Plant Kingdom Part IIAdvanced Plants

Advanced Plants are generally plants that have evolved within the last 300 million

years, utilize seeds for reproduction and are economically important for mankind for

needed food and materials.

Primary Plant Structuresa. Rootsb. Stemsc. Leaves

Roots

• Are underground structures that draw water and minerals into the plant by osmotic pressure.

• May be tap roots, fibrous roots or support roots.• Are made up of a center core of vascular tissue called

the cortex and a thin outer surface called the epidermis.

• The epidermis may also contain finer root hairs for increased surface area

• Stores starch for a food reserve• Is an active area for plant growth• Area of Primary growth toward gravity and water

sources. (geo-trophism and hydro-trophism)

Stems

• • Connect the root system of the plant to the leaves of the plant• Contain two types of conducting tissue.

o Xylem- moves water and dissolved minerals upward through the plant.o Phloem- moves organic compounds (glucose) fom the leaves

downward toward the roots.• May be Herbaceous or Woody depending on the amount of

cellulose in the stem.• Vascular patterns may be ringed or random bundles.• Stem growth is more outward called secondary growth. • In woody stems, the active vascular tissue is just under the bark

and outside the dense cambium of the inner plant.• Ends of the stems are also areas for primary growth and tend

grow toward light (photo-trophism)

Leaves

• The specialized structure where most of a plant’s Photosynthesis occurs.

• Leaves come in many shapes, sizes and may be evergreen or deciduous.

• Generally leaves are broad to capture a maximum amount of sunlight.

• The cross section of a leaf reveals the following structures

a) Upper epidermis- cuticle- waxy outer covering of the leaf

b) Mesophyll- cells that are long and column like cells called the palisade layer and shorter cells called

the spongy layer. Through out the Mesophyll are veins that are made up of xylem and phloem cells.

Chloroplasts in the Mesophyll contain chlorophyll, a photosynthetic pigment.

c) Lower epidermis- where stoma and guard cells regulate gas and water exchange with the outside

air.

Advanced Plant Reproduction•In advanced Plants, reproduction adapted to a drier environment where water wasn’t as plentiful.•Pollen replaced Sperm as the male gamete•Alternation of Generation ended in favor of a large Sporophyte that produced Spores, that then quickly undergo Meiosis to produce Pollen and Egg.•In Gymnosperms, the fertilized zygote (seed embryo ) is housed in a female cone. •In Angiosperms the fertilized egg (seed embryo) is housed in dry or fleshy fruit.

Life Cycle of the Gymnosperms

Life Cycle of a Typical Angiosperm

Structure of a Typical Flower

Plant Pigments• Chlorophyll- includes types• A-green found in land plants only• B-green found in land plants and algae• C-green found in algae and protists like diatoms

• Carotenes- orange and yellow but are accessory pigments b/c they send energy to green chlorophyll first. Includes fucoxanthin (brown)

• Phycobilins-includes cyanin (blue) and erythrin (red)

Plant Hormones

• 5 Primary Plant hormones to know• Auxin- cell elongation• Gibberellins- cell elongation• Cytokinin- cell division• Abscisic Acid- growth inhibitor• Ethylene- fruit ripening

Trophism- the tendency for a plant to grow toward a stimulus

• Phototropism- toward light

• Geotropism (Gravitism)- toward gravity

• Thigmotropism- toward solid objects

• Hydrotropism- toward water

Monocots and Dicots• Within Angiosperms, there are two divisions of Plants,

Monocots and Dicots.

• Monocotyledons are plants that include grasses, lillies, orchids, yuccas and other blade leaf plants. The name comes from the single leaf produced by the plant embryo

• Dicotyledons are plants that include most vegetable plants and broad leaf fruit and nut trees. The name comes from the two seed leaves produced by the plant embryo

Other Monocot and Dicot characteristics

Plant Taxonomy (seedless nonvascular)

• Bryophyta-

• Hepatophyta-

• Anthocerophyta-

Plant Taxonomy (seedless vascular)

• Pterophyta-

• Lycophyta-

• Sphenophyta-

• Psilophyta-

Plant Taxonomy (Seeds in cones and vascular)

• Coniferophyta-

• Cycadophyta-

• Ginkgophyta-

• Gnetophyta-

Plant Taxonomy (seeds from flowers and vascular)

• Anthrophyta (Angiosperms)

o Monocotyledons-

o Dicotyledons-