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1

Physiological effects of glycinebetaine on gamma-irradiated stressed fenugreek plants

100%
Moussa H. R., Jaleel C. A.
Acta Physiologiae Plantarum
|
2011
|
tom 33
|
nr 4
Irradiation stress adversely affects plant growth and development. The radio protective activity by glycinebetaine in plants has not been reported, and its mechanism has not been known. Gamma rays at doses 0.0, 25, 50, 100, and 150 Gray (Gy) when applied pre-sowingly to dry seeds of fenugreek from a cobalt source (⁶⁰Co) with strength of 500 Ci and the dose rate of 0.54 Gy/min significantly reduced chlorophyll content, total protein, photosynthetic efficiency (¹⁴CO₂-fixation), total dry weight, the accumulation of reducing, non-reducing and total soluble sugars in comparison with un-irradiated control. It also significantly repressed the activities of hydrolytic enzymes (α-amylase and invertase), the carboxylating enzyme (ribulose-1,5-bisphosphate-carboxylase/oxygenase) in the developed fenugreek plants. Soaking irradiated seeds with glycinebetaine (50 mM) for 24 h partially alleviated the depression effects of irradiation in these parameters. γ-irradiation treatment increased significantly H₂O₂ content. Presoaking irradiated seeds with GB decreased significantly the H₂O₂ level. The magnitude of the reversal decreased with increasing the irradiation dose. γ-irradiation induced a significant decrease in the level of nucleic acids (DNA and RNA) accompanied by a corresponding induction of hydrolytic activities of DNase and RNase in the developed plants in comparison with un-irradiated control. Those changes were more significant at higher γ-ray doses. Posttreatment of irradiated seeds with GB partially alleviated the adverse effects of radiation. It significantly increased nucleic acid levels and repressed the activities of DNase and RNase. The protective role played by glycinebetaine was more significant at lower γ-ray doses. Pretreatment of seeds with GB may play an effective role in the radiorepair mechanism.
2

Responses of antioxidant defense system of Catharanthus roseus (L.) G. Don. to paclobutrazol treatment under salinity

81%
Jaleel C. A., Gopi R., Manivannan P., Panneerselvam R.
Acta Physiologiae Plantarum
|
2007
|
tom 29
|
nr 3
The effect of paclobutrazol, a plant growth regulator, on antioxidant defense system was investigated in Catharanthus roseus (L.) G. Don. plants subjected to NaCl stress. The growth parameters were significantly reduced under 80 mM NaCl treatment; however, this growth inhibition was less in paclobutrazol-treated (15 mg l⁻¹ plant⁻¹) plants. The non-enzymatic antioxidants ascorbic acid and reduced glutathione were affected under NaCl stress and they increased significantly under paclobutrazol treatment when compared to NaCl treated as well as control plants (P ≤ 0.05). The activity of antioxidant enzyme ascorbate peroxidase showed a significant enhancement under salinity stress. The catalase activity decreased in roots of NaCl-treated plants, but recovered with paclobutrazol treatment. The results suggested that paclobutrazol have significant role in contributing salt stress tolerance of C. roseus by improving the components of antioxidant defense system.
3

Effects of calcium chloride on metabolism of salt-stressed Dioscorea rotundata

81%
Jaleel C. A., Gopi R., Gomathinayagam M., Panneerselvam R.
Acta Biologica Cracoviensia. Series Botanica
|
2008
|
tom 50
|
nr 1
In a pot culture experiment, the effect of calcium chloride (CaCl2) as an ameliorating agent on sodium chloride (NaCl) stress was studied in Dioscorea rotundata plants. Plants were raised in pots and exposed to salinity stress (80 mM NaCl) with or without 5 mM CaCl2. NaCl-stressed plants showed decreased protein and total sugars, and increased free amino acid and proline content. When NaCl treatment was combined with CaCl2, overall plant metabolism was altered, with increased antioxidant enzyme activity, paving the way for partial amelioration of oxidative stress caused by salinity.
4

Interactive effects of triadimefon and salt stress on antioxidative status and ajmalicine accumulation in Catharanthus roseus

61%
Jaleel C. A., Gopi R., Kishorekumar A., Manivannan P., Sankar B., Panneerselvam R.
Acta Physiologiae Plantarum
|
2008
|
tom 30
|
nr 3
The ability of triadimefon (TDM), a triazole group of fungicide, to ameliorate salinity stress was studied in Catharanthus roseus (L.) G. Don. plants subjected to sodium chloride (NaCl) treatment. NaCl treatment at 80 mM level decreased overall growth of this plant and reduced the chlorophyll contents, protein, antioxidant enzymes such as peroxidase (POX), superoxide dismutase (SOD) and polyphenol oxidase (PPO). The root alkaloid ajmalicine got increased under salt treatment. When these stressed plants were treated with TDM at 15 mg l-1 concentration minimized the inhibitory effects of NaCl stress by increasing the root, shoot growth and leaf area and increased dry weight (DW), chlorophyll, protein contents and the activities of antioxidant enzymes like POX, SOD and PPO, thereby paved the way to overcome the salinity injury. The quantity of ajmalicine was again increased with the TDM treatment when compared to both control and NaCl treated plants. From these results, it is proved that the fungicide TDM have great role in the enhancement of plant antioxidative enzymes and the enhanced scavenging of potentially harmful free radicals, as a mechanism of protecting plants against noxious oxidative stress from the environment and also in the enhancement of active principles.
5

Antioxidant defense responses: physiological plastticity in higher plants under abiotic constraints

51%
Jaleel C. A., Riadh K., Gopi R., Manivannan P., Ines J., Al-Juburi H. J., Chang-Xing Z., Hong-Bo S., Panneerselvam R.
Acta Physiologiae Plantarum
|
2009
|
tom 31
|
nr 3
Environmental stresses (salinity, drought, heat/ cold, light and other hostile conditions) may trigger in plants oxidative stress, generating the formation of reactive oxygen species (ROS). These species are partially reduced or activated derivatives of oxygen, comprising both free radical (O₂˙⁻, OH‧, OH₂‧ ) and non-radical (H₂O₂) forms, leading to cellular damage, metabolic disorders and senescence processes. In order to overcome oxidative stress, plants have developed two main antioxidants defense mechanisms that can be classified as non-enzymatic and enzymatic systems. The first class (non-enzymatic) consists of small molecules such as vitamin (A, C and E), glutathione, carotenoids and phenolics that can react directly with the ROS by scavenging them. Second class is represented by enzymes among them superoxide dismutase, peroxidase and catalase which have the capacity to eliminate superoxide and hydrogen peroxide. In this review, we have tried to explore the related works, which have revealed the changes in the basic antioxidant metabolism of plants under various abiotic constraints.
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