Role of Changes in Cell Fatty Acids Composition in the Increasing of Frost Resistance of Winter Wheat Suspension Culture

Influences of low temperatures (4 and 8 ° С) on the frost tolerance and fatty acid compositions of cells in a winter wheat suspension culture have been studied. It has been found that treatment of the culture with 4 °C (7 days) did not protect cells from subsequent freezing temperature action (-8 °С, 6 h) and was not accompanied significant changes in the fatty acid composition. On the contrary, the treatment of the culture with the temperature 8 °C (7 days) prevented the death caused by freezing temperature and the content of saturated fatty acids decreased: pentadecanoic acid (by 35,0%), palmitic acid (by 19,9%) and stearic acid (by 65,4%), and the content of α-linolenic acid increased by 94%. That was the cause of the double bond index (DBI) increase by 16%. The role of fatty acids composition changes in the process of increasing frost tolerance in plants are discussed

Changes of Respiration Activities in Cells of Winter Wheat and Sugar Cane Suspension Cultures During Programmed Cell Death Process

Process of cell death in suspension cultures of winter wheat and sugar cane under high (50 °С) and negative (-8 °С) temperature treatment has been studied. It has been shown, that programmed cell death (PCD) process caused by the negative temperature in the culture of winter wheat was noted for slow rate of realization and it was carried out for 10 days. It has been state that rate of cell respiration was significantly higher than in the control culture. At the same time PCD processes induced by the high temperature in the culture of sugar cane and winter wheat and by the negative temperature in the culture of sugar cane realized for 24-48 h and was accompanied by graduate decrease of respiration activities. We can conclude that the main reason of PCD processes realization differences was a different level of respiration metabolism resistance to high and negative temperatures action

Activation of Cell Death in the Sugar Cane Suspension Culture by the Exposure to High Temperature

The process of cell death in a sugar cane suspension culture after exposure to high temperature (45, 50, 55 and 60 °C) during 10 min has been studied. It has been revealed that treatment of cell culture at 50 °C did not cause an immediate cell death, but 50% of the cells were dying for the next 48 h. Exposure of cell culture to more high temperature (55 - 60 °C) caused a massive cell death occurred instantly after treatment. The development of cell death after the treatment at 50 °C was accompanied by the protoplast condensation, increased generation of reactive oxygen species and hyperpolarization of the mitochondrial inner membrane. Obtained results indicate on the active character of the cell death process, induced by the moderate heat shock in sugar cane suspension culture

Biological Effects of Potato Plants Transformation with Glucose Oxidase Gene and their Resistance to Hyperthermia

It is known that regulation of plant tolerance to adverse environmental factors is connected with short term increase of the concentration of endogenous reactive oxygen species (ROS), which are signalling molecules for the induction of protective mechanisms. Introduction and expression of heterologous gox gene, which encodes glucose oxidase enzyme in plant genome, induce constantly higher content of hydrogen peroxide in plant tissues. It is not known how the introduction of native or modified gox gene affects the plant resistance to high-temperature stress, one of the most commonly used model for the study of stress response and thermal tolerance. In this study, we investigated biological effects of transformation and evaluated the resistance to temperature stress of potato plants with altered levels of glucose oxidase expression. Transformation of potato plants by gox gene led to the more early coming out from tuber dormancy of transformed plants and slower growth rate. Transformants containing the glucose oxidase gene were more sensitive to lethal thermal shock (50 °C, 90 min) than the transformant with the empty vector (pBI) or untransformed plants (CK). Pre-heating of plants at 37 °C significantly weakened the damaging effect of lethal thermal shock. This attenuation was more significant in the non-transformed plants