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During their evolution, plants have developed a number of mechanisms to resist biotic and abiotic stressors. Evolution is an endless process, which continues, of course, even today. In the case of crop plants, however, evolution's original contingency is replaced by targeted breeding. This is based on the same natural processes - mutagenesis, hybridization and selection. However, the classical techniques are now significantly complemented by genetic engineering methods. Based on knowledge of the molecular basis of plant stress resistance mechanisms, these processes are subsequently used to obtain new, practically- useful genotypes. The present paper is therefore aimed at explaining the biological effects of drought or salinity from the molecular level to the complex reactions of the whole organism. Subsequently, the paper illustrates various opportunities for using transgenic techniques (gene modifications, GM) for the construction of crops resistant to these stressors, explains their gene background and illustrates, in selected examples, both the history of partial research strategies, their present status and also their prospects. In addition, the paper briefly informs about a new technique of gene editing (GE) based on the mechanisms of natural repair of the plants' own genes. This precise mutagenesis has also found practical, revolutionary, applications both in human gene therapy and in effective "nature-close" breeding and plant protection. [ABSTRACT FROM AUTHOR]

Global climate change is an important and topical issue that the public, and especially the younger generation, should be well acquainted with. However, relatively little attention is paid to this issue in the currently valid biology textbooks and in the Framework Educational Programme (FEP) for Czech grammar schools. It is not beneficial to pass on knowledge about this issue to students only in the form of bare facts that would have to be memorized. On the contrary, it is desirable that pupils themselves actively acquire information on the issue, think about it critically and understand it. Therefore, the aim of this paper is to follow up on the article "Water and Plant Stress" published in issue number 4/2019 of this journal in order to elaborate the given topic in a didactic manner, in the form of nineteen active learning tasks intended primarily for pupils at upper secondary schools. Pupils have to draw upon information from introductory texts, graphs, tables or pictures to solve them correctly and critically think about them and to some extent can apply previously acquired knowledge and experience. Such acquired knowledge can then be applied more convincingly not only at school but also outside of it. The author's solutions are attached to the tasks. The proposed tasks were selected from a set of 30 tasks elaborated on the given topic, which were tentatively tested during pedagogical practice at a grammar school. [ABSTRACT FROM AUTHOR]