Fundamentals of Biology
Lesson 13
Angiosperms, Flowers, Leaves , Vascular Tissue
I. Angiosperms.
A. General information.
1. "Seed in a vessel" -
ovary surrounds the seed.
2. Flowers and fruits.
3. 95% of all seed plants, 80% of all
plant species.
B. Chief characteristics
1. Flowers that aid in pollen
dispersal, often quite visibly attractive.
2. Fruits that protect the seed and
aid in its dispersal.
3. Rapid growth, esp. of reproductive
structures.
4. Rapid rate of photosynthesis,
broad light-catching leaves.
C. Monocots and Dicots.
|
Monocots |
Dicots |
Number of cotyledons |
1 |
2 |
Flower part groupings |
3's |
4's & 5's |
Leaf venation |
Parallel |
Netted |
Vascular tissue |
Scattered bundles;
Usually no cambium |
Ring of bundles or continuous ring;
Cambium in woody |
Root system |
Fibrous roots |
Taproot |
Forms |
Mostly herbs |
Herbs, shrubs, trees |
II. Flower Structure.
A. Sepal and petal.
B. Stamen.
1. Anther.
2. Filament.
3. Pollen.
C. Carpel.
1. Stigma.
2. Style.
3. Ovary.
III. Angiosperm reproduction.
A. Sporophyte: the mature plant, including the flower.
1. Produces male and female haploid
structures.
B. Gametophyte.
1. Anther produces pollen grains (microgametophyte).
2. Pollen grains fall on the stigma
and grow down into the ovary.
3. Ovary produces a megagametophyte.
C. Seed production.
1. The pollen tube fertilizes the
megagametophyte, producing a diploid zygote.
2. The pollen tube also fertilizes
surrounding cells which become the endosperm - a nutrient store that nourishes
the developing embryo.
3. The zygote grows into the embryo.
4. The seed is formed around the
embryo and the endosperm.
IV. Leaf Structure.
A. Simple and compound.
B. Parts.
1. Petiole.
2. Midrib.
3. Blade.
C. Cross section.
1. Cuticle.
2. Upper epidermis.
3. Palisade mesophyll.
4. Spongy mesophyll.
5. Lower epidermis.
6. Cuticle.
D. Stomata and guard cells.
V. Vascular Tissue
A. Xylem.
1. Transports water and nutrients up
from the roots to the leaves.
2. Two types of cells, both dead when
mature.
a. Tracheids
- pits in the cell walls to conduct water more efficiently.
b.
Vessel cells - cell walls have been digested at the ends, leaving a tube.
3. Theories of the mechanism of
conduction.
a. Root
pressure.
b. Capillary
action.
c.
Transpiration.
B. Phloem.
1. Transports food from leaves to
roots.
2. Two types of cells, both must be
alive to perform.
a. Sieve
cells.
i. Conduct food through many pores at the end of the cell.
ii. Contain cytoplasm, but no nuclei.
b. Companion
cells contain nuclei.
3. Material moves by osmotic flow.
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