Plant Reproduction In Angiosperms (Flowering Plants)

I. Introduction to Seed Plants A. Gymnosperms: B. Angiosperms: Adaptations for terrestrial (land) plant reproduction: fflowers or cones ttransfer of sperm by pollination pprotection of embryos in seeds Seed plants that bear seeds within cones Flowering plants that bear seeds within ovaries (fruit)

Sepals Outermost circle of floral parts Enclose the bud before it opens Protects the flower while it develops Petals Located just inside the sepals Often brightly colored to attract pollinators Stigma Style Ovary Sticky to collect pollen Supports the stigma Pistil/Carpel Anther Filament Site of meiosis to produce pollen grains that will make sperm Supports the anther Stamen II. Structure of Flowers A. Flowers are reproductive organs that consist of 4 specialized leaves: sepals, petals, stamen and pistils/carpels Site of meiosis to produce eggs

Sepals Immature Flower Parts

Sepal Petal

Filament Anther Stamen

It’s a bit dark in here. Nice.

Stigma Style Ovary Pistil

Ovary Ovule

3 Sepals3 Petals 6 Stamen 1 Pistil

Pollen Ovary Embryo Sac Ovule

III. Life Cycle of Angiosperms A.The life cycle begins when a plant develops flowers.

B. Meiosis occurs in the anthers and ovaries to produce pollen & eggs respectively.

Angiosperm

C. Pollination:pollen released from anther lands on stigma 1. Self- Pollination: pollen lands on the stigma of the same plant 2. Cross- Pollination: pollen lands on the stigma of a different plant * Pollen carried by gravity, wind, insects, birds, small animals, etc.

D. Fertilization 1. Part of the pollen grain releases enzymes to “dig” a pollen tube through the style to the ovary 2. Sperm from the pollen grain travel down the pollen tube to fertilize the egg

ex. bean E. Seeds: 2. Seed Coat: surrounds and protects the embryo. 1. Plant embryo surrounded by a food supply

Angiosperm

F. Fruit & Seed Dispersal: 1. After fertilization, ovary walls thicken to form fruit. 2. Seeds may be dispersed by vectors: animals, wind, water, etc. * Seed coats cannot be digested. * Animals eat fruit and egest seeds elsewhere Example:

G. Dormancy:Period when embryo is alive but not growing. H. Germination:Young plant sprouts from seed *germination won’t occur until conditions are suitable