Aesexual Plant Propagation Flashcards
what is plant propogation
the arts and science of the production of more plant
what are the 2 types of plant propagation
sexual -seed
asexual - vegetative
what is fundamental differences between sexual propagation
- sexual exchange of genetic info
- asexual - cloning- no exchange of genetic info
examples of asexual propagation
- divison
- cuttings
- grafting
- tissue culture
what is production of seeds and example of
sexual reproduction - exchange genetic material
between 2 parents
t or f ; ornamental plant come true from seeds
false; use asexual propagation to get exact clones
t or f any seed harvested from a cultivar will not produce seedlings identical to the parent- genetic variation
true
what is seed grown selection termed as
- seed grown selection is ‘ strain’= not genetically identical
what are 5 reasons to use vegetative propagation?
- poor seed production
- poor seed viability
- no seed available- sterile plant
- only 1 specimen available
- clone- preserve genetic info
what are 3 parts of plant can take cuttings from ?
- leaf
- root
- stems - herbaceous, softwood, hardwood
when do you take softwood cuttings? when do you take hardwood cuttings?
- softwood- late spring to early summer
- hardwood- late fall- late inter
what are stock plants/ mother , what should they have
- parent plants used in asexual propagation
- good health, desirable characteristics for production of new plants
describe division
- cutting or breaking up of a crown or clump of suckers into segments
what must characteristics must a segment taken from a cutting possess?
- bud and roots
describe process of cuttings
- removing a piece from parent and that piece the regrows the lost parts of the tissue
t or f cuttings can be done in both woody and herbaceous plants
true- as long as plant will form adventitious roots
- vegetatively growing plants
- once flowering initiated hard to do
why can you use cuttings for asexual reproduction?
each living plant cell contains ability to duplicate all plant parts
describe leaf cuttings?
- leaf blade or leaf with a petiole to propagate new plants
- trim 1/4 of leaf, dip into rooting hormone, insert rooting medium
- new plants from at base of leaf
t or f; in leaf cuttings the original leaf is part of the new plant
false; usually discarded
describe root cuttings
when should it be done
- take cutting of roots on angle
- during dormant season when roots have largest CHO supplies
describe stem cuttings
- injured xylem and phloem cells plug tubes so fluids preserved
what is formed when taken a stem cutting
- callus formed, cells nearby form adventitious roots
what are herbaceous cutting?
- taken from non woody plants (perennials, houseplants)
what are softwood cuttings
- pieces of new growth taken from woody stock plants
- must be taken from new growth before starts to harden into woody
what are hardwood cuttings
- taken from tissue which has become woody- usually dormant
t or f; stem cuttings are most commonly used method to produce herbaceous plants asexually
true
what conditions should be applied for effective cuttings
- healthy plants
- bottom heat
- warm and moist
what is the most common rooting hormones used commercially
- IBA = synthetic IAA (auxin hormone)
what cutting would you want to use the lowest –> highest strength of rooting hormone?
lowest softwood- herbaceous
med is semi hardwood
highest- hardwood
what is also used in addition to rooting hormone? why?
- fungicide ; counters damp conditions
when are softwood cuttings taken?
- first year branches- not woody
- best late spring early summer after rain
why should you make diagonal cut?
- increase surface area for roots to develop
what is the best indicator softwood is ready to cut?
- softwood snaps when bent
when is best time to take hardwood cuttings?
- late fall after a killing frost late winter
describe grafting
- involves joining of different segments of 2 different plants
- scion is joined to an understock
- cambium layers of 2 different segments are aligned and growth together
why use grafting techniques?
- affect mature height of plant - dwarfing rootstocks
- affect hardiness of plant - ex hybrid tea roses
- produce plant that will not grow adventitious roots
- produce plant in an ‘ unnatural form’ or shape ex weeping
true or false, grafting work for all plants
false; only gymnosperms and perennial dicots
why does grafting only work for gymnosperms and perennial dicots
monocots dont have cambium layer –> need secondary growth
what are 3 types of grafting?
- cleft
- budding/ chipping
- whip grafting
what is the scion
- upper part of plant
- ornamental or fruiting characteristics
- plant with features the grower wants
what is the understock?
- roots and stem
- hardiness
- size potential
- upright for weeping branches
when is grafting usually done?
spring - collect several weeks before grafting is to occur
-scion wood collected in winter when dormant
what wood should be selected for grafting
- grew previous year
- have leaf NOT flower buds
what is critical to ensure successful grafting
- cambium layers on scion precisely matches understock
describe cleft graft
- simplest way to graft
- scion cut into vertical to match understock wedge
what tools can be used for grafting
budding knife
budding tape
what is t/ shield budding?
- take bud from scion and graft to understock material
- slit understock, place bud in and tape back over
what is chip budding?
bud is cut out with a chip of the underlying wood
-chip needs to be same size as the stock piece in order for cambia to align
what is tissue culture propagation?
groups of plant cells are manipulated so they can produce a new plant
what are advantages of tissue culture?
- fast
- efficient
- disease- free plants
problems with tissue culture propagation
- increased risk of spontaneous mutations occur
- sterile conditions bust be maintained- exact temp, light, humidity and atmosphere controlled with electronic sensors and computerized controls –> COSTLY
describe stages in tissues
stage 1: start with specimen ; growth tip excised , sterilized
-exposed to tube with nutrients and low auxin to cytokinin ratio
stage 2: shoots multiply , cut again at set intervals
-# increase until desired amount met
** both 1 and 2 done in climate controlled room
stage 3: expose to high auxin low cytokinin ratio –> shoots start to produce roots as opposed to more shoots
stage 4: plants put in soil
