Kingdom Plantae

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Kingdom Plantae

• Botany - the study of plants.

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Summary

• All Plants are autotrophs that produce food by
  photosynthesis.
• cell walls composed of cellulose.
• non-motile
• eukaryotic
• multicellular.
• Plants are loosely organized into 4 groups based
  on the presence or absence of vascular tissue and
  seeds.

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Vascular tissue

• Vascular tissue - tissue that transports water
  and sugars throughout an entire plant.
• Plants lacking vascular tissue are called
  bryophytes.
• Plants which have vascular tissue are called
  tracheophytes.

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• Vascular tissue is made up of xylem and phloem
  cells.
• Xylem carries water and minerals to the leaves.
• Phloem transports food synthesized in leaves
  throughout the plant.

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• Land plants have a cuticle and stomata (singular
  stoma).
• Cuticle is a noncellular layer secreted by
  epidermal cells to protect cells from drying out.
• Stomata are pores in the epidermis of a plant, to
  permit the exchange of gases between the plant
  and the air around it.

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Life Cycles of Plants

• An alternating cycle of both a haploid gamete
  stage (Gametophyte) and a diploid spore stage
  (Sporophyte). This cycle is known as the
  Alternation of Generations
• Sporophytes produce haploid spores through
  meiosis (division of the chromosome) that can
  grow without any fertilization.
• The spore grows into a gametophyte that produce
  male and female gametes that can fuse and develop
  into another sporophyte

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Alternation of Generations
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Bryophytes

• Non-vascular plants
• Mosses, liverworts, and hornworts

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BRYOPHYTES (Phylum Bryophyta)

• Nonvascular land plants use diffusion and osmosis
  to transport materials throughout the plant.
• small in size they grow close to the ground in
  moist, shaded areas.
• lack true roots, stems and leaves, they are
  anchored to the ground by structures called
  rhizoids.
• Bryophytes are the only plants to have a life
  cycle that is predominantly in the haploid
  gametophyte stage. They produce male and female
  gametes that require water to allow the sperm to
  swim to an egg creating a zygote that will
  develop into a new sporophyte.

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Tracheophytes

• Vascular plants
• Ferns, gymnosperms, and angiosperms
• Sporophyte dominated life cycle
• Seedless (spore bearing) Seeded Plants

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TRACHEOPHYTES (Phylum Tracheophyta)

• Tracheophytes have vascular tissues (xylem
  phloem). That allow plants to grow much taller,
  by being able to draw water up through their
  bodies.
• Means of reproduction
• spores for club mosses, horsetails, and ferns.
• seeds for flowering plants (angiosperms) and
  conifers (gymnosperms).

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Seedless Vascular Plants (Ferns)

• Reproduce by spores, and have an alternation of
  generations that is dominated by the sporophyte
  life cycle. (opposite non-vascular)
• Ferns are the most diverse seedless vascular
  plant. (dinner to decorations)
• Life Cycle see page 173
• Write a list of ALL key words that come out of
  the life cycle of the fern. Underline any
  terminology you have encountered before and note
  where you have used the word before.

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Seed Producing Tracheophytes

• There are two main groupings for seed producing
  plants
• Gymnosperms (conifers and relatives)- cone
  bearing plants that have seeds exposed on their
  cones scales.
• Angiosperms (flowering plants) plants with
  protected reproductive structures that have
  adaptations to increase the likelihood of
  reproduction.

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What is a Seed?

• A seed is a multi-cellular structure containing
  an embryo and a food source.
• The embryo consists of a
• An immature root
• An immature shoot
• One or two seed leaves
• Seeds have hard protective structures and can
  survive without water for years. They can also be
  carried great distances by animals etc

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Gymnosperms

• Have all normal plant characteristics
• Have seeds on their cone scales
• Most are coniferous trees (pines, spruce, etc)

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Survival Strategies

• Reproduction with male pollen and pollen tubes
  removes the need for moisture.
• Protective bark prevents water loss
• Shape helps prevent snow/ice damage, and
  increases the area for photosynthesis to occur.
• Needle-like leaves have thick cuticle and sunken
  stomata to prevent water loss.
• Do not loose their needles so photosynthesis can
  begin earlier and they do not need extra
  nutrients to grow new leaves.

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Angiosperms (flowering plants)

• Plants that protect their seeds within the body
  of a fruit.
• Make up ¾s of all plants, including
• Trees, shrubs, herbs, grasses, water plants, etc
• Divided into two large classes based on the
  number of seed leaves (cotyledons)
• Monocots one seed leaf (grasses, lilies)
• Dicots two seed leaves (roses, peas, maple
  trees)

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Diversity and success of the Angiosperms

• The angiosperms are the most diverse plant group.
  
• They can self-pollinate (clone) or
  cross-pollinate with another plant.
• Also, this diversity is due to a variety of other
  factors, such as

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1) Presence of specialized structures

• Plants attract animal pollinators with colour and
  a supply of food (often nectar) to carry pollen
  from plant to plant
• Different flower colors, smells, and shapes
  attract different pollinators.
• Eg. Bees cant see red, so they are often on
  blue or yellow flowers.
• Flies are attracted to flowers such as
  stink-cabbage.
• Many insects see UV spectrum. (See Fig. 6.14,
  pg. 177)

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2) Seeds are protected

• Flowers are sporophytes that do not produce
  spores.
• The pollen grains, and the eggs are all that
  remain of the gametophyte generation.
• The embryo is enclosed in hard tissue to form a
  seed. The seed case enables the embryonic plant
  to survive adverse weather conditions such as
  drought, hot or arid periods and cold.

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3) Function of the fruit in seed dispersal

• Some seeds in fruits are easily dispersed by wind
  and by water. Eg. Coconut
• Some fruits are eaten and dispersed by animals.
  The seed resist digestion and will pass intact in
  an animals feces to germinate in a new spot.

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4) The presence of specialized tissues

• Some plants possess special tissues and
  behaviours to help them survive heat, cold, and
  droughts.
• Eg. small leaf hairs and sunken stomata help to
  reduce water loss.

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Now make like a tree and leave!!