Stress temperature and soil drought effects on amino acid composition in winter wheat

The effect of shortterm high (40 °C, 2 h) and positive low (4 °C, 2 h) temperatures, as well as simulated moderate soil drought, on the total free amino acid and proline contents is studied under controlled conditions on organs of 14dayold Triticum aestivum L. plants, the cultivar Podolyanka. The contents of free amino acids and proline are found to be higher in shoots of control plants and are, respectively, 18.29 mg/g and 0.85 mg/g of dry weight. Under simulated moderate soil drought conditions, the free amino acids and proline contents increase in shoots by 17 % and 71 %, respectively, while in the roots by 50 % and 61 %. During a shortterm hyperthermia, the increases in free amino acid and proline content in shoots by 12 and 47 %, respectively, and in roots by 30 % and 23 %, respectively, are also observed. The response to a shortterm hyperthermia was less pronounced. The involvement of free amino acids and proline in developing the resistance to abiotic stressors in winter wheat is discussed.У контрольованих умовах досліджено вплив короткотривалої високої (40 °C, 2 год) і позитивної низької (4 °C, 2 год) температур та помірної ґрунтової посухи на загальний вміст вільних амінокислот і проліну в органах 14-добових рослин Triticum aestivum L. сорту Подолянка. Встановлено, що вміст вільних амінокислот і проліну був вище у пагонах контрольних рослин і становив відповідно 18,29 та 0,85 мг/г маси сухої речовини. За умов модельованої помірної грунтової посухи вміст вільних амінокислот і проліну підвищився у пагонах відповідно на 17 та 71 %, тоді як у коренях — на 50 та 61 %. У разі короткотривалої гіпотермії також зафіксовано зростання вмісту вільних амінокислот і проліну у пагонах відповідно на 12 та 47 %, а в коренях — на 30 та 23 %. Реакція на короткотривалу гіпертермію була менш виразною. Обговорюється участь вільних амінокислот і проліну у набутті стійкості озимої пшениці до абіотичних стресорів.В контролируемых условиях исследовано влияние кратковременной высокой (40 °C, 2 ч) и положительной низкой (4 °C, 2 ч) температур и умеренной почвенной засухи на общее содержание свободных аминокислот и пролина в органах 14-суточных растений Triticum aesti vum L. сорта Подолянка. Установлено, что содержание свободных аминокислот и пролина было выше в побегах контрольных растений и составляло соответственно 18,29 и 0,85 мг/г массы сухого вещества. В условиях умеренной почвенной засухи содержание свободных аминокислот и пролина повысилось в побегах соответственно на 17 и 71 %, тогда как в корнях — на 50 и 61 %. При кратковременной гипотермии также зафиксирован рост содержания свободных аминокислот и пролина в побегах соответственно на 12 и 47 %, а в корнях — на 30 и 23 %. Реакция на кратковременную гипертермию была менее выраженной. Обсуждается участие свободных аминокислот и пролина в приобретении устойчивости озимой пшеницы к абиотическим стрессорам

Effects of exogenous bacterial quorum sensing signal molecule (messenger) N-hexanoyl- L-homoserine lactone (C₆-HSL) on morpho logical and physiological responses of winter wheat under simulated acid rain

This research aims to investigate the influence of foliar treatment by bacterial quorum sensing signal molecule/messenger N-hexanoyl-L-homoserine lactone (C₆-HSL, 100 ng/ml) on morphological and functional characteristics of Triticum aestivum L. cv. Yatran 60 leaves under simulated acid rain (SAR). Acid rain is one of the most dangerous abiotic stressor, which negatively affects the plant growth and development. It changes the permeability and photochemical activity of membranes, leads to the disruption of a chloroplast ultrastructure, stomata system functioning, reduces CO₂ photofixation. Using the scanning electron microscopy, we identified that, after the foliar treatment by C₆-HSL, the thickness of the leaf cell wall along with the cuticle layer in 20-day-old plants increased by 15 %. Under SAR condition, the plants have suffered the disruption of the cuticular wax layer and uneven wax plates on the epidermis surface, whereas the plants treated with C₆-HSL showed only a partial cracking of the cuticular wax layer, slight disruption of wax plates, and formation of a wax shell. The C₆-HSL-treated plants showed the normal functioning of stomata guard cells and the stabilization in the content of photosynthetic pigments. The protective effect of the foliar treatment with C₆-HSL solution in winter wheat plants under SAR and perspective of its using for the induction of stress resistance has been discussed.Досліджено вплив фоліарної обробки водним розчином сигнальної молекули-медіатора бактеріального походження N-гексаноїл-L-гомосеринлактону (C₆-ГГЛ, 100 нг/мл) на структурно-функціональні характеристики Triticum aestivum L. сорту Ятрань 60 за умов дії модельованого кислотного дощу (МКД). Кислотні дощі належать до найнебезпечніших абіотичних стресорів, які негативно впливають на ріст і розвиток рослин. Наслідком кислотного дощу є зміна проникності мембран, порушення в ультраструктурі хлоропластів, функціонуванні продихової системи, зниження фотофіксації CO₂ і фотохімічної активності. Методом сканувальної електронної мікроскопії встановлено, що товщина клітинної стінки разом із шаром кутикули у 20-добових рослин, оброблених C₆-ГГЛ, збільшилась на 15 %. Під дією МКД у рослин руйнувався шар кутикулярного воску і нерівнокраї воскові пластинки на поверхні епідермісу, тоді як у рослин, що були оброблені C₆-ГГЛ, спостерігалося лише часткове розтріскування шару кутикулярного воску, незначне руйнування воскових пластинок і формування воскових кірок. У рослин, оброблених C₆-ГГЛ, зафіксоване нормальне функціонування замикаючих клітин продихів і стабілізація у вмісті фотосинтетичних пігментів. Обговорюється захисний ефект фоліарної обробки розчином C₆-ГГЛ рослин озимої пшениці в умовах МКД та перспективи використання цієї речовини для підвищення стресостійкості

Peculiarities of the Growth and Photosynthetic Pigments Content in Algaeculture of Acutodesmus dimorphus (Tupin) P.M. Tsarenko under Salt and Acetate Stresses

The objective of this research was to investigate the effect of salt (NaCl) and acetate (NaC2H3O2) stresses on the pattern of biomass accumulation and photosynthetic pigments content in algae culture of the freshwater green alga Acutodesmus dimorphus (Turpin) P.M. Tsarenko IBASU-A 251. We demonstrated that sodium chloride introduced in a culture medium at various concentrations caused a gradual reduction of the microalga biomass whose maximum was recorded at the salt concentration of 1.5%. Addition of sodium acetate at the same concentrations led, on the contrary, to a sharp (more than two times) decrease of A. dimorphus biomass. On the 18th day of culturing under salt stress conditions the chlorophyll a content decreased 1.5-2.5 times, the chlorophyll b content – 1.3-1.7 times, while the carotenoids quantity increased 1.2-1.6 times. Under acetate stress conditions the chlorophyll a content decreased 2-3 times, that of chlorophyll b – 1.7 – 1.8 times whereas the carotenoids quantity increased within the range of 1.4-1.8 times. Increase in chemical stressors concentrations involved some reduction of the chlorophylls а/b ratio and total chlorophylls а+b content, and at the same time, the ratio carotenoids/a+b increased. Sodium acetate appeared to be a more powerful inducer of carotinogenesis than sodium chloride. The highest quantity of carotenoids was registered at 1% and 1.5% concentrations of NaC2H3O2 in the culture medium and 0.75% concentration of NaCl. The results obtained enable to regard Acutodesmus dimorphus (Turpin) P.M. Tsarenko IBASU-A 251 as an active carotenoids producer to be later applied in studies of hypersynthesis of individual classes of this pigment

Adaptive strategy of halophytic plants Polygonum maritimum and Euphorbia paralias

The leaf surface microstructure, pigments spectrum, phytohormones content, and lipids composition of halophytes with various metabolic and physiological strategies of adaptation to salinity of Polygonum maritimum L. and Euphorbia paralias L. grown under natural conditions on dunes of the Pomorie Lake (Bulgaria) are compared. P. maritimum stomata are located on the leaf both sides below the cuticle level, whereas, in E. рaralias, stomata are present only on the abaxial side, and they are surrounded with hump-shaped cuticle constructions. A high amount of carotenoids (as compared with chlorophylls) in P. maritimum leaves indicates that these pigments have a light-collecting function and could transfer an additional energy to chlorophylls. In leaves of E. paralias and P. maritimum, free abscisic acid and conjugated indole-3-acetic acid prevailed. The inactive cytokinins (cis-zeatin and zeatin-O-glucoside) dominated in E. paralias leaves, whereas P. maritimum leaves contained a significant quantity of isopentenyl-type cytokinins. The presence of a large amount of saturated fatty acids provides a decrease of membrane permeability and better resistance against soil salinity. It is concluded that the ecological strategy of halophytes involves the complex of structural and functional adaptations and determines a successful existence under salinity conditions.Проведено порівняння мікроструктури листкової поверхні, пігментного спектра, вмісту фітогормонів і складу ліпідів у галофітів з різною метаболічною і фізіологічною стратегіями адаптації до засолення Polygonum maritimum L. та Euphorbia paralias L., які зростали у природних умовах на дюнах Поморійського озера (Болгарія). У P. maritimum продихи знаходяться по обидва боки листка нижче рівня кутикули, тоді як у E. paralias — лише на абаксіальному боці й оточені складками кутикули. Значна кількість каротиноїдів (порівняно з хлорофілами) у листках P. maritimum указує на те, що ці пігменти виконують світлозбиральну функцію і можуть передавати додаткову енергію на хлорофіли. У листках E. paralias і P. maritimum переважають вільна абсцизова кислота і кон'югована індоліл-3-оцтова кислота. Неактивні цитокініни (цисзеатин і зеатин-О-глюкозид) домінують у листках E. paralias, тоді як у листках P. maritimum міститься значна кількість ізопентенільних форм цитокінінів. Наявність великої концентрації насичених жирних кислот забезпечує зменшення проникності мембран і кращу солестійкість. Зроблено висновок, що екологічна стратегія галофітів поєднує комплекс структурних та функціональних пристосувань і визначає успішне існування в умовах засолення.Проведено сравнение микроструктуры листовой поверхности, пигментного спектра, содержания фитогормонов и состава липидов у галофитов с различной метаболической и физиологической стратегиями адаптации к засолению Polygonum maritimum L. и Euphorbia paralias L., произраставших в естественных условиях на дюнах Поморийского озера (Болгария). У P. maritimum устьица находятся по обе стороны листа ниже уровня кутикулы, тогда как у E. paralias — только на абаксиальной стороне и окружены складками кутикулы. Значительное количество каротиноидов (относительно хлорофиллов) в листьях P. maritimum указывает на то, что эти пигменты выполняют светособирающую функцию и могут передавать дополнительную энергию на хлорофиллы. В листьях E. paralias и P. maritimum преобладают свободная абсцизовая кислота и конъюгированная индолил-3-уксусная кислота. Неактивные цитокинины (цис-зеатин и зеатин-О-глюкозид) доминируют в листьях E. paralias, в то время как в листьях P. maritimum содержится значительное количество изопентенильных форм цитокининов. Наличие высокой концентрации насыщенных жирных кислот обеспечивает уменьшение проницаемости мембран и улучшает солеустойчивость. Сделан вывод, что экологическая стратегия галофитов объединяет комплекс структурных и функциональных приспособлений и определяет успешное существование в условиях засоления

The Microstructure Organization and Functional Peculiarities of Euphorbia paralias L. and Polygonum maritimum L. – Halophytic Plants from Dunes of Pomorie Lake (Bulgaria)

The aim of this research was to investigate the leaf surface microstructure, pigments spectrum, hormones status and lipids composition of halophytes Polygonum maritimum L. and Euphorbia paralias L. that grow under natural conditions on the dunes of Pomorie Lake, (Bulgaria). It was shown that the existence in saline and dry soils provided among others adaptive mechanisms by specific microstructure of leaf. The adaxial and abaxial surfaces of P. maritimum leaves are covered with a dense layer of cuticle wax, stomata are located on the leaf both sides below the cuticle level. In E. paralias the cuticle is also well developed on the adaxial surface of leaf laminas. The epidermis of the leaf lower side is covered with a less dense cuticle layer formed by large wax crystals. This plant has stoma pores only on the abaxial side of small leaves below the cuticle level and they are surrounded with hump-shaped cuticle constructions. A high amount of carotenoids (as compared with that of chlorophylls) in P. maritimum leaves indicates that these pigments have a light-collecting function and could transfer an additional energy to chlorophylls. The high performance liquid chromatography method has been used to provide a qualitative and quantitative analysis of hormones. It was shown that in leaves of E. paralias and P. maritimum free abscisic (ABA) and conjugated indole-3-acetic (IAA) acids prevailed. A high level of active ABA is correlated with the salt tolerance and ability to survive and grow in stress conditions. A high level of conjugated form of IAA demonstrated that activity of this hormone is limited. The cytokinins qualitative and quantitative analyses demonstrated that in E. paralias leaves zeatin forms dominated, and the level of inactive cytokinins (cis-zeatin and zeatin-O-glucoside) was much higher than that of active ones (trans-zeatin and zeatin riboside). P. maritinum leaves contained a significant quantity of isopentenyl forms – isopentenyladenine and isopentenyladenosine, and among zeatin forms, zeatin-O-glucoside prevailed. Studies on the fatty acids content showed that in halophytes the salt resistance mechanism is based on the regulation of plasmatic membrane transport function that involves non-saturated fatty acids. The presence of a large amount of saturated fatty acids provides a decrease of membrane permeability and better resistance against soil salinity

Phase Behavior of Aqueous Na-K-Mg-Ca-CI-NO3 Mixtures: Isopiestic Measurements and Thermodynamic Modeling

A comprehensive model has been established for calculating thermodynamic properties of multicomponent aqueous systems containing the Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cl{sup -}, and NO{sub 3}{sup -} ions. The thermodynamic framework is based on a previously developed model for mixed-solvent electrolyte solutions. The framework has been designed to reproduce the properties of salt solutions at temperatures ranging from the freezing point to 300 C and concentrations ranging from infinite dilution to the fused salt limit. The model has been parameterized using a combination of an extensive literature database and new isopiestic measurements for thirteen salt mixtures at 140 C. The measurements have been performed using Oak Ridge National Laboratory's (ORNL) previously designed gravimetric isopiestic apparatus, which makes it possible to detect solid phase precipitation. Water activities are reported for mixtures with a fixed ratio of salts as a function of the total apparent salt mole fraction. The isopiestic measurements reported here simultaneously reflect two fundamental properties of the system, i.e., the activity of water as a function of solution concentration and the occurrence of solid-liquid transitions. The thermodynamic model accurately reproduces the new isopiestic data as well as literature data for binary, ternary and higher-order subsystems. Because of its high accuracy in calculating vapor-liquid and solid-liquid equilibria, the model is suitable for studying deliquescence behavior of multicomponent salt systems

Effect of Temperature on Lipoxygenase Activity in Varieties of Triticum aestivum L. Differing in Resistance to Abiotic Stressors

Effects of high (+400C, 2 h) and low positive (+40C, 2 h) temperatures on lipoxygenase activity in varieties of Triticum aestivum L. differing in their resistance to abiotic stressors have been analyzed. For the first time 9-lipoxygenase activity was identified in the overground part and roots of 14-day-old plants of the three new winter wheat varieties selected in Ukraine. Increase in lipoxygenase activity both in the plant overground and root parts turned out to be a non-specific response to hyperthermia and hypothermia. Intensity of response to a heat stress was significantly higher than that of cold effects. In the overground part of the heat-resistant variety Yatran 60 a short-term hyperthermia caused a fourfold increase in the activity of lipoxygenase with рНопр5.5 and six-fold increase in lipoxygenase activity with рНопт 6.3. The activity of lipoxygenase with рНопр in roots increased one and the half times. The activity of lipoxygenase with рНопт 7.0 in the overground part of the cold-resistant variety Volodarka exposed to hyperthermia increased one and a half times and that of lipoxygenase with рНопт 6.0 – 1.3 times, and in roots the activity of lipoxygenase with рНопт 6.5 increased three time. In the overground part of the ecologically flexible variety Podolyanka exposed to a short-term hyperthermia the activity of lipoxygenase with рНопт 7.5 increased one and the half times, lipoxygenase with рНопт 5,5 – 1.7 times, and in roots the activity of lipoxygenase with рНопт 6,5 – almost two times. The most pronounced response to hyperthermia occurred in the heat-resistant variety Yatran 60. Prospects for use of lipoxygenase as a plant resistance marker as well as possible involvement of lipoxygenase activity in the formation of cell adaptation mechanisms are discussed

Biochemical contents of highbush blueberry fruits grown in the Western Forest-Steppe of Ukraine

Received: October 26th, 2020 ; Accepted: February 2nd, 2021 ; Published: March 3nd, 2021 ; Correspondence: [email protected] study of the physical and consumption qualitative indices of the highbush blueberries (the cultivars ‘Reca’, ‘Elizabeth’ and ‘Bluegold’) in the Western Lisosteppe of Ukraine has shown that the biggest fruit mass was accumulated by the berries of two last mentioned vs (1.54–1.50 g respectively). ‘Bluegold’ has this indicator as the least variable (V = 10.6%). The accumulation of fruit mass of all studied cultivars was facilitated by a moderately humid period of their development in 2018 with a hydrothermal coefficient of 1.1–1.2. The favorable year for the intensive synthesis of the dry matter and soluble solids was 2017 when the precipitation amount did not exceed 44 mm. The biggest number of the mentioned substances during the research period was accumulated by fruits of ‘Reca’ - 17.48 and 13.24%, respectively. It was established that the dry matter content had high level of stability (V = 8.2%), and middle was for soluble solids (V = 19.5%). The amount of monosaccharides from which glucose and fructose were investigated in fruits varied from 6.11 (‘Bluegold’) to 7.85 (‘Reca’), it was slightly lower in ‘Elizabeth’ berries - 7.78%. ‘Bluegold’ fruits were characterized by high stability (B = 9.6%) of the biggest content of titrated acids among the studied cultivars (2.42%). The dry weather with low number of precipitation in 2017 (hydrothermal coefficient 0.3–0.4) was favourable for the accumulation of both the mentioned acids and vitamin C in fruits of highbush blueberries in the period of their formation and growth. The amount of ascorbic acid in fruits in the specified year varied from 20.00 mg 100 g -1 WM (‘Reca’) to 27.00 mg 100 g -1 WM (‘Elizabeth’) with an intermediate value of 22.50 mg 100 g -1 WM (‘Bluegold’). The latest of the mentioned varieties had the most constant index (V = 7.0%). The content of polyphenolic substances was slightly dependent on weather conditions during the period of fruit growth, the coefficients of variation were 6.2% (‘Reca’), 7.0% (‘Elizabeth’) and 5.8% (‘Bluegold’). The fruits of the last mentioned cultivars were characterized with the biggest anthocyanins and chalcones content (68 and 13 mg 100 g -1 WM, respectively). The substantial indirect dependence of the content of the nutritive substances and anthocyanins on the berry mass was revealed in the ‘Reca’ fruits

Drought Stress Effects on Triticum spelta L. Structural and Functional Characteristics

Effects of a soil drought on the growth, microstructure of leaf surface and photosynthetic pigments composition of Triticum spelta L. 14-days-old plants have been studied. It was shown that the root system whose length diminished by 19% and weight - by 48% turned out to be more sensitive to the impact of a 4-day soil drought. On the 23d day after rehabilitation the difference between biometric parameters of control and experiment samples reduced, but a complete recovery of plants did not occur. A microstructural analysis of the amphistomatic leaf lamina revealed the same number of stomata with similar sizes of stomatal pores on the adaxial and abaxial surface. Following the soil drought, some increase in wax density was observed, stomata on the both leaf surfaces remained closed. The pigment complex of 14-days-old plants responded by decreasing the quantity of chlorophyll and carotenoids. On the 23th day after rehabilitation a further decrease in the photosynthetic pigments level was observed. The changes in the ratio of pigments content after stress and peculiarities of microstructure of leaf surface corresponded with drought tolerance of T. spelta. The retention of rather high parameters of the green pigment content immediately after dehydration on the 18th day corresponded to biometric study data demonstrating a stable growth in the plant over ground part