LEAVES 23.4
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Transcript of LEAVES 23.4
LEAVES23.4
Function Photosynthesis Transpiration – pulling
water up from the roots and out the leaves
Structure
Epidermis Upper – covered by cuticle Lower – contains stoma
with guard cells
Cont. Palisade layer – many
chloroplasts Mesophyll – many air
spaces Vascular bundle – “veins”
Vein
Pallisade Layer
MesophyllStomata
Epidermis with cuticle
External Structures Petiole – structure that
attached leaf to stem Blade – thin, flat area of leaf;
different sizes, shapes & arrangement
Mid rib – main vein Leaf margin – edge of leaf
Venation in Monocots and Dicots
Monocots – parallel leaf venation
Dicots – netted venation
Pop Quiz
Flowers, Fruits & SeedsCh. 24
Angiosperms
reproduce using flowers.
Flowering Plants have:Monocot Dicot
FlowersMultiples of 3 Multiples of 4 or 5
1
2 34
56
23 4
5
67
18
6
Flowers Composed of modified leaves
Sepals – usually green; enclose bud Petals – brightly colored; just inside sepals Stamen – male reproductive organ
Filament - stalkAnther – produces pollen (male gamete)
Carpel (pistil) – female reproductive organ Stigma- sticky; pollen attaches hereStyle – narrow stalkOvary – contains ovules
Parts of a Typical Flower
Stamenmale partof flower
AntherFilament
Parts of a Typical Flower
PistilFemale part
of flower(Sounds like “Pigtail”)
Stigma
Style
Ovary
Plant ReproductionPlants can reproduce asexually by
vegetative propagation.Stems
PlantletsRoots
Stems, plantlets and roots can become a new plant.
Plant ReproductionPlants can reproduce asexually by
plant propagation.
CuttingsGrafting & Budding
A “cut” from a plant cangrow roots when put in soil. Two plants are attached
to form one plant.
Angiosperm Life Cycle Pollination – transfer of pollen from anther
to stigma of carpel Often dependent on pollinators Pollen grows a tube through which
sperm nuclei travel Fertilization –
sperm nuclei fuse with ovule inside produce a seed Ovary ripens into a fruit
Fruits – ripened ovary; type determined by structure of ovary and ovules Dry
Nuts Fleshy
Drupes - apple Pomes - peach Berries Hesperidium - orange Pepo - cucumber Aggregate - raspberry
Seed Dispersal Animal Wind Water
Seed Germination Timing controlled by climate (moisture,
temperature, etc.) Endosperm (food source) swells with
moisture and cracks open seed coat Root emerges first Cotyledons emerge second
Monocot – one seed leaf Dicot – two seed leaves
Plant Growth Controlled by hormones (auxins) Cause “tropisms”
Gravitropism Thigmotropism phototropism