Reproduction in Flowering Plants 9 Ad Parts of

Reproduction in Flowering Plants

9 Ad Parts of a flower

Reproductive Parts Male reproductive organs (stamen): • Anther: produces pollen grains • Filament: supports anther above female reproductive organs Female reproductive organs (carpel): • Stigma: sticky landing site for pollen grains • Style: tube that leads down to ovary • Ovary: contains ovules that develop into seeds

9 Ad Reproductive Mechanisms Pollen (male gamete) from one plant lands on the stigma of another plant. This is called pollination. stigma pollen

Methods of Pollination • Natural Reproduction • Pollination in angiosperms can happen by wind or animals. • Animals can transfer pollen (bees) from one plant to the other. – They are called pollinators • Pollen can be blown from one plant to another. – Wind dispersal

Reproduction

9 Ad Selective breeding in plants texture taste size Selective breeding and cross-breeding are carried out on plants to produce flowers and crops with desirable characteristics… colour

9 A Plant-breeding techniques Anne the plant breeder chooses two parent plants with useful characteristics. One plant will be the female parent. Anne removes the anthers and covers the flower with a bag. Why? female parent The other plant is the male parent. Its anthers develop as normal. Anne collects its pollen and brushes it onto the female plant. collected pollen anthers removed She puts the bag over the flower again. Later she collects the seeds and grows them to produce the new plant.

9 Ad From Pollen to Ovary The pollen grain grows a pollen tube towards the ovary, which contains the ovule and egg cell (female gamete). pollen tube ovary containing ovule

9 Ad Fertilization Fertilisation takes place when the ‘sperm’ nucleus from the pollen grain enters the egg cell. The resulting zygote eventually turns into a seed. pollen tube with pollen grain nucleus ovule Embryo grows inside the ovule. egg cell

Comparing Plant and Human Reproductive Systems • • Plant Male and Female organs Male Gamete is pollen Female Gamete is egg produced in ovule Pollen nuclei fuses with egg nuclei (fertiliation) Diploid zygote Zygote grows into embryo Embryo grows inside protective seed coat Cotyledons provide nourishment • • Human Male or Female organs Male Gamete is sperm Female Gamete is egg produced in ovary Sperm nuclei fuses with egg nuclei (fertilization) Diploid zygote Zygote grows into embryo Embryo grows inside protective womb Placenta provides nourishment

Zygote to Embryo The zygote will grow through the process of mitosis to form an embryo (The ovule is now called a seed and is covered by a protective seed coat. ) seed coat food supply (cotyledon) embryo

Fruit Formation • Some plants produce fruit containing seeds. • Fruit: Mature ovary • Tissue surrounding the embryo develops into fruit. • When the fruit is fully developed it drops off the plant, or is carried away by an animal. • When fruit decomposes it releases the seed and germination can occur.

Germination • A seed requires moisture (water) to germinate. • The as the embryo grows, the root and shoot break through the seed coat. • Nutrients stored in the cotyledon provide nourishment and support early development

Life cycle of an angiosperm