Plant Structure And Function 6q2i72

PLANT STRUCTURE AND FUNCTION

THE PHYLOGENY OF PLANTS… Charophytes (green algae) Bryophytes (non vascular) Trachoephytes (seedless, vascular)

Gymnosperms (“naked seeds”,vascular) Angiosperms (contained seeds, vascular) Monocots / Dicots

Major Parts of a Plant – Leaves 

Where photosynthesis occurs

– Seeds 

Method of sexual reproduction

– Flower 

Site where reproduction occurs

– Stem 

Transports nutrients and s the plant

– Root 

take in nutrients and anchor plant

The Seed 

Parts of a Seed – Cotyledon

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The first leaves of a plant – Seed Coat

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Outside covering of a seed – Endosperm

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Food storage tissue that nourishes the embryo – Embryo – New plant developed after fertilization

Types of Seeds Monocots – A seed with only one cotyledon – All grasses are monocots – Flower parts in threes – Leaves with parallel primary veins Dicots – A seed with two cotyledons – Flower parts in fours or fives – Leaves with distinct vein network – All broadleaf plants are dicots

Seed Parts Fertilizationzygoteseed (embryo) 

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Plumule- is like a leave in its early development becomes the shoot Hypocotyl- develops into the stem Radicle- Becomes roots

Male Parts of the Flower Stamen- Makes up all male parts

Pollen- Male sex cell, similar to sperm Anther- Sac-like structure on top of the filament Filament- Short stalk that holds the anther

Female Parts of the Flower Pistil- Makes up all female parts Ovules- Female sex cell, similar to the egg Stigma- Sticky part of the system, catches pollen Style-Tube that leads from the stigma to the ovary Ovary- Place where ovule is fertilized by the pollen, Turns into a fruit or seed coat

Primary Growth 

Occurs in apical meristems of plant – (found at tips of stems and roots)

PROBLEM! IF THE CUTICLE BLOCKS WATER, WHAT ELSE IS PREVENTED FROM ENTERING/EXITING THE PLANT?

C O

!! 2

Solution? 

STOMATA! – Tiny pores in epidermis surrounded by two guard cells! – Open during the day! Why?  PS

occurs during the day  Transpiration necessary for cooling

VASCULAR TISSUE 

2 MAJOR TYPES: – XYLEM TISSUE – PHLOEM TISSUE – Found together in VASCULAR BUNDLES – Arise primarily from apical meristem – Arise secondarily from vascular cambium

XYLEM TISSUE CONDUCTS WATER  PROVIDES MECHANICAL  2 TYPES OF XYLEM CELLS: 

– TRACHEIDS: – VESSEL ELEMENTS:

PHLOEM TISSUE CONDUCTS SUGARS  COMPOSED OF TWO CELL TYPES: 

– SIEVE-TUBE – COMPANION CELLS

Sieve tube Form sieve tubes to conduct sugars throughout plant  Lack nuclei, ribosomes, vacuoles, etc. 

Vascular bundle

xylem

Stems 

Transports food, water, and nutrients

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s the leaves and flowers

Parts of the Stem – Xylem 

Water and minerals travel up to other plant parts – Phloem

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Manufactured food travels down to other plant parts – Cambium – Separates xylem and phloem

Types of Root Systems – Fibrous Roots – Easier to transplant 

Short, small, compact roots – Tap Root – Difficult to transplant, since most of the tap root is cut-off

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Tap root is primarily used for storage of food

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In both types, most nutrients and water are absorbed by root hair

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Fibrous Roots – Monocots – Several roots of same size w/ branching

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Roots can be adapted for storage of nutrients: – Example: Carrot (Taproot) Sweet Potato (Fibrous Root)

Plant Processes – Photosynthesis 

Mixes light, water, and carbon dioxide in the presence of chlorophyll to produce sugar and oxygen – Respiration

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Combines sugars and oxygen to give off water and heat – Transpiration – Loss of water through the leaves or stems – Causes wilting when soil is dry

Animal

Water

Wind

Dispersal of Seeds Gravity

Wind

Force

Plant Systems 

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There are 3 main plant systems: Reproductive – this is the flower structure Transport – this is the stem and roots and their xylem and phloem Energy – this is the leaf and other areas of photosynthesis.

Leaf Tissue – What happens where?