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

2021 ◽  
Vol 5 (4) ◽  
pp. 846-853
Author(s):  
Fikret YAŞAR ◽  
Özlem ÜZAL

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.

Agronomy ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 279 ◽  
Author(s):  
Zarifth Kamarudin ◽  
Mohd Yusop ◽  
Mahmud Tengku Muda Mohamed ◽  
Mohd Ismail ◽  
Abdul Harun

Drought stress affects various physiological and metabolic processes in rice (Oryza sativa L.) plant. Non-availability of high-yielding varieties suitable for cultivation under drought condition lead towards a sharp decline in rice yield. Induce mutation is an essential auxiliary approach to counterpart conventional breeding to produce stress-tolerance rice variety. The current study was aimed to identify two advanced mutant rice genotypes as drought-tolerant using growth parameters and antioxidant enzyme activities. The advanced mutant rice genotypes, MR219-4 and MR219-9, showed a minimal reduction on all growth parameters, yield, and yield components measured for drought tolerance. MR219-4 had a slight reduction on total dry weight and chlorophyll content under drought stress condition. Proline content increased significantly in drought-tolerant rice genotypes and the highest proline content was obtained from MR219-4 followed by MR219-9 under drought stress. Catalase, ascorbate peroxidase, and guaiacol peroxidase activities were significantly increased in drought stress treatment in all the rice genotypes. MR219-4 and MR219-9 were identified as high-yielding drought-tolerant genotypes as they maintained good performance under drought stress condition for all the measured traits compared to the drought-tolerant check varieties, Aeron1 and MR219, thus, this might be underlying selection criteria for a drought tolerance rice breeding programme.


2021 ◽  
Vol 49 (3) ◽  
pp. 12417
Author(s):  
Parichart SILALERT ◽  
Wattana PATTANAGUL

Melatonin (N-acetyl-5-methoxytryptamine) plays an essential role in abiotic stress in plants, but its mechanism in drought tolerance is unclear. To better understand the protective roles of melatonin against drought stress, we investigated the effect of foliar application with exogenous melatonin on plant growth, physiological responses, and antioxidant enzyme activities in rice seedlings under drought stress. Rice seedlings were grown for 21 days, and foliar sprayed with 0, 50, 100, 200, and 300 µM melatonin. The control plant was watered daily, while the others were subjected to drought stress by withholding water for seven days. The results showed that drought stress significantly reduced plant growth, relative water content, and chlorophyll content. Electrolyte leakage, malondialdehyde (MDA) content and hydrogen peroxide (H2O2) were also negatively affected by drought stress. Application of melatonin alleviated the effects of drought stress by increasing plant growth, improving relative water content and chlorophyll content, and decreasing electrolyte leakage, MDA, and H2O2. Foliar application with melatonin also increased antioxidant enzyme activities, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (GPX). In addition, melatonin also enhanced proline and total soluble sugar accumulation during drought stress. It is, therefore, suggested that foliar application with 100 µM melatonin was the most effective for reducing the adverse effects of drought stress in rice plants.


2011 ◽  
Vol 47 (No. 1) ◽  
pp. 17-27 ◽  
Author(s):  
S. Tale Ahmad ◽  
R. Haddad

The effect of silicon (Si) was investigated on the major antioxidant enzyme activities including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), relative water content (RWC), chlorophyll and soluble protein contents, proline (Pro) and glycine betaine (GB) accumulation in three different growth stages (2<sup>nd</sup>, 4<sup>th</sup> leaf and tillering stages) of wheat (Triticum aestivum L.) plants under drought stress. The experiment was performed in a completely randomized design for three treatments including control, drought and Si-drought (2mM silicate sodium/kg) with three replications in a greenhouse. The results indicated that Si partially offset the negative impacts of drought stress increasing the tolerance of wheat by rising Pro and GB accumulation and soluble protein content. Compared with the plants treated with drought, applied Si significantly enhanced the activities of SOD, CAT, APX and POD. In contrast, drought stress caused a considerable decrease in RWC, chlorophyll and soluble protein contents. This Si effect was time-dependent and became stronger in the tillering stage. The results of the present experiment coincided with the conclusion that Si alleviates water deficit of wheat by preventing the oxidative membrane damage and may be associated with plant osmotic adjustment.


1998 ◽  
Vol 26 (02) ◽  
pp. 133-141 ◽  
Author(s):  
Zhan-Jun Pang ◽  
Mei Zhou ◽  
Yuan Chen ◽  
Jennifer Wan

The aim of this study is to examine whether polysaccharide krestin, a protein-bound polysaccharide, can prevent the progression of therosclerosis and lipoperoxidative injury caused by oxidatively modified low density lipoprotein (Ox-LDL) to macrophages. The alterations of GSHPx (glutathione peroxidase), SOD (superoxide dismutase) activity and NO (nitric oxide) release in PSK-treated mouse peritoneal macrophages, and the effect of LPS on them were investigated. With peritoneal injection of PSK, the following were observed in the mouse peritoneal macrophages: 1) an increase in SeGSHPx activity, 2) elevation in non-SeGSHPx and SOD activity; 3) the enzyme activities were further improved by addition of lipopolysaccharide (LPS); and 4) much NO was found to be released by PSK-treated mouse peritoneal macrophages stimulated by LPS.


2017 ◽  
Vol 107 (4) ◽  
pp. 444-454 ◽  
Author(s):  
Daniel Teshome Lopisso ◽  
Jessica Knüfer ◽  
Birger Koopmann ◽  
Andreas von Tiedemann

Verticillium longisporum is a host-specific vascular pathogen of oilseed rape (Brassica napus L.) that causes economic crop losses by impairing plant growth and inducing premature senescence. This study investigates whether plant damage through Verticillium stem striping is due to impaired plant water relations, whether V. longisporum affects responses of a susceptible B. napus variety to drought stress, and whether drought stress, in turn, affects plant responses to V. longisporum. Two-factorial experiments on a susceptible cultivar of B. napus infected or noninfected with V. longisporum and exposed to three watering levels (30, 60, and 100% field capacity) revealed that drought stress and V. longisporum impaired plant growth by entirely different mechanisms. Although both stresses similarly affected plant growth parameters (plant height, hypocotyl diameter, and shoot and root dry matter), infection of B. napus with V. longisporum did not affect any drought-related physiological or molecular genetic plant parameters, including transpiration rate, stomatal conductance, photosynthesis rate, water use efficiency, relative leaf water content, leaf proline content, or the expression of drought-responsive genes. Thus, this study provides comprehensive physiological and molecular genetic evidence explaining the lack of wilt symptoms in B. napus infected with V. longisporum. Likewise, drought tolerance of B. napus was unaffected by V. longisporum, as was the level of disease by drought conditions, thus excluding a concerted action of both stresses in the field. Although it is evident that drought and vascular infection with V. longisporum impair plant growth by different mechanisms, it remains to be determined by which other factors V. longisporum causes crop loss.


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