Plant Reproduction Travis DeLozier

Terms Propagation/Reproduction –The process of increasing numbers of a species, or perpetuating a species Propagation/Reproduction –The process of increasing numbers of a species, or perpetuating a species Sexual Reproduction – The union of an egg (ovule) and sperm (pollen), resulting in a seed. 2 parents creating a 3 rd individual is referred to as sexual propagation Sexual Reproduction – The union of an egg (ovule) and sperm (pollen), resulting in a seed. 2 parents creating a 3 rd individual is referred to as sexual propagation Asexual Reproduction/Vegetative – Utilizing a part or parts of 1 parent plant. The new plant is a clone (exact duplication) of its parent Asexual Reproduction/Vegetative – Utilizing a part or parts of 1 parent plant. The new plant is a clone (exact duplication) of its parent Hybrid Vigor – Refers to the tendency of hybrid plants to be stronger and survive better than plants of a pure variety Hybrid Vigor – Refers to the tendency of hybrid plants to be stronger and survive better than plants of a pure variety

Sexual/Asexual Comparison Sexual Propagation Advantages Sexual Propagation Advantages Less Expensive Less Expensive Many parts can be produced quickly Many parts can be produced quickly Crosses result in hybrid vigor Crosses result in hybrid vigor Avoids passing on some diseases Avoids passing on some diseases Asexual Propagation Advantages Asexual Propagation Advantages Less time is required to produce a salable (fit for sale) plant Less time is required to produce a salable (fit for sale) plant Plants are genetically identical Plants are genetically identical The only way to produce some plant varieties The only way to produce some plant varieties

Parts of a Seed Embryo- The young multi-cellular organism before it emerges from the seed Embryo- The young multi-cellular organism before it emerges from the seed Endosperm- A source of stored food, consisting primarily of starches Endosperm- A source of stored food, consisting primarily of starches Seed Coat- Consists of 1 or more protective layers that encase the seed Seed Coat- Consists of 1 or more protective layers that encase the seed Cotyledon- A seed leaf that stores food in the form of starch and protein for use by the embryo Cotyledon- A seed leaf that stores food in the form of starch and protein for use by the embryo Epicotyl- The portion of the embryonic stem above the point at which the stem is attached to the cotyledon(s) Epicotyl- The portion of the embryonic stem above the point at which the stem is attached to the cotyledon(s)

Germination Germination – A seed sprouting or starting to grow Germination – A seed sprouting or starting to grow Dormant – Resting stage, no active growth Dormant – Resting stage, no active growth To germinate the seed must be placed in certain favorable conditions To germinate the seed must be placed in certain favorable conditions The 4 environmental factors that must be right for effective germination are water, air, light, and temperature The 4 environmental factors that must be right for effective germination are water, air, light, and temperature

Germination-Water Imbibition (the absorption of water) is the 1 st step in the germination process Imbibition (the absorption of water) is the 1 st step in the germination process It allows the seed to fill all of its cells with water It allows the seed to fill all of its cells with water A good germination medium is important – (Too dry – death of the embryo) (Too wet – Rotting) A good germination medium is important – (Too dry – death of the embryo) (Too wet – Rotting) In some species the seed coat is very hard and water cannot penetrate the endosperm. The seed can be scarified (nicking the seed coat with a knife or file) to remedy this. In some species the seed coat is very hard and water cannot penetrate the endosperm. The seed can be scarified (nicking the seed coat with a knife or file) to remedy this. Also can soak the seed in concentrated sulfuric acid or soaking the seeds in hot water for 12 to 24 hours Also can soak the seed in concentrated sulfuric acid or soaking the seeds in hot water for 12 to 24 hours

Germination - Air Viable seed is alive and capable of germinating, respiration takes place in all viable seed Viable seed is alive and capable of germinating, respiration takes place in all viable seed Oxygen is required Oxygen is required As germination starts, the respiration rate increases As germination starts, the respiration rate increases Germination will be reduced or inhibited if oxygen supply is limited or reduced Germination will be reduced or inhibited if oxygen supply is limited or reduced

Germination - Light Some seeds are stimulated to grow by light and some are inhibited by the presence of light Some seeds are stimulated to grow by light and some are inhibited by the presence of light Many agronomic crops do not require light Many agronomic crops do not require light Many ornamental bedding plants are more likely to require light for germination. Ex – Impatiens, Petunia Many ornamental bedding plants are more likely to require light for germination. Ex – Impatiens, Petunia

Germination-Temperature Heat is important for germination and effects the germination rate Heat is important for germination and effects the germination rate The only way to control field crops is to plant when the ground is warm The only way to control field crops is to plant when the ground is warm A knowledge of the heat requirement is required in plants grown in greenhouses A knowledge of the heat requirement is required in plants grown in greenhouses

Monocot Germination

Dicot Germination Dicot Germination

Asexual Propagation Stem Cuttings Stem Tip Cuttings Stem Tip Cuttings Stem Section Cuttings Stem Section Cuttings Cane Cuttings Cane Cuttings Heel Cuttings Heel Cuttings Single-Eye Cuttings Single-Eye Cuttings Double-Eye Cuttings Double-Eye Cuttings *Cuttings are usually treated with fungicide to prevent diseases and rooting hormone that will react with the newly formed cells and encourage the plants to develop roots faster.

Heel Cutting Single Eye Cutting Cane Cutting Double Eye Cutting

Asexual Propagation Leaf-Type Cuttings Leaf Cuttings Leaf Cuttings Leaf Petiole Cuttings Leaf Petiole Cuttings Leaf Section Cuttings Leaf Section Cuttings Split-Vein Cuttings Split-Vein Cuttings

Asexual Propagation Root Cuttings

Asexual Propagation Simple Layering

Asexual Propagation Tip Layering

Asexual Propagation Air Layering

Asexual Propagation Division

Asexual Propagation Grafting= T-Budding

Asexual Propagation Tissue Culture