Download Plant Physiology

Plant
Physiology
Biology 2
Tuesday, February 26, 2013
Reminders
Exam 2: March 6, 2013
Assignment 1: March 4, 2013
Tuesday, February 26, 2013
Tuesday, February 26, 2013
Review - Plant Organs
Flowers/Fruits
Leaves
Stem
Roots
Tuesday, February 26, 2013
Review - Flower
• Reproductive Organ
Pistil
Stamens
Petals
Sepals
Tuesday, February 26, 2013
Review - Male Development
Pollen is male
gametophyte
Anther
Pollen Sac
Tuesday, February 26, 2013
Mitosis
Meiosis
Microspore
Mother Cell
2N
Microspores Pollen
N
N
Review Female
Development
Ovary
Meiosis
Mitosis
3x
Ovule
Megaspore
Mother Cell
2N
Tuesday, February 26, 2013
Megaspore N
Female
Gametophyte
Pollination/Development
Generative
Nucleus
Ovary becomes Fruit
Pollen
tube
Fruit
Ovule
Endosperm
3N
2 sperm
Nuclei
Seed
Gametophyte
Tuesday, February 26, 2013
Zygote
2N
Embryo
Ovule becomes Seed
Bean - Typical Dicot Seed
Seed
Coat
Hilum
Micropyle
Tuesday, February 26, 2013
Typical Dicot Seed
Hypocotyl
Plummules Embryo
Radicle
Cotyledon
Cotyledon
Endosperm is absorbed by cotyledons
Tuesday, February 26, 2013
Germination
1st true leaves
Cotyledons
Hypocotyl
Imbibation
Tuesday, February 26, 2013
Root
Tuesday, February 26, 2013
Typical Monocot Seed
Pericarp
Endosperm
Embryo
Plummule
Cotyledon
Radicle
Tuesday, February 26, 2013
Monocot Development
1st leaf
Imbibation
Tuesday, February 26, 2013
Root
Prop
Roots
branch
roots
Fruit
• Flowering Plant Organ containing seed(s)
• Forms from ovary
Endocarp
Seed
Mesocarp
Exocarp
Tuesday, February 26, 2013
Pericarp
Simple Fruit
• Derived from a single ovary
• Fleshy Fruits – moist at maturity
• Dry fruits – dry at maturity
Tuesday, February 26, 2013
Simple Fleshy Fruits
peach
tomato
Drupe-stony endocarp
Berry-soft endocarp
avocado
walnut
Tuesday, February 26, 2013
Dry Fruits
Legumesplits along 2 seams
Grainfruit fused to seed
Tuesday, February 26, 2013
NutDoes not split
Compound Fruits
• Derived from a many ovaries
1 flower - many pistils
Multiple flowers
e.g. raspberry
e.g. osage
orange
Tuesday, February 26, 2013
Fruit Function - Seed Dispersal
Wind
Tuesday, February 26, 2013
Animals
Plant Physiology
Study of function
How things work
e.g. what controls growth
e.g. what controls flowering and
fruiting
Tuesday, February 26, 2013
Photoperiodism
Response to day length
Long Day Plants - flower photoperiod > critical length.
Short Day Plants - flower photoperiod < critical length.
Tuesday, February 26, 2013
Short Day (Long Night) Plants
Fig 26.18
Tuesday, February 26, 2013
Circadian Rhythms
Daily movements
Prayer Plant
leaves horizontal in day
vertical at night
Tuesday, February 26, 2013
Sunflower
flower turns to face sun
throughout day/
Phytochrome
plant photoreceptor
Red Light
Fig 26.16
Far red Light
Inactive
•photoperiodism
•seed germination
•circadian rhythms
Tuesday, February 26, 2013
Active
Hormones
•
chemicals made in minute amounts
•
transported to target region
•
affect growth
Auxin
Cytokinins
Gibberellins
Tuesday, February 26, 2013
Abscisic Acid
Ethylene
Auxins
•
•
Generally stimulates growth
Cell elongation
Tuesday, February 26, 2013
Phototropism
•
•
Movement relative to light.
Auxin elongates cells on dark side
Tuesday, February 26, 2013
Gravitropism
• Bending relative to gravity.
• Auxin causes elongation on one side
- gravitropism
Tuesday, February 26, 2013
+ gravitropism
Apical Dominance
• Auxin inhibits axillary bud growth
Remove tip
No auxin, Buds grow
Tuesday, February 26, 2013
Auxin
• Promotes root formation
Tuesday, February 26, 2013
Herbicides
•
•
•
Weed killers
synthetic auxins
overstimulates
Tuesday, February 26, 2013
Agent Orange
•
•
•
•
Used in Vietnam
2,4-D, 2,4-T
Deforest
Stop agriculture
Tuesday, February 26, 2013
Gibberellins
• Stimulate growth
Normal
• Stem elongation - etiolation
• used commercially to get
larger grapes
Tuesday, February 26, 2013
high gibberellin
(shade)
Cytokinins
•
stimulate cell
division
•
interacts with auxin
•
used in tissue
culture
Tuesday, February 26, 2013
Ethylene
•
Fruit ripening (starch to sugar,
green to color)
•
Abscission - leaf loss
H
H
C
Tuesday, February 26, 2013
C
H
H
Abscisic Acid
•
•
•
•
Growth inhibiting hormone
“stress hormone”
Promotes bud and seed dormancy
Closes stomata
Tuesday, February 26, 2013
The End
Tuesday, February 26, 2013