Download Lesson 2

CRSS 2830
Lesson 2
Growth and Development of the
Turfgrass Plant
BOTANICAL CLASSIFICATION
OF TURFGRASSES
Angiosperms
(flowering plants)
•
Dicotyledons (dicots)
– broadleaf plants
•
Monocotyledons (monocots)
– grasslike plants
MONOCOTYLEDONS
• Family= Poaceae (Gramineae)
– Kentucky Bluegrass ‘Merion’
– Genus = Poa (bluegrass) could also be: annual
bluegrass, rough bluegrass, Canada bluegrass,
etc.
– Species = pratensis (Kentucky Bluegrass)
• Cultivar = Merion
MONOCOTS VS. DICOTS
• Monocots:
– Single seed leaf
– Parallel leaf veins
– Growing point soil level
– Fibrous root system
MONOCOTS VS. DICOTS
• Dicots:
– Two seed leaves
– Branched leaf veins
– Growing point at top of stem
– Often tap root system
TURFGRASS PLANT
STRUCTURE
• Roots:
– Stems:
• Crown = growing point (new leaves, roots,
stems)
• Flowering culm (inflorensence seedhead).
Usually not desirable in turfgrass areas.
Lateral stems
–Primary = tillers (vertical, upright)
–Secondary =
»Rhizomes = below ground
»Stolons = above ground
* Rhizomes and stolons have
horizontal or spreading growth
habit. Sod forming grasses.
EXAMPLES
• Stoloniferous turfgrasses:
– St. Augustinegrass
– Centipedegrass
– Creeping bentgrass
– Buffalograss
– Rough bluegrass
EXAMPLES
• Rhizomatous turfgrasses:
– Kentucky bluegrass
– Creeping red fescue
– bahiagrass
EXAMPLES
• Turfgrasses with both
rhizomes and stolons
– Bermudagrass
– Zoysiagrass
EXAMPLES
• Turfgrasses without rhizomes
or stolons (bunch-type):
– Tall fescue
– Perennial ryegrass
– Annual ryegrass
ORGANS OF TURFGRASS PLANTS
LEAVES
TILLER
RHIZOME
CROWN
SHOOT
ROOTS
STOLON
TURFGRASS GROWTH
• Shoot
– stem and leaf (leaf = sheath and blade)
• Sheath is lower portion of leaf and is attached to
the crown where leaf growth initiated. Sheath
rolled or folded around each other and support
leaf blades. When older leaf dies, new leaf
develops with in the sheath of the next oldest leaf
and emerges at the top of the plant. Besides the
crown, there is the meristematic tissue at base of
leaf blade (explains leaf extension).
CARBOHYDRATES AND
GROWTH
• Photosynthesis = production of
carbohydrates from CO2, water, and
sunlight (releases oxygen)
• Respiration = breakdown of
carbohydrates using oxygen. Releases
CO2 and energy.
CARBOHYDRATES &
GROWTH
• Energy released via the
breakdown of carbohydrates
needed to build cells and tissue
(drives enzymatic reactions).
• Photosynthesis must exceed
respiration if the plant is to grow.
CARBOHYDRATES &
GROWTH
• Plants also store carbohydrates for
later use. Carbohydrate
accumulation greatest
when photosynthesis
high and plant growth
slow.
CARBOHYDRATES &
GROWTH
• During dormant states,
respiration draws on stored
carbohydrates to keep cells
alive.