TYPES OF STEMS

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TYPES OF STEMS

• 1. Crown-highly compressed stem
• 2. Tillers-primary lateral stem
• 3. Stolons-above ground, secondary lateral stem
• 4. Rhizomes-below ground, secondary
  lateral stem
• 5. Culm -stem of grass plant, flowering

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Basic Plant Structure
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Basic Plant Structure
apical meristem
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Basic Plant Structure
apical meristem
Leaf Blade (lamina)
Petiole
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Basic Plant Structure
apical meristem
Leaf Blade (lamina)
node

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Basic Plant Structure
apical meristem
Leaf Blade (lamina)
node
internode
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Basic Plant Structure
apical meristem
Leaf Blade (lamina)
node
internode
axillary bud

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Basic Plant Structure
apical meristem
Leaf Blade (lamina)
node
internode
axillary bud
primary root
secondary, branch root
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Basic structure, compressed
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The Grass Plant
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Tillers

• Develop from axillary buds
• Usually live less than 1 year
• Some produced in spring, important for summer
  survival
• Some produced in fall, usually die late spring,
  early summer
• Enhanced by mowing
• Some grasses only produce tillers - Bunch grasses
• Tillers represent the future for bunch grasses
• Intravaginal shoot development

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Stolons

• Grow along soil surface, aboveground
• Live one or more years
• Produced in fall for cool season grasses
• In spring for warm season grasses
• Extravaginal shoot development, involving rupture
  of surrounding sheath tissue
• Stolons may branch profusely
• These grasses are sod-forming

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Rhizomes

• Grow underneath the soil, an underground version
  of the stolon
• Determinate (KBG) are short and non-branching
• Indeterminate (Berm.) are long and
  multi-branched.
• Provides sod strength
• Winter survival
• Wear tolerance
• Major storage organ for long-term survival

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The Crown

• Most important part of plant
• Place where new shoots develop
• Highly compressed series of nodes
• Where all the leaves are attached
• Where all the axillary buds are located
• Where tillers, rhizomes, stolons originate
• Highly protected!

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The Crown
Crown
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The Phytomer Unit

• The smallest complete unit containing all the
  necessary parts of the turf plant
• Node
• Internode (stem piece)
• Axillary bud at node
• Root Primordia at node
• A phytomer can survive on its own - this is the
  basis for vegetative propagation.

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CULM - The Flowering Shoot

• Phases
• a. Maturation - plant must be old enough, big
  enough
• b. induction
• 1. Vernalization - cold treatment - take place
  in growing point - reversible. Cool season
  grasses
• 2. Photoperiod - takes place in leaves
• cool season long day
• warm season short day
• c. Initiation - crown changes from vegetative
  to flowering - elongation occurs
• d. Development - seed head formation

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CULM

• Disadvantages
• b. drains food reserves
• c. death of shoot
• d. mowing is difficult
• e. affects play, Poa annua
• a. unsightly

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II. LEAVES

• The leaves are the major site of food production.
  They contain the green pigment chlorophyll.
  Photosynthesis is the process that produces
  carbohydrates. Leaves originate at the crown,
  both the apical meristem and axillary buds.
• What is a meristem?
• Intercalary meristem?

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II. LEAVES (continued)

• 1. Components
• a. blade
• b. sheath
• c. collar
• d. ligule
• e. auricle
• 2. Vernation
• 3. Leaf /shoot
• a. same for given environ, usually 5-10/shoot

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Leaf Anatomy
Xylem Phloem
Epidermis
Veins
Midrib
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RootsIf you can grow roots, the shoots will
take care of themselves

• Anchorage
• Absorption of water and nutrients
• Storage
• Primary, or seminal develop from seed, short
  lived
• Adventitious roots develop later and then
  continuously from the nodes. Nodal roots.

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Regions of the Root

• Root Cap
• Meristem
• Region of Elongation
• Region of Differentiation - where root hairs
  develop, and also vascular tissue
• Region of Maturation, where suberization occurs.
  Roots become more rigid. Lateral roots form

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Root Systems

• Multibranching and fibrous
• Turf roots not major storage organs
• Source of plant hormones, cytokinins
• Usually 4-18 inches deep
• Warm-season grasses have larger diameter, deeper
  roots than cool-season grasses

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Stele
Maturation
Root Hairs
Differentiation
Elongation
Meristem
Root Cap
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Restrictions to Rooting

• High soil temperatures
• Acidic soils, aluminum toxicity
• Lack of oxygen
• Salts
• Pesticides
• Improper mowing height, frequency
• Excessive N, deficient K nutrition
• Excessive thatch
• Improper irrigation
• Flowering

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Root Longevity

• Death and replacement is continuous
• Some roots last lt 6 months, some gt 2 years (KBG)
• Seasonal root growth cool-season best in spring
  and fall, warm-season best in summer. Spring
  root decline in WS, summer root decline in CS.

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Temperature Effects

• 4. Cool Season
• a. Growth Curve
• b. Temperature
• Min - 33oF
• Opt - 50-65oF
• Max - 80oF

• 5. Warm Season
• a. Growth Curve
• b. Temperature
• Min - 40oF
• Opt - 75-85oF
• Max - 110oF

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WARM SEASON GRASSES

• COMMON
• Bahia
• Barnyard Grass
• Bermuda
• Centipede
• Dallisgrass
• Goosegrass
• Japanese Lawngrass (Zoysia)
• Large Crabgrass
• Smooth Crabgrass
• St. Augustine
• Yellow Foxtail

• SCIENTIFIC
• (Paspalum notatum)
• (Echinochloa crusgalli)
• (Cynodon dactylon)
• (Eremochloa ophiuroides)
• (Paspalum dilatatum)
• (Eleusine indica)
• (Zoysia japonica)
• (Digitaria sanguinalis)
• (Digitaria ischaemum)
• (Stenotaphrum secundatum)
• (Setaria glauca)

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COOL SEASON GRASSES

• COMMON
• Annual Bluegrass
• Kentucky Bluegrass
• Rough Bluegrass
• Colonial Bentgrass
• Creeping Bentgrass
• Italian Ryegrass
• Orchardgrass
• Perennial Ryegrass
• Quackgrass
• Red Fescue
• Tall Fescue

• SCIENTIFIC
• (Poa annua)
• (Poa pratensis)
• (Poa trivialis)
• (Agrostis tenuis)
• (Agrostis palustris)
• (Lolium multiflorum)
• (Dactylis glomerata)
• (Lolium perenne)
• (Agropyron repens)
• (Festuca rubra var. rubra)
• (Festuca arundinacea)

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General Growth Curves
Warm Season
Cool Season
Growth
Jan. Mar May July
Sept Nov.
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Regions of Adaptation
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Regions of Adaptation
Cool Humid
Cool Humid
Cool Arid
Transition
Warm Arid
Warm Humid
Tropical
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PHYSIOLOGY

• 1. Two processes required for growth
• a. photosynthesis
• b. Respiration
• Growth photosynthesis - respiration

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PHYSIOLOGY

• Photosynthesis
• manufactures food
• H2O CO2 light sugar O2 water
• Sugars used to build new tissue, and to maintain
  existing tissue through respiration.
• Sugars stored in crowns, stolons, rhizomes and
  roots.

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Photosynthesis

• Cool season grasses, C3, 60 - 75o
• Warm Season grasses, C4, 80 - 95o
• C4 plants can utilize high light better

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C3 vs. C4 Species
C4 species
Photosynthesis
C3 species
Light Intensity
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Respiration

• Produces energy to build tissue, maintain
  existing tissues
• Carbohydrates broken down
• sugar O2 CO2 H2O energy

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PHYSIOLOGY

• Warm season - respire mainly in dark
• Cool season - respire in dark and light. This is
  called "photorespiration
• Comparison
• Photorespiration Photosynthetic
• rate rate
• C3 High Low
• C4 Low High

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Environmental Effects

• Photosynthesis slightly affected by temperature.
• Respiration affected greatly by temperature. As
  temperature increases, so does respiration.
• Accumulate food in cool temperatures
• Photosynthesis gt respiration
• Deplete food in high temperatures
• Respiration gt photosynthesis
• EX Summer fertilization of cool season
  grasses

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PHYSIOLOGY

• Accumulate food when growth is slow.
• eg. Fall fertilization
• Deplete food when growth is fast
• eg. spring root die back
• eg. Recovery from environment or pest
• eg. Seed head production