Turf Growth and Development

Transcription

1 Turf Growth and Development Germination and Seedling Development Spikelet borne in Inflorescence Germination and Seedling Development Leaf and Stem Formation Inflorescence Roots Spikelet s Apex Caryopsis Palea Lemma Base of Callus Front View Side View Back View Lemma Palea 1

2 Caryopsis Caryopsis Caryopsis Pericarp Seed Coat Aleurone Layer Embryo Endosperm Scutellum Fescue Bluegrass Bentgrass Germination Favorable seed-to-soil contact Endosperm Reserves Planting Depth Moisture Light Temperature Light Germinating Seed Second Seminal Root Coleoptile Colerhiza First Seminal Root Germination Process Enlargement of the coleorhiza Emergence of root-hair like structures t for anchoring. Emergence of the primary root (radicle) Emergence of the coleoptile 2

3 Germination Process Elongation of first leaf within the coleoptile Photosynthesis begins Second leaf emerges Growing point enclose in coleoptile Adventitious roots develop from nodes at base of shoot 3

4 Growth and Development Germination and Seedling Development Leaf and Stem Formation Roots Inflorescence Grass Shoot Grass Shoot Leaf Blade Leaf Sheath Developing Leaves Crown Leaf Sheath Grass Crown Crown Youngest Leaf Apical Meristem Primordial Leaves Growing Point Growing Point Axillary Bud Internode Node Apical Meristem Leaf Primordia Adventitious Root Primary Root 4

5 From leaf primordia on top of crown New primordia continually formed Leaf Formation Young Primordia Leaf Formation Apical Meristem Young Leaves Emerging leaf Leaf Formation Completely hidden within several mature leaf sheaths h Young Leaf Senescing Leaf New Leaf Mature Leaf Developing New Leaf Roots Leaf Photosynthetic Rate Stems Newly emerging leaves Use all the food they manufacture plus more Young fully expanded leaves Highest photosynthetic th ti rate Food for own growth plus storage Older leaves Maintenance production Senescing leaves Recycling of essential building blocks Three types Crown Flowering culm Flowering culm Lateral Stems Rhizomes and stolons 5

6 Crown Highly contracted stem Forms wherever new shoot develop Develops leaves, roots, tillers, stems Stores carbohydrates reserves Grass Crown Axillary Bud Crown Youngest Leaf Apical Meristem Primordial Leaves Internode Node Growing Point Adventitious Root Primary Root Axillary Buds Branching Tillers Intravaginal branching Builds shoot density in the immediate vicinity of the parent shoots Lateral shoots Extravaginal branching Extend the plant population beyond the parent shoots Intravaginal Extravaginal Lateral Shoots Lateral Shoots Stolon Rhizome Stolons Grow along the surface Form new shoots and roots at nodes or at the stolon tip (terminal) Branching at the nodes forms network of lateral stems 6

7 Lateral Shoots Stolonifreous Turfgrasses Creeping Bentgrass Rough hbluegrass Zosiagrass Lateral Shoots Rhizome Grows beneath the ground via stem internode elongation Determinate and indeterminate types Lateral Shoots Determinate rhizome Short Growth in three phases Aerial shoot formation upon reaching the surface Indeterminate Long and branched at nodes Aerial shoots from axillary buds Rhizome Growth Extensor rhizomes Sprout rhizomes 7

8 Lateral Shoots Rhizomatous Turfgrasses Kentucky Bluegrass Creeping Red Fescue Tillering New aerial shoots emerge intravaginally from axillary buds Tillering Tillering Inflorescence Turf Growth and Development Spiklet Borne in Inflorescence Inflorescence 8

9 Inflorescence Inflorescence Flowering portion of the grass shoot The basic unit of organization within the inflorescence is the spikelet. The spikelet is composed of florets, glumes and rachilla. Callus Rachilla Glume Inflorescence Types of Inflorescence Glumes Bent Grass Glume Rye Grass Raceme Panicle Spike Types of Inflorescence Grass Species Raceme Spikelets borne on short stalks, called pedicels, coming off a main culm. Spike Spikelets attached directly to the main culm. Panicle Spikelets spaced along spreading or compressed branches. Raceme Zoysiagrass Panicle Bluegrass St.Augustinegrass Bentgrass Bahiagrass Centipedegrass Fescue Spikes Ryegrass Wheatgrass Bermudagrass 9

10 Glumes Palea Lemma Anther Filament Stigma Style Ovary Stamen Pistil Turf Growth and Development Root Growth Turfgrass Roots Adventitious Roots Adventitious Roots Grow from crowns as well as nodes along rhizomes and stolons Variable lifspan May live as long as the shoot they support Climate specific (cool-season versus warm-season grasses) Species specific 10

11 Root Tip Root Hairs Root Cap Turfgrass Root Root cap Protects the root meristem Senses up and down Aiding root elongation through soil with slime sheath Root hairs Specialized epidermal cells Absorb water and nutrients Longitudinal Section of a Root Epidermis Root Hairs Cortex Steele Branch Root Formation Meristematic Region Root Cap Root Growth Unfavorable soil conditions High soil temperatures ph <5.0 and > 7.0 Oxygen deficiency High salt concentration Root Growth Unfavorable cultural conditions Close mowing Excessive nitrogen fertilization Excessive nitrogen fertilization Potassium deficiency Excessive thatch 11

12 Seasonal Root Growth Cool-Season Warm-Season Turfgrasses Perennials Dying shoots and roots are continually replaced Management facilitates replacement growth Spring Summer Fall Root : Shoot Ratio 12