Comparative radiosensitivity of morphometric, physiological and signaling parameters in wheat plants

Under various scenarios accompanied by increased levels of ionizing radiation, an understanding of how the most important plant parameters change at different radiation doses is essential. In this study, we aimed to perform a comparative analysis of morphometric and physiological parameters and electrical signals in plants at different radiation doses in order to test the hypothesis of higher radiosensitivity of signaling processes compared to other plant parameters.

Studies were conducted on 14-15-day-old wheat plants (Triticum aestivum L.). The irradiation doses (accelerated electrons, 3 MeV) for dry seeds were 25, 50, 75, 100, 200, 400 Gy. Photosynthetic activity, pigment composition, and transpiration rates were recorded using PAM fluorimetry, hyperspectral imaging, and infrared imaging, respectively. Signaling processes were assessed using parameters of electrical signals induced by an additional stimulus.

Threshold doses for statistically significant changes in morphometric parameters such as length, area, and weight are 50-75 Gy. For physiological parameters, including photosynthesis (Ф_PSII, NPQ), and transpiration, thresholds are also 50-75 Gy. Electrical signal parameters statistically significant differences compared to the control group even at the lowest dose studied, 25 Gy.

The key result is the discovery that the highest sensitivity to radiation was demonstrated by signals, rather than traditionally measured morphometric and physiological indicators. This discovery is important for solving the problems of space biology, explaining the behavior of plants in areas contaminated with radionuclides, and for the targeted breeding of radioresistant plants.