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Plants Unit by Mind Map: Plants Unit

1. Reproduction

1.1. Sexual

1.1.1. Seedless plants Non-Vascular - dominant gametophyte plant Vascular - dominant sporophyte plant -unprotected zygote, embryo, and gametophyte

1.1.2. Seed Plants - protected embryo and zygote Gymnosperms - unprotected seeds develop on upper surface of reproductive structures - single fertilization Xylem consists of cells called TRACHEIDS Angiosperms - protected seeds develop within ovary wall - double fertlization Xylem consists of TRACHEIDS and VESSEL elements Life Cycle

1.2. Asexual

1.2.1. Natural Propagation - growth from roots, stems or leaves

1.2.2. Artificial Propagation Splitting - split plant into 2 or more; each piece contains roots & shoots Grafting - shoot or root part is cut and joined to vascular combium - helps repair damaged trees, quicken fruit production Cutting Leaf Cutting Stem Cutting Root Cutting Layering Simple Layering Air Layering Culturing - cell or small piece of tissue is placed in a sterile nutrient medium - promotes shoot and root growth as tiny plantlet develops

2. Organs

2.1. Roots

2.1.1. Root Diagram Epidermis - maximize surface area that absorbs water Cortex - transports substances between vascular tissue and epidermis Endodermis - surrounded by waterproof band that controls absorption of water & minerals Vascular bundles - arrangement of bundles (depends on whether MONOCOT or DICOT)

2.2. Leaves

2.2.1. Leaf Diagram - flat lead blade is attached directly to the stem or via a petiole Veins - made up of vascular tissue

2.2.2. Lead Diagram (Inside) Epidermal cell - produce a waxy cuticle to prevent evaporation Palisade mesophyll cells - made up of parenchyma cells that perform photosynthesis Spongy mesophyll cells - made up of parenchyma cells loosely packed to allow gases to flow between them

2.3. Stems

2.3.1. - provide support for leaves, flowers, and seeds

2.3.2. Herbaceous - flexible

2.3.3. Bark - hard, woody - contain tissue from XYLEM, PHLOEM, cork, and tough outer coating

2.4. Flower

2.4.1. - angiosperm sexual reproduction involves flower organs

2.4.2. Flower Diagram Sepals - protect flower bud Petals - attract pollinators Stamens - male reproductive system Pistils - female reproductive system

3. Vascular Plant Body

3.1. Plant Tissues

3.1.1. Meristematic tissue - areas where new cells are produced by Mitosis

3.1.2. Dermal tissue - outer layers of cells that form a protective covering

3.1.3. Ground tissue - multi functional tissue inside a plant

3.1.4. Vascular tissue - internal system of tubes that run throughout the stems - connects roots & leaves Xylem - transports water, minerals, and other substances from roots to leaves Phloem - transports sugars to where needed, often from leaves to roots for storage Pressure Flow Model - hypothesizes how sucrose moves from a source Two types of cells: SIEVE TUBE elements and COMPANION cells

3.2. Plant Cells

3.2.1. Parenchyma cells - flexible, think-walled spherical cells found throughout plant

3.2.2. Collenchyma cells - often elongated, occur in long strands or cylinders - provide support

3.2.3. Sclerenchyma cells Sclerites - short with an irregular shape - distributed randomly Fibre cells - needle shaped - form tough, elastic tissue stacked end-to-end

3.2.4. - typical plant cells have structures animal cells do not (i.e. cell wall, chloroplasts, large central vacuole)

4. Growth & Development

4.1. - act as chemical signals between cells and tissues

4.2. Hormones

4.2.1. - regulate differentiation of plant cells, growth, and response

4.2.2. Stimulatory Hormones Auxins - can stimulate cell division, cell elongation, regulate cell expansion Cytokinins - stimulate cell division, prevent aging of leaves Gibberellins - stimulate cell elongation and seed germination

4.2.3. Inhibitory Hormones Ethylene - promotes fruit ripening Abscisic Acid - induces and maintains seed dormancy, inhibits shoot growth, closes stomata

4.3. Responses

4.3.1. Tropic Response - growth responses to external stimulation - from one direction in environment

4.3.2. Nastic Response - a movement of the plant that is reversible, repeatable - does NOT include growth

4.3.3. Phototropism - growth response to light produced by unequal distribution of AUXIN

4.3.4. Gravitropism - a "positive" growth response of the roots downward OR - a "negative" growth response of stems upward

4.3.5. Thigmotropism - a growth response to mechanical stimuli

4.4. Growth Factors

4.4.1. Sunlight

4.4.2. Carbon Dioxide (CO2)

4.4.3. Water

4.4.4. Soil pH - each plant grows best within a NARROW pH range Ex. pine, blueberry, and potatoes thrive in acid soil Ex. lawn grass, beans, pears and lettuce thrive in alkaline soil

4.4.5. Macro & micronutrients Macronutrients - needed in amounts < 1% of a plant's dry weight i.e. Nitrogen, potassium, calcium, magnesium, phosphorus, and sulfur Micronutrients - needed in amounts less than 1% of a plant's dry weight

5. Succession

5.1. Ecological Succession

5.1.1. - change in an ecosystem when one community replaces another

5.1.2. Ecological disturbances - events that change the structure of a biological community - sometimes destroy all actively growing organisms Ex. forest fires, floods, volcanic eruptions, glaciers

5.2. Primary Succession

5.2.1. - establishment of a community in an area AFTER an ecological disturbance has left EXPOSED ROCK that does NOT have topsoil

5.2.2. Pioneer Species LIVERWORTS are often the first species to colonize a barren area BACTERIA, ALGAE, and LICHENS form pioneer community that can survive harsh conditions - early organism die and begin to form soil as pioneer species grow

5.2.3. Area continues to change as larger plants move in

5.2.4. Changes continually occur until a stable CLIMAX COMMUNITY of plants and animals form - remains stable until major disturbance occurs

5.3. Secondary Succession

5.3.1. - recolonization of area AFTER an ecological disturbance that has left soil IN TACT

5.4. Ecosystems with HIGH DIVERSITY are better able to withstand disease, competition from invasive species, and extreme weather events!