scholarly journals Acclimation with humic acids enhances maize and tomato tolerance to salinity

Author(s):  
Aline Costa Souza ◽  
Daniel Basílio Zandonadi ◽  
Mirella Pupo Santos ◽  
Natália Oliveira Aguiar Canellas ◽  
Cleiton de Paula Soares ◽  
...  

Abstract Background Salinity is one of the major environmental threats to agriculture, limiting plant growth and reducing crop yield. The use of humic substances to alleviate salt stress in plants is well reported, but the mechanisms remain unclear. This work aimed to apply humic acids on seedlings to acclimate plants to tolerate further salt stress exposition as a pre-treatment. Materials and methods Two independent experiments with mono (maize) and dicot (tomato) seedlings were carried out. Maize was primed by humic acids (4 mM C) and further submitted to moderate salinity exposition (60 mM NaCl). The acclimation period of maize seedlings was characterized by ion balance and transcriptomic analysis of salt response genes. The tomato seedlings were also primed by humic acids (4 mM C) and exposed further to salinity (200 mM NaCl), and we measured only physiological aspect, including the activity of plasma membrane proton pumps and net photosynthesis rate. Results Seedlings primed by humic acids minimized the salinity stress by changing ion balance, promoting plasma membrane proton pumps activity and enhancing photosynthesis rate and plant growth. We showed for the first time that maize seedlings treated with humic acids had a high transcription level of salt responsive genes and transcription factors even before the salt exposition. Conclusion Humic acids previously activate cellular and molecular salt defence machinery, anticipating the response and reducing salinity stress. This is a key knowledge to manipulate manufactured biostimulants based on humic substances towards a maximized crop protection. Graphic abstract

2011 ◽  
Vol 6 (No. 1) ◽  
pp. 21-29 ◽  
Author(s):  
H. Khaled ◽  
H.A. Fawy

In this study, the effects were investigated of salinity, foliar and soil applications of humic substances on the growth and mineral nutrients uptake of Corn (Hagein, Fardy10), and the comparison was carried out of the soil and foliar applications of humic acid treatments at different NaCl levels. Soil organic contents are one of the most important parts that they directly affect the soil fertility and textures with their complex and heterogenous structures although they occupy a minor percentage of the soil weight. Humic acids are an important soil component that can improve nutrient availability and impact on other important chemical, biological, and physical properties of soils. The effects of foliar and soil applications of humic substances on the plant growth and some nutrient elements uptake of Corn (Hagein, Fardy10) grown at various salt concentrations were examined. Sodium chloride was added to the soil to obtain 20 and 60mM saline conditions. Solid humus was applied to the soil one month before planting and liquid humic acids were sprayed on the leaves twice on 20<sup>th</sup> and 40<sup>th</sup> day after seedling emergence. The application doses of solid humus were 0, 2 and 4 g/kg and those of liquid humic acids were 0, 0.1 and 0.2%. Salinity negatively affected the growth of corn; it also decreased the dry weight and the uptake of nutrient elements except for Na and Mn. Soil application of humus increased the N uptake of corn while foliar application of humic acids increased the uptake of P, K, Mg,Na,Cu and Zn. Although the effect of interaction between salt and soil humus application was found statistically significant, the interaction effect between salt and foliar humic acids treatment was not found significant. Under salt stress, the first doses of both soil and foliar application of humic substances increased the uptake of nutrients.


2017 ◽  
Vol 63 (No. 12) ◽  
pp. 545-551 ◽  
Author(s):  
Wu Guo-Qiang ◽  
Liu Hai-Long ◽  
Feng Rui-Jun ◽  
Wang Chun-Mei ◽  
Du Yong-Yong

The objective of this study was to investigate whether the application of silicon (Si) ameliorates the detrimental effects of salinity stress on sainfoin (Onobrychis viciaefolia). Three-week-old seedlings were exposed to 0 and 100 mmol/L NaCl with or without 1 mmol/L Si for 7 days. The results showed that salinity stress significantly reduced plant growth, shoot chlorophyll content and root K<sup>+</sup> concentration, but increased shoot malondialdehyde (MDA) concentration, relative membrane permeability (RMP) and Na<sup>+</sup> concentrations of shoot and root in sainfoin compared to the control (no added Si and NaCl). However, the addition of Si significantly enhanced growth, chlorophyll content of shoot, K<sup>+</sup> and soluble sugars accumulation in root, while it reduced shoot MDA concentration, RMP and Na<sup>+</sup> accumulation of shoot and root in plants under salt stress. It is clear that silicon ameliorates the adverse effects of salt stress on sainfoin by limiting Na<sup>+</sup> uptake and enhancing selectivity for K<sup>+</sup>, and by adjusting the levels of organic solutes. The present study provides physiological insights into understanding the roles of silicon in salt tolerance in sainfoin.


2013 ◽  
Vol 170 (10) ◽  
pp. 915-922 ◽  
Author(s):  
Małgorzata Janicka-Russak ◽  
Katarzyna Kabała ◽  
Anna Wdowikowska ◽  
Grażyna Kłobus

2010 ◽  
Vol 167 (4) ◽  
pp. 261-269 ◽  
Author(s):  
MaŁgorzata Janicka-Russak ◽  
Katarzyna KabaŁa ◽  
Ewa MŁodzińska ◽  
Grażyna KŁobus

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 989 ◽  
Author(s):  
Noshin Ilyas ◽  
Roomina Mazhar ◽  
Humaira Yasmin ◽  
Wajiha Khan ◽  
Sumera Iqbal ◽  
...  

Halo-tolerant plant growth-promoting rhizobacteria (PGPR) have the inherent potential to cope up with salinity. Thus, they can be used as an effective strategy in enhancing the productivity of saline agro-systems. In this study, a total of 50 isolates were screened from the rhizospheric soil of plants growing in the salt range of Pakistan. Out of these, four isolates were selected based on their salinity tolerance and plant growth promotion characters. These isolates (SR1. SR2, SR3, and SR4) were identified as Bacillus sp. (KF719179), Azospirillum brasilense (KJ194586), Azospirillum lipoferum (KJ434039), and Pseudomonas stutzeri (KJ685889) by 16S rDNA gene sequence analysis. In vitro, these strains, in alone and in a consortium, showed better production of compatible solute and phytohormones, including indole acetic acid (IAA), gibberellic acid (GA), cytokinin (CK), and abscisic acid (ABA), in culture conditions under salt stress. When tested for inoculation, the consortium of all four strains showed the best results in terms of improved plant biomass and relative water content. Consortium-inoculated wheat plants showed tolerance by reduced electrolyte leakage and increased production of chlorophyll a, b, and total chlorophyll, and osmolytes, including soluble sugar, proline, amino acids, and antioxidant enzymes (superoxide dismutase, catalase, peroxidase), upon exposure to salinity stress (150 mM NaCl). In conclusion, plant growth-promoting bacteria, isolated from salt-affected regions, have strong potential to mitigate the deleterious effects of salt stress in wheat crop, when inoculated. Therefore, this consortium can be used as potent inoculants for wheat crop under prevailing stress conditions.


Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1687
Author(s):  
Pharada Rangseekaew ◽  
Adoración Barros-Rodríguez ◽  
Wasu Pathom-aree ◽  
Maximino Manzanera

Soil salinity is an enormous problem affecting global agricultural productivity. Deep-sea actinobacteria are interesting due to their salt tolerance mechanisms. In the present study, we aim to determine the ability of deep-sea Dermacoccus (D. barathri MT2.1T and D. profundi MT2.2T) to promote tomato seedlings under 150 mM NaCl compared with the terrestrial strain D. nishinomiyaensis DSM20448T. All strains exhibit in vitro plant growth-promoting traits of indole-3-acetic acid production, phosphate solubilization, and siderophore production. Tomato seedlings inoculated with D. barathri MT2.1T showed higher growth parameters (shoot and root length, dry weight, and chlorophyll content) than non-inoculated tomato and the terrestrial strain under 150 mM NaCl. In addition, hydrogen peroxide (H2O2) in leaves of tomatoes inoculated with deep-sea Dermacoccus was lower than the control seedlings. This observation suggested that deep-sea Dermacoccus mitigated salt stress by reducing oxidative stress caused by hydrogen peroxide. D. barathri MT2.1T showed no harmful effects on Caenorhabditis elegans, Daphnia magna, Eisenia foetida, and Escherichia coli MC4100 in biosafety tests. This evidence suggests that D. barathri MT2.1T would be safe for use in the environment. Our results highlight the potential of deep-sea Dermacoccus as a plant growth promoter for tomatoes under salinity stress.


2021 ◽  
Vol 12 ◽  
Author(s):  
Judith Naamala ◽  
Donald L. Smith

The use of microbial derived compounds is a technological approach currently gaining popularity among researchers, with hopes of complementing, supplementing and addressing key issues associated with use of microbial cells for enhancing plant growth. The new technology is a promising approach to mitigating effects of salinity stress in agricultural crops, given that these compounds could be less prone to effects of salt stress, are required in small quantities and are easier to store and handle than microbial cells. Microorganism derived compounds such as thuricin17, lipochitooligosaccharides, phytohormones and volatile organic compounds have been reported to mitigate the effects of salt stress in agricultural crops such as soybean and wheat. This mini-review compiles current knowledge regarding the use of microbe derived compounds in mitigating salinity stress in crops, the mechanisms they employ as well as future prospects.


Horticulturae ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 49
Author(s):  
Muhammad Aaqil Khan ◽  
Muhammad Imran ◽  
Shifa Shaffique ◽  
Eun-Hae Kwon ◽  
Sang-Mo Kang ◽  
...  

The use of commercial food waste in the Korean agricultural industry is increasing due to its capacity to act as an ecofriendly fertilizer. However, the high salt content of food waste can be detrimental to plant health and increase salinity levels in agricultural fields. In the current study, we introduced halotolerant rhizobacteria to neutralize the negative impact of food waste-related salt stress on crop productivity. We isolated halotolerant rhizobacteria from plants at Pohang beach, and screened bacterial isolates for their plant growth-promoting traits and salt stress-mitigating capacity; consequently, the bacterial isolate Bacillus pumilus MAK9 was selected for further investigation. This isolate showed higher salt stress tolerance and produced indole-3-acetic acid along with other organic acids. Furthermore, the inoculation of B. pumilus MAK9 into Chinese cabbage plants alleviated the effects of salt stress and enhanced plant growth parameters, i.e., it increased shoot length (32%), root length (41%), fresh weight (18%), dry weight (35%), and chlorophyll content (13%) compared with such measurements in plants treated with food waste only (control). Moreover, relative to control plants, inoculated plants showed significantly decreased abscisic acid content (2-fold) and increased salicylic acid content (11.70%). Bacillus pumilus MAK9-inoculated Chinese cabbage plants also showed a significant decrease in glutathione (11%), polyphenol oxidase (17%), and superoxide anions (18%), but an increase in catalase (14%), peroxidase (19%), and total protein content (26%) in comparison to the levels in control plants. Inductively coupled plasma mass spectrometry analysis showed that B. pumilus MAK9-inoculated plants had higher calcium (3%), potassium (22%), and phosphorus (15%) levels, whereas sodium content (7%) declined compared with that in control plants. Similarly, increases in glucose (17%), fructose (11%), and sucrose (14%) contents were recorded in B. pumilus MAK9-inoculated plants relative to in control plants. The bacterial isolate MAK9 was confirmed as B. pumilus using 16S rRNA and phylogenetic analysis. In conclusion, the use of commercially powered food waste could be a climate-friendly agricultural practice when rhizobacteria that enhance tolerance to salinity stress are also added to plants.


2021 ◽  
Vol 25 (03) ◽  
pp. 692-700
Author(s):  
Noreen Zahra

Salinity stress negatively affects key physiological phenomena in plants while plants show great variability and respond differentially for tolerance to salt stress. Usually, nutrients imbalances affect specific plant tissues and physiological processes which are requisite for normal plant growth and development. The aim of this two-year (2017 and 2018) simulated field study was to investigate phenotypic plasticity for growth, relative leaf water content (RLWC) and nutrient status in milk thistle [Silybum marianum (L.) Gaertn.] ecotypes and the potential role of soil supplementation with pre-optimized levels of plant growth promoters (PGPs) in modulating these attributes under control and salinity (12 dS/m) stress. Four ecotypes of milk thistle were collected from three ecologically distinct zones including Faisalabad (FSD) and Kalar Kahar (KK) – semi-arid zone, Gujranwala (GUJ) – hot semi-arid zone and Quetta (QTA) – cool semi-arid zone. The studied nutrients were nitrate-N, phosphate-P, sulfate-S, sodium (Na), potassium (K) and calcium (Ca). The soil supplemented PGPs, applied with irrigation water, were ascorbic acid (AsA), thiourea (TU) and moringa leaf extract (MLE) at 250 μM, 500 μM and 3%, respectively of soil moisture content at field capacity. Results indicated that soil supplementation of PGPs in the field conditions is a feasible approach for enhancing nutrient uptake of milk thistle ecotypes under salt stress, while the effect of salinity stress restricted the uptake of the studied nutrients and caused their imbalance. Although the salinity stress reduced shoot and root dry matter, RLWC and restricted the uptake of these nutrients irrespective of ecotypes, the levels of nitrate-N, phosphate-P, K, sulfate-S, Ca, and RWC contents increased more with the soil supplementation of AsA followed by MLE as compared to other soil supplements in both the study years. Among the ecotypes, QTA followed by KK and FSD ecotypes gained more dry weight with greater leaf RWC and higher tissue nutrient contents due to PGPs under salt stress. The principal component analysis and correlation data revealed the existence of distinct phenotypic plasticity in the milk thistle ecotypes for nutrient acquisition with soil supplementation of PGPs under salinity stress. To conclude, ecotypes from QTA and KK were more promising than the others while AsA and MLE were better soil supplements in improving shoot and root nutrients under salt stress. © 2021 Friends Science Publishers


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