BIO203 - Introductory Plant Morphology and Physiology

Plants are primary producers Vascular plants: diversity from common building blocks Modular, reiterative development (repeating same theme over and over again to get structure) Stems and roots = indeterminate growth Flowers + dicot leaves = determinate growth Organ system Shoot Root system Flowers Organs Lateral roots Stems Leaves Systems (root and shoot) Gene expression and identity Anatomy Physical characteristics Major non reproductive tissues Vascular plants - Simple tissues Parenchyma Th

Biological conversion of inorganic state to organic state C-fixation - byproduct of O Outer membrane of chloroplast - site of C fixation Photosynthesis Conversion of C from CO2 to organic C(Ch2O) using light as source for E Light must be captured by pigment Chlorophyll - photosynthetic pigment Chlorophyll a and b Carotenoids in chlorophyll also absorb light Chloroplasts Chlorophyll associates with thylakoids (grana) (inner membrane region of chloroplast) Stroma - liquid matrix between grana Th

Survive, Grow, Reproduce and Disperse Survive Biotic stresses Herbivores Pest and disease Competition and toxins Abiotic stresses Climate extremes, water-logging, salinity, drought Grow Acquire and make what it needs Support itself Reproduce Sexual and asexual Disperse Seeds, pollen and vegetative The Requirements of Growth Water Usually from soil CHONPS Ions Carbon Co2 from atmosphere NPS +ions Direct from soil N-fixing bacteria Help from fungi Distribute appropriately and assemble componen

Cohesion-Tension Theory Water moves through plants in xylem As water evaporates more water is drawn up tube because of cohesiveness of water molecules Protecting system When leaves shed xylem is sealed at leaf scar Water remains in trunk Protective layer contains suberin Root pressure Does not account for movement of water Cannot maintain column of water Too slow Some plants don't have root pressure Capillary action Doesn't account for water column or flow rate DOESN'T move water Xylem Xylem el

Nitrogen is Essential N atom can form up to 3 covalent bonds Relatively electronegative Forms polar bonds with H (weaker + easier to separate) N2=>78% of atmosphere LIMITING NUTRIENT Only take up + use N in certain forms Triple bond in N2 - stable but inaccessible to plants Only certain bacteria can break bond N-H + N-O bonds need less E to break Available N NH3, NH - ammonia, ammonium NH4 - usable form that can be taken up by plants NO2,NO3 - nitrite, nitrate = usable form that can be taken up

Plant Chemical Defenses Protect plants High E, complex organic molecules from inorganic substrates using E from sunlight Including reserves of storage molecules Herbivores ( insects, nematodes) / pathogens (fungi, bacterial + viral) Worldwide pre-harvest crop losses Insects Disease Weeds Post harvest losses include Worms + insects feeding on seeds/storage organs Fungal + bacterial attack HUMAN USE FOR CHEMICAL DEFENSE Drugs Pesticides, poinson, Flavors Pigment/dyes Perfume The Defenses Plants

Reproduction Clonal asexual Offspring with identical copies of parent genes Resources from parent = rapid colonization Stable environment = well adapted Pando trembling giant = example (hasn't flowered in a long time) Sexual Genetically different from parents May yield progeny that are more fit in changing conditions Sexual versus Asexual Asexual Apomixis Seeds without sex Gamete and duplicate zygote without sex Sexual reproduction Flowering plant - sporophyte life

Sessile Organisms Behaviour not an option Moving not an option Outside-In signal Transduction Cascades External signal Cold, water stree, pathogen attack, light quality, day length Signal perceived/sensed at cell surface Signal transmitted across the membrane Signal transmitted across the cytoplasm to nucleus Inside nucleus signal interacts transcription factors to turn genes ON/OFF/UP/DOWN Signal Transduction Cascades A series of molecular switches to communicate from cell surface to a group

Two Major Trophic Conditions in Plants Autotrophic Able to synthesize in nutritive substances Requires from inorganic substances in its environment Heterotrophic Only partially able/ completely unable to synthesize nutritive substances Requires from inorganic substances in its environment Parasitic Haustorium makes plant a parasite!!! Two major groups Parasites true parasitic plants Attached to host through haustorium Sucker like swelling on root/stem of host Makes direct physical connection o