Vegetative Structures of Plants

Vegetative Structures of Plants

Six Main Parts flower fruit leaves stem seed roots

Leaves • Capture light • Exchange gases • Provide a site for photosynthesis • Some leaves store food and water • Some form new plants and provide support

Photosynthesis • A process by which plants combine water and carbon dioxide in the presence of chlorophyll and sunlight and produce carbohydrates and release oxygen • The chemical equation for photosynthesis is: 6CO2 + 6H2O → C6H12O6 + 6O2

Why is photosynthesis important? • Light is the most important source of energy for living things • Photosynthesis converts light into nutrients that can be used by plants and animals

Photosynthesis Reactions • Light Reactions • Produce chemical energy from light • Dark Reactions • Convert carbon dioxide into carbohy6drates

Gas Exchange Process • O2, CO2, and H2O are exchanged through small pores in the leaves called a stomata • Each stomata is surrounded by two guard cells • Guard cells open during the day allowing water to transpire • Guard cells close at night and during dry conditions to prevent water loss

Respiration • Plants, like animals respire 24 hours a day. • During respiration, plants consume oxygen and give off carbon dioxide, just like animals • Roots, stems, and leaves all use oxygen as they grown and breathe out carbon dioxide. • Poor soil drainage causes roots to suffer most from short oxygen supply and possible plant death.

True or False Plants produce more oxygen through photosynthesis than they consume through respirations and growth processes.

Respiration C6H12O6 + 6O2 →6CO2 + 6H2O + ATP • Respiration is a process in which energy is generated in cells • In respiration, glucose (sugar) and oxygen are converted into CO2, H20, and ATP (adenosine triphosphate) • Respiration takes places in the mitochondrion of both plant and animal cells

Parts of the Leaf midrib petiole internode node stem axillarybud margin blade

External Leaf Parts • Petiole • The stalk of the leaf that attaches it to the stem • Midrib • The main vein of vascular tissue • Blade • The photosynthetic site of the leaf

Internal Parts of the leaf • Cuticle • A LAYER OF FATTY SUBSTANCES ON THE OUTSIDE OF THE LEAF THAT PREVENTS WATER FROM ESCAPING • Epidermis (Lower & Upper) • A layer of transparent cells that permit the passage of light to the photosynthetic cells • Parenchyma • The photosynthetic cells of the leaf

Internal Parts of the Leaf • Mesophyll • The middle of the leaf, composed of parenchyma cells • DIVIDED INTO PALISADE MESOPHYLL AND SPONGY MESOPHYLL • Palisade Mesophyll • Column shaped cells near the surface where most of the photosynthesis takes place • Spongy Mesophyll • Irregular shaped cells that underlie the palisade cells

Internal Parts of the Leaf • Veins • Vascular tissue which brings water from the roots and carries away the products of photosynthesis • Stoma • Function in transpiration and gas exchange • Guard Cells • Regulate the opening and closing of the stomata

Stomata • Stomata are openings with the epidermis of the leaf • Functions • To allow air into the leaf • To allow water and oxygen out of the leaf

Monocot vs. Dicot • Monocot • Tap Root • Dicot • Fibrous Root

Roots • absorb water and minerals • anchor the plant • Stores food • Propagation

Taproots • Advantages • Penetrate soil deeper • Obtain water from lower levels • Anchor the plant • Disadvantages • Difficult to remove and harvest plants • Do not stabilize the soil well

Fibrous Roots • Advantages • Shallower, therefore they respond more quickly to fertilization and irrigation • Stabilize the soil better • Disadvantages • Less drought resistant • Tend to get exposed during cultivation

Parts of the Root root hairs secondary root primary root root cap

Root Part Functions • primary root: the thickest part, grows down • secondary roots: not as thick as primary, grow out to the side • root hairs: thin, fine roots that absorb water and nutrients • root cap: on the end, protects and guides the tip

Root Types • Adventitious Roots • Come from stems of leaves instead of another root • Fibrous Roots • Structures in which the primary and lateral roots develop equally so that there is not a definite taproot • Storage Roots • Structures like carrots and sweet potatoes which are used for foot storage

Root Parts • Apical Meristem • region of active cell division; the growing point of the plant • Region of elongation • cells here grow longitudinally which causes the root to grow longer • Region of differentiation • the region of mature primary tissues which is an area of active water and mineral absorption • Xylem • transports water and nutrients upward • Phloem • transports carbohydrates and sugars downward

Stem • Water and mineral transport by capillary action and cohesion to the leaves • Transport food to the roots • Gas exchange • Produce and support new leaves, branches, and flowers

Internal Parts of the Stem • Phloem • Transports sugars and carbohydrates to roots • Xylem • Transports water and nutrients from roots to rest of tree • Cambium • Lateral meristem is the growing part of the stem

Internal Parts of the STem • Pith • Occupies the central area of the stem • Ray • Cortex • Composed of several layers of thick-walled cells and an area of thin-walled parenchyma cells interior to the thick-walled

External Parts of the Stem • Buds • Axillary and terminal • Nodes • Internodes

Flowers • where reproduction takes place • flowers contain male and female parts • becomes the fruit and seeds

Fruit • helps seeds spread • birds and animals eat the seeds or carry off the fruit • some seeds cling to fur and hair

Seeds • become the new plant • are spread by birds, animals, wind, and water

Parts of the Flower anther stigma style petal pollen filament pistil ovary stamen

Flower Part Functions • sepals: outer section; protects developing flower • petals: attract insects for pollination • pistil: female part of the flower • stigma • style • ovary • stamen: male part of the flower • anther • filament

Vegetative Structures of Plants