Contrarily to chronic stresses, acute (i.e., fast and dramatic) changes in environmental factors like temperature, radiation, concentration of toxic substances, or pathogen attack often lead to DNA damage. Some of the stress factors are genotoxic, i.e., they damage the DNA via physical interactions or via interference with DNA replication/repair machinery. However, cytotoxic factors, i.e., those that do not directly damage the DNA, can lead to secondary genotoxic effects either via the induction of the production of reactive oxygen, carbon, or nitrogen species, or via the activation of programmed cell death and related endonucleases. The extent of this damage, as well as the ability of the cell to repair it, represent a significant part of plant stress responses. Information about DNA damage is important for physiological studies as it helps to understand the complex adaptive responses of plants and even to predict the outcome of the plant’s exposure to acute stress. Single cell gel electrophoresis (Comet assay) provides a convenient and relatively inexpensive tool to evaluate DNA strand breaks in the different organs of higher plants, as well as in unicellular algae. Comet assays are widely used in ecotoxicology and biomonitoring applications; however, they are still relatively rarely used in physiological studies. In this review, we provide an overview of the basic principles and of useful variations of the protocols of Comet assays, as well as of their use in plant studies, in order to encourage plant physiologists to include this tool in the analysis of plant stress responses.

Self-fertility is an economically valuable trait, which allows the genetic diversity of plants in the natural environment to be maintained. The key mechanisms underlying this phenomenon have been extensively studied by the methods of breeding and genetics. However, there is a lack of knowledge in the fi eld of biochemistry concerning the eff ects of various chemical substances on the self-fertility of plants. Although there exist hypotheses about the role of fl avonoids in pollination, their infl uence on the mechanism of self-incompatibility remains unclear for many crops. In this research, we analyse the spectral characteristics of pistil extracts from cultivars of domestic plum (Prunus domestica L.) and common cherry (Prunus cerasus L.), which diff er in self-fertility, and evaluate the content of fl avonoids in pollen. The results showed diff erences in the content of chemical substances between self-fertile and self-incompatible varieties of cherry and plum, which can be further used to study self-compatibility factors in these crops. Future studies will analyze the substances contained in reproductive organs by high-performance liquid chromatography (HPLC) to determine the self-fertility factor of domestic plum and common cherry.