Mohamed Al-Whaibi | King Saud University (original) (raw)

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Papers by Mohamed Al-Whaibi

Protoplasma, Jan 1, 2010

Nitric oxide (NO) has now gained significant place in plant science, mainly due to its properties... more Nitric oxide (NO) has now gained significant place in plant science, mainly due to its properties (free radical, small size, no charge, short-lived, and highly diffusible across biological membranes) and multifunctional roles in plant growth, development, and regulation of remarkable spectrum of plant cellular mechanisms. In the last few years, the role of NO in tolerance of plants to abiotic stress has established much consideration. As it is evident from the present review, recent progress on NO potentiality in tolerance of plants to environmental stresses has been impressive. These investigations suggest that NO, itself, possesses antioxidant properties and might act as a signal in activating ROSscavenging enzyme activities under abiotic stress. NO plays an important role in resistance to salt, drought, temperature (high and low), UV-B, and heavy metal stress. Rapidly increasing evidences indicate that NO is essentially involve in several physiological processes; however, there has been much disagreement regarding the mechanism(s) by which NO reduces abiotic stress.

Int J Plant Develop …, Jan 1, 2010

The main objective of the present studies was to determine the best dose of calcium (Ca +2 ) in E... more The main objective of the present studies was to determine the best dose of calcium (Ca +2 ) in Experiment 1, and in Experiment 2 aimed to test whether the growth and photosynthetic pigments of faba bean (Vicia faba L.) cv. 'TARA' could be enhanced by inclusion of GA 3 in the basal treatments containing Ca +2 . In Experiment 1, application of Ca +2 significantly enhanced almost all growth and photosynthetic pigments and enzyme carbonic anhydrase (CA) activity. Among the treatments, 60 mM Ca +2 proved best. Treatment with 60 mM of Ca +2 significantly increased plant height, shoot fresh weight (FW), shoot dry weight (DW), root length, root FW, root DW and root number, relative water content and chlorophyll (Chl) a, b, total Chl, anthocyanin and CA activity compared to the control. In Experiment 2, application of Ca +2 with GA 3 significantly enhanced almost all growth parameters. Among the treatments, 20 mM Ca +2 with 10 -6 M GA 3 gave the maximum value for almost all parameters studied compared to the control as well as the application of GA 3 (10 -6 ) alone. The application of Ca +2 along with GA 3 more efficiently ameliorates the growth and photosynthetic capacity of faba bean than Ca +2 alone.

Protoplasma, Jan 1, 2010

Nickel toxicity affects many metabolic facets of plants and induces anatomical and morphological ... more Nickel toxicity affects many metabolic facets of plants and induces anatomical and morphological changes resulting in reduced growth and productivity. To overcome the damaging effects of nickel (Ni) stress, different strategies of the application of nutrients with plant hormones are being adopted. The present experiment was carried out to assess the growth and physiological response of wheat plant (Triticum aestivum L.) cv. Samma to pre-sowing seed treatment with GA 3 alone as well as in combination with Ca 2+

Journal of Pure and Applied Microbiology, Jan 1, 2009

Journal of King Saud University-Science, Jan 1, 2011

Plants as sessile organisms are exposed to persistently changing stress factors. The primary stre... more Plants as sessile organisms are exposed to persistently changing stress factors. The primary stresses such as drought, salinity, cold and hot temperatures and chemicals are interconnected in their effects on plants. These factors cause damage to the plant cell and lead to secondary stresses such as osmotic and oxidative stresses. Plants cannot avoid the exposure to these factors but adapt morphologically and physiologically by some other mechanisms. Almost all stresses induce the production of a group of proteins called heat-shock proteins (Hsps) or stress-induced proteins. The induction of transcription of these proteins is a common phenomenon in all living things. These proteins are grouped in plants into five classes according to their approximate molecular weight: (1) Hsp100, (2) Hsp90, (3) Hsp70, (4) Hsp60 and (5) small heat-shock proteins (sHsps). Higher plants have at least 20 sHsps and there might be 40 kinds of these sHsps in one plant species. It is believed that this diversification of these proteins reflects an adaptation to tolerate the heat stress. Transcription of heat-shock protein genes is controlled by regulatory proteins called heat stress transcription factors (Hsfs). Plants show at least 21 Hsfs with each one having its role in regulation, but they also cooperate in all phases of periodical heat stress responses (triggering, maintenance and recovery). There are more than 52 plant species (including crop ones) that have been genetically engineered for different traits such as yield, herbicide and insecticide resistance and some metabolic changes.

Protoplasma, Jan 1, 2011

In the present study, N and S assimilation, antioxidant enzymes activity, and yield were studied ... more In the present study, N and S assimilation, antioxidant enzymes activity, and yield were studied in N and S-treated plants of Brassica juncea (L.) Czern. & Coss. (cvs. Chuutki and Radha) under salt stress. The treatments were given as follows: (1) NaCl 90 mM+N 0 S 0 mg kg -1 sand (control), (2) NaCl 90 mM+N 60 S 0 mg kg -1 sand, (3) NaCl 90 mM+N 60 S 20 mg kg -1 sand, (4) NaCl 90 mM+N 60 S 40 mg kg -1 sand, and (5) NaCl 90 mM+N 60 S 60 mg kg -1 sand. The combined application of N (60 mg kg −1 sand) and S (40 mg kg −1 sand) proved beneficial in alleviating the adverse effect of salt stress on growth attributes (shoot length plant −1 , fresh weight plant −1 , dry weight plant −1 , and area leaf −1 ), physio-biochemical parameters (carbonic anhydrase activity, total chlorophyll, adenosine triphosphate-sulphurylase activity, leaf N, K and Na content, K/Na ratio, activity of nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase, catalase, superoxide dismutase, ascorbate peroxidase and glutathione reductase, and content of glutathione and ascorbate), and yield attributes (pods plant −1 , seeds pod −1 , and seed yield plant −1 ). Therefore, it is concluded that combined application of N and S induced the physiological and biochemical mechanisms of Brassica. The stimulation of antioxidant enzymes activity and its synergy with N and S assimilation may be one of the important mechanisms that help the plants to tolerate the salinity stress and resulted in an improved yield.

Agricultural Sciences in …, Jan 1, 2010

Different strategies of the application of nutrients are required to overcome the adverse effects... more Different strategies of the application of nutrients are required to overcome the adverse effects of mustard (Brassica juncea L.) in response to NaCl stress. The objective of the present study was to determine if different added levels of nitrogen (N) in growth medium could alleviate the adverse effects of salt stress on photosynthetic capacity and accumulation of osmoprotectants and nutrients. 14 days mustard seedlings of salt-sensitive (cv. Chuutki) and salt-tolerant (cv. Radha) genotypes were fed with: (i) 0 mmol L -1 NaCl + 0 mg N kg -1 sand (control), (ii) 90 mmol L -1 NaCl + 30 mg N kg -1 sand, (iii) 90 mmol L -1 NaCl + 60 mg N kg -1 sand, (iv) 90 mmol L -1 NaCl + 90 mg N kg -1 sand and (v) 90 mmol L -1 NaCl + 120 mg N kg -1 sand.

Saudi Journal of …, Jan 1, 2010

Exposure of heavy metals to human beings has risen dramatically in the last 50 years. In today's ... more Exposure of heavy metals to human beings has risen dramatically in the last 50 years. In today's urban and industrial society, there is no escaping from exposure to toxic chemicals and heavy metals. Humans are more likely to be exposed to heavy metal contamination from the dust that adheres to edible plants than from bioaccumulation. This is because it is very difficult to wash off all the dust particles from the plant material before ingesting them. The objectives of this experiment were to determine the concentrations of lead (Pb) and cadmium (Cd) in washing residues and in the tissues of fruits of date palm growing in 14 sites of Riyadh and also to assess whether the fruits were safe for human consumption. The washing residues and tissue of date palm fruits collected from different sites showed the presence of significant amounts of the Pb and Cd. The concentration of Pb in the dust and fruit tissue increased with increasing anthropogenic sources. Therefore, fruits of date palm might be used as a pollution indicator; it might be recommend that fruits of date palm could be safe for human consumption after washing. The mean concentration of Pb and Cd in all the samples collected from different sites is within the safe limits recommended by FAO/WHO.

Protoplasma, Jan 1, 2010

Nitric oxide (NO) has now gained significant place in plant science, mainly due to its properties... more Nitric oxide (NO) has now gained significant place in plant science, mainly due to its properties (free radical, small size, no charge, short-lived, and highly diffusible across biological membranes) and multifunctional roles in plant growth, development, and regulation of remarkable spectrum of plant cellular mechanisms. In the last few years, the role of NO in tolerance of plants to abiotic stress has established much consideration. As it is evident from the present review, recent progress on NO potentiality in tolerance of plants to environmental stresses has been impressive. These investigations suggest that NO, itself, possesses antioxidant properties and might act as a signal in activating ROSscavenging enzyme activities under abiotic stress. NO plays an important role in resistance to salt, drought, temperature (high and low), UV-B, and heavy metal stress. Rapidly increasing evidences indicate that NO is essentially involve in several physiological processes; however, there has been much disagreement regarding the mechanism(s) by which NO reduces abiotic stress.

Int J Plant Develop …, Jan 1, 2010

The main objective of the present studies was to determine the best dose of calcium (Ca +2 ) in E... more The main objective of the present studies was to determine the best dose of calcium (Ca +2 ) in Experiment 1, and in Experiment 2 aimed to test whether the growth and photosynthetic pigments of faba bean (Vicia faba L.) cv. 'TARA' could be enhanced by inclusion of GA 3 in the basal treatments containing Ca +2 . In Experiment 1, application of Ca +2 significantly enhanced almost all growth and photosynthetic pigments and enzyme carbonic anhydrase (CA) activity. Among the treatments, 60 mM Ca +2 proved best. Treatment with 60 mM of Ca +2 significantly increased plant height, shoot fresh weight (FW), shoot dry weight (DW), root length, root FW, root DW and root number, relative water content and chlorophyll (Chl) a, b, total Chl, anthocyanin and CA activity compared to the control. In Experiment 2, application of Ca +2 with GA 3 significantly enhanced almost all growth parameters. Among the treatments, 20 mM Ca +2 with 10 -6 M GA 3 gave the maximum value for almost all parameters studied compared to the control as well as the application of GA 3 (10 -6 ) alone. The application of Ca +2 along with GA 3 more efficiently ameliorates the growth and photosynthetic capacity of faba bean than Ca +2 alone.

Protoplasma, Jan 1, 2010

Nickel toxicity affects many metabolic facets of plants and induces anatomical and morphological ... more Nickel toxicity affects many metabolic facets of plants and induces anatomical and morphological changes resulting in reduced growth and productivity. To overcome the damaging effects of nickel (Ni) stress, different strategies of the application of nutrients with plant hormones are being adopted. The present experiment was carried out to assess the growth and physiological response of wheat plant (Triticum aestivum L.) cv. Samma to pre-sowing seed treatment with GA 3 alone as well as in combination with Ca 2+

Journal of Pure and Applied Microbiology, Jan 1, 2009

Journal of King Saud University-Science, Jan 1, 2011

Plants as sessile organisms are exposed to persistently changing stress factors. The primary stre... more Plants as sessile organisms are exposed to persistently changing stress factors. The primary stresses such as drought, salinity, cold and hot temperatures and chemicals are interconnected in their effects on plants. These factors cause damage to the plant cell and lead to secondary stresses such as osmotic and oxidative stresses. Plants cannot avoid the exposure to these factors but adapt morphologically and physiologically by some other mechanisms. Almost all stresses induce the production of a group of proteins called heat-shock proteins (Hsps) or stress-induced proteins. The induction of transcription of these proteins is a common phenomenon in all living things. These proteins are grouped in plants into five classes according to their approximate molecular weight: (1) Hsp100, (2) Hsp90, (3) Hsp70, (4) Hsp60 and (5) small heat-shock proteins (sHsps). Higher plants have at least 20 sHsps and there might be 40 kinds of these sHsps in one plant species. It is believed that this diversification of these proteins reflects an adaptation to tolerate the heat stress. Transcription of heat-shock protein genes is controlled by regulatory proteins called heat stress transcription factors (Hsfs). Plants show at least 21 Hsfs with each one having its role in regulation, but they also cooperate in all phases of periodical heat stress responses (triggering, maintenance and recovery). There are more than 52 plant species (including crop ones) that have been genetically engineered for different traits such as yield, herbicide and insecticide resistance and some metabolic changes.

Protoplasma, Jan 1, 2011

In the present study, N and S assimilation, antioxidant enzymes activity, and yield were studied ... more In the present study, N and S assimilation, antioxidant enzymes activity, and yield were studied in N and S-treated plants of Brassica juncea (L.) Czern. & Coss. (cvs. Chuutki and Radha) under salt stress. The treatments were given as follows: (1) NaCl 90 mM+N 0 S 0 mg kg -1 sand (control), (2) NaCl 90 mM+N 60 S 0 mg kg -1 sand, (3) NaCl 90 mM+N 60 S 20 mg kg -1 sand, (4) NaCl 90 mM+N 60 S 40 mg kg -1 sand, and (5) NaCl 90 mM+N 60 S 60 mg kg -1 sand. The combined application of N (60 mg kg −1 sand) and S (40 mg kg −1 sand) proved beneficial in alleviating the adverse effect of salt stress on growth attributes (shoot length plant −1 , fresh weight plant −1 , dry weight plant −1 , and area leaf −1 ), physio-biochemical parameters (carbonic anhydrase activity, total chlorophyll, adenosine triphosphate-sulphurylase activity, leaf N, K and Na content, K/Na ratio, activity of nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase, catalase, superoxide dismutase, ascorbate peroxidase and glutathione reductase, and content of glutathione and ascorbate), and yield attributes (pods plant −1 , seeds pod −1 , and seed yield plant −1 ). Therefore, it is concluded that combined application of N and S induced the physiological and biochemical mechanisms of Brassica. The stimulation of antioxidant enzymes activity and its synergy with N and S assimilation may be one of the important mechanisms that help the plants to tolerate the salinity stress and resulted in an improved yield.

Agricultural Sciences in …, Jan 1, 2010

Different strategies of the application of nutrients are required to overcome the adverse effects... more Different strategies of the application of nutrients are required to overcome the adverse effects of mustard (Brassica juncea L.) in response to NaCl stress. The objective of the present study was to determine if different added levels of nitrogen (N) in growth medium could alleviate the adverse effects of salt stress on photosynthetic capacity and accumulation of osmoprotectants and nutrients. 14 days mustard seedlings of salt-sensitive (cv. Chuutki) and salt-tolerant (cv. Radha) genotypes were fed with: (i) 0 mmol L -1 NaCl + 0 mg N kg -1 sand (control), (ii) 90 mmol L -1 NaCl + 30 mg N kg -1 sand, (iii) 90 mmol L -1 NaCl + 60 mg N kg -1 sand, (iv) 90 mmol L -1 NaCl + 90 mg N kg -1 sand and (v) 90 mmol L -1 NaCl + 120 mg N kg -1 sand.

Saudi Journal of …, Jan 1, 2010

Exposure of heavy metals to human beings has risen dramatically in the last 50 years. In today's ... more Exposure of heavy metals to human beings has risen dramatically in the last 50 years. In today's urban and industrial society, there is no escaping from exposure to toxic chemicals and heavy metals. Humans are more likely to be exposed to heavy metal contamination from the dust that adheres to edible plants than from bioaccumulation. This is because it is very difficult to wash off all the dust particles from the plant material before ingesting them. The objectives of this experiment were to determine the concentrations of lead (Pb) and cadmium (Cd) in washing residues and in the tissues of fruits of date palm growing in 14 sites of Riyadh and also to assess whether the fruits were safe for human consumption. The washing residues and tissue of date palm fruits collected from different sites showed the presence of significant amounts of the Pb and Cd. The concentration of Pb in the dust and fruit tissue increased with increasing anthropogenic sources. Therefore, fruits of date palm might be used as a pollution indicator; it might be recommend that fruits of date palm could be safe for human consumption after washing. The mean concentration of Pb and Cd in all the samples collected from different sites is within the safe limits recommended by FAO/WHO.