Geophytes & Other Specialized Structures Flashcards
1
Q
Back Bulbs
A
- the pseudobulbs that do not have foliage
- an old pseudobulb from which the leaves have dehisced
2
Q
Basal Cuttage
A
- the practive of cutting into the base of a bulb to stimulate adventitious bulblet formation on the base of scales
- two types: scooping and scoring
- used for bulbs that have slow natural increase (hyacinth)
3
Q
Basal Plate
A
- the short thickened stem of a bulb
- modified stem
4
Q
Bulb
A
- a specialized underground organ
- consists of:
- modified stem: basal plate (a shot, fleshy, stem axis)
- a growing point or flower primordium at the apex of the basal plate
- enclosed by thick fleshy scales (the leaf base that contains stored food)
- types:
- Tunicate/Laminate (papery covering)
- Type 1 (leaf scales. Tulip)
- Types 2 (swollen leaf bases. Amaryllis)
- Type 3 (both leaf scales and swollen leaf bases. Daffodil & Iris)
- nontunicate (no papery covering. ex: Lily)
- can be propagated by:
- natural offsets - most common
- seed propagation
- aerial bulbils
- stem cuttings (some lilies)
- scaling in non-tunicate bulbs
- leaf cuttings (grape hyacinth, blood lily)
- basal plate cottage - scooping, scoring
- bulb cuttings - chipping, twin-scaling
- micropropagation
5
Q
Bulb Chipping
A
- also called bulb cutting, fractional scale-stem cottage
- a method of propagation in which a bulb is cut into gragments of 3 or 4 bulb scales attached at the basal plate
6
Q
Bulblets
A
- a miniature bulb
- forms in the axil of a bulb scale
- provides a method of vegetative propagation
7
Q
Bulbil
A
- a type of bulblet
- produced in the aerial portion of the plant
- enclosed within a dry, membranous scale
8
Q
Contractile Roots
A
- the thickened, fleshy roots
- that pull the bulb to a deeper layer in the soil
- by shrinking and expanding
- don’t function very well for nutrient uptake (thats what fiberous roots do)
- not all bulbs produce contractile roots
- lilies have them
9
Q
Corm
A
- a unique geophyte structure
- in which the base of the stem axis is:
- swollen,
- has nodes and internodes,
- and is enclosed in a dry membranous tunic
- is a solid piece of stem
- apex of corm is terminal shoot that will develop into leaves and the flowering shoot
- polar
- mostly storage tissue composed of parenchyma cells
- generally have fibruous roots (for nutrient and water uptake) and contractile roots (to get corms to proper depth)
- new corms often form ontop of old corms (which disintergrate) with new cormels forming at base
- sometimes new corms just stack up on old corms, which persist
- sometimes new corms are produced on stolons (produced laterally form the base)
- can be propagated by:
- natural cormel offets - most common
- seed propagation
- division of large corms
- micropropagation
10
Q
Cormels
A
- a miniature corm produced on a short stolon from the base of the corm
- they develop between the old and new corms
11
Q
Droppers
A
- a special kind of bulblike structure
- occuring in tulips
- which grows to a deeper level to produce a new bulb
- a stolon that forms a bulb at its tip
- another mechanism to move the bulb down to its proper depth
12
Q
Eyes
A
- the clusters of buds at the nodes of the potato tuber
13
Q
Geophytes
A
- types of plants that survive part of their annual life cycle as a dormant, fleshy, underground structure
- 2 principle climatic cycles for which geophytes are adapted:
- the warm-cold cycle of temperate zones
- the wet-dry cycle of tropical and subtropical zones
- functions:
- aids in survival in adverse conditions as storage of food, nutrients, and water
- allow clonal regeneration of species (so often reproduce both sexually and asexually)
14
Q
Leptomorph
A
- types of rhizome growth
- that exhibits indeterminate growth
- slender with long internodes
- not as fleshy (more stolon like)
- lateral buds at each node may remain dormant or produce new shoots
- can continue to develop new plants at each node
- will spread far and wide - does not form clumps
15
Q
Mesomorph
A
- the rhizome growth type
- intermediate between the two forms: leptomorphs and pachymorphs
17
Q
Nontunicate Bulb
A
- also called scaly bulbs
- type of bulb
- does NOT have the papery covering
- has seperate ‘scales’ attached at the basal plate
- are easily damaged and prone to drying
- Lily
19
Q
Pachymorph
A
- a type of rhizome growth
- that exhibits determinate type of growth
- are larger
- little more storage
- slow growing
- each season’s growth terminates with a flowering bud
- can see last season’s terminal shoot - scar
- vegetative growth continues at the lateral bud
- forms clumps
20
Q
Pseudobulbs
A
- an enlarged, special storage structure produced by many orchid species
- consisting of an enlarged, fleshy section of the stem made up of several nodes
- assist plants to survive during dry periods
- can be either:
- back bulb - it is leafless
- green bulb - has leaves
- they only differ by age
- can be propagated by:
- seed division
- division - common
- back or green bulb cuttings
- micropropagation
21
Q
Rhizome
A
- a horizontally growing stem of specific plant species at, or near, the surface of the ground
- modified shoot tissue
- growing at or near the surface
- fuctions as sotrage tissues (where as stolons done)
- mostly in monocots
- is two types:
- pachymorphs
- leptomorphs
- can be propagated by:
- seed propagation
- division of rhizome sections - common
- micropropagation - few
23
Q
Scaling
A
- .a propagation procedure in which individual scales are removed from the mother bulb and placed under appropriate conditions to cause the formation of adventitious bulblets
- usually 3 to 5 bulblets will develop from each scale
- on lily species
- is done soon after flowering in midsummer, although it might be done in late fall or even midwinter
24
Q
Scooping
A
- a type of basal cuttage
- carried out by cutting away the basal plant with a special scoop-like device
- need to destroy the apical meristem
- adventitious bulblets develop from the base of the exposed bulb scales
25
Q
Scoring
A
- a type of basal cuttage
- carried out by cutting at right angles across the base of the bulb
- cuts need to be deep enough to destroy the apical meristem
- growing points in the axils of the bulb scales grow into bulblets
26
Q
Tuber
A
- a swollen modified stem with:
- nodes and internodes
- functions as:
- storage structure
- an organ of vegetative propagation
- underground
- can be propagated by:
- division of the tuber - needs to include bud
- seed propagation
- aerial tubercles
- stem cuttings
- micropropagation
27
Q
Tubercle
A
- the small aerial tubers produced in leaf axils of certain plant species
- usually produced in short days
- appear on plants in late summer
- are easily removed from the plant
- can be dried and stored overwinter for spring planting
28
Q
Tuberous Root
A
- an enlarged fleshy root (modified root)
- as a storage organ
- are polar (shoots at one end and roots at the other)
- example: sweet potato, carrots
- tuberous roots are modified root tissue, while tubers are modified stem
- can be propagated by:
- seed propagation - common
- division of crown w/ tuberous roots attached - common
- stem cuttings - common for sweet potato
- micropropagation
29
Q
Tuberous Stem
A
- the swollen stem structure
- produced by enlargement of the hypocotyl
- ex: cyclamen, tuberous begonia
- have a vertical orientation
- one or more vegetative buds produced on the upper end of the crown (at the surface)
- can be perennial
- can be propagated by:
- seed propagation - common
- division
30
Q
Tunicate Bulb
A
- also called Laminate
- type of bulb
- outer layer of bulb scale are dry and papery
- provides protection from drying & mechanical injury (doesnt bruise as easy)
- inner fleshy scales are continious, concentric
- gives bulb solid feel
- 3 types:
- Type 1
- leaf scales
- scales arise from the basal plate
- foilage leaves arise from flowering stem
- Tulip
- Type 2
- leaves with swollen bases
- arise from basal plate and inflorescence
- Amaryllis
- Type 3
- both leaf scales and swollen leaf bases
- Daffodil & Iris
31
Q
Twin Scaling
A
- a variation of bulb cutting
- using a segment of two scales with a portion of the basal plate
- important in propagation of Narcissus
