scholarly journals Effects of silicon in plants with particular reference to horticultural crops - Review article

Author(s):  
O. Bat-Erdene ◽  
A. Szegő ◽  
M. Gyöngyik ◽  
I. Mirmazloum ◽  
I. Papp

Silicon (Si) has long been considered as non-essential element for plant’s growth and production. Numerous efforts are being made for the discovery of its beneficial effects with large scale studies laying foundation for new findings and hypotheses. Therefore, Si has been suggested to be a quasi-essential element due to its positive effects against biotic and abiotic stresses alike. Though Si is the second most abundant element in the soil profile, its availability to plants is limited to the form of monosilicic acid only. Besides, plants’ ability to take-up Si and use it in their physiological processes also depends on the available transporters associated with it. Thus, the present review covers uptake and transport of silicon in plants as well as Si mediated physiological processes, including mechanisms underlying induced tolerance against biotic and abiotic stresses with a particular emphasis on horticultural species.

2019 ◽  
Vol 8 (6) ◽  
pp. 841 ◽  
Author(s):  
Lasse Christiansen ◽  
Mikkel M. Beck ◽  
Niels Bilenberg ◽  
Jacob Wienecke ◽  
Arne Astrup ◽  
...  

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder with a complex symptomatology, and core symptoms as well as functional impairment often persist into adulthood. Recent investigations estimate the worldwide prevalence of ADHD in children and adolescents to be ~7%, which is a substantial increase compared to a decade ago. Conventional treatment most often includes pharmacotherapy with central nervous stimulants, but the number of non-responders and adverse effects call for treatment alternatives. Exercise has been suggested as a safe and low-cost adjunctive therapy for ADHD and is reported to be accompanied by positive effects on several aspects of cognitive functions in the general child population. Here we review existing evidence that exercise affects cognitive functions in children with and without ADHD and present likely neurophysiological mechanisms of action. We find well-described associations between physical activity and ADHD, as well as causal evidence in the form of small to moderate beneficial effects following acute aerobic exercise on executive functions in children with ADHD. Despite large heterogeneity, meta-analyses find small positive effects of exercise in population-based control (PBC) children, and our extracted effect sizes from long-term interventions suggest consistent positive effects in children and adolescents with ADHD. Paucity of studies probing the effect of different exercise parameters impedes finite conclusions in this regard. Large-scale clinical trials with appropriately timed exercise are needed. In summary, the existing preliminary evidence suggests that exercise can improve cognitive performance intimately linked to ADHD presentations in children with and without an ADHD diagnosis. Based on the findings from both PBC and ADHD children, we cautiously provide recommendations for parameters of exercise.


2011 ◽  
Vol 57 (No. 3) ◽  
pp. 95-100 ◽  
Author(s):  
A.N. Misra ◽  
M. Misra ◽  
R. Singh

Nitric oxide (NO) is a gaseous diatomic molecule with a wide variety of physiological and pathological implications in plants. Presence of unpaired electron in its molecular orbital makes it highly reactive; it can react directly with metal complexes, radicals, DNA, proteins, lipids and other biomolecules. Nitric oxide (NO) and reactive oxygen species (ROS) are known to play essential role in a number of important plant physiological processes. This manuscript reviews the role of NO on these processes during various biotic and abiotic stresses.  


2021 ◽  
Vol 16 (1) ◽  
pp. 186-194
Author(s):  
Domenico Prisa

Research goal: Based on the information found in the literature on biochar, its ability to improve the quality and yield of productions and to influence soil microflora. In this work, studies were carried out at different concentrations in pots to assess whether the addition of this material to the growing medium can influence the growth and control of biotic and abiotic stresses on Astrophytum myriostigma and Astrophytum capricorne. Materials and Methods: The experiments, started in June 2020, were conducted in the greenhouses of CREA-OF in Pescia (PT), Tuscany, Italy (43°54′N 10°41′E). The experimental groups were: i) group control, irrigated with water and substrate previously fertilized; ii) group with biochar 5%, irrigated with water and substrate previously fertilized; iii) group with biochar 10%, irrigated with water and substrate previously fertilized; iv) group with biochar 15%, irrigated with water and substrate previously fertilized; On June 30, 2021, plant height and circumference, number and length of thorns, vegetative weight, root weight, number of fruits, fruit weight, number of flowers, flower life, plants dead from cold stress, plants dead from Rhizoctonia solani. Results and Discussion: The test showed a significant increase in the agronomic parameters analyzed in biochar-treated plants on Astrophytum myriostigma and Astrophytum capricorne. The test also showed an improvement in plant quality in terms of increased number of thorns, fruits, flowers and increased resistance to cold stress and the pathogen Rhizoctonia solani. The trial also showed that an increase in substrate biochar content of 10%-15% improved plant growth performance compared to lower 5% contents. Conclusions: The experimentation carried out at CREA-OF in Pescia showed how the application of biochar to the cultivation substrate of Astrophytum myriostigma and Astrophytum capricorne can significantly improve the quality and the resistance to biotic and abiotic stresses of the plants. As in other experiments in the literature, the application of this soil conditioner also resulted in positive effects in the control of pathogenic fungi, particularly Rhizoctonia solani. This effect was probably mediated by the presence of microorganisms in the biochar that, in addition to having an effect on plant stimulation, may have a fundamental role in their biocontrol activity of substrate pathogens. Interesting results have also been the increase in the number of thorns, flowers and fruit duration and resistance to cold stress in plants grown with biochar.


2021 ◽  
Author(s):  
Vinaykumar Rachappanavar ◽  
Arushi Padiyal ◽  
Jitender Kumar Sharma ◽  
Satish Kumar Gupta ◽  
Narender Negi

Abstract Silicon (Si) is the most abundant element after oxygen on the earth crust surface. It plays essential role in crop production by stimulating the growth and development. Very substantial efforts have been performed to better explore Si derived benefits for horticulture crops. In the present review, molecular and physiological mechanisms explaining the observed beneficial effects plant derive from the Si supplementations, more particularly in horticultural species have been discussed. In general, horticulture crops need extensive management and higher crop protection measures compared to agronomical crops. Therefore, integrated approaches including Si supplementations will help to improve plant resilience under biotic and abiotic stresses. Application of Si to plants promotes cell walls strength and provides additional support through increased mechanical and biochemical support. Horticultural crop production is frequently subjected to the naturally occurring different biotic and abiotic stresses that can substantially reduce the absorption and translation of essential elements and ultimately decrease the crop yield. Fruit and vegetable production in Drought, salinity, high and low temperature, toxic metals and pest infection prone areas is the key to meet the world minimum nutrients demand. Here, molecular mechanism involved in the Si uptake by root and subsequent transport to areal tissues is also illustrated. However, Si uptake mechanism at molecular level poorly studied in horticulture crops. Here we described the role of Si and its transporters in mitigating abiotic stress condition in horticultural plants.


2011 ◽  
Vol 50 ◽  
pp. 145-160 ◽  
Author(s):  
Tobias Kretzschmar ◽  
Bo Burla ◽  
Youngsook Lee ◽  
Enrico Martinoia ◽  
Réka Nagy

ABC (ATP-binding cassette) proteins are ubiquitously found in prokaryotes and eukaryotes and generally serve as membrane-intrinsic primary active pumps. In higher plants, ABC proteins constitute a large family, grouped phylogenetically into eight clusters, subfamilies ABCA–ABCI (ABCH is not found in plants). ABC transporters shuttle substrates as diverse as lipids, phytohormones, carboxylates, heavy metals, chlorophyll catabolites and xenobiotic conjugates across a variety of biological membranes. To date, the largest proportions of characterized members have been localized to the plasma membrane and the tonoplast, with dominant implications in cellular secretion and vacuolar sequestration, but they are also found in mitochondrial, plastidal and peroxisomal membranes. Originally identified as tonoplast-intrinsic proteins that shuttle xenobiotic conjugates from the cytosol into the vacuole, thus being an integral part of the detoxification machinery, ABC transporters are now recognized to participate in a multitude of physiological processes that allow the plant to adapt to changing environments and cope with biotic and abiotic stresses.


Author(s):  
Priyanka Singh ◽  
Yamshi Arif ◽  
Andrzej Bajguz ◽  
Shamsul Hayat

Flavonoids are a special category of hydroxylated phenolic compounds having an aromatic ring structure. Quercetin is a special subclass of flavonoid. It is a bioactive natural compound built upon the flavon structure nC6(ring A)-C3(ring C)-C6(ring B). Quercetin facilitates several plant physiological processes, such as seed germination, pollen growth, antioxidant machinery, and photosynthesis, as well as induces proper plant growth and development. Quercetin is a powerful antioxidant, so it potently provides plant tolerance against several biotic and abiotic stresses. This review highlights quercetin’s role in increasing several physiological and biochemical processes in under stress and non-stress environments. Additionally, this review briefly assesses quercetin’s role in mitigating biotic and abiotic stresses (e.g., salt, heavy metal, and UV stress). The biosynthesis of flavonoids, their signaling pathways, and quercetin’s role in plant signaling are also discussed.


2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Fangwei Yu ◽  
Shenyun Wang ◽  
Wei Zhang ◽  
Hong Wang ◽  
Li Yu ◽  
...  

Abstract The members of myeloblastosis transcription factor (MYB TF) family are involved in the regulation of biotic and abiotic stresses in plants. However, the role of MYB TF in phosphorus remobilization remains largely unexplored. In the present study, we show that an R2R3 type MYB transcription factor, MYB103, is involved in phosphorus (P) remobilization. MYB103 was remarkably induced by P deficiency in cabbage (Brassica oleracea var. capitata L.). As cabbage lacks the proper mutant for elucidating the mechanism of MYB103 in P deficiency, another member of the crucifer family, Arabidopsis thaliana was chosen for further study. The transcript of its homologue AtMYB103 was also elevated in response to P deficiency in A. thaliana, while disruption of AtMYB103 (myb103) exhibited increased sensitivity to P deficiency, accompanied with decreased tissue biomass and soluble P concentration. Furthermore, AtMYB103 was involved in the P reutilization from cell wall, as less P was released from the cell wall in myb103 than in wildtype, coinciding with the reduction of ethylene production. Taken together, our results uncover an important role of MYB103 in the P remobilization, presumably through ethylene signaling.


Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1670
Author(s):  
Waheeb Abu-Ulbeh ◽  
Maryam Altalhi ◽  
Laith Abualigah ◽  
Abdulwahab Ali Almazroi ◽  
Putra Sumari ◽  
...  

Cyberstalking is a growing anti-social problem being transformed on a large scale and in various forms. Cyberstalking detection has become increasingly popular in recent years and has technically been investigated by many researchers. However, cyberstalking victimization, an essential part of cyberstalking, has empirically received less attention from the paper community. This paper attempts to address this gap and develop a model to understand and estimate the prevalence of cyberstalking victimization. The model of this paper is produced using routine activities and lifestyle exposure theories and includes eight hypotheses. The data of this paper is collected from the 757 respondents in Jordanian universities. This review paper utilizes a quantitative approach and uses structural equation modeling for data analysis. The results revealed a modest prevalence range is more dependent on the cyberstalking type. The results also indicated that proximity to motivated offenders, suitable targets, and digital guardians significantly influences cyberstalking victimization. The outcome from moderation hypothesis testing demonstrated that age and residence have a significant effect on cyberstalking victimization. The proposed model is an essential element for assessing cyberstalking victimization among societies, which provides a valuable understanding of the prevalence of cyberstalking victimization. This can assist the researchers and practitioners for future research in the context of cyberstalking victimization.


2020 ◽  
Vol 22 (1) ◽  
pp. 155
Author(s):  
Mikhail V. Diachkov ◽  
Karoll Ferrer ◽  
Jana Oklestkova ◽  
Lucie Rarova ◽  
Vaclav Bazgier ◽  
...  

Brassinosteroids are a class of plant hormones that regulate a broad range of physiological processes such as plant growth, development and immunity, including the suppression of biotic and abiotic stresses. In this paper, we report the synthesis of new brassinosteroid analogues with a nitrogen-containing side chain and their biological activity on Arabidopis thaliana. Based on molecular docking experiments, two groups of brassinosteroid analogues were prepared with short and long side chains in order to study the impact of side chain length on plants. The derivatives with a short side chain were prepared with amide, amine and ammonium functional groups. The derivatives with a long side chain were synthesized using amide and ammonium functional groups. A total of 25 new brassinosteroid analogues were prepared. All 25 compounds were tested in an Arabidopsis root sensitivity bioassay and cytotoxicity screening. The synthesized substances showed no significant inhibitory activity compared to natural 24-epibrassinolide. In contrast, in low concentration, several compounds (8a, 8b, 8e, 16e, 22a and 22e) showed interesting growth-promoting activity. The cytotoxicity assay showed no toxicity of the prepared compounds on cancer and normal cell lines.


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