Plant Reproduction

Alternation of Generations All plants have a diploid(2n) sporophyte generation that alternates with a haploid (1n) gametophyte generation In bryophytes (mosses), the sporophyte is attached and dependent on the larger gametophyte sporophyte In vascular plants, the sporophyte is the larger generation.

Life Cycle of Flowering Plants

Flower: Function and nonessential parts Function: to attract animals that carry pollen Nonessential parts (not directly involved in reproduction) Receptacle-the swollen tip of the branch Sepals-leaflike structures that protect and surround a developing flower Petals-brightly colored to attract animals

Essential Flower Parts: Female Carpels often fuse to form one pistil. The ovary is the base of the pistil. The style is the stalk that arises from the pistil. The stigma is the sticky tip of the style that captures pollen.

Essential Flower Parts: Male The stamen is the male reproductive structure. The anther is the tip of the stamen that produces pollen. The filament is the stalk that supports the anther.

Gamete Formation: Pollen (male) 1.Through meiosis, pollen grains form in the anther. 2.In the pollen are the generative cell and tube cell.pollen 3.The tube cell forms the pollen tube through which the generative cell travels. 4.The generative cell will form 2 sperm.

Gamete Formation: Ovule (female) 1.Ovules are compartments within the ovary. 2.Within each ovule, 8 nuclei form (1n). 3.5 of the nuclei disintegrate. 4.1 of the nuclei becomes the egg. 5.2 nuclei are in the center and are called polar nuclei.

Pollination: The transfer of pollen from anther to stigma (same species) Cross pollination is when pollen goes to another plant structure (different genes). Self-pollination is when the pollen stays on the same plant (less variety).

Fertilization: Gametes fuse. 1.After pollination, the tube cell forms a tube.tube 2.The generative cell becomes 2 sperm. 3.Both sperm enter the micropyle. 4.One sperm fertilizes the egg. 5.One sperm fertilizes the polar nuclei.

Results of Fertilization An embryo (2n) surrounded by endosperm tissue (3n) that will nourish the embryo in the seed before germination. This fertilization of egg and polar nuclei is known as double fertilization.double fertilization

Dispersal of Fruits and Seeds Wind Water Animals

Seed Germination Certain conditions are needed: Water Light Temperature Harsh conditions