Effects of lead on root growth, cell division, and nucleolus of Allium cepa

Sound waves affect plants at the biochemical, physical, and genetic levels. However, the mechanisms by which plants respond to sound waves are largely unknown. Therefore, the aim of this study was to examine the effect of sound waves on Arabidopsis thaliana growth. The results of the study showed that Arabidopsis seeds exposed to sound waves (100 and 100 + 9k Hz) for 15 h per day for 3 day had significantly longer root growth than that in the control group. The root length and cell number in the root apical meristem were significantly affected by sound waves. Furthermore, genes involved in cell division were upregulated in seedlings exposed to sound waves. Root development was affected by the concentration and activity of some phytohormones, including cytokinin and auxin. Analysis of the expression levels of genes regulating cytokinin and auxin biosynthesis and signaling showed that cytokinin and ethylene signaling genes were downregulated, while auxin signaling and biosynthesis genes were upregulated in Arabidopsis exposed to sound waves. Additionally, the cytokinin and auxin concentrations of the roots of Arabidopsis plants increased and decreased, respectively, after exposure to sound waves. Our findings suggest that sound waves are potential agricultural tools for improving crop growth performance.

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Phyto-toxic Influence of an Atrazine-based Selective Herbicide – Arda-force® on Onions (Allium cepa L)

Chemical Science International Journal ◽

10.9734/csji/2020/v29i330169 ◽

2020 ◽

pp. 40-46

Author(s):

Doris Fovwe Ogeleka ◽

Esther Obasi

Keyword(s):

Root Growth ◽

Growth Inhibition ◽

Allium Cepa ◽

Environmental Protection Agency ◽

Toxic Effects ◽

Root Growth Inhibition ◽

Allium Cepa L ◽

Test Concentration ◽

Maximum Root ◽

Selective Herbicide

Introduction: The constant impact on the environment occasioned by pollution, indiscriminate application of agricultural chemicals, security challenges and crisis in the Niger Delta ecological area of Nigeria has caused severe damage to plants, soil organisms and humans. Aim and Methodology: In this research, onions (Allium cepa L) was exposed to varying concentrations of an atrazine-based selective herbicide Arda-force® to estimate the phyto-toxic effects on the plant species using the Organization for Economic Co-operation and Development, (OECD) protocol #208. Results: The mean effective concentration (EC50) using root growth inhibition produced indications of phyto-toxicity to the exposed species at a concentration of 0.55 ± 0.06 mg/L. Similarly, the maximum root growth inhibition efficiency relative to the control was 65% as recorded in the highest test concentration of 1.25 mg/L. Discussion: The study indicated that constant application / indiscriminate use of the herbicide Arda-force® could cause deleterious influence on these plant and vegetable species, daily consumed by humans as a rich source of anti-oxidants. Conclusion: This study concluded that atrazine-based herbicide Arda-force® used in this assessment resulted in phyto-toxic effects to Allium cepa L. At the exposed concentrations of the herbicide to non-target specie – Allium cepa L. that are integral parts of the ecosystems, the ‘‘harmless’’ status of atrazine acclaimed by the United State Environmental Protection Agency (USEPA) is still very much in doubt.

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Reversible inhibition of root growth and cell proliferation by pentavalent arsenic in Allium cepa L.

Environmental and Experimental Botany ◽

10.1016/0098-8472(88)90040-8 ◽

1988 ◽

Vol 28 (1) ◽

pp. 9-18 ◽

Cited By ~ 7

Author(s):

I. Pepper ◽

N. Galanti ◽

J. Sans ◽

J.F. Lopez-Saez

Keyword(s):

Cell Proliferation ◽

Root Growth ◽

Allium Cepa ◽

Reversible Inhibition ◽

Allium Cepa L ◽

Pentavalent Arsenic

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Nitrate Induction of Primary Root Growth Requires Cytokinin Signaling in Arabidopsis thaliana

Plant and Cell Physiology ◽

10.1093/pcp/pcz199 ◽

2019 ◽

Vol 61 (2) ◽

pp. 342-352 ◽

Cited By ~ 5

Author(s):

Pamela A Naulin ◽

Grace I Armijo ◽

Andrea S Vega ◽

Karem P Tamayo ◽

Diana E Gras ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Cell Division ◽

Root Growth ◽

Primary Root ◽

Growth Arrest ◽

Root Tip ◽

Wild Type ◽

Cytokinin Signaling ◽

Control Growth ◽

Primary Root Growth

Abstract Nitrate can act as a potent signal to control growth and development in plants. In this study, we show that nitrate is able to stimulate primary root growth via increased meristem activity and cytokinin signaling. Cytokinin perception and biosynthesis mutants displayed shorter roots as compared with wild-type plants when grown with nitrate as the only nitrogen source. Histological analysis of the root tip revealed decreased cell division and elongation in the cytokinin receptor double mutant ahk2/ahk4 as compared with wild-type plants under a sufficient nitrate regime. Interestingly, a nitrate-dependent root growth arrest was observed between days 5 and 6 after sowing. Wild-type plants were able to recover from this growth arrest, while cytokinin signaling or biosynthesis mutants were not. Transcriptome analysis revealed significant changes in gene expression after, but not before, this transition in contrasting genotypes and nitrate regimes. We identified genes involved in both cell division and elongation as potentially important for primary root growth in response to nitrate. Our results provide evidence linking nitrate and cytokinin signaling for the control of primary root growth in Arabidopsis thaliana.

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