Оценка антиоксидантного потенциала лекарственных растений при действии Уф-B-облучения

The UV-B irradiation action (6 -36,9 dg/m2) on medical plants Artemisia lerchiana L., Nigella sativa L., Ocimum basilicum L., grown in water culture, was studying. In plant leaves and roots the content of malondialdehyde, pigments, phenols, flavonoids, proline, and activities of antioxidant enzymes were determined. Investigated plants were able to resist to action of UV-B-irradiation (low and middle dose) without any power input for increasing of biosynthesis of low and high molecular component of antioxidant defense system. The damage level under stress conditions was low. At first hours plants used the constitutive level of antioxidants and after 24 h it was needed the antioxidant pool refilling. Carotinoids, flavonoids and proline were used by plants in 4 h after irradiation, the antocian synthesis increased after 12 h.В статье рассматривается методика изучения действия УФ-B-облучения (6,0, 12,3 и 36,9 Дж/кв. м) на лекарственные растения: полынь Artemisia lerchiana L., чернушку Nigella sativa L., базилик Ocimum basilicum L., выращенные в водной культуре в условиях фитотрона. Исследованные растения способны адаптироваться к действию низкой и средней доз УФ-B-радиации без значительных энергозатрат на усиление биосинтеза как низкомолекулярных компонентов антиоксидантной защиты, так и высокомолекулярных. Степень повреждения растений при действии данного стрессора незначительна. В первые часы растения в основном использовали конститутивный уровень антиоксидантов, и лишь через 24 часа требовалось пополнение их пула. Каротиноиды, флавоноиды и пролин используются растениями уже через 4 часа после облучения, синтез антоцианов усиливается через 12 ч

Сравнительный анализ физиологических механизмов солеустойчивости различных сортов горчицы

The comparison and assessment have been performed to characterize salt tolerance of some varieties of Indian mustard (Brassica juncea Czern.) seedlings and young plants. Some mechanisms of NaCl tolerance have been studied and the indirect relationship between accumulation of Cl ions in leaves and their proline content have been established. After 10-15 days of mustard plant salinisation, proline content decreased and the correlation between proline and proline dehydrogenase activity has been proved.Проведена сравнительная оценка устойчивости сортов горчицы cарептской (Brassica juncea Czern.) при воздействии засоления на стадии прорастания и роста молодых растений. Изучены некоторые механизмы адаптации растений к воздействию NaCl и установлена непрямая взаимосвязь между поступлением ионов хлора в листья растений и содержанием в них пролина. Было обнаружено падение пролина после 10-15 суток засоления растений горчицы и установлена корреляция между содержанием пролина и активностью фермента пролиндегидрогеназы

Osmolyte accumulation in different rape genotypes under sodium chloride salinity

Physiological mechanisms of two rape (Brassica napus L.) genotype adaptation to chlorine salinity were investigated. The plants of two cultivars (Olga and Westar) differing in salt tolerance were grown in the pots filled with Perlite on the Hoagland and Snyder's medium under controlled conditions. At a stage of 3-4 true leaves, the plants experienced 7-day-long salinity induced by a single addition of NaCl to the nutrient medium in order to attain desired final salt concentration (from 50 to 400 mM). The obtained results showed that a greater salt tolerance of cv. Olga plants (as compared with cv. Westar) could be accounted for by a capability of their root cells to uptake water under high salinity (300-400 mM NaCl), which is evident from a greater content of water in the tissues of cv. Olga. This was ensured by a sharp fall of the osmotic potential of the cellular contents (down to -2.3 MPa) at a low water potential of nutrient solution owing to more active uptake of Na+ (57-61 μeq/g fr wt) and K+ (210-270 μeq/g fr wt) as well as active accumulation of proline (30-50 μmol/g fr wt). The latter is caused by a reduced activity of proline dehydrogenase and retarded degradation of this osmolyte. It is important that, in contrast to less tolerant genotype, the rape plants of salt-resistant cultivar were able to maintain the K +/Na+ ratio at a rather high level at salinity of different degree, which made it possible to preserve ionic homeostasis under adverse conditions. © MAIK "Nauka/Interperiodica"

Osmolyte accumulation in different rape genotypes under sodium chloride salinity

Physiological mechanisms of two rape (Brassica napus L.) genotype adaptation to chlorine salinity were investigated. The plants of two cultivars (Olga and Westar) differing in salt tolerance were grown in the pots filled with Perlite on the Hoagland and Snyder's medium under controlled conditions. At a stage of 3-4 true leaves, the plants experienced 7-day-long salinity induced by a single addition of NaCl to the nutrient medium in order to attain desired final salt concentration (from 50 to 400 mM). The obtained results showed that a greater salt tolerance of cv. Olga plants (as compared with cv. Westar) could be accounted for by a capability of their root cells to uptake water under high salinity (300-400 mM NaCl), which is evident from a greater content of water in the tissues of cv. Olga. This was ensured by a sharp fall of the osmotic potential of the cellular contents (down to -2.3 MPa) at a low water potential of nutrient solution owing to more active uptake of Na+ (57-61 μeq/g fr wt) and K+ (210-270 μeq/g fr wt) as well as active accumulation of proline (30-50 μmol/g fr wt). The latter is caused by a reduced activity of proline dehydrogenase and retarded degradation of this osmolyte. It is important that, in contrast to less tolerant genotype, the rape plants of salt-resistant cultivar were able to maintain the K +/Na+ ratio at a rather high level at salinity of different degree, which made it possible to preserve ionic homeostasis under adverse conditions. © MAIK "Nauka/Interperiodica"

Physiological mechanisms of adaptation of alloplasmic wheat hybrids to soil drought

We studied physiological mechanisms of plant adaptation to drought for two alloplasmic wheat (Triticum aestivum L.) hybrids (APHs) on the cytoplasm of rye (Secale cereale L.) or ovate goatgrass (Aegilops ovata L.) and two standard regionalized spring wheat cultivars, Kometa and Priokskaya. In response to plant tissue dehydration, APHs rapidly reduced the transpiration rate and lost much less water than standard cultivars. During drought, peroxidase activity was significantly increased only in APH on the rye cytoplasm, whereas it declined substantially in cv. Kometa. Peroxidation of lipids (POL) was activated in cv. Kometa stronger than in hybrids, which also indicates that, in this cultivar, there was no complete detoxification of hydrogen peroxide under stress conditions. After watering resumption, APHs displayed a better capacity for reparation than standard cultivars, which was manifested in peroxidase activation and POL suppression, i.e., in more complete reduction of the oxidative stress consequences. We concluded that a higher APH drought resistance, as compared with standard cultivars, was determined by their more efficient antioxidant defense and a better capacity for recovery. © 2007 Pleiades Publishing, Ltd

Physiological mechanisms of adaptation of alloplasmic wheat hybrids to soil drought

We studied physiological mechanisms of plant adaptation to drought for two alloplasmic wheat (Triticum aestivum L.) hybrids (APHs) on the cytoplasm of rye (Secale cereale L.) or ovate goatgrass (Aegilops ovata L.) and two standard regionalized spring wheat cultivars, Kometa and Priokskaya. In response to plant tissue dehydration, APHs rapidly reduced the transpiration rate and lost much less water than standard cultivars. During drought, peroxidase activity was significantly increased only in APH on the rye cytoplasm, whereas it declined substantially in cv. Kometa. Peroxidation of lipids (POL) was activated in cv. Kometa stronger than in hybrids, which also indicates that, in this cultivar, there was no complete detoxification of hydrogen peroxide under stress conditions. After watering resumption, APHs displayed a better capacity for reparation than standard cultivars, which was manifested in peroxidase activation and POL suppression, i.e., in more complete reduction of the oxidative stress consequences. We concluded that a higher APH drought resistance, as compared with standard cultivars, was determined by their more efficient antioxidant defense and a better capacity for recovery. © 2007 Pleiades Publishing, Ltd

Possible contribution of blast spores to the oxidative burst in the infection droplet on rice leaf

The infection-induced overproduction of reactive oxygen species (ROS) in resistant plants is usually ascribed to the host. Here we tested the possible contribution of the parasite, the rice blast fungus to ROS production. Droplets of spore suspensions or water were kept on rice leaves or on a plastic. After one day, superoxide radical and hydrogen peroxide were chemically assayed in drop diffusates. Similar measurements were done on diffusates of rice calli submerged in spore suspension or water. Negligible amounts of ROS were found in diffusates of plant tissues treated with water. In contrast, diffusates from tissues treated with spore suspensions had appreciable levels of ROS, usually higher in incompatible combinations than in compatible ones. However, diffusates of spores incubated on plastic produced ROS to an extent comparable to those of infected tissues. In diffusates of spores, O2 - was found after their germination, and H2O2 was found after appressorium formation. Various fungal strains differed in ROS production. The results suggest that spores of the blast inoculum may contribute significantly to ROS production on rice leaves, at least, at early stages of the disease. This might be a factor of incompatibility suppressing a parasite and/or inducing defense responses of a host. © 2007 Akadémiai Kiadó, Budapest

Inducible and constitutive mechanisms of salt stress resistance in Geum urbanum L.

The avens (Geum urbanum L.) seedlings were grown for 6 weeks until the expansion of five to six leaves and then exposed to salinity shock (300 mM NaCl in the nutrient medium) or to a gradual (within 4 days) increase in NaCl concentration from 100 to 400 mM. The dynamics of stress-dependent accumulation of Na+, Cl-, proline, and polyamines in leaves and roots was measured, together with activities of antioxidant enzymes, namely, superoxide dismutase (SOD) and guaiacol-dependent peroxidase occurring in soluble, ionically bound, and covalently bound forms. It is shown that avens plants can adapt to gradual salinization by mobilizing stressinducible protective mechanisms (accumulation of proline and spermine) and by activating constitutive enzyme systems (SOD and peroxidase). © 2007 Pleiades Publishing, Ltd

Possible contribution of blast spores to the oxidative burst in the infection droplet on rice leaf

The infection-induced overproduction of reactive oxygen species (ROS) in resistant plants is usually ascribed to the host. Here we tested the possible contribution of the parasite, the rice blast fungus to ROS production. Droplets of spore suspensions or water were kept on rice leaves or on a plastic. After one day, superoxide radical and hydrogen peroxide were chemically assayed in drop diffusates. Similar measurements were done on diffusates of rice calli submerged in spore suspension or water. Negligible amounts of ROS were found in diffusates of plant tissues treated with water. In contrast, diffusates from tissues treated with spore suspensions had appreciable levels of ROS, usually higher in incompatible combinations than in compatible ones. However, diffusates of spores incubated on plastic produced ROS to an extent comparable to those of infected tissues. In diffusates of spores, O2 - was found after their germination, and H2O2 was found after appressorium formation. Various fungal strains differed in ROS production. The results suggest that spores of the blast inoculum may contribute significantly to ROS production on rice leaves, at least, at early stages of the disease. This might be a factor of incompatibility suppressing a parasite and/or inducing defense responses of a host. © 2007 Akadémiai Kiadó, Budapest

Inducible and constitutive mechanisms of salt stress resistance in Geum urbanum L.

The avens (Geum urbanum L.) seedlings were grown for 6 weeks until the expansion of five to six leaves and then exposed to salinity shock (300 mM NaCl in the nutrient medium) or to a gradual (within 4 days) increase in NaCl concentration from 100 to 400 mM. The dynamics of stress-dependent accumulation of Na+, Cl-, proline, and polyamines in leaves and roots was measured, together with activities of antioxidant enzymes, namely, superoxide dismutase (SOD) and guaiacol-dependent peroxidase occurring in soluble, ionically bound, and covalently bound forms. It is shown that avens plants can adapt to gradual salinization by mobilizing stressinducible protective mechanisms (accumulation of proline and spermine) and by activating constitutive enzyme systems (SOD and peroxidase). © 2007 Pleiades Publishing, Ltd