scholarly journals Effect of foliar-applied silicon on photochemistry, antioxidant capacity and growth in maize plants subjected to chilling stress

2016 ◽  
Vol 107 (1) ◽  
pp. 33 ◽  
Author(s):  
Ghader HABIBI

Low temperature is one of the major adverse climatic factors that suppress plant growth and sustainable agricultural development. In these climate conditions, silicon (Si) can mitigate various abiotic stresses including low temperature. In this study, the roles of foliar-applied silicon (10 mM potassium metasilicate) in enhancing tolerance to chilling stress were investigated in maize (<em>Zea mays</em> ‘Fajr’) plants. The low temperature stress caused significant reduction of plant growth and relative water content; however, Si ameliorated these effects. Si supply in maize exhibited a significantly positive effect on accumulation of free amino acids, and reduced the necrotic leaf area. The decrease in maximum quantum yield of PSII (F<sub>v</sub>/F<sub>m</sub>) was reversible during recovery, but not in the non-Si-treated leaves. This can be explained by enhancement of protective pigments; carotenoid and anthocyanin leading to the protection of PSII from damage. Additionally, analysis of OJIP transients revealed that Si reduced cold damaging effect on performance index (PI<sub>abs</sub>) and F<sub>v</sub>/F<sub>m</sub> through improvement of excitation energy trapping (TR<sub>0</sub>/CS) and electron transport (ET<sub>0</sub>/CS) per excited cross-section of leaf. The malondialdehyde (MDA) concentration, which was significantly increased under chilling stress, was decreased by Si. The reduced glutathione and ascorbate concentrations were higher in Si-treated plants as compared to those without application of Si under chilling stress. These results indicated that Si could enhance the chilling stress tolerance of maize plants through improving the biomass accumulation, maintaining a high level of glutathione, ascorbic acid, protein, protective pigments, and enhancing the photochemical reactions. This study also suggests that the foliar-applied Si increases recovery ability from chilling injury.

2021 ◽  
Vol 12 ◽  
Author(s):  
Jie Dong ◽  
Lei Cao ◽  
Xiaoying Zhang ◽  
Wuhua Zhang ◽  
Tao Yang ◽  
...  

A sudden cooling in the early spring or late autumn negatively impacts the plant growth and development. Although a number of studies have characterized the role of the transcription factors (TFs) of plant R2R3-myeloblastosis (R2R3-MYB) in response to biotic and abiotic stress, plant growth, and primary and specific metabolisms, much less is known about their role in Rosa multiflora under chilling stress. In the present study, RmMYB108, which encodes a nuclear-localized R2R3-MYB TF with a self-activation activity, was identified based on the earlier published RNA-seq data of R. multiflora plants exposed to short-term low-temperature stress and also on the results of prediction of the gene function referring Arabidopsis. The RmMYB108 gene was induced by stress due to chilling, salt, and drought and was expressed in higher levels in the roots than in the leaves. The heterologous expression of RmMYB108 in Arabidopsis thaliana significantly enhanced the tolerance of transgenic plants to freezing, water deficit, and high salinity, enabling higher survival and growth rates, earlier flowering and silique formation, and better seed quantity and quality compared with the wild-type (WT) plants. When exposed to a continuous low-temperature stress at 4°C, transgenic Arabidopsis lines–overexpressing RmMYB108 showed higher activities of superoxide dismutase and peroxidase, lower relative conductivity, and lower malondialdehyde content than the WT. Moreover, the initial fluorescence (Fo) and maximum photosynthetic efficiency of photosystem II (Fv/Fm) changed more dramatically in the WT than in transgenic plants. Furthermore, the expression levels of cold-related genes involved in the ICE1 (Inducer of CBF expression 1)-CBFs (C-repeat binding factors)-CORs (Cold regulated genes) cascade were higher in the overexpression lines than in the WT. These results suggest that RmMYB108 was positively involved in the tolerance responses when R. multiflora was exposed to challenges against cold, freeze, salt, or drought and improved the cold tolerance of transgenic Arabidopsis by reducing plant damage and promoting plant growth.


2019 ◽  
Vol 72 (2) ◽  
Author(s):  
Rositsa Cholakova-Bimbalova ◽  
Veselin Petrov ◽  
Andon Vassilev

Biostimulants offer a novel approach for the regulation of crucial physiological processes in plants. Recently, it has been observed that the application of biostimulants on both seeds and plants may ameliorate to some extent the negative effects of abiotic stresses such as drought, heat, salinity, and others. In the climate conditions of Bulgaria, the early developmental stages of warm climate crops, like maize, often occur under suboptimal temperatures. Although the mitigation of abiotic stress is perhaps the most frequently cited benefit of biostimulant formulations, little is known about their influence on chilling-stressed plants. The aim of our study was to evaluate the effects of a biostimulant from the group of protein hydrolysates on both the growth and the photosynthetic performance of chilling-exposed young maize plants grown in controlled environment. Here, we report that application of a protein hydrolysate increased the performance of chilled maize plants, as demonstrated by leaf gas exchange, photosynthetic pigment content, and chlorophyll fluorescence, but did not affect their growth. Nevertheless, based on the better preserved photosynthetic performance of the biostimulant-treated maize plants exposed to chilling, we assume that under subsequent favorable conditions their growth would recover more quickly as compared to the untreated ones.


2017 ◽  
Vol 5 ◽  
pp. 1118-1123 ◽  
Author(s):  
Rositsa Cholakova-Bimbalova ◽  
Andon Vassilev

: In the climate conditions of Bulgaria, early stages of maize plants development often go under suboptimal temperatures. Chilling stress is known to cause different physiological disturbances in young maize plants during the transition period from heterotrophic to autotrophic nutrition. However, the effect of chilling may differ among maize hybrids. Photosynthetic performance could be a good indicator for the hybrid tolerance to chilling. The aim of our study was to evaluate the tolerance of young maize plants from two hybrids – the new Bulgarian hybrid - Kneza 307 and the hybrid P9528 using as criteria the changes in their photosynthetic performance.Plants at the third leaf stage were exposed for seven days to chilling stress. At the end of the experimental period, growth, leaf lipid peroxidation, and several photosynthetic parameters were measured. We found that chilling stress reduced the fresh mass accumulation, increased lipid peroxidation, diminished net photosynthetic rate and chlorophyll content, and enhanced non-photochemical quenching of chlorophyll fluorescence. Although the responses of both hybrids were similar, some specificity were observed and discussed.


Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1817
Author(s):  
Fernanda Leiva ◽  
Pernilla Vallenback ◽  
Tobias Ekblad ◽  
Eva Johansson ◽  
Aakash Chawade

Controlled plant growth facilities provide the possibility to alter climate conditions affecting plant growth, such as humidity, temperature, and light, allowing a better understanding of plant responses to abiotic and biotic stresses. A bottleneck, however, is measuring various aspects of plant growth regularly and non-destructively. Although several high-throughput phenotyping facilities have been built worldwide, further development is required for smaller custom-made affordable systems for specific needs. Hence, the main objective of this study was to develop an affordable, standalone and automated phenotyping system called “Phenocave” for controlled growth facilities. The system can be equipped with consumer-grade digital cameras and multispectral cameras for imaging from the top view. The cameras are mounted on a gantry with two linear actuators enabling XY motion, thereby enabling imaging of the entire area of Phenocave. A blueprint for constructing such a system is presented and is evaluated with two case studies using wheat and sugar beet as model plants. The wheat plants were treated with different irrigation regimes or high nitrogen application at different developmental stages affecting their biomass accumulation and growth rate. A significant correlation was observed between conventional measurements and digital biomass at different time points. Post-harvest analysis of grain protein content and composition corresponded well with those of previous studies. The results from the sugar beet study revealed that seed treatment(s) before germination influences germination rates. Phenocave enables automated phenotyping of plants under controlled conditions, and the protocols and results from this study will allow others to build similar systems with dimensions suitable for their custom needs.


2019 ◽  
Vol 18 (2) ◽  
pp. 29-37 ◽  
Author(s):  
Fardin Ghanbari ◽  
Sajad Kordi

Chilling stress is of major limiting factors influencing the growth and development of warm-season crops like cucumber. In this research, the possibility of chilling tolerance of cucumber seedlings was investigated through employing the drought and low-temperature pretreatments. The factorial experiment consisted of two factors including cucumber cultivars (i.e. ‘Super Dominos’ and ‘Super Star’) and hardening treatments (control, low temperatures at 10°C, and 15°C and drought simulated by 10% and 20% PEG) based on completely randomized design (CRD) in 3 replications. After applying treatments and providing them 48 h opportunity to be recovered, the seedlings were subjected to 3°C for a six-day period and 6 h for each day. All hardening treatments improved seedlings’ growth, chlorophyll content, total phenol (TP) and antioxidant enzyme activities, while reducing chilling injury index and malondialdehyde (MDA) content. Comparing to temperature hardening, the drought pretreatment showed to have a better effect on inducing the chilling tolerance into cultivars. Overall, the results of this experiment showed that employing drought and low-temperature pretreatments enabled cucumber seedlings to mitigate the harmful effects of chilling.


2021 ◽  
Vol 9 (4) ◽  
pp. 870
Author(s):  
Muhammad Aammar Tufail ◽  
María Touceda-González ◽  
Ilaria Pertot ◽  
Ralf-Udo Ehlers

Plant growth promoting endophytic bacteria, which can fix nitrogen, plays a vital role in plant growth promotion. Previous authors have evaluated the effect of Gluconacetobacter diazotrophicus Pal5 inoculation on plants subjected to different sources of abiotic stress on an individual basis. The present study aimed to appraise the effect of G. diazotrophicus inoculation on the amelioration of the individual and combined effects of drought and nitrogen stress in maize plants (Zea mays L.). A pot experiment was conducted whereby treatments consisted of maize plants cultivated under drought stress, in soil with a low nitrogen concentration and these two stress sources combined, with and without G. diazotrophicus seed inoculation. The inoculated plants showed increased plant biomass, chlorophyll content, plant nitrogen uptake, and water use efficiency. A general increase in copy numbers of G. diazotrophicus, based on 16S rRNA gene quantification, was detected under combined moderate stress, in addition to an increase in the abundance of genes involved in N fixation (nifH). Endophytic colonization of bacteria was negatively affected by severe stress treatments. Overall, G. diazotrophicus Pal5 can be considered as an effective tool to increase maize crop production under drought conditions with low application of nitrogen fertilizer.


2021 ◽  
Vol 9 (8) ◽  
pp. 1647
Author(s):  
Gui-E Li ◽  
Wei-Liang Kong ◽  
Xiao-Qin Wu ◽  
Shi-Bo Ma

Phytase plays an important role in crop seed germination and plant growth. In order to fully understand the plant growth-promoting mechanism by Rahnella aquatilis JZ-GX1,the effect of this strain on germination of maize seeds was determined in vitro, and the colonization of maize root by R. aquatilis JZ-GX1 was observed by scanning electron microscope. Different inoculum concentrations and Phytate-related soil properties were applied to investigate the effect of R. aquatilis JZ-GX1 on the growth of maize seedlings. The results showed that R. aquatilis JZ-GX1 could effectively secrete indole acetic acid and had significantly promoted seed germination and root length of maize. A large number of R. aquatilis JZ-GX1 cells colonized on the root surface, root hair and the root interior of maize. When the inoculation concentration was 107 cfu/mL and the insoluble organophosphorus compound phytate existed in the soil, the net photosynthetic rate, chlorophyll content, phytase activity secreted by roots, total phosphorus concentration and biomass accumulation of maize seedlings were the highest. In contrast, no significant effect of inoculation was found when the total P content was low or when inorganic P was sufficient in the soil. R. aquatilis JZ-GX1 promotes the growth of maize directly by secreting IAA and indirectly by secreting phytase. This work provides beneficial information for the development and application of R. aquatilis JZ-GX1 as a microbial fertilizer in the future.


Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 140 ◽  
Author(s):  
Ahmed Mohamed Aly Khalil ◽  
Saad El-Din Hassan ◽  
Sultan M. Alsharif ◽  
Ahmed M. Eid ◽  
Emad El-Din Ewais ◽  
...  

Endophytic fungi are widely present in internal plant tissues and provide different benefits to their host. Medicinal plants have unexplored diversity of functional fungal association; therefore, this study aimed to isolate endophytic fungi associated with leaves of medicinal plants Ephedra pachyclada and evaluate their plant growth-promoting properties. Fifteen isolated fungal endophytes belonging to Ascomycota, with three different genera, Penicillium, Alternaria, and Aspergillus, were obtained from healthy leaves of E. pachyclada. These fungal endophytes have varied antimicrobial activity against human pathogenic microbes and produce ammonia and indole acetic acid (IAA), in addition to their enzymatic activity. The results showed that Penicillium commune EP-5 had a maximum IAA productivity of 192.1 ± 4.04 µg mL−1 in the presence of 5 µg mL−1 tryptophan. The fungal isolates of Penicillium crustosum EP-2, Penicillium chrysogenum EP-3, and Aspergillus flavus EP-14 exhibited variable efficiency for solubilizing phosphate salts. Five representative fungal endophytes of Penicillium crustosum EP-2, Penicillium commune EP-5, Penicillium caseifulvum EP-11, Alternaria tenuissima EP-13, and Aspergillus flavus EP-14 and their consortium were selected and applied as bioinoculant to maize plants. The results showed that Penicillium commune EP-5 increased root lengths from 15.8 ± 0.8 to 22.1 ± 0.6. Moreover, the vegetative growth features of inoculated maize plants improved more than the uninoculated ones.


2020 ◽  
Vol 12 (1) ◽  
pp. 1497-1511
Author(s):  
Alexey Naumov ◽  
Varvara Akimova ◽  
Daria Sidorova ◽  
Mikhail Topnikov

AbstractDespite harsh climate, agriculture on the northern margins of Russia still remains the backbone of food security. Historically, in both regions studied in this article – the Republic of Karelia and the Republic of Sakha (Yakutia) – agricultural activities as dairy farming and even cropping were well adapted to local conditions including traditional activities such as horse breeding typical for Yakutia. Using three different sources of information – official statistics, expert interviews, and field observations – allowed us to draw a conclusion that there are both similarities and differences in agricultural development and land use of these two studied regions. The differences arise from agro-climate conditions, settlement history, specialization, and spatial pattern of economy. In both regions, farming is concentrated within the areas with most suitable natural conditions. Yet, even there, agricultural land use is shrinking, especially in Karelia. Both regions are prone to being affected by seasonality, but vary in the degree of its influence. Geographical location plays special role, and weaknesses caused by remoteness to some extent become advantage as in Yakutia. Proximity effect is controversial. In Karelia, impact of neighboring Finland is insignificant compared with the nearby second Russian city – Saint Petersburg.


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