1. PLANT REPRODUCTION Sporophyte- Gametophyte-
First, some more weird words for you….
Sporophyte-
the recognizable “plant”
Produces haploid “sporangia”
Gametophyte-
The haploid gametes of the sporophyte
Male Gametophyte- pollen grains
Female Gametophyte- embryo sac

2. Floral variations Floral organs: sepals, petals, stamens (male )
Anthers for pollen production
Filaments hold the anthers
carpels (female)
Ovary holds the developing ovum
Style connects the ovary to the…
(sticky) Stigma where pollen is received.

3. “Kinds” of Flowers:
Complete- has all four (sepals, petals, stamens, carpels)
Incomplete- missing one or more of the above 4
Perfect- has both stamens & carpels
also called: MONOECIOUS (one house)
Imperfect- missing either stamens or carpels
also called DIOECIOUS (2 houses)
Staminate- only stamens
Carpelate- only carpels
incomplete
perfect!
So.. A plant can be “___________” but still “_______”

4. Most Monoecious Plants Do NOT self-pollinate:
WHY?????
They have “self-incompatability mechanisms”:
For Example:
Stamens & carpels may mature at different time.
Structural arrangements may prevent pollinators from successful transfer.
Gene-based rejection:
If “S-locus” genes are too similar the stigma releases an RNA digesting ribonuclease which inactivates the tube cell of the pollen grain.
Tube cell?? OK- so let’s start at the beginning….

5. Gametophyte development
Male gametophyte: microsporocyte (diploid cells in pollen sacs of anther)
divides by meiosis into 4 haploid microspores;
mitosis produces a generative cell (sperm) and a tube cell (pollen tube)
a pollen grain contains both generative cell and a tube cell.
Female gametophyte: megasporocyte (diploid cells in ovule)
divides by meiosis to 4 haploid cells,
only 1 survives to a haploid megaspore;
3 mitotic divisions forms the embryo sac;
includes:
1 egg cell (female gamete)
2 polar nuclei
3 Antipodal cells
2 synergids

6. Double fertilization
Pollination (pollen grain lands on a receptive stigma)
Tube cell (pollen tube produced down the style)
Generative cell (2 sperm by mitosis)
Enters ovary through micropyle
1 sperm fertilizes egg to form zygote
Other sperm combines with 2 polar nuclei to form 3n endosperm (food-storing tissue)
Ovary develops into a “fruit” which surrounds the seed(s).

7. The Seed From fertilized ovule...the mature seed.
•seed coat (protection)
•cotyledons (seed leaves)
In dicots, most endosperm is converted into cotyledons; stays mostly endosperm in monocots.
•hypocotyl (lower embryonic axis)
•radicle (embryonic root)
•epicotyl (upper embryonic axis)
•plumule (shoot tip)
•coleoptile (sheath for monocot shoot)
•coleorhiza (sheath for monocot root)

8. The Fruit
From ovary….
Fruit protects seeds and aids in their dispersal
Pericarp (thickened wall of fruit from ovary wall)
Fruit types:
•simple (1 ovary/1 flower)~ cherry, soybean
•aggregate (1 flower with many carpels/ovaries)~ blackberry
•multiple (inflorescence; group of flowers/ovaries) ~ pineapple

9. From Seed to Seedling….
Dormancy is broken by IMBIBITION (absorption of water)
Causes seed to swell & rupture seed coat
Abseisic acid washes away, increasing relative concentration of gibberellins.
Gibberellins send signal to aleurone (outer layer of endosperm)
Aleurone secretes amylase which turns starch into sugar
Radicle 1st, then shoot tip:
Dicots: hypocotyl hook breaks through, then straightened by light.
Monocots: Coleoptile pushes through.
campbell animation