Purpose. High temperature is one of the biggest abiotic stress challenges for agriculture. The aim this study was to investigate the influence of high temperatures (+38°C, +41°C, +45°C) and these temperature in combination with nitric oxide (NO) donor or scavenger on microtubule organization in living plant cells using A. thaliana (GFP-MAP4) line.

Methods. Light microscopy, сonfocal laser scanning microscopy, methods of statistical analysis.

Results. It has been found that 100 µM SNP stimulates formation of root hairs and their active growth, whereas 100 µM cPTIO treatment leads to cell swelling in transition and elongation zones of primary roots and induction of primordial formation of root hairs. Exposure of roots at +38°C did not cause visible changes in microtubule organization of cells, they only changed their orientation. Reorganization of microtubules occurred after exposure to temperatures +41°С and +45°С: from singly disorganized microtubules to partially and completely depolymerization microtubules in some cells. The exogenous NO donor (100 µM SNP) favors to microtubules network reorganization, while both high temperatures and NO scavenger (100 µM cPTIO) increase its randomization and fragmentation.

Conclusions. The obtained results testify the existence of a functional relationship between changes in the intracellular NO content and the organization of microtubules after high temperature treatment of plant cells. The obtained results allow us to conclude that microtubules are important intermediates in the realization of high temperature effects in plant cells, and NO is involved in cell response to heat stress by signaling through these cytoskeletal structures.