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Obtaining Temperature-Resistant Sugar Beet Lines (Beta vulgaris L.)

Kliachenko Oksana, Prysiazhniuk Larysa, Bokiy Olena, Syplyva Natalia, Melnyk Serhii

Ecological Engineering & Environmental Technology

2023

Vol. 24, iss. 1

22--28

This study aimed to investigate the sugar beet genotypes for resistance to hyperthermia and obtain temperatureresistant lines. Nine hybrids and one variety of sugar beet were screened. Cotyledonary leaves and hypocotyls isolated from aseptic seedlings were used for induction of callus and subsequent subcultivation. To create hyperthermic conditions, the callus lines were maintained in thermostats at temperatures of +27 °C, +41 °C, +45 °C, and +47 °C. The effect of high temperatures on the callus tissue was assessed by the specific callus diameter index. The free proline was detected with chromatography. As result of callus tissue exposed to temperatures of +41 °C, 45 °C and 47 °C, on the 9th day of cultivation at high temperatures, significant differences were observed in the size and colouration of the callus tissues. At a moderate temperature (+41 °C), the growth of the callus mass was somewhat higher compared to the control. At a high temperature (+45 °C), the intensity of the growth processes decreased and ceased at a temperature of +47 °C. After transfer and subsequent cultivation of callus tissues in regeneration medium MSR – Murashige and Skoog medium for regeneration, all genotypes demonstrated the formation of morphological structures that initiated the formation of regenerated plants. The number of regenerated plants largely fluctuated over temperatures and almost was not related to genotypes. Consequently, the temperature-resistant lines obtained as a result of extreme heat treatment, differ in terms of the specific diameter of callus.

Trends in monthly, seasonal, and annual fluctuations in flood peaks for the upper Dniester River

Melnyk Serhii, Loboda Nataliia

Meteorology Hydrology and Water Management. Research and Operational Applications

2020

Vol. 8, Iss. 2

28--36

The importance of the Dniester River in the socio-economic life of Moldova and Ukraine necessitates research into the main trends in the river’s runoff characteristics and dynamics, especially now, when climate change is significantly altering the water regime of rivers. This paper presents a solution for the problems of identifying the main trends in daily maximum river discharge by seasons and months for various calculation intervals. Two calculation intervals (1981-1998; 1999-2015) with different climatic conditions are considered. Each interval corresponds to one complete cycle of river water discharge. Climatic conditions as a result of global warming are changing differently in the mountains and on the plain, therefore, the identification of trends was performed separately for the alpine and lowland parts of the Dniester River annual runoff formation zone. The search for statistically significant trends was carried out by means of the MannKendall test. The analysis of the frequency of maximum discharges (peak over threshold; POT3) was performed for selected rivers in the studied area. The earlier period (1981-1998) showed statistically significant positive trends for both alpine and lowland rivers of the Upper Dniester. The later period (1999-2015) differed, exhibiting exclusively negative significant trends in daily peaks both by months and by seasons. This result indicates a persistent tendency toward decreasing maximum water runoff for all rivers of the Upper Dniester catchment. There were no statistically significant trends in the frequency of floods.