Plant reproduction and development

I sometimes think that never blows so red
The Rose as where some buried Caesar bled;
That every Hyacinth the Garden wears
Dropt in her Lap from some once lovely Head.
--Omar Khayyam, Rubaiyat, FitzGerald, Fifth Edition

Campbell and Reece Chapter 38

Alternation of Generations:
sporophyte, 2n, diploid -> gametophyte, 1n, haploid

VERY CONFUSING, so look back at Fig. 13.5 (meiosis chapter)
Bottom Line: Meiosos makes spores, not gametes

Also by way of review: Female=Carpel, Male=Stamen in "ordinary" flower
This would be a perfect flower
Imperfect flower
Staminate - male
Carpellate - female
Already mentioned:
monoecious (even in corn)
dioecious: blue "prince or boy" (right of figure) vs "princess or girl" (left of figure) holly, date palm

Inflorescences = clusters of flowers, like lupines
Composite flowers, like sunflowers, look at Fig. 38.3

Pollen sac is called sporangium
MALE microsporocyte is diploid and microspore is haploid
(of course, since meiosis is shown on diagram)
pollen grain is immature gametophyte
tube cell grows into pollen tube
generative cell makes two sperm nuclei
REMINDER the gametophyte makes gametes
FEMALE megasporocyte -> meiosis -> megaspore by analogy with male
only one survives
Develop. of female gametophyte is not quite as obviously diff. generation
embryo sac is female gametophyte 8 specified cells
haploid cells can have mitosis you may not have considered

Pollination (as mentioned when we talked about angiosperms)
cross pollination, coevolution of angiosperms and pollinators
TRANSPARENCY (Fig. 38.7) self incompatible (pollen fails to develop)

Fertilization 1 sperm fertilizes egg.
other fertilizes two polar nuclei to make endosperm (3n).
monocot - endosperm is nutrient
dicot - endosperm goes into cotyledons

Embryology TRANSPARENCY Fig. 38.10
first division lays down up and down, basal cell becomes suspensor
In mature seed, embryp has shoot apex and root apex
plumule at top, hypocotyl between
radicle is embryonic root
beans and corn are examples in TRANSPARENCY Fig. 38.11

Ovary and parts of flower can contribute to "fruit"
cherry, bean pod: simple fruit
strawberry: aggregate fruit (one flower with several carpels)
pineapple: multiple fruit (inflorescence)

TRANSPARENCY Germination Fig. 38.14
monocot - coleoptile = cotyledon
foliage leaves vs. cotyledons
Dormancy, imbibation
embryo releases gibberellin
allerone (layer of cells) releases alpha-amylase
breaks down starch.

There's also asexual reproduction

Plant growth and development will not be emphasized

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this page was last updated 2/5/03