Potassium, the most abundant cation in plant cells, is responsible for numerous physiological functions. In saline environment, similarity of Na+ and K+ causes an unbalance in K+ uptake and disorder in the its functions. In the present research, changes of four biochemical parameters (proline, glycinebetaine, photosynthetic pigments and malondialdehyde) have been investigated in Aeluropus lagopoides seedling under salinity and potassium deficiency. Sterile seeds had been cultured on modified Murashige-Skoog containing 0, 1.75 or 100 mM potassium, with or without 600 mM NaCl for 30 days. The results showed that maximum proline content was observed in root and shoot by 600 mM NaCl + 1.75 mM K+ treatment. Also in this treatment, amount of carotenoids and chlorophyll a was more decreased. Potassium deficiency caused to reduced MDA and chlorophyll b content. The highest amount of glycinebetaine was measured in the presence of 600 mM NaCl in the company of 100 mM K+. It can conclude that chlorophyll oxidation was occurred in K+ deficiency because of increasing lipid peroxidation and disruption of protein-pigment complexes. The accumulation rates of two osmolite in different organ was shown that in A. lagopoides proline and glycinebetaine play more important role in osmotic adjustment of the shoot and root, respectively.
Differential responses of seven contrasting species to high light using pigment and chlorophyll a fluorescence
Mittal S., Kumari N., Sharma V.
High light intensity may induce severe photodamage to chloroplast and consequently cause decreases in the yield capacity of plants and destruction of pigments, causing an overall yellowing of the foliage. Thus, study related to light adaptation becomes necessary to understand adaptation processes in higher plants on the basis of which they are characterized as full sunlight or shade plants. Chlorophyll can be regarded as an intrinsic fluorescent probe of the photosynthetic system. The ecophysiological parameter related to plant performance and fitness i.e. in-situ chlorophyll fluorescence measurements were determined for different plant species in the medicinal plant garden of Banasthali University, Rajasthan. Miniaturized Pulse Amplitude Modulated Photosynthetic Yield Analyzers are primarily designed for measuring effective quantum yield (ΔF/Fm') of photosystem II under momentary ambient light in the field. Photosynthetic yield measurements and light-response curves suggested a gradation of sun-adapted to shade-adapted behaviour of these plants in following order Withania somnifera> Catharanthus roseus> Datura stamonium> Vasica minora> Vasica adulta> Rauwolfia serpentina. As indicated by light response curves and pigment analysis, Datura stramonium, Withania somnifera and Catharanthus roseus competed well photosynthetically and are favoured while Rauwolfia serpentina, Vasica minora, Vasica adulta and Plumbago zeylanica were observed to be less competent photosynthetically. These light response curves and resultant cardinal points study gave insight into the ecophysiological characterization of the photosynthetic capacity of the plant and provides highly interesting parameters like electron transport rate, photo-inhibition, photosynthetically active photon flux density and yield on the basis of which light adaptability was screened for seven medicinally important plants.
Role of Nitric oxide in regulation of H2O2 mediating tolerance of plants to abiotic stress: A synergistic signaling approach
Mohd Mazid, Taqi Ahmed Khan, Firoz Mohammad
The relationship between abiotic stress, nitric oxide (NO) and Hydrogen peroxide (H2O2) is a challenging one. It is now clear that H2O2 and NO function as signaling molecules in plants. A wide range of abiotic stresses results in H2O2 generation, from a variety of sources and it has many essential roles in plant metabolism but at the same time, accumulation related to virtually any environmental stress is potentially damaging. NO is gaining increasing attention as a regulator of diverse pathophysiological processes in plant science, mainly due to its properties (free radicals, small size, no charge, short-lived, and highly diffusible across biological membranes) and multifunctional roles in plant growth, development and regulation of remarkably broad myriad of plant cellular mechanisms. Various abiotic stresses can induce NO synthesis, but its origin and mode of action in plants have not yet been completely resolved. Recent studies on NO production have tended to high light the questions that still remain unanswered rather than telling us more about NO metabolism. But regarding NO-H2O2 signaling and functions, new findings have given an impression of the intricacy of NO-H2O2 related signaling networks against abiotic stresses. Cellular responses to NO-H2O2 are complex, with considerable cross-talk between responses to several abiotic stresses. In last few years, the role of NO in H2O2 mediating tolerance in plants to abiotic stress has established much consideration.
Status of secondary plant products under abiotic stress: an overview
Taqi Ahmed Khan, Mohd Mazid, Firoz Mohammad
The plants produce various secondary plant products with an economic value in normal conditions but various kinds of abiotic stress factors can result in an enhanced production of the secondary plant products. Especially, a wide array of abiotic stimuli like salinity and drought are capable to triggering changes in the plant metabolism, results enhanced production of plant secondary products. As a fact that plants under stress conditions, a strong oversupply of reduction equivalents is generated. A account of study for comparative analysis tells that amount of secondary plant products is maximum in plants, severely affected or grown under abiotic stress conditions than plants cultivated under optimal conditions of growth and productivity. In order to prevent damage by ROS, NADPH+H+ is reoxidized by photorespiration or violaxanthine cycle. Yet, the higher concentration of reduction equivalents also precedes to a stronger rate of synthesis of highly reduced secondary plant products i.e. isoflavones, isoprenoids, phenols or alkaloids and phytosterols etc. In this review we consider the physiology and biochemistry of secondary metabolism and also include, special emphasis on aspects of quantity and quality improvement by enhancing the average concentration of secondary compounds in plants bearing great economic values by deliberately applying abiotic stress like salinity, drought.
Protective Effect of Humic acid and Chitosan on Radish (Raphanus sativus, L. var. sativus) Plants Subjected to Cadmium Stress
Farouk S., Mosa A.A., Taha A. A., Ibrahim Heba M., EL-Gahmery A.M.
Background Humic acid or chitosan has been shown to increase plant growth, yield and improving physiological processes in plant, but its roles on alleviating the harmful effect of cadmium on plant growth and some physiological processes in plants is very rare. Pot experiments were conducted to study the role of 100 and 200 mg/kg dry soil from either humic acid or chitosan on counteracted the harmful effects of cadmium levels (100 and 150 mg/kg dry soil) on radish plant growth and some physiological characters Results Cadmium at 100 and 150 mg kg-1 soil decreased significantly length, fresh and dry weights of shoot and root systems as well as leaf number per plant in both seasons. Chlorophyll, total sugars, nitrogen, phosphorus, potassium, relative water content, water deficit percentage and soluble proteins as well as total amino acids contents were also decreased. Meanwhile, cadmium concentration in plants was increased. On the other hand, application of chitosan or humic acid as soil addition at the concentration of 100 or 200 mg kg-1 increased all the above mentioned parameters and decreased cadmium concentrations in plant tissues. Chitosan at 200 mg kg-1 was the most effective than humic acid at both concentrations in counteracting the harmful effect of cadmium stress on radish plant growth. Conclusion In conclusion, both natural chelators, in particular, chitosan at 200 mg/kg dry soil can increase the capacity of radish plant to survive under cadmium stress due to chelating the Cd in the soil, and then reduced Cd bio-availability.
Osmotic adjustment in wheat flag leaf in relation to flag leaf area and grain yield per plant
Background Salinity stress causes ion toxicity and osmotic imbalances, leading to oxidative stress in plants. Antioxidants are considered ameliorators of saline stress and could develop salinity tolerance in crop plants. To ascertain the role of antioxidants in inducing osmotic adjustment in salt stressed wheat flag leaf in terms of compatible solutes accumulation, water relations parameters and osmotic adjustment as well as flag leaf area and grain yield per plant, in addition, flag leaf anatomy were examined. Results Salt stress up to 11.5 dSm-1 causes a significant reduction in water potential, osmotic potential, as well as relative water content, and water content. On the other hand, turgor potential and osmotic adjustment were significantly increased due to inducing increasing the higher accumulation of compatible osmolytes which leads to decreasing flag leaf area and grain yield per plant. Application of both antioxidants, in particular, ascorbic acid increased significantly flag leaf area, and grain yield per plant due to osmotic adjustment and maintaining leaf turgor potential as a consequence of increasing leaf water potential, water content and relative water content as compared to control plants. On the other hand, application of both antioxidants under all salinity levels, nullify the harmful effects of salinity on flag leaf area and grain yield per plant due to increasing osmolyte accumulation, maintaining turgor potential and osmotic adjustment. Anatomically, increasing salinity levels decreased thickness of leaf blade at midrib region, thickness of mesophyll tissue, tangential dimension of midrib vascular bundle, thickness of upper and lowerepidermis, thickness of big motor cell, and tangential dimension of big xylem vessel. Treatment with either ascorbic acid or tocopherol at 100 mg/L and their interactions with salinity increased all the above mentioned parameters in both nonsalinized and salinized plants. Ascorbic acid is the most effective in this concern. Conclusion In conclusion, wheat plants responded to an increased ion influx in their cells by increasing the osmolytes synthesis and accumulation under salt stress, which further increased with antioxidants treatment and helped in maintaining the osmotic balance.
REDUCED ANTIOXIDANT STATUS FOR PROLONGED PERIOD DUE TO REPEATED STRESS EXPOSURE IN RAT
Devaki M, Nirupama R., Yajurvedi H.N.
The objective of the study was to find out whether or not exposure to a stressor after an initial stressful experience augments stress response. Antioxidant status was determined by measuring changes in the activities of the hepatic free radical scavenging enzymes viz, superoxide dismutase (SOD), glutathione-S-transferase (GST), glucose-6-phosphate-dehydrogenase (G6PDH) and catalase (CAT) and levels of hepatic malondialdehyde (MDA) following exposure to 1 h restraint (RS) and after a gap of 4 h to forced swimming exercise (FS) in rats. The activities of hepatic CAT, SOD, G6PDH and GST were significantly reduced 2 h after RS compared to controls and 4 h after FS the activities of CAT and G6PDH remained at lower levels i.e. they were similar to those found after RS , whereas SOD and GST showed further significant decrease compared to those found after RS. On the other hand the MDA levels, indicative of lipid peroxidation were significantly increased after RS and showed further significant increase after FS. The results reveal that after initial stressful experience, the stress response is augmented due to exposure to another stressor whereas the system does not get habituated to stress exposure.
METABOLIC PROFILE OF FOOT AND MOUTH DISEASE STRESSED SHEEP IN SEMI ARID REGION
Gattani Anil, Gupta Koshal K, Joshi Gurudutt, Gupta Sita R
The present study was designed to evaluate serum biochemical parameters in twenty local bred sheep infected with Foot-and-Mouth disease virus (FMDV) serotype O. Ten healthy sheep were used as controls. Peripheral blood was collected from both diseased and control group and serum was separated which was further used to estimate the concentration of glucose, total protein, albumin, urea, calcium, phosphorus, cholesterol and activity of AST, ALT and ALP. It was found that there was a significant increase in glucose, AST and phosphorus in FMD affected sheep (p<0.01). Total protein, albumin, calcium, cholesterol and urea level were significantly lower (p<0.05) in FMD group compared to those in the control group. The biochemical alteration indicates the development of pancreatic dysfunction in Foot and Mouth disease affected sheep with FMDV serotype O.
INFLUENCE OF SALICYLIC AND SUCCINIC ACIDS ON ANTIOXIDANT ENZYMES ACTIVITY, HEAT RESISTANCE AND PRODUCTIVITY OF PANICUM MILIACEUM L.
Kolupaev Yu.Ye., Yastreb T.O., Karpets Yu.V., Miroshnichenko N.N.
The influence of treatment of millet (Panicum miliaceum L.) seeds with the solutions of salicylic and succinic acids on the heat resistance of plantlets and activity of antioxidant enzymes - superoxide dismutase (SOD), catalase and peroxidase - in them have been investigated. In the micro-field experiment the influence of these acids on the millet yield was estimated. The action of salicylic (10 μM) and succinic (1 mM) acids caused the increase of plantlets resistance to the damaging heating that expressed in the rise of relative quantity of survived plantlets in 5 days after heating at the temperature of 47°С and in the reduced content of lipid peroxidation product malonic dialdehyde during the poststress period. The increase of activity of SOD, catalase and peroxidase took place in millet plantlets under the influence of salicylic and succinic acids. The increase of productivity of millet grain under the action of salicylic and succinic acids on 13,3-52,0 and 6,4-38,8% respectively depending on weather conditions in the field experiments was noted.
PHYSICAL AND PSYCHOLOGICAL STRESS HAVE SIMILAR EFFECTS ON GASTRIC ACID AND PEPSIN SECRETIONS IN RAT
Nabavizadeh Fatemeh, Vahedian Mohammad, Sahraei Hedayat, Adeli Soheila, Salimi Ehsan
Stress is one of the most important health and social problems. Previous studies have demonstrated stress influence on the clinical course of a number of gastrointestinal diseases, but its physical and psychological effects on gastric acid and pepsin secretions are largely unknown. 48 male wistar rats weighing 200-250 gr were used in this study. Animals were divided into 6 groups (n=8); Control, Physical stress, Psychological stress, L-NAME+ Physical stress and L-NAME+ Psychological stress groups. In this study, electrical shock generated in a communication box was used as physical shock and the emotional stress was as psychological stress. Gastric juice was collected by washout technique. Acid output was also measured by digital titrator. Gastric pepsin and nitric oxide (NO) metabolites were quantified using Anson and Griess micro assay methods respectively. Basal and stimulated gastric acid and pepsin in physical and psychological stress groups were significantly more than others. NO metabolites level of gastric tissue in physical and psychological stress groups (286.9 ± 5.8, 287.7 ± 5.7 μmol/gr weight wet tissue, respectively) were significantly more than other groups. But no significant differences among basal and stimulated gastric acid, pepsin and NO metabolites level were seen in physical and psychological stress groups.
SMALL HSPs MOLECULAR WEIGHTS AS NEW INDICATION TO THE HYPOTHESIS OF SEGREGATED STATUS OF THERMOPHILIC RELICT GMELINOIDES FASCIATUS AMONG BAIKAL AND PALEARCTIC AMPHIPODS
Protopopova M.V., Takhteev V.V., Shatilina Zh.M., Pavlichenko V.V., Axenov-Gribanov D.V., Bedulina D.S., Timofeyev M.A.
Among the great diverse of Baikal fauna of amphipods (more than 350 species and subspecies) Gmelinoides fasciatus (Stebbing 1899) takes the special place. It is characterized by a high morphological variability and wide thermal-adaptive possibilities. By common opinion G. fasciatus is a thermophilic relict segregated from other Baikal temperature sensitive amphipods' fauna. In present study we tested hypothesis of segregated status of G. fasciatus among some Baikal and some Palearctic amphipods using of heat-shock proteins' (HSP) molecular weight as comparative biomarkers. We used heat-shock proteins (HSP) from two families: HSP70 and small HSP (sHSP) immunochemically related to α-crystalline. 15 species of Baikal amphipods from different genera and families and 2 Palearctic species from genus Gammarus were tested. It was shown, that molecular weights of HSP70 were the same in all investigated species and corresponds close to 70 kD. In the contrast, the molecular weights of sHSP in G. fasciatus was 37 kD and differed from all other species, in which molecular weights of sHSP were 35 kD. In sum, this study showed that sHSPs molecular weights may relate to evolutional differences between the close related species. Additionally, obtained data can be taken as new indication of segregated status of thermophilic relict G. fasciatus which linked with its phylogenetic history in Lake Baikal.