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Plant Reproduction
Chapter 24

I. Major Groups of Land Plants

A. Moss
B. Ferns
C. Seeded Plants

1. Gymnosperm- uncovered seed plants that are cone bearing (pines)
2. Angiosperms- covered seed plants from flowering plants that produce fruits

II. Alternation of Generation- life cycles of land plants that show an alternation between a haploid gamete producing generation (gametophyte) and a diploid, spore producing (sporophyte) generation

A. Gametophyte- gamete producing by means of mitosis & not meiosis
B. Sporophyte- develops from the zygote & is diploid

1. Spores produced from the sporophyte are haploid
2. Spores produce the gametophyte

III. Life Cycles of Nonseed Plants

A. Ferns- dominant generation is the sporophyte (doesn't have to alternate)
B. Ferns are tracheophytes (plants that contain vascular tissue)

1. Fronds- large leaves from the rhizome
2. Sori- from underneath the fronds, spores are produced & releases (visible in the fall)
3. Prothallus- found in gametophyte generation, a heart shaped structure produced from the spores that contain both an antheridia & archegonia

a. antheridia- male, sperm producer
b. archegonia- female, egg producer

C. Moss- gametophyte generation is dominant

1. contain rhizoids that anchor the plant like roots do
2. antheridia- male, sperm producer
3. archegonia- female, egg producer
4. bryophyte

IV. Life Cycle of Gymnosperms- sporophyte generation is dominant

A. Development of gametes

1. pollen cone- male contain 2 sporangia (spore cases) & produces a male gametophyte- pollen grain
2. seed cone- female 2 sporangia & produces the female gametophyte which produces an archegonium (egg cell)

B. Fertilization & Seed Development

1. pollen cones mature, sporangia burst releasing pollen grains that land on the micropyle of an ovule (egg)
2. pollen tube grows from the pollen grain into the ovule & sperm fertilizes the egg & a zygote (seed) forms

V. Life Cycle of Angiosperms (examples: cherry tree, lily, beans, apples)

A. Flower- reproductive organ

1. pedicel- supports the flower
2. receptacle- top of the pedicel, holds the flower
3. calyx- (circle of sepals) leaf like structures that form a green ring around the base of the flower for protection
4. corolla- (circle of pedals) colorful, attracts insects
5. stamens- male reproductive organ; has 2 parts

a. anther- male gametes (pollen grains) produced here
b. filament- holds the anther

6. pistil- female reproductive organ

a. stigma- top portion of pistil, receives the pollen
b. style- supports the stigma
c. ovary- contains the ovules (females gametes develops into seed) ovary develops into the fruit

B. Essential organs- stamens, pistils
C. Accessory organs- corolla, calyx
D. Pistillate flowers- contain only the pistil, no stamen- female plants
E. Staminate flowers- contain only the stamen, not the pistil- male plants
G. Pollination- transfer of pollen grains from the stamen to the pistil

1. self-pollination in the same plant
2. cross-pollination in different plants
3. Bee pollination of crops 

H. Fertilization (occurs in the ovaries)

1. pollen grains leave the stamen; land on the stigma & germinates
2. pollen tube grows down through the stigma & style and into the ovary
3. enters the ovule through the micropyle
4. pollen grains forms 2 haploid sperm nuclei as it travels down the pollen tube into the ovule; THIS LEADS to DOUBLE FERTILIZATION

a. one sperm fertilizes the egg cell to form 2n sporophyte embryo
b. the other sperm fuses with 2 polar nuclei to form 3n endosperms which is a tissue that stores food for developing embryo

I. Fruits, after fertilization, the ovary ripens, and surrounds the seeds to form into a fruit
J. Seed- ripened ovule (egg)
K. Structure of Seed and Embryo

1. seed coat- covers embryo, and endosperms
2. hilum- scar on outside of the seed where the ovule was attached to the ovary
3. endosperms- food for the seed
4. cotyledons- (monocots, dicots)- modified leaves provide for germinating seed
5. epicotyl- gives rise to the terminal bud, leaves and upper part of the stem
6. hypocotyl- gives rise to the lower part of the stem & in some plants the roots
7. radicle- gives rise to the roots
8. embryo
9. short review of seed structures

L. Seed dispersal- scattering of seeds (wind, touch, water)
M. Germination- seed begins to sprout

1. factors affecting germination

a. temperature, oxygen, nutrients, water supply

N. Dormancy- a resting period before germination

1. What are the major groups of land plants? answer

2. All cells of the gametophyte are... answer

3. Into what generation does the zygote develop? answer

4. Which plant form is diploid? answer

5. A saclike structure where pollen grains are produced is ... answer

6. What is the difference between pollination and fertilization? answer

7. How do fruits aid in the dispersal of the seeds that they contain? answer

8. This structure formed when the tube cell of a pollen grain grows through the micropyle and into the ovule... answer

9. The ovule will turn into... answer

10. The male reproductive organs of the flower are called... answer

11. The ovary of angiosperms develops into this... answer

12. The ovule-containing part of the pistil is... answer

13. Where are nutrients stored in a mature bean seed? answer

14. A complete circle of petals that surround the reproductive organs of the flower are... answer

15. What part of the developing seed produces the upper part of the stem, terminal buds & leaves. answer

16. A complete circle of leaf like structures that encircle the base of a flower are... answer

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