Журнал стресс-физиологии и биохимии / Journal of Stress Physiology & Biochemistry

Soil salinity is a serious environmental problem that has negative effect on plant growth, production and photosynthesis. Fresh and dry plant weights decreases with salinity treatments. The very important role of salicylic acid (SA) in response to different stress and modification and decline damages due to stresses has established in different studies. In this research tomato seeds planted in pots containing perlite in a growth chamber under controlled conditions of 27±2°c and 23±2°c temperature , 16h lightness and 8h darkness respectively, 15 Klux light intensity and 75% humidity; NaCl concentration of 0, 25, 50, 75 and 100 mM and salicylic acid concentration of 0, 0.5, 1 and 1.5 mM were used in the form of factorial experiment in a complete randomized design (CRD). Results show that germination was decreased with salinity increasing. At low levels of salinity, SA leads to decrease in germination and had no effect in high levels of salinity. The length of shoot were not effected by salinity but decrease with increase in SA concentration. Low salinity concentrations led to significant increase in root length and high concentrations dont have significant difference with control. SA also had no effect on it. The highest amount of a, b, c and total chlorophyll and carotenoid was show in 50 mM salinity levels.

Ключевые слова

The present investigation was planned to explore stress induced changes in the levels of IgE by correlating them with the important parameters of stress like cortisol and free radical scavengers in the serum of Indian dromedaries. The mean values of serum IgE and cortisol were significantly (p ≤ 0.05) higher in wound affected dromedaries than the respective healthy values. A positive significant (p ≤ 0.05) correlation was observed between the values of serum IgE and cortisol. The mean values of serum vitamin C, vitamin E and glutathione decreased whereas of serum catalase, superoxide dismutase, monoamine oxidase, glutathione reductase, xanthine oxidase, oxidase and peroxidase increased significantly (p ≤ 0.05) from their respective healthy mean values. A negative significant (p ≤ 0.05) correlation was observed between the values of serum IgE and vitamin C; serum IgE and vitamin E and serum IgE and glutathione activities. A positive significant (p ≤ 0.05) correlation was observed between the values of serum IgE and catalase; serum IgE and superoxide dismutase; serum IgE and monoamine oxidase; serum IgE and glutathione reductase; serum IgE and xanthine oxidase; serum IgE and oxidase; and serum IgE and peroxidase activities. It was concluded that stress was able to induce marked changes in the levels of IgE in the Indian dromedaries. Wounds altered the immune status as well as levels of cortisol and free radical scavengers in the serum.

Ключевые слова

The present work has been performed to study the growth and metabolic activities of maize and broad bean plants which are shown to have a degree of sensitivity to salinity and to determine the role of amino acids proline or phenylalanine in increasing the salt tolerance of theses plants. Dry mass, water content, leaf area and photosynthetic pigment of maize and broad bean plants decreased with increasing salinity. These changes were accompanied with a drop in the contents of soluble sugars, soluble proteins and amino acids. This was accompanied by a marked increase in the proline content. When maize and broad bean plants sprayed with proline or phenylalanine the opposite effect was occurred, saccharides as well as proteins progressively increased at all sanitization levels and proline concentration significantly declined. Salinity significantly increased the sodium content in both shoots and roots of maize and broad bean plants, while a decline in the accumulation of K+, Ca++, Mg++ and P was observed. Amino acids treatments markedly altered the selectivity of Na+, K+, Ca++ and P in both maize and broad bean plants. Spraying with any of either proline or phenylalanine restricted Na+ uptake and enhanced the uptake of K+, K+/Na+ ratio, Ca++ and P selectivity in maize and broad bean plants.

Ключевые слова

Ключевые слова

Acute stress induced alterations in the activity levels of rate limiting enzymes and concentration of intermediates of different pathways of carbohydrate metabolism have been studied. Adult male Wistar rats were restrained (RS) for 1 h and after an interval of 4 h they were subjected to forced swimming (FS) exercise and appropriate controls were maintained. Five rats were killed before the commencement of the experiment (initial controls), 5 control and equal number of stressed rats were killed 2 h after RS and remaining 5 rats in each group were killed 4 h after FS. There was a significant increase in the adrenal 3в- hydroxy steroid dehydrogenase activity following RS, which showed further increase after FS compared to controls and thereby indicated stress response of rats. There was a significant increase in the blood glucose levels following RS which showed further increase and reached hyperglycemic condition after FS. The hyperglycemic condition due to stress was accompanied by significant increases in the activities of glutamate- pyruvate transaminase, glutamate- oxaloacetate transaminase, glucose -6- phosphatase and lactate dehydrogenase and significant decrease in the glucose -6- phosphate dehydrogenase and pyruvate dehydrogenase activities, whereas pyruvate kinase activity did not show any alteration compared to controls. Further, the glycogen and total protein contents of the liver were decreased whereas those of pyruvate and lactate showed significant increase compared to controls after RS as well as FS. The results put together indicate that acute stress induced hyperglycemia results due to increased gluconeogenesis and glycogenolysis without alteration in glycolysis. The study first time reveals that after first acute stress exposure, the subsequent stressful experience augments metabolic stress response leading to hyperglycemia. The results have relevance to human health as human beings are exposed to several stressors in a day and such an experience might lead to insulin resistance because prolonged hyperglycemic condition is known to cause insulin resistance.

Ключевые слова

Effect of mercury on the seedling of Vigna mungo seedlings was studied by culturing the seedlings in Hoagland medium artificially contaminated with 5 and 10mM Mercuric Chloride. Histochemical localization of the mercury in shoot and root tissues was done by staining with dithizone and quantitative analyses of mercury content accumulated in root, stem and leaf tissues were done using mercury analyser. Localization of mercury was observed as coloured masses in the cells of root and stem. Stem tissues of seedlings showed anatomical modification in the epidermal cells as trichomes. Patterns of bioaccumulation of mercury was root> stem> leaves revealing feeble translocation to the shoot system. A comparison of residual mercury content retained in the growth medium after sample harvesting and quantity accumulated in the plant body reveals that some quantity of mercury is lost presumably through the trichomes developed on the stem and/ or through stomata of the leaves.

Ключевые слова

Several environmental factors adversely affect plant growth and development and final yield performance of a crop. Drought, salinity, nutrient imbalances (including mineral toxicities and deficiencies) and extremes of temperature are among the major environmental constraints to crop productivity worldwide. Development of crop plants with stress tolerance, however, requires, among others, knowledge of the physiological mechanisms and genetic controls of the contributing traits at different plant developmental stages. In the past 2 decades, biotechnology research has provided considerable insights into the mechanism of biotic stress tolerance in plants at the molecular level. Furthermore, different abiotic stress factors may provoke osmotic stress, oxidative stress and protein denaturation in plants, which lead to similar cellular adaptive responses such as accumulation of compatible solutes, induction of stress proteins, and acceleration of reactive oxygen species scavenging systems. Recently, the authores try to improve plant tolerance to salinity injury through either chemical treatments (plant hormones, minerals, amino acids, quaternary ammonium compounds, polyamines and vitamins) or biofertilizers treatments (Asymbiotic nitrogen-fixing bacteria, symbiotic nitrogen-fixing bacteria and mycorrhiza) or enhanced a process used naturally by plants to minimise the movement of Na+ to the shoot, using genetic modification to amplify the process, helping plants to do what they already do - but to do it much better."

Ключевые слова

Effect of water pollution on Bacopa monnieri was studied by culturing their rooted propagules in various polluted water samples and Hoagland nutrient medium artificially contaminated with different micro-level concentrations of HgCl2. Anatomical observations of those plants showed safranin-stained masses deposited in the xylem vessels of stem. The plants treated in chemical solutions which are free from metallic ions, under threshold level of HgCl2, and control plants were devoid of such deposits. Similar deposits were observed in plants cultured in various local water samples. Atomic Absorption Spectrophotometric analyses of these water samples and the bioaccumulation property of the plant detected the presence of Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn at various levels. The occurrence of the localized stained deposits in the xylem vessels of the stem of the plants cultured in polluted/contaminated aqueous medium, eventhough the growth medium contamination is micro-levels, is indicative of high sensitivity of Bacopa monnieri plants towards water pollution irrespective of the chemical nature of the pollutants. Although these stained deposits are not specific to any individual element that causes pollution, detection of water contamination is possible by observing the safranin-stained masses in the xylem vessels of this medicinal plant.

Ключевые слова

Salicylic acid is involved in the regulation of metabolic activity and defense mechanism in plants under various stress conditions. Present study was conducted to determine the effects of salicylic acid (10 to 500 ƒM) on seedling growth, development and nitrogen use efficiency in cucumber (Cucumis sativus L.) plants with or without nitrogen nutrient. Salicylic acid increased contents of chlorophyll, total non-structural carbohydrate and total nitrogen, as well as nitrate assimilation through the induction of nitrate reductase (EC 1.6.6.1) activity in isolated cucumber cotyledons. Accumulation of salicylic acid was two-fold higher in cotyledons without nitrate supply in comparison to that with nitrate supply. Further 50 ƒM of SA induced enhancement in seed germination and growth characteristics. However higher salicylic acid concentrations inhibited above physiological characteristics. Results show that, field application of salicylic acid need optimum physiological concentration (e.g., 50 ƒM) to increase nitrogen use efficiency particularly during germination and seedling growth.

Ключевые слова

The effects of salinity on some growth and physiological parameters in rosemary were investigated. 2 month-old plants were subjected to three salt treatments (50, 100, and 150 mM) by adding NaCl to the pots. Plant growth parameters not affected by low concentrations of NaCl, but it decreased with higher concentrations. The content of photosynthetic pigments decreased at all salinity levels. The Na+ content of leaves increased, whereas the K+ content decreased with the progressive increase in NaCl concentration. Salinity increased proline and malondealdehyde contents. Stress induced by NaCl caused an accumulation of proline, total phenolic and antioxidant in rosemary plant.

Ключевые слова