Environmental Science 150: Chapter 8

Mound layering

method of propagation in which various woody-stemmed plants (as currants, gooseberries, quinces) are cut back to the ground in early spring and the new shoots that they develop are covered with soil to a depth of six to eight inches to induce root growth which forms individual plants that can be removed in the fall - also called stool layering

Stem cutting

must have nodes above and below the media

Scion

a detached living portion of a plant (such as a bud or shoot) joined to a stock in grafting and usually supplying solely aerial parts to a graft

Propagule

a plant portion that can develop into a new plant

Layering to produce rooted cuttings

a portion of the plant is placed in contact with the soil while it is still attached to the mother plant and nicked to interrupt phloem flow - simple - mound - serpentine - air

Grafting

accomplished by joining two different plants to form a more desirable new plant

cleft graft

allows the union of a rootstock limb that is much larger in size than the scion piece

Micropropagation

very small portions of a plant are removed and placed on a nutrient enriched agar media in sealed containers

Underground plant: Separation

bulbs and corms

Totipotency

cell is capable of developing into a complete organism or differentiating into any of its cells or tissues

5. Chemical pinching agents

chemicals that selectively kill or disrupt shoot tips to remove apical dominance - atrial - off-shoot - maleic hydrazide - emgard 2007 *Know for test- the types*

Types of grafting

cleft graft, whip graft, and whip and tongue graft

hardwood cutting

cut from previous seasons growth

softwood cutting

cut from soft flexible spring growth

whip graft

graft made by interlocking a small tongue and notch in the obliquely cut base of the scion with corresponding cuts in the stock ex. predominant propagation method used on apples and is widely used on pear

whip and tongue graft

graft prepared by cutting both the scion and the stock in a sloping direction and inserting a tongue in the scion into a slit in the stock

2. dehorning

heavy drastic pruning of large limbs; should be avoided at all times; also called pollarding

Grafting Vegtabales

in the past, grafting was primarily used on trees, shrubs, and vines

Simple layering

layered shoots are encouraged to form roots while still attached to the parent plant

Grafting: Prerequisite-

match cambium of stock and scion

Air layering

method of propagating new trees and shrubs from stems still attached to the parent plant

3. Reduce water loss by removing

- flowers - lower leaves by using - bench covers - mist

Objectives for pruning

- health and safety - maintain desired form - dwarfing - Invigoration - increase productivity - equalize root-shoot ratio - develop strong branch framework

Types of Grafting: Best Practice

- make sure the cambium lines up - The two plants must be compatible - graft compatibility increases when the two plants are genetically related, have similar stem diameter and are dormant

1. place in damp media to root

- moisture - nutrients - support When a portion of a stem, root or leaf is cut from the sock plant

Disadvantages Asexual Propagation

- plant approaches lose viability quickly - number of plant propagules from a stock plant is low - diseases spread easily - more expensive than seed propagation

leaf cutting

- prevalent in propgating herbaceous plants - rely on meristemic tissues on the lead and petiole leaves that root without a stem or node

Apomixis

- produces seeds without the benefit of fertilization - produces genetically identical plants - occurs more frequently in polyploids - can be induced by using mutagens

Vegetative cuttings: Best Practice

- put two or more nodes in the soil - some foilage must be above the soil - remove 2/3 foilage, flower and flower buds - use weed and disease free media - orient the stem cutting correctly - use long and study tip or stem cuttings

Reasons for grafting

- quick maturation of new varieties - disease resistance - cold resistance

_____ are difficult to produce from seeds, so tissue culture is used to generate many clones

Orchids

advantages of asexual propagation:

- reaches maturity quickly - allows propagation of difficult plants - produces uniform growth - maintains unique characteristics

Asexual Reproduction:

- requires one individual - does not use gametes - produces genetically identical offspring: Clone - does not produce genetic variation

Sexual Reproduction:

- requires two individuals - use gametes - produces genetically different offspring: hybrid - produces genetic variation

1. vegetative cuttings as propagules

1. Place in damp media to root 2. process rate depends on 3. reduce water loss by removing 4. Different Cuttings

Asexual Propagation types:

1. Totipotency 2. Propagule

Branch Angles:

1. Wide (Y) crotch angle - very strong, select for when pruning 2. Narrow (Y) ctoch angle - very weak, selectively prune-out

Stages in graft union formation

1. callus formation by both stock and scion 2. the intermingling of calluses 3. new cambium develops in callus region 4. formation of new xylem and phloem to connect stock and scion

Types of pruning and Training:

1. heading back 2. dehorning 3. thinning out 4. pinching 5. chemical pinching agents 6. hedging 7. disbudding 8. root pruning *Know for test*

Commonly grafted species

- roses - citrus - apples - grapes

2. Success rate depending on:

- time of year - time of day - light source and intensity - water and humidity - temperature and bottom heat - age of wood - hormones - removal of flowers - removal of stem tips

Types of Asexual Propagation

- vegetative cuttings - grafting - budding - layering - underground plant parts - micropropagation - apomixis

Root Cuttings

- prevalent in propagating woody and tropical plants - root tissue is excised and placed in damp medium

_______ Roots only at the very obvious nodes; wax begonia roots easily at the nodes

Wandering traveler roots

8. root pruning

pruning of roots, usually with a shove, to prepare plants for transplanting

3. thinning out

removal of branches back to their point of origin, used to: - decrease density of the canopy - encourage other branches to grow and rejuvenate the plant - redirect growth

7. disbudding

removal of excessive flower buds on flowering plants

6. hedging

removal of growth flushes on hedges or shrubs to shape canopy and induce dense growth

1. heading back

removal of the terminal portions of a branch - increase density of the canopy - encourage branching

4. Pinching

removal of the young succulent tips of shoots

Underground plant: Division

rhizomes, tubers, stolons

Serpentine layering

simple layering repeated over and over again with the same stem - simply snake it in and out of the soil

Training

the practice that allows tree/shrubs growth to be directed into a desired shape and form

Pruning

the removal of a portion of a tree/shrub and is used to correct or maintain tree/shrub structure. - removal of plant parts, brnches, shoot tips, buds, roots, etc.

Budding

the reudimentary bud along with a small portion of the stem is used as scion material

Tip cutting

the terminal bus remains intact