Plants

1
Plants

• Chapters 22-25

FYI GREEN ALGAE is believed by most scientists
to be the ancient ancestor of land plants
What three characteristics do they share in
common?
2
What is a PLANT?

• Members of Kingdom Plantae
• Multicellular eukaryotes
• Cell walls made of cellulose
• Undergo photosynthesis (autotrophic)
• Include trees, shrubs, grasses, mosses, and ferns

3
Plant Requirements

• Sunlight (energy to carry out photosynthesis)
• Water (must have water in all cells important
  for photosynthesis)
• Movement of Water and Nutrients (water and
  minerals taken up through roots/ food made in
  leaves)
• Minerals (needed for growth and development)
• Gas Exchange (require CO2,carbon dioxide, for
  photosynthesis and require O2 oxygen for
  respiration)

4
Problems plants had adapting to life on land

• 1) Preventing WATER LOSS.
• 2) Obtaining enough FOOD and WATER.
• 3) Dealing with WIND and WEATHER.
• 4) Exposed GAMETES and EMBRYOS.

5

• FYI The first plants are believed to have been
  spore producing plants, MOSSES AND FERNS

FERN
MOSS
GREEN ALGAE
6
Early Plants

• Origins
• Evolved from plant-like protists (algae)
• Many plants evolved from water-dependent plants
  that only lived in watery environments

7

• MOSSES (BYROPHYTA)
• FERNS (PTEROPHYTA) will always be
• found near water or in very moist areas,
• because the sperm, found in spores,
• need a film of water in order to
• Attach to the egg, which also
• are found in spores

8
Spores from mosses and ferns contain SPERM OR
EGG
Section 22-2
MEIOSIS
Antheridia sperm Archegonia egg
FERTILIZATION
Figure 2211  The Life Cycle of a Moss
Go to Section
9
FYI Plants are sometimes grouped together based
upon common characteristics

• 1st) Are they SPORE producing or SEED producing?
• 2nd) Are they VASCULAR OR NON-VASCULAR
• VASCULAR (plants that have vascular tissues that
  transport water up and food down their stems).
• NON-VASCULAR (plants do not have vascular
  tissues OR stems).

10
Simple vs. Vascular Complex Plants

• The plant kingdom include complex plants,
  vascular plants, and simple plants that are not
  vascular.
• Vascular plants have vascular tissue tubes that
  carry water and nutrients throughout the plant.
  The simple plants do not have vascular tissue.
  Simple plants are unusually small.

11

• FYI MOSSES are
• the only nonvascular
• plants on earth!

12
Kingdom Plantae

• There are 4 Divisions (aka, phyla) you need to
  know
• 1) BRYOPHYA (aka, MOSSES)
• 2) PTEROPHYTA (aka, FERNS)
• 3) CONIFEROPHYTA (aka, CONIFERS or GYMNOSPERMS)
• 4) ANTHOPHYTA (aka, FLOWERING PLANTS or
  ANGIOSPERMS)

13
4 Phylums
Section 22-1

• 1. Mosses and their relatives
• 2. Ferns and their relatives
• 3. Cone-bearing plants
• 4. Flowering plants

Go to Section
Figure 226  A Cladogram of Plant Groups
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Bryophytes - Mosses

• Most common
• Grow in swamps, near streams and in tropical rain
  forests
• Tolerate low temps
• Miniature evergreen trees ? small carpet like
  filaments

15
Bryophytes - Mosses

• Depend on water for reproduction
• Lack vascular tissue
• Draw up water via osmosis
• Include the following phyla
• mosses, liverworts, and hornworts

16
Bryophyte Structure
Capsule
Sporophyte
Stalk
Stem-like structure
Gametophyte
Leaf-like structure
17
Life Cycle of Bryophytes

• The gametophyte is dominant and the
  photosynthetic stage
• Must have water for fertilization to occur (sperm
  must swim to egg)

18

• Mosses make up part of the bryophytes
  (nonvascular plants. They live in moist shady
  places and need little soil. There are separate
  male and female moss plants.)
• The Zygote generation in mosses grows on top of
  the female plant. It produces spores from a
  capsule at the top.
• Mosses are important to the soil. They make new
  soil by breaking down rock. Sphagnum moss is an
  important fertilizer and sometimes used as fuel.

19
Sphagnum Moss

• Can accumulate to form peat moss that can be
  used in gardening.
• It helps the soil retain water.
• Peat also has a low pH, so it can add to the
  soils acidity.
• Plants like azaleas, grow well only if they are
  in this type of soil.

20
Liverworts

• Liverworts are flat, scaly
• bryophytes. The liverwort alternation of
  generations is similar to that of mosses.
  Sometimes they reproduce by a combination of
  budding and regeneration.
• Named due to the shape of the leaves
• Produce sexually and asexually

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Hornworts

• Found in damp soil
• Look like liverworts but smaller

22
Basic characteristics of plants

• 1) MULTICELLULAR
• 2) EUKARYOTIC (HAVE ORGANELLES)
• 3) AUTOTROPHS
• 4) CELL WALLS CONTAIN CELLULOSE

23
Plants have organs

• 1) Leaves- trap SUNLIGHT for PHOTOSYNTHESIS Food
  (i.e., glucose) is made here and transported to
  the rest of the plant.
• 2) Stems- support UPRIGHT growth, transport WATER
  up from the roots through a special kind of
  vascular tissue called XYLEM, and FOOD down to
  the rest of the plant through another kind of
  vascular tissue called PHLOEM

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Gas in.
CO2
O2
and
H2Og
. Gases OUT
25
FYI the evolution of vascular tissue allowed
plants to grow big and tall and live away from
WATER.

• 3) Roots- ANCHOR the plant to the
• ground, ABSORB water and minerals,
• and sometimes STORE excess sugar as
• starch.
• 4) Flowers- REPRODUCTION organs for angiosperms
• 5) Cones- REPRODUCTIVE organs for gymnosperms.

26
Nitrogen Fixation

• FYI Plants need NITROGEN to live, but cannot
  use the N2(g) in the atmosphere as it is. So,
  they have evolved a symbiotic relationship With
• BACTERIA which fix
• the nitrogen for plants and
• turn it into nitrates
• through a process called NITRIFICATION.

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Environmental factors that affect plants

• 1) Light (aka, PHOTOTROPISM)
• 2) Gravity (aka, GRAVITROPISM)
• 3) Winter - Plants become inactive (aka, DORMANT)
• FYI POSITIVE tropism means that the plant grows
  toward or with the environmental factor.
  NEGATIVE tropism means that the plant grows away
  from the environmental factor.

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• END OF FIRST TWO PAGES OF PLANT BOOK

29
The Plant Life Cycle

• Characterized by alternation of generations
• One generation is gametophyte (haploid)
• Other is sporophyte (diploid)

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Alternation of Generations
Haploid (N)
MEIOSIS
Diploid (2N)
Gametophyte Plant (N)
Sporophyte Plant (2N)
FERTILIZATION
31
Tracheophytes

• Tracheophytes include all of the vascular plants.
  The tracheophytes include ferns and seed plants.
  Ferns and seed plant have vascular tissue and
  roots, stems, and leaves.

32
What are Vascular Plants? Plants with Vascular
Tissue

• Vascular Tissue ? move fluids through the plant
  body
• 1. Xylem carries water from the root to the
  other parts of the plant
• 2. Phloem transports
• nutrients and carbohydrates
• made by photosynthesis

33
Seedless Vascular Plants

• Have roots, leaves, and stems
• Reproduce by Spores
• INCLUDES
• Club Mosses- small plants that live
• in moist woodlands
• Horsetails have wispy leaves
• Ferns thrive in areas with little light and
  much water

34
Seed Plants

• Seed plants are different form all simple plants,
  algae, mosses, and ferns because they make seeds.
  A seed contains a tiny new plant and food
  supply. There are two kinds of seed plants.
• Reproduce without water

35

• Please hand out 2nd part of notes

36
Seed plants

• Two groups
• 1. Gymnosperms
• Bear seeds on surface of cones
• 2. Angiosperms
• Flowering plants (seeds deep inside for
  protection)

37
Pollen

• Male gametophyte
• Carried by wind, insects, birds, small animals,
  and bats
• Transfer of pollen to the female gametophyte is
  called pollination

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GymnospermsCone-Bearing Plants Conifers

• Cone-bearing gymnosperms are conifers.
• Conifers have needles for leaves
• and are called evergreens because they stay
  green with needles all their life.
• Conifers produce spores in both male and female
  cones.

39
Examples of Gymnosperms

• Gnetophytes
• Cycads
• Ginkgoes
• Conifers

40
Angiosperms

• Unique reproductive organs (flowers)
• Flowers contain ovaries (protect the seed)
• Fruit (tissue that surrounds the seed)
• Very diverse group which includes
• monocots and dicots
• Woody and herbacious plants
• Annuals, biennials, perennials

41
Monocots and Dicots

• Named for number of seed leaves (cotyledons) in
  the plant embryo
• Monocots ? one seed leaf
• Ex. Corn, wheat, lilies, orchids, and palms
• Dicots ? two seed leaf
• Ex. Roses, clover, tomatoes, oaks, and daisies

42
Woody and Herbaceous Plants

• Based on the stems
• Woody plants include ? trees, shrubs, and vines
• Herbaceous plants include ? dandelions, zinnias,
  petunias, and sunflowers

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Annuals, Biennials, and Perennials

• Annuals ? life cycle in one year
• Ex. Pansies
• Biennials ? complete life cycle in two years
• Ex. Foxglove
• Perennials ? live for more than two years
• Ex. Azaleas

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Chapter 23 Roots, Stems and Leaves
Monocot
Dicot
Single cotyledon
Seed
Two cotyledon
Branch veins
Parallel veins
Leaves
parts in multiples 0f 3
Flower
Parts in multiples of 4 or 5
Vascular bundles arranged in a ring
Vascular bundles scattered throughout the stem
stems
Fibrous Roots
Roots
Taproot
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Structure of Seed Plants

• Three principal structures
• 1. Roots
• Anchor plant Absorb water and nutrients
• 2. Stems
• Supports plant body Transports nutrients
• 3. Leaves
• Part where photosynthesis occurs
• Pores in leaves control gas exchange

47
Tissue Systems

• Four types
• 1. Dermal Tissue
• Outer most layer
• Like the SKIN
• 2. Vascular Tissue
• Transport of water and minerals
• Like the BLOOD STREAM
• 3. Ground Tissue
• Everything else
• 4. Meristematic Tissue
• At the tips of shoots and roots

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Leaves

• Designed for absorbing light and carrying out
  photosynthesis
• Two types of leaves
• 1. Simple (one leaf)
• 2. Compound (many leaflets)

50
Leaf Functions

• Photosynthesis
• mesophyll layer is composed of many chloroplasts
• Palisade mesophyll absorb the light
• Spongy mesophyll air spaces that connect the
  stomata with outside
• Stomata pore-like openings on the underside of
  a leaf to absorb carbon dioxide
• Transpiration
• Loss of water from a plant through leaves
• Gas Exchange
• Stomata remains open enough just to allow
  photosynthesis to take place

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Chapter 24Reproduction in Seed Plants
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With Cones and Flowers

• Alternation of Generations
• Gymnosperms
• Reproduction occurs in cones
• Two types
• 1. Pollen Cones produce male gametophytes
  called pollen grains
• 2. Seed Cones- produce female gametophytes
  (ovules)

54
Flowers

• Composed of 4 kinds of specialized leaves
• 1. Sepals
• Outermost
• Green and look like little leaves
• Enclose bud before it opens
• 2. Petals
• Often brightly colored
• Attract insects and pollinators
• Also called sterile leaves because no
  reproductive part

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Flowers (continued)

• 3. Stamens
• Male parts
• Consist of the anther (where meiosis takes place)
  and filament (supports anther)
• 4. Pistil (aka carpel)
• Inner floral part
• Each carpel has a broad base forming the ovary

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Fruits

• As angiosperms mature, the ovary walls will
  thicken to form a fruit
• ex. Apples
• May be fleshy, tough, may have a pit (where seed
  is attached to ovary)

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Chapter 25 Plant Responses and Adaptations
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25-1 Plant Growth

• Plant cells send signals to one another to
  indicate
• when to divide,
• when not to divide,
• and when to develop into a new kind of cell.

60
Meristems

• Regions of tissue that can produce cells to later
  develop into specialized tissues (Found at
  growing stems and roots)

61
Plant Hormones

• Plant hormones control the plants growth and
  responses to environmental conditions.
• Auxins substances regulate cell growth at the
  tip of plant by stimulating cell elongation.

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Figure 25-2 Hormone Action on Plants
Section 25-1
Hormone-producing cells
Movement of hormone
Target cells
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Phototrophism

• tendency of a plant to grow towards light
• auxins build up on the shaded side of the plant

64
Gravitropism

• tendency of a plant to grow in a direction in
  response to gravity
• Auxins build up on the lower sides of the roots
  and stems
• Stems grow up (cell elongation)
• Roots grow down (inhibit cell growth elongation)

65
Cytokinins

• Produced in growing roots and developing fruits
  and seeds.
• Stimulate cell division, growth of lateral buds,
  and cause dormant seeds to sprout.
• Instead of cell elongation, cells grow thicker.

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Gibberellins -

• Growth promoting substance produced by a fungus
  or the plant
• dramatic increase in size (stems and fruits)

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Ethylene

• In response to auxins fruit tissues release small
  amounts of hormone
• Stimulate fruits to open.

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25-2 Plant Responses

• Tropisms responses of plants to environmental
  stimuli
• Gravitropism response of plant to gravity
• Ex. Shoot of germinating seed to grow out of the
  soil and roots to grow into soil.
• Phototrophism grow toward a light source.
• Thigmotropism responses of plant to touch can
  stunt growth
• Ex. Growth of vines and climbing plants to wrap
  around things.

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Photoperiodism

• Plants respond to periods of light and dark.
• Responsible for timing of seasonal activities
  such as flowering and growth.
• Short-day vs. Long-day Plants Flowering times

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Short-day vs. Long-day Plants Flowering times
Short-Day Plant
Long-Day Plant
Midnight
Noon Long Day
Midnight
Noon Short Day
Midnight
Noon Interrupted Night
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Winter Dormancy

• growth and activity decreases or stops

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25-3 Plant Adaptations
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Aquatic Plants

• Tissues with large air filled spaces for oxygen
  diffusion

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Salt-Tolerant

• Special tissues to pump out salt onto leaf
  surfaces, washed away by Rain

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Desert Plants (Xerophytes)

• Extensive roots, reduced leaves, thick stems
  stores water.

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Nutrition Specialists

• Live in areas with low concentrations of
  nutrients in the soil.
• Ex. Carnivorous plants (Venus Fly Trap)
• Parasites (Mistletoe)

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Epiphytes

• Grow directly on other plants to obtain their
  nutrients Ex. Spanish Moss

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Chemical Defenses

• manufactured by the plant itself to protect it
  from insects.

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Compare/Contrast Table
Section 25-3
Comparing Carnivorous Plants, Epiphytes, and
Parasites
Characteristics Environment Method of obtaining
nutrients Examples
Carnivorous Plants bog leaves that trap and
digest insects pitcher plant, sundew, Venus
flytrap
Epiphytes host plant gather moisture from
rainfall and produce their own food Spanish moss,
orchid
Parasites host plant extract moisture and
nutrients from host plant dodder, mistletoe
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Plant Quiz Review

• Label each part
• Petal
• Sepal
• Stamen
• Anther
• Filament
• Pistil
• Stigma
• Style
• Ovary

E
A
F
B
G
C
H
D
I