Cytological Applications of the Vacuolization Phenomenon as a Means of Determining Saline Cytotoxicity

Salt stress induces cytotoxicity at the cellular level, influencing the vacuolization process, disrupting mitotic division, and thus inhibiting plant growth. The results for a range of species used in agriculture have shown that high soil salt levels affect germination, chlorophyl content and yield. In this study, an experiment was carried out in the laboratory using NaCl concentration treatments of 0, 100, 125 and 150 mM on sunflower seeds of the inbred line HA-89 obtained from the USDA gene bank. For the experiment, the seeds were germinated in a salt solution and analyzed cytologically by calculating the mitotic index, chromosomal aberration index, provacuolar index and vacuolization index. Following our cytological studies, we observed that the vacuolization phenomenon was caused by salt stress and progressively accentuated by the salt concentration levels and exposure times. The formation of vacuolized cells is due to the fusion of provacuoles, which contributes to a uniform or non-uniform distribution of genetic material around them. According to our results, the vacuolization index showed high values depending on the NaCl concentration and stress exposure time. Similarly, high salt concentrations significantly decreased the mitotic index and increased the chromosomal aberration index. The effect of salt stress causes cell vacuolization, a decrease in the mitotic index and an increase in the number of chromosomal aberrations in meristematic tissues, inhibiting growth and development and consequently leading to a reduction in productivity per unit area.