scholarly journals Silicon Foliar Application Mitigates Salt Stress in Sweet Pepper Plants by Enhancing Water Status, Photosynthesis, Antioxidant Enzyme Activity and Fruit Yield

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 733 ◽  
Author(s):  
Khaled A. A. Abdelaal ◽  
Yasser S.A. Mazrou ◽  
Yaser M. Hafez

Silicon is one of the most significant elements in plants under abiotic stress, so we investigated the role of silicon in alleviation of the detrimental effects of salinity at two concentrations (1500 and 3000 ppm sodium chloride) in sweet pepper plants in two seasons (2018 and 2019). Our results indicated that relative water content, concentrations of chlorophyll a and b, nitrogen, phosphorus and potassium contents, number of fruits plant−1, fruit fresh weight plant−1 (g) and fruit yield (ton hectare−1) significantly decreased in salt-stressed sweet pepper plants as compared to control plants. In addition, electrolyte leakage, proline, lipid peroxidation, superoxide (O2−) and hydrogen peroxide (H2O2) levels, soluble sugars, sucrose, and starch content as well as sodium content significantly increased under salinity conditions. Conversely, foliar application of silicon led to improvements in concentrations of chlorophyll a and b and mineral nutrients, water status, and fruit yield of sweet pepper plants. Furthermore, lipid peroxidation, electrolyte leakage, levels of superoxide, and hydrogen peroxide were decreased with silicon treatments.

2019 ◽  
Vol 42 ◽  
pp. e42463
Author(s):  
Lorena Gabriela Almeida ◽  
Paulo César Magalhães ◽  
Décio Karam ◽  
Eder Marcos da Silva ◽  
Amauri Alves Alvarenga

The present research seeks to elucidate the feasibility of chitosan (CHT) in the induction of water deficit tolerance in different maize hybrids, contrasting tolerance to water restriction, tolerance and sensitivity. The maize plants were subjected to water deficit and foliar application of different chitosan doses (60, 100, 140, and 180 mg L-1) at the pre-flowering growth stage and evaluated during the stress period of fifteen days. To understand the induction behaviour of the tolerance to water restriction, biophysical parameters, such as water potential, relative water content and chlorophyll content, gas exchange, and biochemical assays, were quantified based on the activity of SOD, CAT, APX, and PAL antioxidant enzymes, lipid peroxidation activity and hydrogen peroxide content. Among the treatments, maize plants subjected to chitosan foliar application at a dose of 140 mg L-1 presented similar behavioural responses to plants under favourable irrigation conditions. Such positive responses are related to the high degree of activity of antioxidant enzymes, gas exchange and low levels of lipid peroxidation and hydrogen peroxide. The results support the potential use of CHT to increase tolerance to water stress.


2013 ◽  
Vol 50 (2) ◽  
pp. 65-78 ◽  
Author(s):  
Ewa Gajewska ◽  
Daniel Drobik ◽  
Marzena Wielanek ◽  
Joanna Sekulska-Nalewajko ◽  
Jarosław Gocławski ◽  
...  

Abstract Hydroponically grown wheat seedlings were treated with 50 μM N i and/or 15 μM Se. After a 7-day culture period, their growth parameters, N i, Se, F e, and M g contents, electrolyte leakage, photosynthetic pigment concentrations, and photochemical activity of photosystem II were determined. Exposure of wheat seedlings to N i alone resulted in reduction in the total shoot and root lengths, by 22% and 50%, respectively. Addition of Se to the N i-containing medium significantly improved the growth of these organs, compared to the seedlings subjected to N i alone. Application of Se decreased the accumulation of N i in shoots and roots and partially alleviated the N i-induced decrease in F e and M g concentations in shoots. Electrolyte leakage increased in response to N i stress, but in shoots it was diminished by Se supplementation. Exposure to N i led to a decrease in chlorophyll a and b contents and enhancement of chlorophyll a/b ratio, but did not influence the concentration of carotenoids. Enrichment of the N i-containing medium with Se significantly increased chlorophyll b content, compared to the seedlings treated with N i alone. Photochemical activity, estimated in terms of the maximum quantum yield of photosystem II , decreased in response to N i treatment but was significantly improved by simultaneous addition of Se. Results of our study suggest that alleviation of N i toxicity in wheat seedlings by Se supplementation may be related to limitation of N i uptake.


Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1180 ◽  
Author(s):  
Muneera D. F. ALKahtani ◽  
Kotb A. Attia ◽  
Yaser M. Hafez ◽  
Naeem Khan ◽  
Ahmed M. Eid ◽  
...  

Salinity stress deleteriously affects the growth and yield of many plants. Plant growth promoting rhizobacteria (PGPR) and chitosan both play an important role in combating salinity stress and improving plant growth under adverse environmental conditions. The present study aimed to evaluate the impacts of PGPR and chitosan on the growth of sweet pepper plant grown under different salinity regimes. For this purpose, two pot experiments were conducted in 2019 and 2020 to evaluate the role of PGPR (Bacillus thuringiensis MH161336 106–8 CFU/cm3) applied as seed treatment and foliar application of chitosan (30 mg dm−3) on sweet pepper plants (cv. Yolo Wonder) under two salinity concentrations (34 and 68 mM). Our findings revealed that, the chlorophyll fluorescence parameter (Fv/Fm ratio), chlorophyll a and b concentrations, relative water content (RWC), and fruit yield characters were negatively affected and significantly reduced under salinity conditions. The higher concentration was more harmful. Nevertheless, electrolyte leakage, lipid peroxidation, hydrogen peroxide (H2O2), and superoxide (O2−) significantly increased in stressed plants. However, the application of B. thuringiensis and chitosan led to improved plant growth and resulted in a significant increase in RWC, chlorophyll content, chlorophyll fluorescence parameter (Fv/Fm ratio), and fruit yield. Conversely, lipid peroxidation, electrolyte leakage, O2−, and H2O2 were significantly reduced in stressed plants. Also, B. thuringiensis and chitosan application regulated the proline accumulation and enzyme activity, as well as increased the number of fruit plant−1, fruit fresh weight plant−1, and total fruit yield of sweet pepper grown under saline conditions.


2014 ◽  
Vol 26 (3) ◽  
pp. 268-277 ◽  
Author(s):  
Andresa Lana Thomé Bizzo ◽  
Aline Chaves Intorne ◽  
Pollyana Honório Gomes ◽  
Marina Satika Suzuki ◽  
Bruno dos Santos Esteves

AIM: To evaluate, in a short-time exposure, the physiological responses of Salvinia auriculata Aubl. under different concentrations of Cu. METHODS: The plants were exposed to treatments with 0.01, 0.1, 1 and 10 mM of Cu in a period of 2 days. Then development variables of S. auriculata (weight, photosynthetic pigments, and soluble carbohydrate), lipid peroxidation (malondialdehyde, aldehydes, and electrolyte leakage) and production of antioxidants (anthocyanins, carotenoids, flavonoids, and proline) were evaluated. RESULTS: It was observed fresh weight reductions in concentrations above 1 mM of Cu. Chlorophyll a decreased with the increase of Cu concentrations unlike chlorophyll b. The ratio chlorophyll a / chlorophyll b was changed due to the degradation of photosynthetic pigments. The reductions of carotenoids were more pronounced than that of total chlorophyll. The values of electrolyte leakage ranged from 14 to 82 % and lipid peroxidation from 7 to 46 nmol.g-1. Flavonoids and soluble carbohydrates showed reductions with the increase of Cu concentration. Anthocyanins, phenolic compounds, and proline when subjected to 0.1 mM of Cu had increased, suggesting adaptability of plant stress caused directly by metal and reactive oxygen species. In higher concentrations, degradation and/or direct modifications of these molecules possibly occurred. CONCLUSIONS: The data suggest that S. auriculata is provided with an efficient mechanism against stress caused by Cu in the concentration of 0.1 mM. As for higher concentrations (1 and 10 mM), despite its role as micronutrients, Cu was toxic to the plant due to the redox behavior of this metal, which leads to the exacerbated formation of reactive oxygen species, inducing to severe damage such as biological membrane degradation and protein denaturation.


2016 ◽  
Vol 4 (4) ◽  
pp. 103-107
Author(s):  
Deepa Srivastava ◽  
K. Shukla

Photosynthetic effects of the leaves extracts from Ipomoea cairica on Partheniumhysterophorus L were studied. Ipomoea cairica dried leaf powder (20g) was dissolved in distilled water (200ml) for foliar application. The seedlings were maintained under natural condition in Insect free net house. The experiment was carried out to analyze the effects of Ipomoea cairica leaves extract by measuring chlorophyll ‘a’, chlorophyll ‘b’, total chlorophyll and carotenoid contents in Parthenium. The experimental plants were sprayed 20 days after emergence and control plants were maintained by a simultaneous spray of distilled water. Leaves of Partheniumhysterophorus were collected at 5 days interval following the foliar application of Ipomoea cairica leaves extract up to 15th day. Results showed that Chlorophyll (total chlorophyll, chlorophyll a and b) and carotenoid content was adversely affected as the duration of Ipomoea cairica leaves extract increased. This potential of Ipomoea cairica can be used as herbicide to control noxious weed Partheniumhysterophorous.


Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 510
Author(s):  
Khaled Abdelaal ◽  
Kotb A. Attia ◽  
Gniewko Niedbała ◽  
Tomasz Wojciechowski ◽  
Yaser Hafez ◽  
...  

Garlic is an important vegetable in terms of its economic value and also as a medicinal plant. In this study, chitosan (300 mM) and yeast extract (8 g/L) were used individually or in combination to improve the yields of garlic plants under drought conditions (i.e., 75% and 50% of the water they would normally receive from irrigation) for two seasons. Significant decreases in numbers of leaves per plant and plant height, plant dry weight, relative water content, and chlorophyll a and b concentrations were found in stressed garlic plants in both seasons. The greatest reductions in these characters were recorded in plants that received only 50% of the normal irrigation in both seasons. Levels of hydrogen peroxide, products of lipid peroxidation such as malondialdehyde, and superoxide, as well as percentages of electrolyte leakage, were elevated considerably and were signals of oxidative damage. The application of the yeast extract (8 g/L) or chitosan (300 mM) individually or in combination led to a remarkable increase in the most studied characters of the stressed garlic plants. The combination of yeast extract (8 g/L) plus chitosan (300 mM) led to increase plant height (44%), ascorbic acid levels (30.2%), and relative water content (36.8%), as well as the chlorophyll a (50.7%) and b concentrations (79%), regulated the proline content and levels of antioxidant enzymes in stressed garlic plants that received 75% of the normal irrigation, and this decreased the signs of oxidative stress (i.e., percentage of electrolyte leakage and levels of malondialdehyde, hydrogen peroxide, and superoxide).


2013 ◽  
Vol 8 (5) ◽  
pp. 499-503
Author(s):  
Konstantina Kocheva ◽  
Peter Petrov ◽  
Georgi Georgiev

AbstractHydroponically grown wheat seedlings of two prominent Bulgarian cultivars (Katya and Prelom) were subjected to 48 h osmotic stress with PEG 8000 and were then rehydrated. The degree of stress was evaluated by monitoring relative water content, lipid peroxidation level, and accumulation of free proline and hydrogen peroxide in the leaves. Anatomy and ultrastructure of leaf tissue were observed under light microscopy. After imposition of stress, drought tolerant cultivar Katya displayed higher free proline content and significantly lower malondialdehyde and peroxide concentration in leaves than in the leaves of susceptible cultivar Prelom. After 24 h of rehydration Katya showed better ability to restore leaf water status and an apparent tendency towards recovery, whereas Prelom sustained higher levels of hydrogen peroxide, lipid peroxidation products and free proline and markedly low relative water content. Here, we have uncovered some of the characteristics displayed by cultivar Katya that enable it to survive and recover from severe osmotic stress. Interestingly, there was congruence between our results and the high level of cultivar Katya drought tolerance observed in the field.


Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1927
Author(s):  
Mostafa H. M. Mohamed ◽  
Rokayya Sami ◽  
Amina A. M. Al-Mushhin ◽  
Maha Mohamed Elsayed Ali ◽  
Heba S. El-Desouky ◽  
...  

Sweet pepperincludes several vitamins and is regarded as a great source of bioactive nutrients, such as carotenoids and phenolic compounds, for human growth and activities. This work aimed to investigate the effects of the soil addition of growth stimulants, namely, effective microorganisms (EM), compost tea, fulvic acid, and yeast extract, and foliar applications of seaweed extract, on the vegetative growth, enzyme activity, phytohormones content, chemical constituents of plant foliage, fruit yield, and fruit quality of sweet pepper plants (Capsicum annuum L. cv. Zidenka) growing under greenhouse conditions. The results showed that the tallest plant, largest leaf area/plant, and heaviest plant fresh and dry weights were recorded after combining a soil addition of yeast extract and foliar spray with seaweed extracts at 3 g/L in two growing seasons. The highest number of fruit/plant, fruit yield/m2, fruit values of vitamin C (VC), total sugars, total soluble solids (TSS), and carotenoids, along with the highest leaf of cytokines, P, K, Fe, and total carbohydrates values, were obtained using a soil addition of fulvic acid and spray with seaweed extract at 3 g/L in the two seasons of study. These treatments also provided the lowest abscisic acid, peroxidase, and super oxidase dismutase values in the same conditions. Sweet pepper plants supplemented with compost tea and seaweed extract foliar spray at 3 g/L were the most promising for inducing the highest values of fruit fresh and dry weights, fruit length and diameter, and the leavesrichest in N, Zn, and Mn; inversely, it induced the lowest catalase levels in both seasons. The applications of EM, yeast extract, and seaweed extract could be applied for high growth, mineral levels, enzymatic activity, fruit yield, and nutritional value of sweet pepper fruit and minimizing environmental pollution.


2019 ◽  
Vol 29 (2) ◽  
pp. 170-178 ◽  
Author(s):  
Abdullah Ibrahim ◽  
Hesham Abdel-Razzak ◽  
Mahmoud Wahb-Allah ◽  
Mekhled Alenazi ◽  
Abdullah Alsadon ◽  
...  

The present study reports on the effect of humic and salicylic acids on the growth, yield, and fruit quality of three red sweet pepper (Capsicum annuum) cultivars: Barbero, Ferrari, and Imperio. The plants were grown in a greenhouse and the leaves were treated with humic or salicylic acids at 0, 0.5, 1.0, and 1.5 g·L−1 at 20, 40, and 60 days after transplanting. Foliar application of humic or salicylic acids significantly increased vegetative growth, fruit yield, and quality of the three cultivars as compared with the control plants. However, salicylic acid treatment proved more effective than humic acid treatment. Red sweet pepper plants of all three cultivars sprayed with 1.5 g·L−1 salicylic acid showed the greatest vegetative growth; fruit yield components, such as fruit number, diameter, and fresh and dry weights; and fruit quality traits, such as vitamin C content, total soluble solid content, titratable acidity, and total sugar content, than the plants in all other treatments. There were significant differences (P ≤ 0.05) among cultivars in response to humic and salicylic acid foliar application; ‘Ferrari’ showed significantly higher yield and productivity than ‘Barbero’ or ‘Imperio’. ‘Ferrari’ plants sprayed with 1.5 g·L−1 salicylic acid showed the highest fruit weight (202.41 g) and flesh thickness (68 mm), both of which are preferred by consumers, and therefore, have increased market value. This treatment also increased total yield by 27.7% (16.03 t·ha−1), 15.9% (12.38 t·ha−1), and 17.9% (11.88 t·ha−1) in ‘Barbero’, ‘Ferrari’, and ‘Imperio’, respectively. Therefore, salicylic acid foliar application is recommended for enhancing fruit yield and quality of greenhouse-grown red sweet pepper.


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