Plant Propagation, Pruning, Bonsai, & Genetics

Division

A plant propagation technique, which involves cutting the crown of a plant into parts so that each part has a portion of shoot and root attached

Grafting

The joining together of plant parts so that they grow as one, must be done within a clone, species, or a genus

Scion

In grafting, the portion of the graft that is attached; chosen because it is a desirable genotype or cultivar for fruit production or pollination

Rootstock

In grafting, the portion of the graft on which the scion is attached; chosen because it can control size, influence maturity of fruit, increase winter hardiness, and offer disease, insect, or other stress resistance

Micropropagation

The multiplication of plants in vitro (in glass) under sterile conditions on an agar medium, which includes all nutrients, hormones, and sugars needed for optimum growth

Hardwood

The mature growth of a species that forms hardwood; somewhat difficult to propagate using stem cuttings

Humidity Tent

White plastic shading used during plant propagation to create a high humidity environment and reduce heat build-up

Intermittent mist system

Watering system on a timer used during plant propagation to maintain a film of water on the leaf surface, reduce transpiration and respiration, and lower leaf temperature

Layering

A plant propagation technique where the roots of the new plant are formed while still attached to the parent plant, two kinds: air layering and tip layering

Leaf Cutting

A type of asexual (vegetative) propagation, which includes a leaf or a portion of a leaf, must form both roots and shoots

Leaf-bud cutting

A type of asexual (vegetative) propagation, which includes node, bud, and leaf, used when leaf cutting will not form a shoot, must only form roots

Physiological dormancy

A type of dormancy in which the seed's physiology inhibits germination; stratification (moist chilling) will overcome it

Physical dormancy

A type of dormancy in which the seed's physical structure inhibits germination; scarification (abrading the seed coat) will overcome it

Clone

A population of individuals that originate from one individual and are genetically uniform; however, they may differ in phenotypic expression due to environmental factors

Plant Propagation

Use of seeds or vegetative plant parts to produce more plants under the proper growing conditions of sanitation, moisture, and temperature

Primary dormancy

A dormancy which occurs as the seeds are harvested, sometimes due to an immature ovary or due to a need to receive an after-ripening treatment

Root Cutting

A type of asexual (vegetative) propagation, which includes a piece of a root, must form both roots and shoots; cuttings taken during winter because of maximum stored energy

Secondary dormancy

A dormancy which occurs in a seed caused by physiological or physical reasons

Seed dormancy

When viable seed fail to germinate when given optimal conditions due to inhibition by their own physiology, anatomy, or both; usually determined by environmental conditions of the native habitat

Semi-Hardwood

The mid-summer growth of a species which forms hardwood; somewhat easy to propagate using stem cuttings

Softwood

The early spring growth of a species which forms hardwood; fairly easy to propagate using stem cuttings

Stem Cutting

A type of asexual (vegetative) propagation, which includes a portion of the stem, with or without the apical bud, can be made from softwood, semi-hardwood, or hardwood, needs to form roots only

Bonsai

A specialty type of pruning of roots and shoots allowing the plant to be maintained as a miniature

Branch Collar

An area where the xylem from the trunk wraps around the xylem from the branch but is separate from it allowing the branch to be cut off with only branch's xylem damaged

Compartmentalization

A response in a plant to a wound where the plant walls off or forms a compartment around the injury to prevent disease and closes the wound using the plant's branch collar

Crossing Branches

Limbs that rub against each other so that there is always an open wound present; should be removed to promote and maintain the health of the plant

Dead Zone

In pruning of needle evergreens, an area where there are no needles and no latent buds; pruning should be done to just outside this area

Espalier

A specialty type of pruning where a plant is trained on a trellis or a wall

Hand Pruners

A pruning tool used to remove material < ½ inch in diameter; want the scissor type not the anvil type

Heading Back

A type of pruning, which cuts back to a bud

Loppers

A pruning tool used to remove material ½ inch to 1 ½ inches in diameter

Pruning

The removal of parts of the tops or roots of plants

Rejuvenation

A type of pruning, which cuts everything back to 12 inches or less used on some shrubs that have many latent buds that can break; good for invigorating a non-flowering shrub, reducing a shrub's size, or re-establishing a shrub's shape

Saw

A pruning tool used to remove material > 1 ½ inches in diameter

Shearing

A specialty type of pruning that should be confined to formal hedges; used on plants with small leaves, short internodes, dense branches, and latent buds that will break; the base should be wider than the top, and only sheared to within ½ inch of the previous

Thinning

A type of pruning, which removes the entire branch at its base

Topiary

A specialty type of pruning where plant is pruned into an interesting shape

Topping

A type of pruning, which removes large branches without regard to location of the cut, causing many latent buds to break and grow very aggressively; these buds, however, are weakly attached; should never be used

Water Sprout

Latent buds that grow very rapidly and should be removed to promote and maintain the health of the plant

3-Step Cut

A type of pruning for large branches to prevent tearing of the wood on the trunk; the three steps are: 1. undercut ½ way through the branch, 2. cut ½ way through on the upper side of the branch, and then 3. remove the stub at the branch collar

Cross-Pollination

Process where the pollen from the flower's anthers pollinates and fertilizes another flower's stigma and ovules

Fertilization

Process that occurs after pollination, when the pollen grain germinates on the stigma and a pollen tube grows down through the style, and enters the ovary resulting in the formation of a seed

Genotype

The genetic makeup of the plant, which is defined by the nucleotide sequence of the DNA, and is responsible for how the plant grows and develops

Heredity

Passing of genetic information from one generation to the next, like begets like

Hybrids

In plant breeding, a plant whose parents are from two different specimens, e.g. a nectarine is a cross between a peach and a plum; often done to increase size or vigor of the offspring by bring together favorable dominant genes

Meiosis

A process of cell division in which the chromosomes do not replicate themselves in the nucleus, resulting in cells with only half the number of chromosomes; occurs in the reproductive parts of the plant: anthers to form pollen and ovaries to form the ovule

Mitosis

A process of cell division in which chromosomes replicate themselves in the nucleus before the cell divides resulting in two daughter cells that are genetically identical to the mother cell; it occurs in the meristem of plants

Mutation

A sudden, unexpected heritable change in a gene or chromosome that can produce a sport; it can occur spontaneously, or may be induced by radiation or chemical mutagens

Nucleus

Structure inside the cell, contains the plant's genetic material (DNA and RNA); it also has a membrane

Phenotype

The visible result of an interaction between the genotype and the environment, what it looks like to the eyes

Pollination

The process where pollen lands on the stigma for the purpose of fertilization; pollen can be transmitted by the wind and insects, such as bees and butterflies

RNA

Ribonucleic acid acts as a messenger between DNA and the ribsosomes and is used in the process of protein synthesis; three forms: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA)

Replication

The process in cell division where two identical daughter DNA molecules are formed

Self-Pollination

Process where the pollen from the flower's anthers pollinates and fertilizes its own stigma and ovules

Stable Varieties

In plant breeding, a plant that nearly always breeds true, that is the offspring have the same characteristics as their parents, e.g. Mackintosh apples

Transcription

Process where RNA is copied and synthesized from a DNA sequence; the transfer of genetic information from DNA to RNA

Translation

Process where RNA, which was transcribed from a DNA sequence (gene), serves as the template for the translation of genes into proteins, by transferring amino acids, to the correct place in the protein; proteins are chains of amino acids.