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Vliv nízké teploty na propustnost buněčných membrán a přežití rostlin
Kubovčíková, Anna
Plants are naturally exposed to low temperatures in nature. During the winter, the temperatures are the lowest and in certain places they even reach very low values. Jasmonic acid plays an important role in the plant's resistance to low temperatures. In the thesis, we have focused on the effect of the PLIP genes that produce precursors of jasmonic acid. The role of the genes in cold resistance in Arabidopsis thaliana was studied after acclimation in different light conditions. The observed parameters in plants acclimated to low temperatures were the parameters of photosynthesis, intactness of cell membranes and survival after exposure to freezing. The results of the experiments proved that the mutation of the PLIP genes cause a decrease in the integrity of the cell membranes when exposed to freezing, and conversely, the ectopically increased expression of the PLIP3 gene results in an increase in plant resistance. Based on ion leakage, we determined LT50 values for each variant, and it was shown that the difference between the most resistant transgenic line plip3 ox and the mutant line in all three PLIP genes is more than 4 °C. Subsequently, a plant survival test after freezing was performed, where it was demonstrated that the LT50 value correlated with plant survival. Chlorophyll fluorescence analysis showed that after acclimation to low temperature, there are no large differences in photosynthetic parameters between individual genotypes with modified PLIP level. The light that was applicated during acclimation had a more pronounced effect on the plants. Plants acclimated at low intensity showed higher values of non-photochemical quenching as well as greater maximum quantum yield of photosystem II. The results prove that the PLIP genes are significantly involved in the resistance of plants to low temperatures.
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