Asexual Reproduction

Question 1

asexual (nonsexual)

Answer 1

no fertilized ovules

Question 2

clone

Answer 2

genetically identical

Question 3

Why clone?

Answer 3

uniformity in plants

Question 4

Why asexual propagation?

5 key reasons

Answer 4

• to multiply sterile or seedless species
• combine properties of two plants (grafting/budding)
• more efficient
• minimize juvenile period
• avoid seed dormancy

Question 5

Categories of Vegetative Propagatoin Methods

Answer 5

Specialized Stuctures
Cutting & Layering
Grafting & Budding
Tissue Culture
Apomixis

Question 6

apomixis

Answer 6

asexual reproduction in plants

Question 7

Specialized structures take advantages of..

Answer 7

naturally occurring plant structures

Question 8

Types of specialized structures

Answer 8

bulb (underground stem and leaves)
tuber (underground fleshy stem)
corm (underground stem)
stolon (runner above soil surface)
rhizome (horizontal stem below ground)
offshoot (lateral shoot from stem)
foliar embryos (plantlets along leaf margins) 
suckers (shoots arising from roots)

Question 9

Cutting

Answer 9

a vegetative structure is removed from the plant, then new shoots/roots develop

Question 10

Layer

Answer 10

new roots/shoots develop first, the the vegetative structure is removed from the plant

Question 11

stock plant

Answer 11

the plant that provides the vegetative structures

Question 12

Types of cuttings

Answer 12

herbaceous; stem tip, leaf-bud, leaf-petiole

woody; hardwood, semi-hardwood

Question 13

Conditions for success with cuttings

Answer 13

reduced transpiration & avoid drying
-shading, humidity tent, sprinkling, misting, fogging
energy source
-light source, keep leaves on cutting
warm roots / cool shoots
-promotes root development over shoot growth
good rooting medium
-hold water, excellent aeration, no disease organisms
root-promoting hormone
-auxin

Question 14

Negatives of layering

Answer 14

• labor intensive
• # of plants produced is smaller than relative cuttings
• used for species that cannot be propagated by cuttings

Question 15

Types of layering

Answer 15

• stem tip
• simple (place stem under soil, but tip of stem is exposed)
• trench (multiple of simple layering)
• mound or stool (vertically growing plants)
• air (when stem cannot make direct contact with soil)

Question 16

Grafting & Budding

Answer 16

joining of structures from two or more plants

grafting: twig section (scion) joined to shoot of another
budding: bud (scion) joined to shoot of another (rootstick)

Question 17

Why graft and bud?

Answer 17

• no other way
• “create a plant”
• avoid juvenility

Question 18

Types of grafts

Answer 18

cleft, whip & tongue, side (approach)

Question 19

Types of buds

Answer 19

chip, T-bud (shield), patch, flute

Question 20

Essential aspect for success of grafting & budding

Answer 20

the stem cambium layers of scion and rootstock must be joined and grow on together

Question 21

Tissue culture (definition for asexual propagation)

Answer 21

generation of new plants from small pieces of a plant’s tissue (leaf cells, bud cell, etc.) under sterile conditions

Question 22

Why use tissue culture?

Answer 22

• fast way to produce a huge number of plants
• can rid some plants of diseases they carry
• but high cost

Question 23

Tissue culture method

Answer 23

a piece of stockplant is removed, disinfected, and placed in vitro on nutrient medium under sterile conditions

induce shoots to form on tissue (hormones)

induce roots to form on shoots (hormones)

remove from in vitro culture and acclimate to “real world”

Question 24

Apomictic seed

Answer 24

a seed that develops without fertilization of an ovule

-all genetic information in the seed is a clone from the female parent