TYPES OF STEMS n 1. Crown-highly compressed stem n 2. Tillers-primary lateral stem n 3. Stolons-above ground, secondary lateral stem n 4. Rhizomes-below.

TYPES OF STEMSTYPES OF STEMS 1. Crown-highly compressed stem1. Crown-highly compressed stem 2. Tillers-primary lateral stem2. Tillers-primary lateral stem 3. Stolons-above ground, secondary lateral 3. Stolons-above ground, secondary lateral

stem stem 4. Rhizomes-below ground, secondary 4. Rhizomes-below ground, secondary

lateral stem lateral stem 5. Culm -stem of grass plant, flowering5. Culm -stem of grass plant, flowering

Basic Plant StructureBasic Plant Structure

Basic Plant StructureBasic Plant Structureapicalmeristem

Basic Plant StructureBasic Plant Structureapicalmeristem Leaf Blade

(lamina)

Petiole

Basic Plant StructureBasic Plant Structureapicalmeristem

node

Leaf Blade (lamina)

Basic Plant StructureBasic Plant Structureapicalmeristem

internode

node

Leaf Blade (lamina)

Basic Plant StructureBasic Plant Structureapicalmeristem

internode

node

axillary bud

Leaf Blade (lamina)

Basic Plant StructureBasic Plant Structureapicalmeristem

internode

node

axillary bud

primaryroot

secondary, branch root

Leaf Blade (lamina)

Basic structure, compressedBasic structure, compressed

The Grass PlantThe Grass PlantThe Grass Plant

TillersTillers Develop from axillary budsDevelop from axillary buds Usually live less than 1 yearUsually live less than 1 year Some produced in spring, important for summer survivalSome produced in spring, important for summer survival Some produced in fall, usually die late spring, early Some produced in fall, usually die late spring, early

summersummer Enhanced by mowingEnhanced by mowing Some grasses only produce tillers - Bunch grassesSome grasses only produce tillers - Bunch grasses Tillers represent the future for bunch grassesTillers represent the future for bunch grasses IntravaginalIntravaginal shoot developmentshoot development

StolonsStolons Grow along soil surface, abovegroundGrow along soil surface, aboveground Live one or more yearsLive one or more years Produced in fall for cool season grassesProduced in fall for cool season grasses In spring for warm season grassesIn spring for warm season grasses Extravaginal shoot development, involving Extravaginal shoot development, involving

rupture of surrounding sheath tissuerupture of surrounding sheath tissue Stolons may branch profuselyStolons may branch profusely These grasses are sod-forming These grasses are sod-forming

RhizomesRhizomes Grow underneath the soil, an underground version Grow underneath the soil, an underground version

of the stolonof the stolon Determinate (KBG) are short and non-branchingDeterminate (KBG) are short and non-branching Indeterminate (Berm.) are long and multi-branched.Indeterminate (Berm.) are long and multi-branched. Provides sod strengthProvides sod strength Winter survivalWinter survival Wear toleranceWear tolerance Major storage organ for long-term survivalMajor storage organ for long-term survival

The CrownThe Crown

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

The CrownThe Crown

Crown

The Crown

Crown

Enlarged Crown

apical meristem

leafprimordia

The Phytomer UnitThe Phytomer Unit– The smallest complete unit containing all the The smallest complete unit containing all the

necessary parts of the turf plant:necessary parts of the turf plant:» Node Node

» Internode (stem piece)Internode (stem piece)

» Axillary bud at nodeAxillary bud at node

» Root Primordia at nodeRoot Primordia at node

– A phytomer can survive on its own - this is the A phytomer can survive on its own - this is the basis for basis for vegetative propagationvegetative propagation..

CULM - The Flowering ShootCULM - The Flowering Shoot Phases:Phases:

– a. Maturation - plant must be old enough, big enougha. Maturation - plant must be old enough, big enough

– b. inductionb. induction

» 1. Vernalization - cold treatment - take place in 1. Vernalization - cold treatment - take place in growing point - reversible. Cool season grassesgrowing point - reversible. Cool season grasses

» 2. Photoperiod - takes place in leaves2. Photoperiod - takes place in leaves cool season = long daycool season = long day warm season = short daywarm season = short day

– c. Initiation - crown changes from vegetative to c. Initiation - crown changes from vegetative to flowering - elongation occursflowering - elongation occurs

– d. Development - seed head formationd. Development - seed head formation

CULMCULM

Disadvantages:Disadvantages:– b. drains food reservesb. drains food reserves– c. death of shootc. death of shoot– d. mowing is difficultd. mowing is difficult– e. affects play, Poa annuae. affects play, Poa annua– a. unsightlya. unsightly

II. LEAVESII. LEAVES

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

What is a meristem?What is a meristem? Intercalary meristem?Intercalary meristem?

II. LEAVES (continued)II. LEAVES (continued) 1. Components1. Components

– a. bladea. blade– b. sheathb. sheath– c. collarc. collar– d. liguled. ligule– e. auriclee. auricle

2. Vernation 2. Vernation 3. Leaf #/shoot3. Leaf #/shoot

– a. same for given environ, usually 5-10/shoota. same for given environ, usually 5-10/shoot

Leaf structure

Leaf AnatomyLeaf Anatomy

Midrib

Veins

Xylem

Phloem

Epidermis

RootsRoots“If you can grow roots, the shoots will take “If you can grow roots, the shoots will take

care of themselves”care of themselves” AnchorageAnchorage Absorption of water and nutrientsAbsorption of water and nutrients StorageStorage Primary, or seminal develop from seed, Primary, or seminal develop from seed,

short livedshort lived Adventitious roots develop later and then Adventitious roots develop later and then

continuously from the nodes. Nodal roots. continuously from the nodes. Nodal roots.

Regions of the RootRegions of the Root

Root CapRoot Cap MeristemMeristem Region of ElongationRegion of Elongation Region of Differentiation - where root hairs Region of Differentiation - where root hairs

develop, and also vascular tissuedevelop, and also vascular tissue Region of Maturation, where suberization Region of Maturation, where suberization

occurs. Roots become more rigid. Lateral occurs. Roots become more rigid. Lateral roots formroots form

Root SystemsRoot Systems

Multibranching and fibrousMultibranching and fibrous Turf roots not major storage organsTurf roots not major storage organs Source of plant hormones, cytokininsSource of plant hormones, cytokinins Usually 4-18 inches deepUsually 4-18 inches deep Warm-season grasses have larger diameter, Warm-season grasses have larger diameter,

deeper roots than cool-season grassesdeeper roots than cool-season grasses

Root Hairs

Stele

Root Cap

Meristem

Elongation

Differentiation

Maturation

Restrictions to RootingRestrictions to Rooting High soil temperaturesHigh soil temperatures Acidic soils, aluminum toxicityAcidic soils, aluminum toxicity Lack of oxygenLack of oxygen SaltsSalts PesticidesPesticides Improper mowing height, frequencyImproper mowing height, frequency Excessive N, deficient K nutritionExcessive N, deficient K nutrition Excessive thatchExcessive thatch Improper irrigationImproper irrigation FloweringFlowering

Root LongevityRoot Longevity

Death and replacement is continuousDeath and replacement is continuous Some roots last < 6 months, some > 2 years Some roots last < 6 months, some > 2 years

(KBG)(KBG) Seasonal root growth: cool-season best in Seasonal root growth: cool-season best in

spring and fall, warm-season best in spring and fall, warm-season best in summer. Spring root decline in WS, summer. Spring root decline in WS, summer root decline in CS. summer root decline in CS.

Temperature EffectsTemperature Effects

4. Cool Season4. Cool Season– a. Growth Curvea. Growth Curve– b. Temperature:b. Temperature:

» Min - 33Min - 33ooF F » Opt - 50-65Opt - 50-65ooF F » Max - 80Max - 80ooFF

5. Warm Season5. Warm Season– a. Growth Curvea. Growth Curve– b. Temperatureb. Temperature

» Min - 40Min - 40ooF F » Opt - 75-85Opt - 75-85ooFF» Max - 110Max - 110ooFF

WARM SEASON GRASSESWARM SEASON GRASSES

COMMONCOMMON BahiaBahia Barnyard GrassBarnyard Grass BermudaBermuda CentipedeCentipede DallisgrassDallisgrass GoosegrassGoosegrass Japanese Lawngrass (Zoysia)Japanese Lawngrass (Zoysia) Large CrabgrassLarge Crabgrass Smooth CrabgrassSmooth Crabgrass St. AugustineSt. Augustine Yellow FoxtailYellow Foxtail

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

COOL SEASON GRASSESCOOL SEASON GRASSES COMMONCOMMON Annual BluegrassAnnual Bluegrass Kentucky BluegrassKentucky Bluegrass Rough BluegrassRough Bluegrass Colonial BentgrassColonial Bentgrass Creeping BentgrassCreeping Bentgrass Italian RyegrassItalian Ryegrass OrchardgrassOrchardgrass Perennial RyegrassPerennial Ryegrass QuackgrassQuackgrass Red FescueRed Fescue Tall FescueTall Fescue

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

General Growth CurvesGeneral Growth Curves

Jan. Mar May July Sept Nov.

Growth

Warm SeasonCool Season

Regions of AdaptationRegions of Adaptation

Regions of AdaptationRegions of Adaptation

Cool Humid

Warm Arid Warm Humid

Tropical

Transition

Cool Humid

Cool Arid

PHYSIOLOGYPHYSIOLOGY

1. Two processes required for growth:1. Two processes required for growth:

– a. photosynthesisa. photosynthesis

– b. Respirationb. Respiration Growth = photosynthesis - respirationGrowth = photosynthesis - respiration

PHYSIOLOGYPHYSIOLOGY

PhotosynthesisPhotosynthesis– manufactures foodmanufactures food

– HH22O + COO + CO22 + light = sugar + O + light = sugar + O22 + water + water

– Sugars used to build new tissue, and to Sugars used to build new tissue, and to maintain existing tissue through respiration.maintain existing tissue through respiration.

– Sugars stored in crowns, stolons, rhizomes and Sugars stored in crowns, stolons, rhizomes and roots.roots.

PhotosynthesisPhotosynthesis

Cool season grasses, C3, 60 - 75Cool season grasses, C3, 60 - 75oo

Warm Season grasses, C4, 80 - 95Warm Season grasses, C4, 80 - 95oo

C4 plants can utilize high light C4 plants can utilize high light better better

C3 vs. C4 Species C3 vs. C4 Species

Light Intensity

Pho

tosy

nthe

sis

C3 species

C4 species

RespirationRespiration

Produces energy to build tissue, Produces energy to build tissue, maintain existing tissuesmaintain existing tissues

Carbohydrates broken down Carbohydrates broken down

sugar + Osugar + O22 = CO = CO22 + H + H22O + O + energyenergy

PHYSIOLOGYPHYSIOLOGY Warm season - respire mainly in darkWarm season - respire mainly in dark Cool season - respire in dark Cool season - respire in dark andand light. light.

This is called "photorespiration”This is called "photorespiration” ComparisonComparison

Photorespiration PhotosyntheticPhotorespiration Photosynthetic rate raterate rate

C3 High LowC3 High LowC4 Low HighC4 Low High

Environmental EffectsEnvironmental Effects Photosynthesis slightly affected by Photosynthesis slightly affected by

temperature.temperature. Respiration affected greatly by temperature. Respiration affected greatly by temperature.

As temperature increases, so does respiration.As temperature increases, so does respiration.– Accumulate food in cool temperaturesAccumulate food in cool temperatures

– Photosynthesis > respirationPhotosynthesis > respiration

Deplete food in high temperaturesDeplete food in high temperatures– Respiration > photosynthesisRespiration > photosynthesis

EX: Summer fertilization of cool season grassesEX: Summer fertilization of cool season grasses

PHYSIOLOGYPHYSIOLOGY

Accumulate food when growth is slow.Accumulate food when growth is slow.» eg. Fall fertilizationeg. Fall fertilization

Deplete food when growth is fastDeplete food when growth is fast» eg. spring root die back eg. spring root die back

» eg. Recovery from environment or pesteg. Recovery from environment or pest

» eg. Seed head productioneg. Seed head production