Physiology Reproduction and Classification Plant Hormones Tropism the directional movement of a plant in response to an environmental stimulus positive or negative Caused by the hormone Auxin ID: 600876
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Slide1
Kingdom Plantae
Physiology, Reproduction, and ClassificationSlide2
Plant Hormones
Tropism: the directional movement (growth response) of a plant in response to an environmental stimulus (positive or negative)
Caused by the hormone Auxin
Phototropism: toward a light source
Thigmotropism
: to touching a solid object
Gravitropism: directional growth toward/against gravity (roots/stems)
Chemotropism: toward a positive chemical stimulus or away from a negative oneSlide3
Difference between tropism & nastic movement:
Tropism: cell growth due to plant hormone auxin; happens slowly
Nastic movement: due to turgor pressure; happens fasterSlide4
Five additional plant hormones:
Gibberellin
Cytokinins
Abscisic acid
Ethylene
: ripens fruit; causes leaves to detach
Florigen
Slide5
Asexual Reproduction
Called vegetative reproduction
Formed from stem, roots, or leaves
Grafting: stem or branch
Stolon: stem that runs along ground and forms a new plant
Exact genetic copySlide6
Sexual Reproduction in Plants:
Alternation of generations
one generation as haploid gametophyte (n)
one generation as diploid sporophyte (2n)
Nonvascular plants:
gametophyte stage is dominant
Vascular plants
sporophyte stage is dominantSlide7
Mosses: Sexual Reproduction
Nonvascular
Produce sperm and eggs
antheridium: male gametes
archegonium
: female gametes
gametophyte stage is dominantSlide8
Ferns: Sexual Reproduction
Vascular plants
Sporophyte phase is dominant
Sporophyte grows leaves called fronds
Sporangia: cells that produce spores
Spores released from
sori
on underside of frondsSlide9
Gymnosperms: Sexual Reproduction
Diploid sporophyte dominant phase
Produce male and female spores
male (microspores) female (megaspores)
When fertilized the gametophytes form a diploid zygote (the seed)
The seed matures, releases
from cone, lands on ground,
grows into diploid sporophyteSlide10
Angiosperms: Sexual Reproduction
Flowering plants; flowers are the reproductive organs
vascular plants; sporophyte phase is dominant
Pollen is the male gametophyte
Female gametophyte is contained in the sporophyteSlide11
Steps for Angiosperm reproduction:
Production of the egg (female) p. 542
Diploid megaspore in ovary undergoes meiosis to form 4 haploid spores; one survives and undergoes mitosis to form 8 haploid nuclei.
Single egg cell formed from one of these.
Production of pollen (male) p. 543
Anther has diploid microspore which undergoes meiosis to form 4 haploid microspores; undergoes mitosis to form 4 sets of 2 haploid spores.
Called pollen
Pollination/Fertilization p. 544
Slide12
Pollination
Transfer of pollen from anther to stigma
Pollen grain has tube cell which grows down the style toward ovary.
2 sperm cells travel down tube to ovary
One fertilizes the egg (2n = zygote)
Second sperm cell fuses with polar bodies, forms triploid cell (3n) that becomes the endosperm (nutrition)
Fertilization results in a seed packaged inside fruit
(chart on page 546)Slide13
Germination
Favorable conditions leads seed to break out of seed coat and sprout
(grow into new plant)
See page 545Slide14
Phyla in Kingdom Plantae
chart on page 537 & 548
Nonvascular: >17,000 species
-reproduce with spores
-dominant phase is gametophyte
-no xylem and phloem
(small in size)
-moist environmentSlide15
Vascular >255,000 species
-have xylem and phloem
-dominant phase is sporophyte
Seedless:
-reproduce with spores
Seed:
-reproduce with seed (contained in fruit)