<sub>2</sub>O<sub>2</sub> short-term treatments on the activity of ascorbate-glutathione recycling enzymes in barley root tip. Even a short transient exposure of barley roots to low 15 &micro;mol Cd concentration caused a marked approximately 70% root growth inhibition. Higher Cd concentrations caused root growth cessation during the first 6 h after short-term Cd treatment. Similarly, a marked root growth inhibition was also detected after the short-term exposure of barley seedlings to H<sub>2</sub>O<sub>2</sub>. Our results indicate that root ascorbate pool is more sensitive to Cd treatment than glutathione pool. Rapid activation of dehydroascorbate reductase and monodehydroascorbate reductase is the important component of stress response to the Cd-induced alterations in barley root tips. H<sub>2</sub>O<sub>2</sub> is probably involved in the Cd-induced activation of monodehydroascorbate reductase, but it is not involved in the Cd-induced increase of dehydroascorbate reductase activity.

Primary root growth: a biophysical model of auxin-related control

2005 ◽  
Vol 32 (9) ◽  
pp. 849 ◽  
Author(s):  
Andrés Chavarría-Krauser ◽  
Willi Jäger ◽  
Ulrich Schurr
Keyword(s):  
Growth Rate ◽  
Root Growth ◽  
Relative Growth Rate ◽  
Primary Root ◽  
Biophysical Model ◽  
Root Tip ◽  
Growth Equation ◽  
Root Tips ◽  
Relative Growth ◽  
Wall Extensibility

Plant hormones control many aspects of plant development and play an important role in root growth. Many plant reactions, such as gravitropism and hydrotropism, rely on growth as a driving motor and hormones as signals. Thus, modelling the effects of hormones on expanding root tips is an essential step in understanding plant roots. Here we achieve a connection between root growth and hormone distribution by extending a model of root tip growth, which describes the tip as a string of dividing and expanding cells. In contrast to a former model, a biophysical growth equation relates the cell wall extensibility, the osmotic potential and the yield threshold to the relative growth rate. This equation is used in combination with a refined hormone model including active auxin transport. The model assumes that the wall extensibility is determined by the concentration of a wall enzyme, whose production and degradation are assumed to be controlled by auxin and cytokinin. Investigation of the effects of auxin on the relative growth rate distribution thus becomes possible. Solving the equations numerically allows us to test the reaction of the model to changes in auxin production. Results are validated with measurements found in literature.

Inhibited Mitotic Entry is the Cause of Growth Inhibition by Cinmethylin

Weed Science ◽  
1986 ◽  
Vol 34 (5) ◽  
pp. 684-688 ◽  
Author(s):  
Mahmound H. El-Deek ◽  
F. Dan Hess
Keyword(s):  
Root Growth ◽  
Growth Inhibition ◽  
Avena Sativa ◽  
Cell Elongation ◽  
Shoot Growth ◽  
Mitotic Arrest ◽  
Root Tips ◽  
Mitotic Entry ◽  
Mitotic Frequency

The herbicide cinmethylin {exo-1-methyl-4-(1-methylethyl)-2-[(2-methylphenyl)methoxy]-7-oxabicyclo [2.2.1] heptane} inhibited oat (Avena sativaL. ‘Porter’) root growth during the first 6 h of treatment at a concentration of 6.7 × 10-8M. A concentration of 1 × 10-8M cinmethylin inhibited root growth within 12 to 18 h. Inhibition of shoot growth was less sensitive, but was inhibited by 36 to 48 h after treatment with 1 × 10-7M and by 12 to 24 h after treatment with 1 × 10-5M cinmethylin. Cinmethylin concentrations of 1 × 10-5M and lower did not inhibit cell elongation in isolated oat coleoptiles during a 24-h exposure. Mitotic frequency in oat root tips was reduced after 12 h of treatment with 1 × 10-7M cinmethylin. The frequency of all stages of mitosis (prophase, metaphase, and anaphase + telophase) was reduced. Concentrations of 1 × 10-6M cinmethylin resulted in nearly complete arrest (87% inhibition) of mitosis. These data suggest cinmethylin inhibits growth by inhibiting entry of cells into mitosis. The cause of mitotic arrest is unknown; however, the mechanism appears to be different from other herbicides known to inhibit mitosis.

scholarly journals The piperazine compound ASP activates an auxin response in Arabidopsis thaliana

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Fengyang Xu ◽  
Shuqi Xue ◽  
Limeng Deng ◽  
Sufen Zhang ◽  
Yaxuan Li ◽  
...  
Keyword(s):  
Root Growth ◽  
Root Development ◽  
Gene Knockout ◽  
Primary Root ◽  
Inhibitory Effect ◽  
Root Tip ◽  
Ethylene Response Factor ◽  
Auxin Response ◽  
Root Tips ◽  
Chemical Library

Abstract Background Auxins play key roles in the phytohormone network. Early auxin response genes in the AUX/IAA, SAUR, and GH3 families show functional redundancy, which makes it very difficult to study the functions of individual genes based on gene knockout analysis or transgenic technology. As an alternative, chemical genetics provides a powerful approach that can be used to address questions relating to plant hormones. Results By screening a small-molecule chemical library of compounds that can induce abnormal seedling and vein development, we identified and characterized a piperazine compound 1-[(4-bromophenoxy) acetyl]-4-[(4-fluorophenyl) sulfonyl] piperazine (ASP). The Arabidopsis DR5::GFP line was used to assess if the effects mentioned were correlated with the auxin response, and we accordingly verified that ASP altered the auxin-related pathway. Subsequently, we examined the regulatory roles of ASP in hypocotyl and root development, auxin distribution, and changes in gene expression. Following ASP treatment, we detected hypocotyl elongation concomitant with enhanced cell elongation. Furthermore, seedlings showed retarded primary root growth, reduced gravitropism and increased root hair development. These phenotypes were associated with an increased induction of DR5::GUS expression in the root/stem transition zone and root tips. Auxin-related mutants including tir1–1, aux1–7 and axr2–1 showed phenotypes with different root-development pattern from that of the wild type (Col-0), and were insensitive to ASP. Confocal images of propidium iodide (PI)-stained root tip cells showed no detectable damage by ASP. Furthermore, RT-qPCR analyses of two other genes, namely, Ethylene Response Factor (ERF115) and Mediator 18 (MED18), which are related to cell regeneration and damage, indicated that the ASP inhibitory effect on root growth was not attributable to toxicity. RT-qPCR analysis provided further evidence that ASP induced the expression of early auxin-response-related genes. Conclusions ASP altered the auxin response pathway and regulated Arabidopsis growth and development. These results provide a basis for dissecting specific molecular components involved in auxin-regulated developmental processes and offer new opportunities to discover novel molecular players involved in the auxin response.

scholarly journals Bacterial-type plant ferroxidases tune local phosphate sensing in root development

2021 ◽  
Author(s):  
Christin Naumann ◽  
Marcus Heisters ◽  
Wolfgang Brandt ◽  
Philipp Janitza ◽  
Carolin Alfs ◽  
...  
Keyword(s):  
Root Growth ◽  
Bacterial Colonization ◽  
Root System Architecture ◽  
Root Tip ◽  
Root Growth Inhibition ◽  
Root Tips ◽  
Metal Interactions ◽  
Ferroxidase Activity ◽  
Fe Homeostasis ◽  
Pi Deficiency

Fluctuating bioavailability of inorganic phosphate (Pi), often caused by complex Pi-metal interactions, guide root tip growth and root system architecture for maximizing the foraged soil volume. Two interacting genes in Arabidopsis thaliana, PDR2 (P5-type ATPase) and LPR1 (multicopper oxidase), are central to external Pi monitoring by root tips, which is modified by iron (Fe) co-occurrence. Upon Pi deficiency, the PDR2-LPR1 module facilitates cell type-specific Fe accumulation and cell wall modifications in root meristems, inhibiting intercellular communication and thus root growth. LPR1 executes local Pi sensing, whereas PDR2 restricts LPR1 function. We show that native LPR1 displays specific ferroxidase activity and requires a conserved acidic triad motif for high-affinity Fe2+ binding and root growth inhibition under limiting Pi. Our data indicate that substrate availability tunes LPR1 function and implicate PDR2 in maintaining Fe homeostasis. LPR1 represents the prototype of an ancient ferroxidase family, which evolved very early upon bacterial colonization of land. During plant terrestrialization, horizontal gene transfer transmitted LPR1-type ferroxidase from soil bacteria to the common ancestor of Zygnematophyceae algae and embryophytes, a hypothesis supported by homology modeling, phylogenomics, and activity assays of bacterial LPR1-type multicopper oxidases.

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