Module 3 Flashcards
Parts of Mature Seed (3)
Seed Coat
Cotyledon(s)
Embryonic Axis
Parts of the Embryonic Axis (3)
Plumule
Radicle
Hypocotyl
Rudimentary leaf of the embryo of the seed plant that could either remain or emerge upon germination
Cotyledon
Protective outer covering of a seed
- Derived from outer integument of the ovule
- Smooth, thick and impermeable
- Brownish in color
- Plays a role in seed dormancy
Testa (Endo- and Exo-)
Protective inner layer of the seed
- Derived from inner integument of the ovule
- Thin and membranous
- White or hyaline in color
- Protects embryo from dehydration and mechanical damage
Tegmen (Endo- and Exo-)
Part of the embryonic axis that projects above the cotyledon
Epicotyl
Portion between cotyledon and radicle
Hypocotyl
Composed of epicotyl, young leaves, and SAM
Plumule
Embryonic Root
Radicle
Food reserve in monocots
Endosperm, absorbed by the scutellum (single cotyledon)
Main differences of non-endospermic seed from endospermic seed (4)
- Absent endosperm
- Food stored in cotyledons
- Thick and fleshy cotyledons
- Perisperm form nucellus
Sum of events that begins with hydration of the seed and culminate in emergence of the embryonic axis (usually the radicle) from the seed coat
Seed Germination
Two types of germination
Epigeal and Hypogeal
Characteristics of Epigeal Germination (2)
- Cotyledons emerge form soil w/ plumule
- Hypocotyl Elongates and forms hook for foliage expansion
Characteristics of Hypogeal Germination (2)
- Cotyledons remain in soil
- Epicotyl elongates pushing plumule out to form hook with plumule pointing downward
2 sheaths enclosing the embryo and their funcitons
Coleorhiza - Covers the radicle
Coleoptile - Covers the shoot
2 main types of root systems
Tap root and Fibrous
Taproots are defined by
Large downward vertical primary root from which secondary roots arise
Fibrous roots are:
Also called adventitious roots
Located close to soil surface
Dense network of roots
In areas with abundant water
True or False: A plant can both be fibrous and tap
True.
Types of root modifications based on physiological functions (8)
Storage
Aerial
Assimilatory
Reproductive
Respiratory
Epiphytic
Saprophytic
Parasitic
Type of root based on mechanical functions (7)
Prop
Stilts
Buttress
Climbing
Contractile
Floating
Root-thorns
Type of root present in mangroves, allows for gas exchange
Pneumatophores, Stilts
Types of storage tap root (4)
Conical
Fusiform
Napiform
Tuberous
Thicker at upper side and tapers at basal end, cone-like.
Ex. Carrot, give scientific name
Conical enlarged tap root
Daucus carota
Tapers at both ends
Ex. Radish/Labanos, give scientific name
Fusiform Enlarged tap root
Raphanus sativus
Swollen and spherical at upper end and tapering to thread like at lower end
Ex. Turnip/singkamas and sugar beets, give scientific names
Napiform Enlarged taproot
Turnip/Singkamas: Brassica rapa
Sugar Beet: Beta vulgaris
Do not have regular
shape; swollen and fleshy at any portion of roots
Ex. Four-o-clock flower, give scientific name
Tuberous enlarged taproot
Mirabilis jalapa
Types of Adventitious Storage roots (6)
Tuberous
Fasciculated
Nodulose
Moniliform
Annulated
Palmated
Do not have definite
shape and occurs singly swollen to store food; presence of pencil root
Ex. Sweet Potato, give scientific name
Tuberous Adventitious Roots
Ipomoea batatas
Arising in cluster
from the base of the stem
Ex. Dahlia, Cassava/Kamoteng-kahoy, Asparagus,
give scientific name of cassava and asparagus
Fasciculated Adventitious Roots
Manihot esculenta
Asparagus officinalis
Swollen at tips commonly in legumes, shelter N-fixing bacteria (Rhizobium)
ex. Mango ginger, give scientific name
Nodulated adventitious roots
Curcuma amanda (Mukhang luya shape na parang gagamba na may matatabang legs)
Swollen at frequent intervals
Ex. Purple yams/Ube and Ampalaya, give scientific name of both
Moniliform or beaded adventitious roots
Dioscorea alata
Momordica
Yields emetine that
looks like discs placed one above another
Annulated Adventitious roots
In Orchis there is a pair of succulent tuberous root, one of which perishes every year while another new one is formed by its side.
Such orchid roots may sometimes be of palmate shape
Palmate adventitious roots
Adventitious roots for Mechanical Support (7)
Prop
Stilt
Climbing
Buttress
Floating
Contractile
Root thorns
Arising from horizontal aerial branches of trees
Provide support to the spreading branches of the tree
Hygroscopic when young
Possess root caps at their apices
Grow vertically downward penetrating the soil
Become thick and assume the shape of pillars
Prop roots
ex. balete tree (Ficus stipulosa)
Aerial adventitious obliquely growing roots from the lower nodes of the stem
Stilt roots
ex. Pandan tree (Pandanus sp.)
Special type of stilt roots in mangrove provides aeration through this structure
Lenticels
Differentiate stilt from pneumatophore roots
Stilt: Attachment point of all roots above water
Pneumatophore: Roots go under and then spike back up
arise from the nodes or internodes of weak stemmed plants to climb up their support
Can be tendrillar or clinging
Climbing roots
Differentiate tendrillar from clinging
Tendrillar Single at each node
Clinging (short branched, adventitious roots arise from each node
Horizontal plank aerial roots that develop at the base of the stem on the soil surface
Buttress/Ballast
store air, become inflated and spongy, project above the level of water, make the plant light and function as floats
Floating Roots
Plants with underground stems contract or swell so that the aerial shoots are kept in a proper depth in the soil
Contractile/Pull roots