Transcript Plant Parts

Plant Structures
Plant Science
Major Plant Parts
• roots
• stems
• leaves
• buds
• flowers
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Functions of Roots
• anchor the plant
• absorb water and minerals
• store manufactured food
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Parts of the Root
• primary root: the single main root
• secondary roots: small branches
that form off the main root
• root hairs: tiny roots that increase
the absorption surface area
• root cap: protects the growing tip
of roots
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Root System Types
1. adventitous roots: grow from the stem
or leaf of a plant (ex. corn stalks have prop
roots)
2. tap root system: root system with one
thick main root (examples: pine trees,
carrots, dandilions)
3. fibrous root system: root system with
many small main roots (examples:
grasses, soybeans, impatiens)
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Functions of Stems
• support the leaves, flowers, and fruit
• conduct water, minerals, and food
• store food and water
• produce new stem tissues
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Parts of the Stem
• 2 types of conductive tissues
– xylem: transports water and
minerals from the roots
– phloem: transports food from the
leaves
• cambium: the layer of dividing cells that
creates the xylem and phloem
– becomes growth rings in trees
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Vascular Bundles
• made up of the xylem and
pholem
• in monocots, they are
scattered
• in dicots, they are in a circle
(or a ring)
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Buds
• contain undeveloped plant structures
• bud scales: protect and cover the bud
• terminal bud: a large bud at the tip of a stem
• lateral buds: grow along the side of stems
• apical meristem: primary growing point of the
stem
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Leaves
• produce food for the plant through photosyntheis
• epidermis: a protective layer of cells on the leaf
• cuticle: a waxy coating that prevents water loss
• stomata: pore-like openings on the underside of the
leaf that allow gas exchange
• guard cells: control the opening and closing of the
stomata
• veins: carry nutrients and products of photosynthesis
(contain the xylem and phloem)
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Mesophyll
• layer of the leaf where photosynthesis takes
place
• made up of two layers:
– palisade layer
– spongy layer
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Function of Flowers
• reproduction (to produce seeds)
• sepals: protect the unopened flower
• calyx: the collection of sepals
• petals: attract pollinators (insects and birds)
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Male Part of the Flower
• as a whole, known as the stamen
• made up of two structures:
1. filament: supports the anther
2. anther: produces pollen
• pollen: contains the male sex cells
• pollination has to occur for seeds
to develop
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Female Part of the Flower
• as a whole, known as the pistil
• made up of three parts:
1. stigma: sticky surface for pollen to
land on
2. style: supports the stigma
3. ovary: contains the female sex cells
• fruit: contains the seeds; develops from
the ovary
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Types of Flowers
• complete flowers: have sepals, petals,
stamen, and pistil
• incomplete flowers: are lacking one of
the four main parts
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Monoecious vs. Dioecious
• monoecious plants: have male and
female flowers on the same plant
• dioecious plants: have male and
female flowers on separate plants
• imperfect flowers: do not have
male and female parts on the
same flower
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Thank you for learning with us!
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