Saqib Mahmood

Bio: Saqib Mahmood is an academic researcher from Government College University, Faisalabad. The author has contributed to research in topics: Salinity & Drought tolerance. The author has an hindex of 6, co-authored 17 publications receiving 73 citations. Previous affiliations of Saqib Mahmood include Government College University.

Effect of Salinity Stress on Various Growth and Physiological Attributes of Two Contrasting Maize Genotypes

Abstract: The response of two local maize (Zea mays L.) genotypes designated as Sahwal-2002 (salt-tolerant) and Sadaf (salt-sensitive) to salt stress was investigated under controlled growth conditions. The role of phenylalanine and seed priming under salt stress in maize with different morphological parameters were studied. The genotype Sadaf, being salt-tolerant, experienced more oxidative damage than the Sahiwall-2002 genotype under salt stress. The salinity affected both growth and physiological attributes of the maize species whereas the phenylalanine successfully increased the salinity tolerance in maize species at the seedling stage.

Salinity stress on various physiological and biochemical attributes of two distinct maize (Zea mays L.) genotypes

Abstract: Present study investigates the effect of salinity stress on physiological and biochemical characteristics of two maize genotypes cultivated under controlled growth conditions. The selected maize genotypes being salt-tolerant and salt-sensitive were respectively designated as Sahwal-2002 and Sadaf. The experiment was conducted in triplicates, two varieties, three priming treatments and two salinity levels, in the Government College University, Faisalabad. The antioxidants activity was measured by comparing the tolerance in response to acute and prolonged salinity treatment. The difference of genotype with salinity tolerance as well as seed priming with phenylalanine were not dependent on antioxidant activity when salt exposure was prolonged. The results show that an indirect relationship was present for PAL seed priming and oxidative damage due to salt. The antioxidant enzymes present in plant effectively reduced the oxidative damage of salt and thus, increased the overall crop yield.

Possible mechanism of medium-supplemented thiourea in improving growth, gas exchange, and photosynthetic pigments in cadmium-stressed maize ( Zea mays )

Abstract: Cadmium (Cd) stress is highly damaging to plant growth but its toxicity can be alleviated with exogenous supply of growth promoters. In this greenhouse study, we determined the effectiveness of medium-supplemented thiourea (TU) in improving growth, leaf gas exchange, and photosynthetic pigments contents. Pak-Afgoi (Cd-tolerant) and EV-20 (Cd-sensitive) maize (Zea mays L.) varieties were grown in pots containing sand supplemented with nutrient solution for 30 days. The plants were treated with 1,000 µM or without Cd. On the appearance of Cd-toxicity symptoms (in about 10 days), a pre-optimized level of TU (0.25 mM) was supplemented in the rooting medium, and plants were allowed to grow for further 15 days. Data for various growths, leaf gas exchange characteristics, chlorophyll (Chl), and carotenoids (Car) contents were recorded in spring (February–April) and autumn (August–October) seasons. Results showed that Cd-stress significantly decreased length, fresh and dry weight of shoot and root, number of green leaves and leaf area per plant, net photosynthetic rate (P n), transpiration rate (TR), stomatal conductance (g s), Chl-a, -b, Chl-a-to-b ratio, and Car but increased substomatal CO2 concentration (C i ) in the varieties in both the seasons. Although Cd was toxic to maize, medium-supplemented TU nullified the Cd-toxicity as was evident from improved growth, P n, g s, and Chl-b and Car contents in both varieties. Overall, 0.25 mM TU level was quite effective in reducing the Cd-toxicity on both the maize varieties; especially, sensitive maize more profoundly responded to Cd-toxicity under medium supplementation of TU. Cd-tolerance produced by TU was superior in the autumn- than in spring-grown maize. From the reduced Cd content of leaf and root, the results suggested a possible role of TU in reducing Cd-availability to the root and its transport to shoot. Presence of thiol group in TU appears to be important to Cd-binding/inactivation, and thus its tolerance by maize.

Dynamic Proline Metabolism: Importance and Regulation in Water-Limited Environments

Abstract: Proline is an important imino acid that accumulates in plants in response to different environmental constraints including water-limited conditions. The literature shows a positive association between proline accumulation and drought tolerance in plants. However, some recent findings highlighted that induction of drought tolerance in plants is not only due to proline accumulation and turnover, but also due to metabolism of proline that is responsible for maintaining plant growth during drought conditions. Plants mutant for enzymes involved in the biosynthesis Δ1-pyrroli [pyrroline-5-carboxylate synthetase 1 (P5CS1)] and catabolism [proline dehydrogenase 1 (ProDH1)] of proline exhibited significant growth reduction under drought conditions. Plants exposed to drought show accumulation of proline that in turn maintains the redox status. A variety of cellular processes mediate the biosynthesis and catabolism of proline. Presently, only a few mechanisms dealing with this imino acid are fully elucidated. For instance, highly abscisic acid (ABA)-induced protein phosphatase 2Cs differentially influenced the endogenous levels of PDH1 and P5CS1 proteins apart from the same increase in the cellular levels of proline. Proline biosynthetic (P5CS1) and catabolic (PDH1) genes are regulated via some posttranslational changes that are not fully known. In this chapter, we have discussed proline metabolism in plants under limited water regimes. We have also provided the details of proline association with other key physiochemical attributes under water deficit conditions.

Magneto-Priming Improved Nutraceutical Potential and Antimicrobial Activity of Momordica charantia L. Without Affecting Nutritive Value.

Abstract: The need for some economic strategies for increased growth and nutraceuticals of medicinal plants is well acknowledged now. It was hypothesized that external magnetic field treatment (MFT) of seeds affecting internal magnet of cells may affect growth and metabolism. In this study, seeds were subjected to pre-sowing magnetic field (50 mT at 5 mm for 5 s). At vegetative stage, the leaf growth, chlorophyll content, catalase (CAT), peroxidase (POD), amino acids, proteins, flavonoids, soluble sugars, total soluble phenolics, carotenoids, anthocyanins, phenolic profile (HPLC based), and antimicrobial activity of leaves (in terms of the minimum inhibitory concentration against Staphylococcus aureus and Pseudomonas aeruginosa) were studied. Yield was evaluated for nutritive components in fruit (peel+pulp) and peel. MFT improved germination percentage, growth, leaf chlorophyll, antimicrobial activity, peel amino acids, phenolics, and POD with negligible effect on fruit nutritive value. Moreover, photosynthetic pigments and cinnamic acid exhibited direct correlation with antimicrobial potential against both pathogens. However, sinapic acid showed positive correlation against Staphylococcus aureus only. Cinnamic acid, coumaric acid, syringic acid, and quercetin were in direct correlation against Pseudomonas aeruginosa; it was directly correlated with total flavonoids too. In conclusion, magnetic field can be used to manipulate plant cell metabolism promising improvement of growth, antimicrobial activity, and phenolics of interest.

Methods Of Enzymatic Analysis

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Cadmium stress in plants: A critical review of the effects, mechanisms, and tolerance strategies

Abstract: Cadmium accumulation in crops and the possibility of Cd entering the food chain are serious concerns for public health. This review discusses the deleterious effects of Cd in plants and the toleran...

Potential Mechanisms of Abiotic Stress Tolerance in Crop Plants Induced by Thiourea.

Abstract: Abiotic stresses, such as temperature extremes, drought, salinity, and heavy metals are major factors limiting crop productivity and sustainability worldwide. Abiotic stresses disturb plant growth and yield formation. Several chemical compounds, known as plant growth regulators (PGRs), modulate plant responses to biotic and abiotic stresses at the cellular, tissue, and organ levels. Thiourea (TU) is an important synthetic PGR containing nitrogen (36%) and sulfur (42%) that has gained wide attention for its role in plant stress tolerance. Tolerance against abiotic stresses is a complex phenomenon involving an array of mechanisms, and TU may modulate several of these. An understanding of TU-induced tolerance mechanisms may help improve crop yield under stress conditions. However, the potential mechanisms involved in TU-induced plant stress tolerance are still elusive. In this review, we discuss the essential role of TU-induced tolerance in improving performance of plants growing under abiotic stresses and potential mechanisms underlying TU-induced stress tolerance. We also highlight exploitation of new avenues critical in TU-induced stress tolerance.