Introduction to Plant Reproduction Introduction To Plant Reproduction

Introduction to Plant Reproduction

Introduction To Plant Reproduction Sexual Reproduction p Asexual Reproduction p p These processes occur in seed plants, and seedless plants.

p Seed Plants p Seedless Plants

Types of Reproduction p Asexual Reproduction n n Does not involve or require the production of sex cells. One organism produces offspring that are genetically identical to it.

Examples of Asexual Reproduction Strawberry Plant - Runner Liverwart - Gemmae Plantlet on Leaf

Types of Reproduction p Sexual Reproduction n Requires the production of sex cells – sperm and egg – in reproductive organs. n Offspring produced are genetically different from either parent organism. In some plants, water and wind help bring the sperm to the egg. p For other plants, animals such as insects help bring the sperm and egg together. p

Sexual Reproduction (continued) p Reproductive Organs n Male reproductive organs produce sperm. n Female reproductive organs produce eggs. n If a plant has both organs it can reproduce by itself. n If organs are present on separate plants, sperm and egg must come together with the help of the elements.

Sexual Reproduction (continued) p For sexual reproduction, plants can either reproduce with seeds, or without seeds.

What is a Seed? n n A structure that contains an embryo, stored food (in the cotyledon), and a protective coat. Because the seed is so well protected and fed, the plant grown from it will grow faster compared to seedless plants. Seedless plants use spores to reproduce. Why would the seed want stored food and a protective coat?

Types of Seed Reproducers

Two Types of Seed Reproducers p Angiosperms What’s the difference? p Gymnosperms

Angiosperm p Angiosperms produce flowers which are used for sexual reproduction.

Angiosperm n The stamen is the male reproductive organ. n The pistil, the female reproductive organ, contains the ovary at its base. n The appearance of a plant’s flower can give clues about how the plant is pollinated. n After pollination and fertilization, a zygote forms and grows into the plant embryo.

Parts of a Flower Petal Stigma Anther Style Pistil Filament Stamen Sepals Ovary

Where are the seeds found? p THE FRUIT. So…fruit is like the plant’s baby. Fact: Fruits have seeds. Vegetables do not. A true vegetable is usually a root. (potato, carrots, onion)

Angiosperm - Parts of the ovule develop into the seed coat and store food for the embryo. Some seeds store food in cotyledons. p Other seeds store food in endosperm tissue p

Angiosperm Life Cycle A. Pollination happens when pollen grains from the anthers land on the sticky stigma of a pistil. B. The pollen tube grows from the pollen grain down through the style and into the ovary at the ovule. C. The sperm travels down and fertilizes the egg. The zygote develops.

Gymnosperm p Gymnosperms develop seeds in cones.

Gymnosperm n A pine tree or shrub is a sporophyte plant that produces male and female cones. n A female cone has two ovules which produce eggs. n Male cones produce and release pollen.

Gymnosperm n When pollen blows into a female cone, fertilization and seed formation can occur. n Seed released by a female cone can take two or three years.

Seed Dispersal p Seeds are dispersed by wind, gravity, animals, and water. Some seeds have trapped air which helps them float. n n Germination occurs when the seed coat swells and breaks open. Environmental conditions affect germination.

Behold! A Fruit!

Plant Earth