Tag Archives: hyperthermia

Differential impact of the temperature stress and soil drought on lipoxygenase activity in winter rye plants

L. M. Babenko, K. O. Romanenko*, I. V. Kosakivska

M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, Kyiv;
*e-mail: katerynaromanenko4@gmail.com

Received: 5 July 2021; Accepted: 12 November 2021

Lipoxygenase cascade is a source of physiologically active compounds, the presence of which is considered not only as a sign of damage but also as a trigger of adaptive responses to stress. The aim of the study was to determine the effects of short-term (2 h) heat (40°C) and cold (4°C) temperature stress and moderate soil drought on lipoxygenase (LOX) activity in 14-day-old winter rye (Secale cereale L. ‘Boguslavka’) plants. The shoots were found to have both membrane-bound 9-LOX1 and 9-LOX2 and soluble 13-LOX activity, the roots – membrane-bound 9-LOX activity. After heat stress, the activity of 9-LOX1 and 9-LOX2 in the shoots increased by 3 and 2 times, respectively, the activity of 9-LOX in the roots – by 2 times, and 13-LOX activity in the shoots decreased by 1.5 times. After the cold stress, the activity of 9-LOX1 and 9-LOX2 in the shoots raised by almost 1.5 times, the activity of 9-LOX in the roots – by 1.2 times. Moderate soil drought caused enhancement in the activity of both membrane-bound isoforms of 9-LOX in the shoots by 1.5–2 times and in the roots – by 3 times. The established fluctuations indicate that molecular forms of LOX with different localization are differentially involved in the winter rye response to temperature stress and moderate soil drought.

Crassula genus plants response to temperature stress depends on anatomical structure and antioxidant system

N. V. Nuzhyna*, M. M. Gaidarzhy, A. V. Holubenko

ESC “Institute of Biology and Medicine”, Taras Shevchenko National University of Kyiv, Ukraine;
*e-mail: nuzhynan@gmail.com

Received:  09 October 2020; Accepted: 15 May 2020

Plant adaptation to climate conditions of certain territories has emerged within the course of evolution, shows at all organizational levels from morphological-anatomical to biochemical and is embedded into the plant genes. Survival of plants in such conditions as rapid temperature drops and rises in the range of 20 °C or more depends on their biochemical defense system’s ability to quickly respond to such stress, as well as on the plant’s structural features. Therefore, our goal was to analyze changes of biochemical parameters under conditions of abrupt hyperthermia in four species of Crassula Linne genus and to establish the connection between their anatomical and morphological features and the peculiarities of the biochemical reactions. Plants of Crassula brevifolia Harvey, Crassula lanuliginosa Harvey, Crassula muscosa Linne and Сrassula perfoliata var. minor (Haworth) G.D. Rowley species were held in air thermostats at 40 °C and 50 °C for 3 h, the control temperature being 26 °C. Stress response was analyzed by malondialdehyde content, superoxide dismutase and peroxidase activity and pigments content. Additionally, anatomical structure of the leaves was investigated. Antioxidant response to short-term high temperature varied in different species of the Crassula genus by its directionality and intensity, and depended on the anatomical features of the plant. The additional protective mechanisms were involved in the least heat-resistant plants, such as increased carotenoids­ and flavonoids contents. More powerful SOD and peroxidase activities under rapid heating in plants with more effective protection at the anatomical level were showed.

Influence of salicylic and succinic acids on formation of active oxygen forms in wheat coleoptiles

Yu. Ye. Kolupaev, T. O. Yastreb, M. V. Shvidenko, Yu. V. Karpets

V. V. Dokuchaev Kharkiv National Agrarian University, Ukraine;
e-mail: plant_biology@mail.ru

The comparative study of influence of exogenous salicylic (SaA) and succinic (SuA) acids on the production of reactive oxygen species by isolated wheat coleoptiles has been provided. Under the action of both acids the increase of generation of superoxide anion-radical (O2•–) was observed. This increase was partially suppressed by treatment of coleoptiles with inhibitors of peroxidase (salicylhydroxamic acid) and NADP·H-oxidase (imidazole and α-naphthol). The increase of hydrogen peroxide content, activity of peroxidase and superoxide dismutase (SOD) was registered under the influence of SaA and SuA; catalase activity did not change essentially. The treatment of coleoptiles with the indicated acids resulted in the increase of their resistance to abiotic stress (damaging heating, 43±0.1 °С, 10 min). The conclusion is made, that the increase of O2•– generation in wheat coleoptiles under the action of SaA and SuA is related, probably, to the increase of apoplast peroxidase and NADP·H-oxidase activity, and the rise of H2O2 content is related to the growth of SOD activity. These enzymatic systems are involved in the induction of plant cells protective reactions to the hyperthermia.