Plants and environmental stresses 1400-235RaSCS

The aim of our lecture is to present the mechanism of plant response to environmental stress factors. The mechanisms of plant response are described at the level of whole organism, at the level of plant cell functioning and at molecular level. During the lecture the following problems will be explained:
1. Abiotic and biotic stress factors. Phases of plant response to stress. Adaptation and acclimatization. Mechanisms of adaptation to stress factors. Receptors and signal transduction. The role of phytohormones in response to stress. Programmed cell death under stress conditions.
2. Oxidative stress. The sources of reactive oxygen species (ROS) in plant cells. Enzymatic and non-enzymatic antioxidative systems in plant cells. The impairment of cell compounds by ROS. The prevention of ROS production due to mitochondrial alternative oxidase activity. The role of ROS in signalling. Mutants with modified capacity of antioxidative systems.
3. Water deficit. Plant-water relationship. The soil-plant-atmosphere continuum. Poikilo- and homoiohydric plants. Structural and functional disturbances during water stress. Secondary stresses. Induction of resistance: signal perception, ABA-dependent and nondependent pathways. Morphological and osmotic adjustments of plant cells. The role of plant hormones. Osmoprotection. Synthesis of LEA (late embryogenesis abundant), osmotin and aquaporin proteins. Consequences of temporary and permanent water deficit for farming.
4. Anaerobiosis: hypoxia and anoxia. The up-regulation of fermentative pathways. Anaerobic stress proteins. Accumulation of organic acids under hypoxic conditions. The engagement of cytochrome pathway, AOX and type II dehydrogenases in respiration under limited oxygen availability. The role of non-symbiotic hemoglobins in regulation of NO concentration under anerobiosis. Production of ROS under post-hypoxic and post-anoxic conditions.
5. Temperature - cold, freezing and heat. Signals reception and transduction. Steps of cold acclimation - structural and metabolic changes, osmotic adjustments. Consequences of water freezing. Freeze-induced dehydration. Freezing resistance - evergreen and deciduous plants, structural and metabolic adjustments. Deacclimation. Role of cell wall in plant cell protection. Ice-nucleation and ice-structuring proteins. Heat: effects and protections. Heat stress proteins. Secondary stresses.
6. Mineral nutrition deficiency and ammonium syndrome. Acquiring of mineral compounds in plants. Ion homeostasis in plant cells. The changes in plant metabolism in response to nitrogen and phosphate deficiency, e.g. sugar accumulation, up-regulation of fermentative pathways and mitochondrial respiration. Re-assimilation of ions. Nitrate versus ammonium supply. The influence of ammonium supply on redox homeostasis.
7. Salinity and heavy metals toxicity. The factors determining salinity. Physiological drought. The strategies to avoid salt injury. Proline and betaine synthesis under salt stress. Halophytes. The sequestration and transport of heavy metals. The use of hyperaccumulators in phytoremediation.
8. Radiation: photosynthetically active radiation, UV. Increased ROS production in chloroplasts and photoinhibition under high light stress. The turn-over of D1 protein. The role of photorespiration under high light conditions. The influence of UV radiation on cell components. Up-regulation of phenolic synthesis.
9. Anthropogenic stress. Metabolism of xenobiotics in plants. Emission of air pollutants in Poland. Acid rains. Inhibition of stomatal movements, photosynthesis and growth by polluting gases.
10. Plant-plant interactions. Competition for light and nutrients. Signals in plant-plant interactions. Parasitic plants. Allelopathy.
11. Biotic stresses. The synthesis of cyanogenic glycosides to protect against herbivores. Local and systemic response to pathogens. Hypersensitive response. Involvement of salicylic acid, jasmonic acid, etylene and hydrogen peroxide in systemic response. Gene for gene and non-host interactions. Signalling pathways in response to pathogens.