Exam 1 Flashcards
Legumes
member of the Fabacea 600 genra and 12,000 species can fix atmosperic nitrogen symbiotically with N-fixing bacteria often seeded into pasture as important component to increase forage quality and yield
Rhizobia
N-fixing bacteria that grow on nodules on roots
Monocarpellary
one-chamber, containing one seed per pod or a single row of seeds in a pod
2= alfalfa: more than one seed/pod
4= Hairy Vetch: more than one seed/pod
6= Korean lespedeza: one seed/pod
8= Cowpea: more than one seed/pod
1= sweetclover: one seed/pod
3=Red clover: one seed/pod
5= Common lespedeza: one seed/pod
7= Field Pea: more than one seed/pod
Legumes
-Seeds dehisces along sutures or ribs
Advantage: naturally disperse seeds
Disadvantage: problem for commercial seed production because of easy shattering
Legume Leaves
arranged alternately on stem, usually attached to the stem by a stalk called a petiole
Simple leaf
single leaf blade attached directly to the petiole
(unifoliate)
Compound leaf
three (trifoliate) or more leaf blades are individually connected to the petiole by a short stalk called the petiolule
Stipules
leaf-like appendages connected directly to the stem near the junction with petiole
Pinnate
when petiolule of central leaflet is longer than the lateral leaflets
Palmate
all petiolules are equally short in length
Most important stages
- Vegetative
- Elongation
- Boot
- Heading
- Anthesis
- Mature Seed
Vegetative
unelongation tillers producing leaves only
Elongation
elongated internode with elevating shoot apices
Boot
inflorescences are sheath of flag leaf
Heading
inflorescensces emerged and expanded
anthesis
flowers started shedding pollen
Mature Seed
fully developed inflorescences and ripened seed
Florets
grass flowers, consisting lemma, palea, and flower parts; two glumes are attached at the base of the spikelet
Inflorescence
reproductive part consists of spikelets (basic reproductive unit or floret)
-cluster of flowers
Spike
spikelets are sessile i.e. directly attached to rachis (central stalk)
e.g. wheat, western wheatgrass, perennial ryegrass
Raceme
spikelets have short stalks (pedicels)
e.g. big bluestem
Panicle
most common, branched and has pedicels
e.g. smooth bromegrass, switchgrass
Tillers
new leaves and stem originating from axillary buds
phytomer
consists of 5 parts:
- node
- internode
- leaf sheath
- leaf blade
- axillary bud
Rhizomes
underground horizontal stems with scalelike leaves (cataphylls) and axillary buds at the nodes
Stolons
- aboveground* lateral stems with nodes, capable of producing new plants
- good for persistence and growth
Stems: 2 distinct forms
- short, non-reproductive or vegetative tillers having nodes and unelongated nodes
- adaptive mechanism to keep shoot apex and short stem in the older sheaths and near the ground, thus escaping from grazing
- elongated stems (culms) bearing distinct nodes and internodes
1.
sheath
tubular basal protion that encloses stem
-open, closed, overlapping
Blade
flat, expanded part, above the sheath, major photosynthetic organ
Ligules
appendages (fringe of hairs) at the joining place of sheath and blade
Auricles
earlike appendages projecting from blade near collar
Collar
hardened region at the junction of the sheath and blade
Leaves
Grow on stem, appear alternately at each node in two opposite rows
Consist of: sheath, blade, ligule (includes collar), auricles (some cases)
morphology
structure and arrangement of plant parts; in general- growth habit and structure
Structure
form or shape of plant parts
-in way which plant parts are organized, built or put together
Grasses
*Importance
- ~785 genera worldwide
- ~10,000 species worldwide
- ~170 genera; ~1400 species only in the US
- One of the largest plant families
- Poaceae
- old name Graminae
- Poaceae
- Consists of both c3 and c4 plants making wider range of adaptation
Annuals
eg. small grains, corn
perennials
eg. tall fescue, western wheatgrass
Grass seed
Caryopsis
all grass seed units
specialized fruit
What arae the roles of lemma, palea and seed coat?
Lemma, Palea, and Seed coat (ovary wall) protect caryopsis from mechanical damage, moisture loss, and attack from biological pests
Caryopsis
consists largely of endosperm (starchy tissue)- storehouse of energy!
Embryo consists of two parts:
- Cotyledon (Scutellum)- first leaf
-
Embryo axis- central cylindder connected to scutellum; consists of three major parts
- coleoptile
- subcoleoptile internode
- primary root (radicle)
Coleorhiza
a protective sheath for protecting the root tip during germination
Legume Stems
vary significanty in terms of length, diameter, branching, and woodiness
Legumes Prostrate
lateral growth of stem allows shoot apex to be remained in near ground, thus protecting shoot tips by cutting or grazing
Inflorescence:
usually two types:
Raceme
Umbel
Raceme
may be spikelike (eg. alfalfa or sweetclover) or very compact (eg red and white clovers) reffered to as head
Umbel
umbrella like flowering
papilionaceous
buterfly or pea-like
Corolla consists of 5 petals, namely
standard
wing
keel
epigeal
epi=above
geal= earth
emergence in which cotyledons are pulled above the surface
hypogeal
hypo= below
emergence in which cotyledons remain below ground
Contractile growth
the process by which the first node where crown forms pulls back below the surface soil
Advantages/disadvantages to epigeal and hypgeal emergence
- epigeal:
- cotyledons protect epictyle including the shoot apex and young leaves during germination
- through sunlight, cotyledons produce food for seedling by photosynthesis
- Hypogeal
- advantageous if young seedling is cut or frosted back to soil level
- because of the belowground cotyledons with nodes, they can regrow from buds, while epigeal cannot
