3/9/16 Botany (Plants)

Plants Adapting to Land Vascular vs. Nonvascular Structural and Physiological Adaptations Response to Environment

Plantae Characteristics : multi-cellular photosynthetic cell wall of cellulose Autotrophic (producer)

Adaptations : Trait to help a species survive Adaptations had to include ways to: Prevent drying out Absorb nutrients Reproduce without water

Structural Adaptations Cuticle: Waxy covering, prevents water loss Leaves: photosynthesis (stomata) Roots: absorbs water and minerals, – anchors plant – may also store starch

Structural Adaptations Stems : transports food, water, and minerals – supports plant – some store food – some carry out photosynthesis

Evolution of Plants Evolution: green algae - waxy cuticle - vascular tissue - roots - seeds

Vascular vs. Non-vascular Plants Non-vascular – Have No real leaves, stems, roots Vascular – Have leaves, roots, stems and vascular tissue (xylem and phloem)

Non-Vascular Small Live close to soil (moist) Need water for reproduction

Evolution of Plants

Bryophytes Mosses Most common Have cuticle & stomata

Mosses

Hepaticophyta Liverworts Mats of flat “leaves” No leaves or stomata

Liverworts

Anthocerophyta Hornworts Have stomata and cuticle

Hornworts

Non- Seed Plants produce spores can be vascular or non- vascular – all non-vascular are non-seeded – whisk ferns, horse tails, club mosses, and ferns are vascular non-seeded

Horse Tails Arthrophyta

Ferns Pterophyta

Seed Plants produce seeds more effective than spores – cones, flowers, pollen and seeds are adaptations that allow fertilization without water all are vascular

Reproduction Structural Adaptations for Reproduction: – Cones – Flowers – Pollen – Seeds

Cones and Flowers Cones - the seed bearing structure of non-flowering plants Flowers - the seed bearing structure of flowering plants – Do not need water to fertilize

Pollen and Seeds Pollen – The male sex cell (sperm) is carried in a pollen grain Seed – A structure that carries the embryo of a plant – Do not need water to fertilize

Functions of Seeds Protection -from drying out and disease Nourishment –contain cotyledons (seed leaf) that supply organic nutrients

Functions of Seeds Dispersal –wind, water, and animals Delayed growth – do not germinate until conditions are favorable

Gymnosperms any vascular plant that reproduces by means of an exposed seed, or ovule, as opposed to an angiosperm, or flowering plant, whose seeds are enclosed by mature ovaries, or fruits. ovuleangiosperm Sometimes referred to as “naked seed” plants.

Gymnosperms Examples Cycads - look like palm trees, but they're not. Palm trees are angiosperms, as they produce fruit and flowers. Cycads have male and female cones that grow on different trees.

Gymnosperms Examples Conifers -These include things like pines, firs, spruces, yews, junipers, cedars, cypress, and redwoods. Many conifers are evergreen, that is they retain their leaves in winter. The leaves are needle- shaped to conserve moisture

Angiosperms (Flowering Plants) Most seed plants are flowering plants These seeds develop inside a fruit Angiosperms are most successful because of the fruits and flowers (Evolution)

Flowers Reproductive structure of the plant Male and Female gametophytes (egg and sperm) develop in the flower Meiosis in plants happens in the Ovule

Pistil

Flowers attractive colors and odors attract pollinators size and shape help pollination to occur self-pollination can also occur

Fruits structures in which seeds develop promote seed dispersal through the digestive track of animals

Diversity of Angiosperms Monocots and Dicots Annuals, Biennials, and Perennials

Monocots one cotyledon (seed leaf) Parallel venation of leaves scattered vascular bundles in stems flower petal in multiples of three

Dicots two cotyledons leaf venation is net-like stem vascular bundle is in a ring flower petals are in multiples of four or five

Types of plant tissue Dermal tissue: – flattened cells, cover plant’s parts – protection – produces waxy cuticle

Vascular Tissue : – transports, food, minerals and water – two types: Xylem Phloem

Vascular Tissue Xylem and Phloem are the conducting tissues of a plant.

Xylem xylem- Water and mineral transport from roots to top parts of the plant. Unidirectional – Only moves one way – UP

Phloem Phloem – Transportation of food and nutrients such as sugar and amino acids from leaves to storage organs and growing parts of plant. Bidirectional – Move up and down the plant stem.

Roots, Stems, Leaves Roots anchor plants absorb water and minerals two types of roots – taproots (carrot) – fibrous roots (grass)

Stems usually above ground supports leaves and flowers have vascular tissue two types: – herbaceous- soft, flexible, green – woody- dense, brown (shrubs and trees)

Leaves function in photosynthesis leaf variation- different shapes and sizes petiole- stalk that holds leaf to stem Stoma of Pea Plant

Veins of Leaves Veins in leaves are used to transport materials for metabolic activities.

Leaf Venation – palmate (netlike)- dicots – pinnate – parallel (monocots)

Types of Leaves – simple- leaf with one blade – compound-blades divided into leaflets

Arrangement – alternate – opposite – whorled

Plant Response respond to hormones that cause growth, fruiting, cell division, and ripening tropisms- response to external stimuli – may be positive (toward the stimuli) – negative (away from the stimuli)

Hormones in Plants Auxin – Stimulates stem growth Cytokinins – Affects root growth, stimulates cell division Gibberellins – Promotes seed and bud germination Abscisic Acid – Inhibits growth, closes stomata, seed dormancy Ethylene – Promotes fruit ripening

Types of Tropism gravitropism- response to gravity (stems and roots); (negative and positive) phototropism- positive, plants grow toward light thigmatropism- response to pressure (Venus flytrap) nastic movement- touch; vines attach to wall – Ex - Venus Flytrap (decrease in turgor pressure

Things to know Auxin distribution will cause plant to grow toward the light Plants on lying on their side will accumulate on one side causing unequal cell growth. Ripening hormones slow down in lower temperatures.

More things to know Plants have specialized cell organelles like cell walls and chloroplasts because they function differently than animal cells. Transpiration is slower in areas with increased humidity. Transpiration flow = root hair  Xylem  Vascular bundle of the leaf  Stoma (plural = Stomata) Mitosis in plants happens in the Meristem

Euglena – Kingdom Protista Moveable autotroph Will move towards the light in order to use photosynthesis for food. Towards the light is Positive Phototropism

Chloroplast

Light Reactions

Light Reactions Continued Light-dependent reaction (LIGHT Reaction) – Energy lost along electron transport chain – Lost energy used to recharge ATP from ADP – NADPH produced from e- transport chain Stores energy until transfer to stroma Plays important role in light-independent reaction – Total byproducts: ATP, NADPH, O 2

Light – Independent Reaction Also called Dark Reaction – Does not require light – Calvin Cycle Occurs in stroma of chloroplast Requires CO 2 Uses ATP and NADPH as fuel to run Makes glucose sugar from CO 2 and Hydrogen

Calvin Cycle

What affects Photosynthesis Rates Light intensity: as light increases, rate of photosynthesis increases Carbon Dioxide: As CO 2 increases, rate of photosynthesis increases Temperature: Temperature Low = Rate of photosynthesis low Temperature Increases = Rate of photosynthesis increases If temperature too hot, rate drops