CRSS 2830CRSS 2830Lesson 2Lesson 2

Growth and Development of the Growth and Development of the Turfgrass PlantTurfgrass Plant

BOTANICAL CLASSIFICATION BOTANICAL CLASSIFICATION OF TURFGRASSESOF TURFGRASSES

Angiosperms Angiosperms

(flowering plants)(flowering plants)

• Dicotyledons Dicotyledons (dicots)(dicots) – broadleaf plantsbroadleaf plants

• Monocotyledons Monocotyledons (monocots)(monocots) – grasslike plantsgrasslike plants

MONOCOTYLEDONSMONOCOTYLEDONS• Family= Poaceae (Gramineae)Family= Poaceae (Gramineae)

– Kentucky Bluegrass ‘Merion’Kentucky Bluegrass ‘Merion’

– Genus = Poa (bluegrass) could also be: annual Genus = Poa (bluegrass) could also be: annual bluegrass, rough bluegrass, Canada bluegrass, bluegrass, rough bluegrass, Canada bluegrass, etc.etc.

– Species = pratensis (Kentucky Bluegrass)Species = pratensis (Kentucky Bluegrass)• Cultivar = MerionCultivar = Merion

MONOCOTS VS. DICOTSMONOCOTS VS. DICOTS

• Monocots:Monocots:– Single seed leafSingle seed leaf

– Parallel leaf veinsParallel leaf veins

– Growing point soil levelGrowing point soil level

– Fibrous root systemFibrous root system

MONOCOTS VS. DICOTSMONOCOTS VS. DICOTS

• Dicots:Dicots:– Two seed leavesTwo seed leaves

– Branched leaf veinsBranched leaf veins

– Growing point at top of stemGrowing point at top of stem

– Often tap root systemOften tap root system

TURFGRASS PLANT TURFGRASS PLANT STRUCTURESTRUCTURE

• Roots:Roots:– Stems:Stems:

• Crown = growing point (new leaves, roots, Crown = growing point (new leaves, roots, stems)stems)

• Flowering culm (inflorensence seedhead). Flowering culm (inflorensence seedhead). Usually not desirable in turfgrass areas.Usually not desirable in turfgrass areas.

Lateral stemsLateral stems

–Primary = tillers (vertical, upright)Primary = tillers (vertical, upright)–Secondary = Secondary =

»Rhizomes = below groundRhizomes = below ground»Stolons = above groundStolons = above ground

* Rhizomes and stolons have * Rhizomes and stolons have horizontal or spreading growth horizontal or spreading growth habit. Sod forming grasses. habit. Sod forming grasses.

EXAMPLESEXAMPLES

• Stoloniferous turfgrasses:Stoloniferous turfgrasses:

– St. AugustinegrassSt. Augustinegrass

– CentipedegrassCentipedegrass

– Creeping bentgrassCreeping bentgrass

– BuffalograssBuffalograss

– Rough bluegrassRough bluegrass

EXAMPLESEXAMPLES• Rhizomatous turfgrasses:Rhizomatous turfgrasses:

– Kentucky bluegrassKentucky bluegrass

– Creeping red fescueCreeping red fescue

– bahiagrassbahiagrass

EXAMPLESEXAMPLES

• Turfgrasses with both Turfgrasses with both rhizomes and stolonsrhizomes and stolons

– BermudagrassBermudagrass

– ZoysiagrassZoysiagrass

EXAMPLESEXAMPLES

• Turfgrasses without rhizomes Turfgrasses without rhizomes or stolons (bunch-type):or stolons (bunch-type):

– Tall fescueTall fescue

– Perennial ryegrassPerennial ryegrass– Annual ryegrassAnnual ryegrass

RHIZOMETILLER

STOLON

ROOTS

SHOOT

LEAVES

CROWN

ORGANS OF TURFGRASS PLANTS

TURFGRASS GROWTHTURFGRASS GROWTH• Shoot Shoot

– stem and leaf (leaf = sheath and blade)stem and leaf (leaf = sheath and blade)

• Sheath is lower portion of leaf and is attached to Sheath is lower portion of leaf and is attached to the crown where leaf growth initiated. Sheath the crown where leaf growth initiated. Sheath rolled or folded around each other and support rolled or folded around each other and support leaf blades. When older leaf dies, new leaf leaf blades. When older leaf dies, new leaf develops with in the sheath of the next oldest leaf develops with in the sheath of the next oldest leaf and emerges at the top of the plant. Besides the and emerges at the top of the plant. Besides the crown, there is the meristematic tissue at base of crown, there is the meristematic tissue at base of leaf blade (explains leaf extension).leaf blade (explains leaf extension).

CARBOHYDRATES AND CARBOHYDRATES AND GROWTHGROWTH

• PhotosynthesisPhotosynthesis = production of = production of carbohydrates from CO2, water, and carbohydrates from CO2, water, and sunlight (releases oxygen)sunlight (releases oxygen)

• RespirationRespiration = breakdown of = breakdown of carbohydrates using oxygen. Releases carbohydrates using oxygen. Releases CO2 and energy.CO2 and energy.

CARBOHYDRATES & CARBOHYDRATES & GROWTHGROWTH

• Energy released via the Energy released via the

breakdown of carbohydrates breakdown of carbohydrates

needed to build cells and tissue needed to build cells and tissue

(drives enzymatic reactions).(drives enzymatic reactions).

• Photosynthesis must exceed Photosynthesis must exceed respiration if the plant is to grow. respiration if the plant is to grow.

CARBOHYDRATES & CARBOHYDRATES & GROWTHGROWTH

• Plants also store carbohydrates for Plants also store carbohydrates for

later use. Carbohydrate later use. Carbohydrate

accumulation greatest accumulation greatest

when photosynthesis when photosynthesis

high and plant growth high and plant growth

slowslow..

CARBOHYDRATES & CARBOHYDRATES & GROWTHGROWTH

• During dormant states, During dormant states, respiration draws on stored respiration draws on stored carbohydrates to keep cells carbohydrates to keep cells alive.alive.