All living things will eventually leave our planet, either by dying of old age, disease or accidents. If living organisms did not reproduce, life would cease to continue in our planet until each member of life forms become extinct.

Nature ensures that life continues in every type of living organism through the process of reproduction.

Reproduction Process by which organisms replace themselves, the “old circle of life”.

Reproduction in Lower life forms

Plants, just like other living organisms, are also part of the “circle of life”. They cannot live forever and therefore each species of plants must replace themselves with younger members. Plants do this in two ways, asexually and sexually.

Plant Reproduction

Asexual• does not involve the fusion of sex cells•only one parent is required•offspring are genetically identical to parents known as clones

Natural Vegetative Reproduction•Rhizome•Bulb•Corm•Runner/Stolon•Tuber

Artificial Vegetative Propagation•Cutting•Budding and Grafting•Tissue Culture

Sexual•involves fusion of two sex cells to form a zygote•usually requires two parents•offspring shows variations or not the exact copy of parents

Reproduction by Flowers

Parts of the Flowers

Accessory•Pedical (flower stalk)•Sepal•Petals

Male Organ (pollen producing)Stamen•Filament•Anther(produces haploid pollen grains)

Female Organ (egg producing)•Stigma•Style•Ovary•Ovules (each containing haploid ovum)

Advantage of Sexual and Asexual Reproduction

Asexual and Sexual Reproduction

Asexual and Sexual Reproduction

Asexual Reproduction in Flowering Plants

Vegetative parts:

Stems

Roots

Leaves

•The new plant that results is genetically identical to its parent plant.•

•Can occur naturally or artificially with the aids of humans

Asexual Reproduction in Flowering Plants

Natural Vegetative Reproduction

◘ Reproduction in plants from its vegetative parts or specialized reproductive structures

Modified stem Description Representative Species

Tuber New shoots arise from axillary bud on swollen, short, fleshy, underground stem

Potato

Runner New plants arise at nodes of above-ground horizontal stem

Bermuda Grass, Strawberry plants

Corm New plants arise from every short thickened, underground stem with thin, scaly leaves

Gladiolus

Rhizome New plants arise at nodes of underground horizontal rootlike stem

Sugar cane, ginger

Bulb New bulbs arise from axillary bud on very short stem with thick fleshy leaves (only in monocots)

Onion, Garlic

Tubers-various types of modified plant structures that are enlarged to store nutrients

Runners or Stolons stems which grow at the soil surface or just below ground that form adventitious roots at the nodes, and new plants from the buds.

Runners or Stolons

Strawberries

Bermuda Grass

Corm (bulbotuber)-is a short, vertical, swollen underground plant stem that serves as a storage organ used by some plants to survive winter or other adverse conditions such as summer drought and heat (estivation).

Corm (bulbotuber)

Gladiolus

Rhizome-characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes. Rhizomes may also be referred to as creeping rootstalks or rootstocks.

Bulb a short stem with fleshy leaves or leaf bases. The leaves often function as food storage organs during dormancy.

Artificial Propagation Methods

-Asexual methods practiced with a little help from humans.

- Often faster than growing plants from seeds.

- Farmers propagate plants by using a piece of plant material.

- Each plant generated that is identical and genetically the same as the parent tree is said to be a clone

Method Description Examples

Cutting Leaves or pieces of stems or roots are cut from one plant, planted in soil and used to grow new individuals

Ornamental trees and shrubs (grapes, apples)

Budding and Grafting Small stems from one plant are attached to larger stems or roots of another plant.

Some fruit and nut trees (oranges)

Tissue culture(laboratory technique only)

Pieces of tissues from one plant are placed on a sterile medium and used to grow new individuals in mass numbers

Orchids, potatoes, many house plants

Methods of Vegetative Plant Propagation

Methods of Vegetative Plant Propagation

Cutting

Methods of Vegetative Plant Propagation

Stem Cutting

Methods of Vegetative Plant Propagation

Root Cutting

Methods of Vegetative Plant Propagation

Leaf Cutting

Grafting

Inosculation- Vascular joining

Budding

Tissue Culture

Sexual Reproduction in Flowering Plants

•All flowering plants reproduce sexually•Sexual Reproduction happens in the sexual organs of flowering plants.•Most plants are Hermaphrodites•Involves the fusion of sex cells from parent plants.

Simplified overview of angiosperm life cycle

PARTS OF A FLOWER

PARTS OF A FLOWER

Male Organs:

Stamen- male reproductive partAnther- makes tiny grains (pollens) which contain sex cellsFilament- holds up the anther

PARTS OF A FLOWER

Female Organs:

Carpel- female reproductive partStigma- top part of the carpel with sticky surface to trap pollenStyle- joins the stigma and the ovaryOvary- contains female sex cells called ovules

Pollination

-Transfer of pollen grains from the stamen to the stigma-Pollen grains produced in the anther of one plant land of the stigma of the flower of another plant.-The stigma is often quite sticky, so the pollen grains stick to it easily.

Self-pollinationIt is the transference of the pollen grains from the anther to the stigma of either the same or of another flower borne on the same plant.

Self-pollinationAutogamy- The pollen grains are transferred from the anther to the stigma of the same flower. It occurs in bisexual flowers.

Self-pollinationGeitonogamy- Flower is pollinated by pollen from another flower on the same plant.

Cross PollinationIt is the transference of the pollen grains from the anther of one flower to the stigma of another flower borne on a different plant of the same species. It is also known as allogamy or xenogamy.

Cross pollination increases variety and can give rise to changes that help species survive.

Fertilization

Seed Dispersal

In order to prevent overcrowding and competition for basic needs, such as space, light, and water, seeds together with its fruit are sometimes carried away from the parent plant in a process called dispersal.

Seed Dispersal

GerminationThe process in which a new plant grows from a seed.

Factors affecting Germination

-Water – is needed for metabolism. The uptake of water by seeds is called imbibition.-Oxygen- is needed for respiration, which breaks down food, releasing energy for growth.-Temperature- affects the cellular metabolic and growth rate.