Perspective Chapter: Plant Abiotic Stress Factors – Current Challenges of Last Decades and Future Threats

All life forms, from the simplest to the most complicated, are inevitably exposed to altering environmental conditions in their natural habitats, gradually depending on their lifestyle. Unfavorable alterations drive these life forms either to avoidance or defense as a response. Most of the essential plant growth-promoting environmental factors can also turn out to be stress factors. Water as the most abundant molecule of all living cells can cause stress either in deficit as drought or in excess as waterlogging. Temperature is important for the maintenance of all biomolecules and metabolic reactions; hence, both low and high temperatures are deleterious stress factors. Even though the plants were exposed to various volcanic origin, heavy metals and pollutants and evolved molecular mechanisms during millions year of evolution, rapid urbanization, and industrial progress introduce brand new pollutants as micro- and nanoplastics as well as nanoparticles to plants like never before. This chapter defines and evaluates major environmental abiotic stress factors with an emphasis on the latest knowledge of molecular effects on plants. In addition, novel stress factors, such as nanoparticles and microplastics, are looked over as hot prospects for the future of plant abiotic stress areas.