scholarly journals Effects of green seaweed extract on Arabidopsis early development suggest roles for hormone signalling in plant responses to algal fertilisers

2018 ◽  
Author(s):  
Fatemeh Ghaderiardakani ◽  
Ellen Collas ◽  
Deborah Kohn Damiano ◽  
Katherine Tagg ◽  
Neil S. Graham ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Growth Inhibition ◽  
Early Development ◽  
Land Plant ◽  
Root Growth Inhibition ◽  
Plant Responses ◽  
Germination Inhibition ◽  
Green Seaweed ◽  
Algal Extracts

AbstractThe growing population requires sustainable, environmentally-friendly crops. The plant growth-enhancing properties of algal extracts have suggested their use as biofertilisers. The mechanism(s) by which algal extracts affect plant growth are unknown.We examined the effects of extracts from the common green seaweed Ulva intestinalis on germination and root development in the model land plant Arabidopsis thaliana. Ulva extract concentrations above 0.1% inhibited Arabidopsis germination and root growth. Ulva extract <0.1% stimulated root growth. All concentrations of Ulva extract inhibited lateral root formation. An abscisic-acid-insensitive mutant, abi1, showed altered sensitivity to germination- and root growth-inhibition inhibition. Ethylene- and cytokinin-insensitive mutants were partly insensitive to germination-inhibition. This suggests that different mechanisms mediate each effect of Ulva extract on early Arabidopsis development and that multiple hormones contribute to germination-inhibition.Elemental analysis showed that Ulva contains high levels of Aluminium ions (Al3+). Ethylene and cytokinin have been suggested to function in Al3+-mediated root growth inhibition: our data suggest that if Ulva Al3+ levels inhibit root growth, this is via a novel mechanism. We suggest algal extracts should be used cautiously as fertilisers, as the inhibitory effects on early development may outweigh any benefits if the concentration of extract is too high.

Melatonin alleviates aluminium toxicity through modulating antioxidative enzymes and enhancing organic acid anion exudation in soybean

2017 ◽  
Vol 44 (10) ◽  
pp. 961 ◽  
Author(s):  
Jiarong Zhang ◽  
Bingjie Zeng ◽  
Yawen Mao ◽  
Xiangying Kong ◽  
Xinxun Wang ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Critical Role ◽  
Aluminium Toxicity ◽  
Al Toxicity ◽  
Root Growth Inhibition ◽  
H2o2 Production ◽  
Plant Responses ◽  
Al Stress ◽  
High Concentrations

Aluminium (Al) toxicity is a major chemical constraint limiting plant growth and production on acidic soils. Melatonin (N-acetyl-5-methoxytryptamine) is a ubiquitous molecule that plays crucial roles in plant growth and stress tolerance. However, there is no knowledge regarding whether melatonin is involved in plant responses to Al stress. Here, we show that optimal concentrations of melatonin could effectively ameliorate Al-induced phytotoxicity in soybean (Glycine max L.). The concentration of melatonin in roots was significantly increased by the 50 μM Al treatment. Such an increase in endogenous melatonin coincided with the upregulation of the gene encoding acetyltransferase NSI-like (nuclear shuttle protein-interacting) in soybean roots. Supplementation with low concentrations of melatonin (0.1 and 1 μM) conferred Al resistance as evident in partial alleviation of root growth inhibition and decreased H2O2 production: in contrast, high concentrations of melatonin (100 and 200 μM) had an opposite effect and even decreased root growth in Al-exposed seedlings. Mitigation of Al stress by the 1 μM melatonin root treatment was associated with enhanced activities of the antioxidant enzymes and increased exudation of malate and citrate. In conclusion, melatonin might play a critical role in soybean resistance to Al toxicity.

JAR1 negatively regulates root growth under boron deficiency in Arabidopsis

2021 ◽  
Author(s):  
Yupu Huang ◽  
Sheliang Wang ◽  
Lei Shi ◽  
Fangsen Xu
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Growth Inhibition ◽  
Primary Root ◽  
Root Growth Inhibition ◽  
Boron Deficiency ◽  
Ethylene Signaling ◽  
Protein Levels ◽  
Primary Root Growth ◽  
Ja Signaling

Abstract Boron (B) is an essential micronutrient for plant growth and development. Jasmonic acid (JA) plays pivotal roles in plant growth. However, the underlying molecular mechanism of JA involvement in B-deficiency-induced root growth inhibition is yet to be explored. In this study, we investigated the response of JA to B deficiency and the mechanism of JAR1-dependent JA signaling in root growth inhibition under B deficiency. B deficiency enhanced JA signaling in roots, and root growth inhibition was partially restored by JA biosynthesis inhibition. jar1-1 (jasmonate-resistant 1, JAR1) mutant, mutants of coronatine-insensitive 1 (coi1-2) and myc2 defective in JA signaling showed insensitivity to B deficiency. Ethylene-overproduction mutant eto1 and ethylene-insensitive mutant etr1 showed sensitivity and insensitivity to B deficiency, respectively, suggesting that ethylene is involved in the inhibition of primary root growth under B deficiency. Furthermore, after a declined in EIN3 protein levels, which may contribute to root growth, ethylene signaling was weakened in the jar1-1 mutant root under B deficiency. Under B deficiency, B concentrations were increased in the roots and shoots of the jar1-1 mutant, owing to the large root system and its activity. Therefore, our findings revealed that JA, which is involved in the inhibition of root growth under B deficiency, is regulated by JAR1 activated JA and ethylene signaling pathways.

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

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.

Interplay between 1-aminocyclopropane-1-carboxylic acid, γ-aminobutyrate and D-glucose in the regulation of high nitrate-induced root growth inhibition in maize

Plant Science ◽  
2020 ◽  
Vol 293 ◽  
pp. 110418
Author(s):  
Iñigo Saiz-Fernández ◽  
Maite Lacuesta ◽  
Usue Pérez-López ◽  
M. Carmen Sampedro ◽  
Ramon J. Barrio ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Root Growth ◽  
Growth Inhibition ◽  
Root Growth Inhibition

scholarly journals The mechanism of root growth inhibition by the endocrine disruptor bisphenol A (BPA)

2020 ◽  
Vol 257 ◽  
pp. 113516 ◽  
Author(s):  
Ramin Bahmani ◽  
DongGwan Kim ◽  
Mahsa Modareszadeh ◽  
Andrew J. Thompson ◽  
Jeong Hoon Park ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Root Growth ◽  
Growth Inhibition ◽  
Endocrine Disruptor ◽  
Root Growth Inhibition

scholarly journals Root Microbiome Modulates Plant Growth Promotion Induced by Low Doses of Glyphosate

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Dario X. Ramirez-Villacis ◽  
Omri M. Finkel ◽  
Isai Salas-González ◽  
Connor R. Fitzpatrick ◽  
Jeffery L. Dangl ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Growth Inhibition ◽  
Growth Promotion ◽  
Action Spectrum ◽  
Dry Weight ◽  
Agricultural Fields ◽  
Low Doses ◽  
Shoot Dry Weight ◽  
Root Microbiome

ABSTRACT Glyphosate is a commonly used herbicide with a broad action spectrum. However, at sublethal doses, glyphosate can induce plant growth, a phenomenon known as hormesis. Most glyphosate hormesis studies have been performed under microbe-free or reduced-microbial-diversity conditions; only a few were performed in open systems or agricultural fields, which include a higher diversity of soil microorganisms. Here, we investigated how microbes affect the hormesis induced by low doses of glyphosate. To this end, we used Arabidopsis thaliana and a well-characterized synthetic bacterial community of 185 strains (SynCom) that mimics the root-associated microbiome of Arabidopsis. We found that a dose of 3.6 × 10−6 g acid equivalent/liter (low dose of glyphosate, or LDG) produced an ∼14% increase in the shoot dry weight (i.e., hormesis) of uninoculated plants. Unexpectedly, in plants inoculated with the SynCom, LDG reduced shoot dry weight by ∼17%. We found that LDG enriched two Firmicutes and two Burkholderia strains in the roots. These specific strains are known to act as root growth inhibitors (RGI) in monoassociation assays. We tested the link between RGI and shoot dry weight reduction in LDG by assembling a new synthetic community lacking RGI strains. Dropping RGI strains out of the community restored growth induction by LDG. Finally, we showed that individual RGI strains from a few specific phyla were sufficient to switch the response to LDG from growth promotion to growth inhibition. Our results indicate that glyphosate hormesis was completely dependent on the root microbiome composition, specifically on the presence of root growth inhibitor strains. IMPORTANCE Since the introduction of glyphosate-resistant crops, glyphosate has become the most common and widely used herbicide around the world. Due to its intensive use and ability to bind to soil particles, it can be found at low concentrations in the environment. The effect of these remnants of glyphosate in plants has not been broadly studied; however, glyphosate 1,000 to 100,000 times less concentrated than the recommended field dose promoted growth in several species in laboratory and greenhouse experiments. However, this effect is rarely observed in agricultural fields, where complex communities of microbes have a central role in the way plants respond to external cues. Our study reveals how root-associated bacteria modulate the responses of Arabidopsis to low doses of glyphosate, shifting between growth promotion and growth inhibition.

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