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Photomorphogenesis

Class at Faculty of Science |
MB130P21

Syllabus

Photomorphogenesis - definition. Light - character and composition of solar radiation, ab-sorption of light, excitation, deexcitation.

Arteficial light sources. Photomorphogenic photoreceptors - photosensors.

Sensors of red light - phytochromes - characterization. Properties of phytochrome proteins.

Chromophore - character and biosyn-thesis. Photoreversibility . phototransformation, photoreversion, dark reversion.

Estimation of phytochrome. Control of phytochrome level - protein biosynthesis, degradation.

Phytochromes in the plant kingdom. Phytochrome localisation in plant.

Phytochrome local-isation in the cell - phytochrome transfer to the nucleus. Modes of phytochrome action - VLFR, LFR, HIR.

Mechanisms of phytochrome action, known components of signal trans-duction in the cytoplasm. Genes controlled by light signals and properties of their promotors (LRE ).

Mechanisms of phytochrome action in the nucleus - known DNA interacting com-ponents. Components without any direct DNA interaction, COP1, COP9 signalosome.

Blue light sensors - cryptochromes, phototropin, RPT2. Cryptochrome proteins, properties and relationship to photolyases.

Chromophores. Cryptochromes in the plant kingdom.

Cryp-tochrome localisation in plant and cell. Interaction with phytochromes.

Mechanisms of action. Phototropin - the protein, localisation in the cell, chromophores.

Mechanism of action. Blue light receptor systém in fungi - mycochrome.

Photomorphogenic responses in plants - red light and blue light signal relationship. Effects of UV-radiation.

Photomorphogenesis in cyanobacteria, fungi, slime molds and algae. Light and seed germination.

Deetiolation - etioplast transformation, chlorophyll biosynthesis, development of photosynthetic apparatus. biosynthesis and role of carotenoids, xanthophyll cycle. Thylakoid membrane lipid biosynthesis.

Light and flavonoid biosynthesis. Growth and structural changes during deetiolation. Light and growth of green plants.

Light conditions in different types of environment. Plant growth in canopy, R/FR ratio and plant growth responses.

Light conditions within plant. Rhythmicity in plants - definitions, time measuring.

Changes of photoperiod during the year. Discovery of photoperiodism.

Definitions - photoperiod, critical photoperiod, short day and long day plants and derived categories. Absolute and quantitative demand of photoperiod.

Photoperiodic control of flowering, photoperiodic flower induction. Genetic aspects, practical use of photoperiodism.

Rhythmicity and photoperiodical induction of flowering. Photoperi-odism and dormancy, bud dormancy, storage organ formation.

Light and plant movements - phototropisms, phototaxes and photonastic movements. Light and opening and closure of stomata.

Annotation

Lectures deal with plant adaptation to light conditions of environment. Lectures inform about solar radiation sensors - phytochromes, cryptochromes, UV-sensor and photropin, about growth, developmental, metabolic responses of plant to light quality and quantity and about light signal transduction.

Lectures deal with adaptation to changes in photoperiod during year - photoperiodism and the effect of light pollution and its effect on plat communities.