LEAVES 23.4

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 PalisadeLayer Mesophyll Stomata 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

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Flowers, Fruits & Seeds Ch. 24

Angiosperms reproduce using flowers.

Flowering Plants have: Monocot Dicot Flowers Multiples of 3Multiples of 4 or

Flowers Composed of modified leaves Sepals – usually green; enclose bud Petals – brightly colored; just inside sepals Stamen – male reproductive organ Filament - stalk Anther – produces pollen (male gamete) Carpel (pistil) – female reproductive organ Stigma- sticky; pollen attaches here Style – narrow stalk Ovary – contains ovules

Anther filament

Parts of a Typical Flower Stamen Male part of flower Anther Filament

Parts of a Typical Flower Pistil Female part of flower (Sounds like “Pigtail”) Stigma Style Ovary

Plant Reproduction Plants can reproduce asexually by vegetative propagation. Stems Plantlets Roots Stems, plantlets and roots can become a new plant.

Plant Reproduction Plants can reproduce asexually by plant propagation. Cuttings Grafting & Budding A “cut” from a plant can grow 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