1. Reproductive Structures in Flowering Plants
Flowers
Reproductive shoots of sporophytes
Flowering plants make sexual spores in male stamens and female carpels of floral shoots
Gametophytes develop from the spores
Pollen grains contain male gametophytes
Ovules contain female gametophytes

2. Flowering Plant Life Cycle and Floral Structures

3. Coevolution
Flowering plants coevolved with pollination vectors that transfer pollen from stamens to carpels of flowers of the same species
Pollinators receive nectar and pollen

4. Attracting Pollinators

5. From Gametophyte to Fertilization
Male gametophyte formation
Pollen sacs form in anthers of stamens
Haploid microspores form by meiosis of diploid spore-producing cells
Microspore develops into a sperm-bearing male gametophyte, housed in a pollen grain

6. From Gametophyte to Fertilization
Female gametophyte formation
A carpel’s base has one or more ovaries
Ovules form from the inner ovary wall
One cell in the ovule (haploid megaspore) gives rise to the mature female gametophyte
One cell of the gametophyte becomes the egg

7. From Gametophyte to Fertilization
Pollination
Arrival of pollen grains on a receptive stigma
Germination
Pollen grain forms a pollen tube (two sperm nuclei inside); grows through ovary to egg
Double fertilization
One sperm nucleus fertilizes the egg, forming a zygote; one fuses with the endosperm mother cell

8. From Zygote to Seed and Fruit
A mature ovule: Embryo sporophyte and endosperm inside a seed coat
Eudicot embryos have two cotyledons; monocot embryos have one
Fruit
Seed-containing mature ovary (and accessory tissues)

9. Embryo Development: Eudicot

10. From Flowers to Fruits

11. remnants of sepals, petals ovary tissue seed enlarged receptacle
Fig. 28.7d, p.461

12. Fruits: Seed Dispersal
Fruits help seeds disperse by adaptations to air or water currents, or diverse animal species

13. The Plant Body Aboveground shoots Roots
Stems that support upright growth
Photosynthetic leaves
Reproductive shoots (flowers)
Roots
Typically grow downward and outward in soil

14. shoot tip (terminal bud)
young leaf
flower
lateral (axillary) bud
node
internode
dermal tissue
vascular tissues
leaf
seeds
in fruit
withered
seed leaf
(cotyledon)
ground tissues
SHOOTS
ROOTS
stem
primary root
lateral root
root hairs
root tip
root cap

15. Epidermis

16. Leaf Structure Between upper and lower epidermis Stomata
Mesophyll (photosynthetic parenchyma)
Veins (vascular bundles)
Stomata
Openings in cuticle-covered epidermis that control passage of water vapor, oxygen, and carbon dioxide

17. leaf vein (one vascular bundle)
xylem
phloem
cuticle
upper
epidermis
palisade
mesophyll
Water,
dissolved
mineral ions
from roots and
stems move
into leaf vein
(blue arrow).
spongy
mesophyll
lower
epidermis
Photosynthetic
products (pink
arrow) enter
vein, will be
distributed
through plant.
epidermal
cell
stoma
(small gap
across lower
epidermis)
Oxygen and
water vapor
(blue arrow)
diffuse out of
leaf through
stomata.
Carbon dioxide
(pink arrow)
in outside air
diffuses into
leaf through
stomata.

18. Water Conservation Cuticle
Waxy covering that protects all plant parts exposed to surroundings
Helps the plant conserve water

19. Water Conservation Stomata Gaps across the cuticle-covered epidermis
Closed stomata limit water loss (but prevent gas exchange for photosynthesis and aerobic respiration)
Environmental signals cause stomata to open and close

20. How Stomata Work A pair of guard cells defines each stoma
Water moving into guard cells plumps them and opens the stoma
Water diffusing out of guard cells causes cells to collapse against each other (stoma closes)

21. guard cell guard cell chloroplast (guard cells are the only epidermal
cells that
have these
organelles)
stoma
20 µm
Fig , p.448

22. Effects of Pollution on Stomata

23. Complex Vascular Tissues
Xylem
Vessel members and tracheids are dead at maturity; their interconnected walls conduct water and dissolved minerals
Phloem
Sieve-tube members are alive at maturity, form tubes that conduct sugars
Companion cells load sugars into sieve tubes

24. one cell’s wall sieve plate of sieve tube cell pit in wall companion
parenchyma
fibers of
sclerenchyma
vessel
of xylem
phloem
Fig. 26.8, p.429

25. Vascular Bundles Bundles of xylem and phloem run through stems
Monocot stems: Vascular bundles distributed through ground tissue
Herbaceous and young woody eudicots: Ring of bundles divides ground tissue into cortex and pith
Woody eudicot stems: Ring of bundles becomes bands of different tissues

26. How to distinguish between monocots and dicots
Stem
Monocot-randomly distributed vascular bundles
Dicot--ring of vascular bundles
Leaf
Monocot--parallel veins
Dicot--branched veins
Flowers
Monocot--petals in 3’s
Dicot--petals in 4’s or 5’s

27. Primary Structure of Eudicot and Monocot Stem

28. Eudicot and Monocot Leaves and Vein Patterns

29. Transpiration and Cohesion-Tension Theory
Evaporation of water from plant parts (mainly though stomata) into air
Cohesion–tension theory
Transpiration pulls water upward through xylem by causing continuous negative pressure (tension) from leaves to roots

30. Cohesion and Hydrogen Bonds
Hydrogen bonds among water molecules resist rupturing (cohesion) so water is pulled upward as a continuous fluid column
Hydrogen bonds break and water molecules diffuse into the air during transpiration

31. Root Functions
Roots
Absorb water and mineral ions for distribution to aboveground parts of plant
Store food
Support aboveground parts of plant

32. Roots Roots absorb water and mineral ions Root hairs
Expand through soil to regions where water and nutrients are most concentrated
Root hairs
Greatly increase root absorptive surface

33. Root Symbionts Draw products of photosynthesis from plants
Give up some nutrients in return
Mycorrhizae (fungal symbionts)
Increase mineral absorption
Root nodules (bacterial symbionts)
Perform nitrogen fixation

34. Root Nodules

35. Dendroclimatology
Wood cores and climate history

36. Processes of Survival
Plants and animals adapted in similar ways to environmental challenges
Gas exchange with the outside environment
Transportation of materials to and from cells
Maintaining internal water-solute concentrations
Integrating and controlling body parts
Responding to signals from other cells, or cues from the outside environment

37. Rhythmic Leaf Movements

39. Responses to Environment: Thigmotropism
In some plants, direction of growth changes in response to contact with an object

40. 28.9 Biological Clocks
Internal timing mechanisms respond to daily and seasonal cycles
Circadian rhythms (24-hour cycle)
Solar tracking