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2. Growth and photosynthetic characteristics in pearl millet under water stress and different potassium supply
- Creator:
- Ashraf, M., Ahmad, Ashfaq, and McNeilly, T.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- drought, leaf area, net assimilation rate, net photosynthetic rate, relative growth rate, stomatal conductance, supra-optimal nutrition, transpiration rate, water potential, and water use efficiency
- Language:
- Multiple languages
- Description:
- Influence of supra-optimal concentrations of K on growth, water relations, and photosynthetic capacity in pearl millet under severe water deficit conditions was assessed in a glasshouse. Nineteen-days-old plants of two lines, ICMV-94133 and WCA-78, of Pennisetum glaucum (L.) R.Br. were subjected for 30 d to 235.0, 352.5, and 470.0 mg(K) kg-1(soil) and two water regimes (100 and 30 % field capacity). Increasing K supply did not alleviate the effect of water deficit on the growth of two lines of pearl millet since additional amount of K in the growth medium had no effect on shoot dry mass, relative growth rate, plant leaf area, net assimilation rate, or leaf area ratio, although there was significant effect of drought stress on these variables. Soil moisture had a significant effect on net photosynthetic rate (PN), transpiration rate, stomatal conductance, and water use efficiency of both pearl millet lines, but there was no significant effect of varying K supply on these variables. In WCA-78 an ameliorative effect of increasing supply of K on PN was observed under water deficit. Chlorophyll (Chl) a and b contents increased significantly in both lines with increase in K supply under well watered conditions, but under water deficit they increased only in ICMV-94133. Chl a/b ratios were reduced significantly in WCA-78 with increasing K supply under both watering regimes, but by contrast, in ICMV-94133 this variable was decreased only under water stress. Leaf water potential and osmotic potential of both lines decreased significantly with the imposition of drought. Leaf pressure potential in both lines increased with increase in K supply under water stress. Contents of total free amino acids in the leaves of both pearl millet lines increased significantly with increase in K supply under water stress. Potassium supply had no effect on leaf soluble sugars or soluble proteins. Considerable osmotic adjustment occurred in pearl millet plants experiencing water deficit under high K supply. and M. Ashraf, Ashfaq Ahmad, T. McNeilly.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. The restorative effect of apocynin and catalase in L-arginine induced hypotension on normotensive subjects – the role of oxidative stress
- Creator:
- Chia, Tan Yong, Murugaiyah, Vikneswaran, Sattar, Munavvar Abdul, Karim Khan, Nurzalina Abdul, Ahmad, Ashfaq, Abdulla, Mohammed Hadi, Johns, Edward James, Mei, Ho Yoke, Akhtar, Safia, and Ahmad, Fiaz Uddin
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- apocynin, catalase, L-arginine, nitric oxide, oxidative stress, and hypotension
- Language:
- English
- Description:
- L-arginine is a substrate for nitric oxide synthase (NOS) responsible for the production of NO. This investigation studied the effect of apocynin, an NADPH oxidase inhibitor and catalase, an H2O2 scavenger on L-arginine-induced oxidative stress and hypotension. Forty Wistar-Kyoto rats were treated for 14 days with vehicle, L-arginine (12.5 mg/ml p.o.), L-arginine + apocynin (2.5 mmol/l p.o.), L-arginine + catalase (10000 U/kg/day i.p.) and L-arginine plus apocynin + catalase respectively. Weekly renal functional and hemodynamic parameters were measured and kidneys harvested at the end of the study for histopathological and renal NADPH oxidase 4 (Nox4) assessments. L-arginine administration in normotensive rats decreased systolic blood pressure (120±2 vs. 91±2 mmHg) and heart rate (298±21 vs. 254±15 bpm), enhanced urinary output (21.5±4.2 vs. 32±1.9 ml/24 h, increased creatinine clearance (1.72±0.56 vs. 2.62±0.40 ml/min/kg), and fractional sodium excretion (0.88±0.16 vs. 1.18±0.16 %), caused proteinuria (28.10±1.93 vs. 35.26±1.69 mg/kg/day) and a significant decrease in renal cortical blood perfusion (292±3 vs. 258±5 bpu) and pulse wave velocity (3.72±0.20 vs 2.84±0.13 m/s) (all P<0.05). L-arginine increased plasma malondialdehyde (by ~206 % P<0.05) and NO (by ~51 %, P<0.05) but decreased superoxide dismutase (by ~31 %, P<0.05) and total antioxidant capacity (by ~35 %, P<0.05) compared to control. Renal Nox4 mRNA activity was approximately 2.1 fold higher (P<0.05) in the L-arginine-treated rats but was normalized by apocynin and apocynin plus catalase treatment. Administration of apocynin and catalase, but not catalase alone to rats fed L-arginine, restored the deranged renal function and structure, prevented hypotension and enhanced the antioxidant capacity and suppressed Nox4 expression. These findings suggest that apocynin and catalase might be used prophylactically in the states of oxidative stress.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public