TURF PHYSIOLOGY

Photosynthesis

• 2-ranked leaf arrangement • Chlorophyll gives green color• Photosynthesis is process of using

light to create carbohydrates (food)

Carbohydrates (CHO)

ExcessExcess CHO can be produced CHO can be produced and storedand stored• Favorable conditionsFavorable conditions• High mowing heightHigh mowing height• Adequate NAdequate N

Carbohydrates (CHO)

Lack of CHO available during temperature stress

• High respiration– Process of CHO

consumption

• Lower CHO production

CLIMATE ZONES

• Cool season zones (humid and dry)• Warm season zones (humid and dry)• Transition zone: too hot is summer,

too cold in winter– Zoysia and tall fescue

COOL-SEASON VS. WARM-SEASON TURFGRASSES

Cool-season turfgrassCool-season turfgrass• Spring and fall are favorableSpring and fall are favorable• 65 to 75 F 65 to 75 F • Semi-dormant in winter Semi-dormant in winter • C3 plants (# of carbon atoms in PS)C3 plants (# of carbon atoms in PS)• 12 to 18” roots12 to 18” roots

COOL-SEASON VS. WARM-SEASON SPECIES

Warm-season turfgrassWarm-season turfgrass• Summer Summer • 80 to 95 F 80 to 95 F • Semi to dormant in winter Semi to dormant in winter • Lose chlorophyll below 50 F Lose chlorophyll below 50 F • C4 (# of carbon atoms in PS)C4 (# of carbon atoms in PS)• 36” roots36” roots

MORPHOLOGY

Shoots: aboveground parts

Blade: upper part of leaf

Sheath: lower part of leaf

• Older leaves on outside, new leaves develop on the inside of sheath

MORPHOLOGY

Meristem: region of cell division where growth occurs

• Its location tolerates mowing

MORPHOLOGY

Collar: blade growth occurs

MORPHOLOGY

Crown: heart of the turfgrass plant

• Highly compressed nodes– Nodes: region of

new growth

MORPHOLOGY

• All shoots and roots produced from crown

MORPHOLOGY

Ligule: growth on inside of collar• Thin membrane or fringe of hairs, or

both

MORPHOLOGY

Auricles: appendages growing from the edges of collar

MORPHOLOGY

Vernation: sheath orientation• Rolled or folded

Turfgrass Cultivar

Cultivar: short for “cultivated variety”• Differences within species that are

bred• Tolerances, color, texture, growth

rate…

Non-Spreading Turf

Bunch type: tillers are formed from crown

• New plants develop from nodes on crown (daughter plants)

• Tight bunch of turfgrass plants

Non-Spreading Turf

Bunch type: tillers are formed from crown

• New plants develop from nodes on crown (daughter plants)

• Tight bunch of turfgrass plants

Spreading Turf

Stoloniferous: crowns develop lateral stems that grow aboveground

• Nodes along stem capable of rooting and forming new plant

Spreading Turf

Rhizomatous: lateral stems underground

• Large and white

ROOTING

Highly fibrous• Great ability to “mine” the soil• Low P fertilizersRoots are dependant on shoots for

CHOStorage of excess CHO

ROOTING

Over-irrigation reduces root systemDrier soils stimulate root growth• High hormone production that slows

shoot growth

ROOTING

Mowing• Reduces CHO production and root

allocation

ROOTING

Fertility• Excessive N causes overgrowth of

shoots and fewer roots

ROOTING

Light• Shade reduces CHO (PS) production,

less goes to roots