Ameliorative effect of melatonin improves drought tolerance by regulating growth, photosynthetic traits and leaf ultrastructure of maize seedlings

Abstract Background Melatonin is considered a potential plant growth regulator to enhance the growth of plants and increase tolerance to various abiotic stresses. Nevertheless, melatonin’s role in mediating stress response in different plant species and growth cycles still needs to be explored. This study was conducted to understand the impact of different melatonin concentrations (0, 50, 100, and 150 μM) applied as a soil drench to maize seedling under drought stress conditions. A decreased irrigation approach based on watering was exposed to maize seedling after drought stress was applied at 40–45% of field capacity. Results The results showed that drought stress negatively affected the growth behavior of maize seedlings, such as reduced biomass accumulation, decreased photosynthetic pigments, and enhanced the malondialdehyde and reactive oxygen species (ROS). However, melatonin application enhanced plant growth; alleviated ROS-induced oxidative damages by increasing the photosynthetic pigments, antioxidant enzyme activities, relative water content, and osmo-protectants of maize seedlings. Conclusions Melatonin treatment also enhanced the stomatal traits, such as stomatal length, width, area, and the number of pores under drought stress conditions. Our data suggested that 100 μM melatonin application as soil drenching could provide a valuable foundation for improving plant tolerance to drought stress conditions.

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Drought Stress Triggers Shifts in the Root Microbial Community and Alters Functional Categories in the Microbial Gene Pool

Frontiers in Microbiology ◽

10.3389/fmicb.2021.744897 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jianbo Xie ◽

Ghada E. Dawwam ◽

Amira E. Sehim ◽

Xian Li ◽

Jiadong Wu ◽

...

Keyword(s):

Microbial Community ◽

Drought Stress ◽

Plant Growth ◽

Crop Productivity ◽

Plant Tolerance ◽

Functional Categories ◽

Crop Failure ◽

Drought Treatment ◽

The Impact ◽

Root Microbiome

Drought is a major threat to crop productivity and causes decreased plant growth, poor yields, and crop failure. Nevertheless, the frequency of droughts is expected to increase in the coming decades. The microbial communities associated with crop plants can influence how plants respond to various stresses; hence, microbiome manipulation is fast becoming an effective strategy for improving the stress tolerance of plants. The effect of drought stress on the root microbiome of perennial woody plants is currently poorly understood. Using Populus trees as a model ecosystem, we found that the diversity of the root microbial community decreased during drought treatment and that compositional shifts in microbes during drought stress were driven by the relative abundances of a large number of dominant phyla, including Actinobacteria, Firmicutes, and Proteobacteria. A subset of microbes, including Streptomyces rochei, Bacillus arbutinivorans, B. endophyticus, B. megaterium, Aspergillus terreus, Penicillium raperi, Trichoderma ghanense, Gongronella butleri, and Rhizopus stolonifer, was isolated from the drought-treated poplar rhizosphere soils, which have potentially beneficial to plant fitness. Further controlled inoculation experiments showed that the isolated bacterial and fungal isolates positively impacted plant growth and drought tolerance. Collectively, our results demonstrate the impact of drought on root microbiome structure and provide a novel example of manipulating root microbiomes to improve plant tolerance.

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Antioxidant enzymes changes in response to drought stress in ten cultivars of oilseed rape (Brassica napus L.)

Czech Journal of Genetics and Plant Breeding ◽

10.17221/67/2009-cjgpb ◽

2010 ◽

Vol 46 (No. 1) ◽

pp. 27-34 ◽

Cited By ~ 123

Author(s):

T. Abedi ◽

H. Pakniyat

Keyword(s):

Drought Stress ◽

Brassica Napus ◽

Oilseed Rape ◽

Polyacrylamide Gel Electrophoresis ◽

Field Capacity ◽

Stress Conditions ◽

Antioxidant Enzyme Activities ◽

Guaiacol Peroxidase ◽

Brassica Napus L ◽

Irrigation Regimes

The study was undertaken to identify the responses of antioxidant enzyme activities and their isozyme patterns in seedlings of 10 oilseed rape (Brassica napus L.) cultivars under drought stress conditions. Plants were grown under three irrigation regimes (FC; field capacity, 60% FC and 30% FC) in a greenhouse. Drought stress preferentially enhanced the activities of superoxide dismutase (SOD) and guaiacol peroxidase (POD) whereas it decreased catalase (CAT) activity. Licord with the highest level of enzyme activity under both optimum and limited irrigation regimes is reported as the most tolerant cultivar. Whereas Hyola 308 and Okapy, having the lowest enzymes activities, are mentioned as cultivars sensitive to drought stress. The native polyacrylamide gel electrophoresis (PAGE) analysis detected eight SOD isozymes. Oilseed rape leaves contained three isoforms of Mn-SOD and five isoforms of Cu/Zn-SOD. The expression of Mn-SOD was preferentially enhanced by drought stress. Five POD isoforms were detected in oilseed rape leaves. The intensities of POD-4 and -5 were enhanced under drought stress. According to the results, the appearance of new isozyme bands under drought stress conditions may be used as a biochemical marker to differentiate drought tolerant cultivars under drought stress.

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Exogenous melatonin confers drought stress by promoting plant growth, photosynthetic capacity and antioxidant defense system of maize seedlings

PeerJ ◽

10.7717/peerj.7793 ◽

2019 ◽

Vol 7 ◽

pp. e7793 ◽

Cited By ~ 11

Author(s):

Shakeel Ahmad ◽

Muhammad Kamran ◽

Ruixia Ding ◽

Xiangping Meng ◽

Haiqi Wang ◽

...

Keyword(s):

Drought Stress ◽

Plant Growth ◽

Growth And Development ◽

Antioxidant Defense ◽

Antioxidant Defense System ◽

Maize Seedling ◽

Oxygen Species ◽

Maize Seedlings ◽

Defense System ◽

Plant Growth And Development

Melatonin is an important biologically active hormone that plays a vital role in plant growth and development. In particular, it has been investigated for its roles in abiotic stress management. The current experiment was carried out to investigate the protective role of melatonin in photosynthetic traits and the antioxidant defense system of maize seedling under drought stress. Maize seedlings were subjected to drought stress (40–45% FC) after two weeks of seedling emergence, followed by a foliar spray (0, 25, 50, 75 and 100 µM) and soil drench of melatonin (0, 25, 50, 75 and 100 µM). Our results indicated that drought stress negatively affected maize seedling and decreased plant growth and development, biomass accumulation, reduced chlorophyll, and carotenoid content, and significantly declined photosynthetic rate and stomatal conductance. On the other hand, reactive oxygen species, soluble protein, and proline content increased under drought stress. However, the application of exogenous melatonin reduced the reactive oxygen species burst and enhanced the photosynthetic activity by protecting from damages through activation of various antioxidant enzymes under drought stress. Foliar application of 100 µM and soil drench of 50 µM melatonin was the most effective treatment concentrations under drought stress. Our current findings hereby confirmed the mitigating potential of melatonin application for drought stress by maintaining plant growth, improving the photosynthetic characteristics and activities of antioxidants enzymes.

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Drought-stress Effects on Physiology, Growth and Biomass Production of Rainfed and Irrigated Bell Pepper Plants in the Mediterranean Region

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.126.3.297 ◽

2001 ◽

Vol 126 (3) ◽

pp. 297-304 ◽

Cited By ~ 44

Author(s):

Sebastiano Delfine ◽

Francesco Loreto ◽

Arturo Alvino

Keyword(s):

Drought Stress ◽

Plant Growth ◽

Water Potential ◽

Crop Yield ◽

Biomass Production ◽

Stress Conditions ◽

Bell Pepper ◽

Area Index ◽

Stress Effects ◽

The Impact

Physiological characteristics, growth, and biomass production of rainfed and irrigated bell pepper [Capsicum annuum L. var. anuum (Grossum Group) `Quadrato d'Asti'] plants were measured in the semiarid conditions of a Mediterranean summer to determine if drought stress effects are transient and do not affect plant growth and crop yield or are persistent and adversely affect plant growth and crop yield. A low midday leaf water potential indicated the occurrence of transient drought stress episodes in rainfed plants during the first 2 months of the study. Later on, predawn water potential also increased, indicating a persistent drought stress condition despite the occurrence of some rainfall. Photosynthesis was reduced when stress conditions developed, but the reduction was transient and limited to the central part of the day during the first 2 months. As plants aged, however, the impact of drought stress on photosynthesis was not relieved during the overnight recovery period. Stomatal conductance was reduced both during transient and permanent stress conditions while CO2 transfer conductance (i.e., conductance to CO2 inside the leaf) was only reduced when photosynthesis inhibition was unrecoverable. However, chloroplast CO2 concentration was higher in rainfed than in irrigated leaves indicating that CO2 availability was not limiting photosynthesis. Nonphotochemical quenching of fluorescence increased significantly in rainfed leaves exposed to permanent stress indicating the likely impairment of ATP synthesis. Transient inhibition of photosynthesis did not significantly affect leaf area index and biomass production, but growth was significantly reduced when photosynthesis was permanently inhibited. Fruit dry weight was even higher in rainfed plants compared to irrigated plants until drought stress and photosynthesis reduction became permanent. It is suggested that bell pepper growth without supplemental irrigation over the first part of the vegetative cycle does not impair plant growth and may even be useful to improve yield of early fruit.

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Copper Nanoparticle Application Enhances Plant Growth and Grain Yield in Maize Under Drought Stress Conditions

Journal of Plant Growth Regulation ◽

10.1007/s00344-021-10301-w ◽

2021 ◽

Cited By ~ 1

Author(s):

Dong Van Nguyen ◽

Huong Mai Nguyen ◽

Nga Thanh Le ◽

Kien Huu Nguyen ◽

Hoa Thi Nguyen ◽

...

Keyword(s):

Drought Stress ◽

Plant Growth ◽

Grain Yield ◽

Stress Conditions ◽

Copper Nanoparticle

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Effects of Nitric Oxide Application on Antioxidant Enzyme Activities of Pepper Plants under Drought Stress

ISPEC Journal of Agricultural Sciences ◽

10.46291/ispecjasvol5iss4pp846-853 ◽

2021 ◽

Vol 5 (4) ◽

pp. 846-853

Author(s):

Fikret YAŞAR ◽

Özlem ÜZAL

Keyword(s):

Nitric Oxide ◽

Drought Stress ◽

Plant Growth ◽

Nutrient Solution ◽

Enzyme Activities ◽

Growth Parameters ◽

Antioxidative Enzyme ◽

High Dose ◽

Antioxidant Enzyme Activities ◽

Hoagland Nutrient Solution

The purpose of the study was to determine the relationship between the messenger molecule Nitric oxide (NO) and antioxidative enzyme (SOD: Superoxide Dismutase; CAT: Catalase; APX: Ascorbate Peroxidase) activities in some metabolic changes that occur under the effect of drought stress in plants, to determine the possible roles of Nitric Oxide and to obtain complementary information. The experiment conducted in a controlled environment, and plant were cultured in containers containing Hoagland nutrient solution. For drought stress application, 10% Polyethylene Glycol (PEG 6000) was added to the nutrient solution, which is equivalent to -0.40 MPa osmotic potential. Before the drought stress is applied, pepper seedlings of Demre cv were pre-treated with different doses of Sodium Nitroprusside (SNP) and Carboxy-PTIO (potassium salt) (cPTIO) (SNP 0.01, SNP 1, SNP 100 and SNP 0.01 + cPTIO, SNP + cPTIO, SNP 100+ cPTIO). On the 10th day of the drought application, the growth parameters of the plants; the plant fresh weights and their Antioxidative Enzyme Activities (SOD, CAT, APX) were determined. In terms of plant growth parameters, both plant growth and antioxidant anzyme activities of plants pretreated with 0.01 and 1 doses of SNP were lower than the high dose of SNP and the PEG application without pretreatment. The reason for the low enzyme activities in these applications can be attributed to factors such as the excess accumulation of organic acids such as proline in the cells of the plants and the decrease in H2O2 and O-2 levels in the presence of SNP.

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The Arabidopsis Cys2/His2 zinc finger transcription factor ZAT18 is a positive regulator of plant tolerance to drought stress

Journal of Experimental Botany ◽

10.1093/jxb/erx157 ◽

2017 ◽

Vol 68 (11) ◽

pp. 2991-3005 ◽

Cited By ~ 27

Author(s):

Mingzhu Yin ◽

Yanping Wang ◽

Lihua Zhang ◽

Jinzhu Li ◽

Wenli Quan ◽

...

Keyword(s):

Drought Stress ◽

Zinc Finger ◽

Zinc Finger Protein ◽

Leaf Water ◽

Pathway Enrichment Analysis ◽

Antioxidant Enzyme Activities ◽

Sequencing Analysis ◽

Plant Tolerance ◽

Drought Treatment ◽

Positive Regulator

Abstract Environmental stress poses a global threat to plant growth and reproduction, especially drought stress. Zinc finger proteins comprise a family of transcription factors that play essential roles in response to various abiotic stresses. Here, we found that ZAT18 (At3g53600), a nuclear C2H2 zinc finger protein, was transcriptionally induced by dehydration stress. Overexpression (OE) of ZAT18 in Arabidopsis improved drought tolerance while mutation of ZAT18 resulted in decreased plant tolerance to drought stress. ZAT18 was preferentially expressed in stems, siliques, and vegetative rosette leaves. Subcellular location results revealed that ZAT18 protein was predominantly localized in the nucleus. ZAT18 OE plants exhibited less leaf water loss, lower content of reactive oxygen species (ROS), higher leaf water content, and higher antioxidant enzyme activities after drought treatment when compared with the wild type (WT). RNA sequencing analysis showed that 423 and 561 genes were transcriptionally modulated by the ZAT18 transgene before and after drought treatment, respectively. Pathway enrichment analysis indicated that hormone metabolism, stress, and signaling were over-represented in ZAT18 OE lines. Several stress-responsive genes including COR47, ERD7, LEA6, and RAS1, and hormone signaling transduction-related genes including JAZ7 and PYL5 were identified as putative target genes of ZAT18. Taken together, ZAT18 functions as a positive regulator and plays a crucial role in the plant response to drought stress.

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EFEITOS DA SUPLEMENTAÇÃO COM RESÍDUO DA ATIVIDADE DA CARCINICULTURA EM PLANTAS DE GIRASSOL SUBMETIDAS A CONDIÇÕES DE ESTRESSE HÍDRICO

Irriga ◽

10.15809/irriga.2017v22n3p591-605 ◽

2018 ◽

Vol 22 (3) ◽

pp. 591-605

Author(s):

BRENNDA BEZERRA BRAGA ◽

Franklin Aragão Gondim ◽

Francisco Holanda Nunes Junior ◽

Sabrina Isabel De Oliveira Paiva ◽

Rifandreo Monteiro Martins ◽

...

Keyword(s):

Drought Stress ◽

Plant Growth ◽

Helianthus Annuus ◽

Antioxidative Enzymes ◽

Stress Conditions ◽

Shrimp Farming ◽

Production Costs ◽

Shrimp Waste ◽

Helianthus Annuus L ◽

Federal Institute

EFEITOS DA SUPLEMENTAÇÃO COM RESÍDUO DA ATIVIDADE DA CARCINICULTURA EM PLANTAS DE GIRASSOL SUBMETIDAS A CONDIÇÕES DE ESTRESSE HÍDRICO BRENNDA BEZERRA BRAGA1; FRANSCISCO HOLANDA NUNES JUNIOR2; SABRINA ISABEL DE OLIVEIRA PAIVA1; RIFANDREO MONTEIRO BARBOSA1; ROBERTO ALBUQUERQUE PONTES FILHO1 E FRANKLIN ARAGÃO GONDIM1* 1Instituto Federal de Educação, Ciência e Tecnologia do Estado do Ceará – Campus Maracanaú. Av. Contorno Norte, 10, Distrito Industrial, Maracanaú, Ceará, Brasil. Email: [email protected]; [email protected]; [email protected]; [email protected]; *[email protected] (autor correspondente). 2Instituto Federal de Educação, Ciência e Tecnologia do Estado do Ceará – Campus Jaguaribe. Av. B - Bairro Manoel Costa Moraes, Jaguaribe, Ceará, Brasil. Email: [email protected] 1 RESUMO Objetivou-se identificar os efeitos da utilização de resíduo de carcinicultura sobre o crescimento e sistema enzimático antioxidativo de girassol em condições de estresse hídrico. O trabalho foi conduzido na casa de vegetação do Instituto Federal do Ceará – campus Maracanaú, Ceará, Brasil. As sementes foram semeadas em baldes contendo: 1) areia de granulometria fina; 2) areia + adubo; 3) areia + 7g de resíduo de carcinicultura; 4) areia + 14g de resíduo de carcinicultura. Decorridos 16 dias da semeadura, metade de cada grupo de plântulas descrito foi submetido à suspensão de rega. Foram realizadas 2 coletas:19 e 21 dias após a semeadura. Determinaram-se: as matérias frescas e secas da parte aérea, das raízes e total e as atividades das enzimas antioxidativas em folhas e raízes. De modo geral, a utilização de resíduo de carcinicultura no substrato proporcionou melhoria no crescimento das plantas. Isso pode ter ocorrido devido ao aumento nas atividades das enzimas antioxidativas. Em condições controle, a aplicação de 14g de resíduo ocasionou maiores produções de matéria seca total e atividades das enzimas antioxidativas. Concluiu-se que o resíduo de carcinicultura pode ser uma alternativa aos fertilizantes, reduzindo os custos de produção, além de ser uma destinação adequada ao resíduo de carcinicultura. Palavras-chave: estresse oxidativo, Helianthus annuus L., biofertilizante BRAGA, B. B.; NUNES JUNIOR, F. H.; PAIVA, S. I. O.; BARBOSA, R. M.; PONTES FILHO, R. A.; GONDIM, F. AEFFECTS OF SUPPLEMENTATION WITH WASTE OF SHRIMP FARMING ON SUNFLOWER PLANTS UNDER DROUGHT STRESS CONDITIONS 2 ABSTRACT The aim of this study was to identify the effects of the use of shrimp waste on plant growth and the antioxidative enzymatic defense system of sunflower under drought stress conditions. The experiment was carried out under greenhouse conditions at the Instituto Federal de Educação, Ciência e Tecnologia (Federal Institute of Education, Science and Technology), Maracanaú Campus, Ceará, Brazil. The seeds were sown in plastic pots containing: 1) fine-grained sand; 2) sand + fertilizer; 3) sand + 7g of shrimp waste; 4) sand + 14g shrimp waste. At 16 days after sowing, half of each seedling group described was submitted to irrigation suspension. Two plant harvests were performed: at 19 and 21 days after sowing. The following parameters were determined: shoots, roots and total fresh and dry masses, and activities of antioxidative enzymes in shoots and roots. In general, the use of shrimp waste in the substrate provided higher plant growth. This could be attributed to the increased activity of antioxidative enzymes. Under control conditions, the application of 14g of waste led to higher total dry mass and higher activities of antioxidative enzymes. It is concluded that the shrimp waste may be an alternative to fertilizers, reducing production costs. Moreover, it seems to be an adequate disposal for shrimp farming waste. Keywords: oxidative stress, Helianthus annuus L., biofertilizer

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Gibberellic Acid Induced Changes on Growth, Yield, Superoxide Dismutase, Catalase and Peroxidase in Fruits of Bitter Gourd (Momordica charantia L.)

Horticulturae ◽

10.3390/horticulturae6040072 ◽

2020 ◽

Vol 6 (4) ◽

pp. 72

Author(s):

Mazhar Abbas ◽

Faisal Imran ◽

Rashid Iqbal Khan ◽

Muhammad Zafar-ul-Hye ◽

Tariq Rafique ◽

...

Keyword(s):

Plant Growth ◽

Gibberellic Acid ◽

Growth Yield ◽

Growth And Yield ◽

Bitter Gourd ◽

Antioxidant Enzyme Activities ◽

Yield And Quality ◽

Dual Action ◽

Induced Changes ◽

The Impact

Bitter gourd is one of the important cucurbits and highly liked among both farmers and consumers due to its high net return and nutritional value. However, being monoecious, it exhibits substantial variation in flower bearing pattern. Plant growth regulators (PGRs) are known to influence crop phenology while gibberellic acid (GA3) is one of the most prominent PGRs that influence cucurbits phenology. Therefore, a field trial was conducted at University of Agriculture Faisalabad to evaluate the impact of a commercial product of gibberellic acid (GA3) on growth, yield and quality attributes of two bitter gourd (Momordica charantiaL.) cultivars. We used five different concentrations (0.4 g, 0.6 g, 0.8 g, 1.0 g, and 1.2 g per litre) of commercial GA3 product (Gibberex, 10% Gibberellic acid). Results showed that a higher concentration of gibberex (1.0 and 1.20 g L−1 water) enhanced the petiole length, intermodal length, and yield of bitter gourd cultivars over control in Golu hybrid and Faisalabad Long. A significant decrease in the enzyme superoxidase dismutase, peroxidase, and catalase activities were observed with an increasing concentration of gibberex (1.0 and 1.20 gL−1 water) as compared to control. These results indicate that the exogenous application of gibberex at a higher concentration (1.2 g L−1) has a dual action in bitter gourd plant: i) it enhances the plant growth and yield, and ii) it also influenced the antioxidant enzyme activities in fruits. These findings may have a meaningful, practical use for farmers involved in agriculture and horticulture.

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Microbial Diversity of Upland Rice Roots and Their Influence on Rice Growth and Drought Tolerance

Microorganisms ◽

10.3390/microorganisms8091329 ◽

2020 ◽

Vol 8 (9) ◽

pp. 1329

Author(s):

Zhiqiang Pang ◽

Ying Zhao ◽

Peng Xu ◽

Diqiu Yu

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Plant Growth ◽

Upland Rice ◽

Oryza Sativa L ◽

Soluble Sugar ◽

Stress Conditions ◽

Rice Roots ◽

Microbial Resources

Among abiotic stresses, drought is one of the most important factors limiting plant growth. To increase their drought tolerance and survival, most plants interact directly with a variety of microbes. Upland rice (Oryza sativa L.) is a rice ecotype that differs from irrigated ecotype rice; it is adapted to both drought-stress and aerobic conditions. However, its root microbial resources have not been explored. We isolated bacteria and fungi from roots of upland rice in Xishuangbanna, China. Four hundred sixty-two endophytic and rhizospheric isolates (337 bacteria and 125 fungi) were distributed. They were distributed among 43 genera on the basis of 16S rRNA and internal transcribed spacer (ITS) gene sequence analysis. Notably, these root microbes differed from irrigated rice root microbes in irrigated environments; for example, members of the Firmicutes phylum were enriched (by 28.54%) in the roots of the upland plants. The plant growth-promoting (PGP) potential of 217 isolates was investigated in vitro. The PGP ability of 17 endophytic and 10 rhizospheric isolates from upland rice roots was evaluated under well-irrigated and drought-stress conditions, and 9 fungal strains increased rice seedling shoot length, shoot and root fresh weight (FW), antioxidant capability, and proline (Pro) and soluble sugar contents. Our work suggests that fungi from upland rice roots can increase plant growth under irrigated and drought-stress conditions and can serve as effective microbial resources for sustainable agricultural production in arid regions.

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