1. The Grass Plant Inflorescence Culm Leaf blade Leaf sheath Ligule Stolon daughter plant Rhizome daughter plant Auricles Seed

2. Growth and Development Understanding turfgrass growth and development is essential to the successful culture of turf. Turf cultural programs are best when based on a knowledge of basic physiological processes, the environment, and turfgrass species and variety characteristics.

3. Growth and Development Growth is an irreversible increase in size. Growth is an irreversible increase in size. Cell division Cell expansion

4. Growth and Development Growth is an irreversible increase in size. Growth is an irreversible increase in size. Cell division Cell expansion Development is a change in form. Development is a change in form. Vegetative vs. reproductive stage Formation of tillers, rhizomes, or stolons

5. Process of seed germination. Caryopsis with embryo Emergence of primary root and coleoptile Root branching

6. Components of the grass floret Palea Lemma Caryopsis Pericarp Seed coat Endosperm Embryo

7. Coleoptile First leaf Second leaf Apical dome Scutellar node Epiblast Primary root Scutellum Root cap Coleorhiza Grass embryo

8. Process of seed germination. Caryopsis with embryo

9. Process of seed germination. Caryopsis with embryo Emergence of primary root and coleoptile

10. Process of seed germination. Caryopsis with embryo Emergence of primary root and coleoptile Root branching Emergence of first leaf

12. Shoot growth After germination, the embryo develops into After germination, the embryo develops into a seedling plant.

13. Shoot growth After germination, the embryo developes into After germination, the embryo developes into a seedling plant. The crown becomes more fully developed. The crown becomes more fully developed.

14. Shoot growth After germination, the embryo developes into After germination, the embryo developes into a seedling plant. The crown becomes more fully developed. The crown becomes more fully developed. The crown gives rise to leaves, roots, tillers, The crown gives rise to leaves, roots, tillers, and in some cases elongated lateral stems.

15. A highly compressed stem with apical meristem, nodes, internodes, axillary buds, and roots. The crown is one of four types of stems that occur in grasses. The Crown

16. A highly compressed stem with apical meristem, nodes, internodes, axillary buds, and roots. The crown is one of four types of stems that occur in grasses. Crowns form from the embryo of germinating seed, axillary buds and terminals of rhizomes and stolons, and from axillary buds on more mature crowns. The Crown

17. Apical meristem Primordial leaves Axillary bud Internode Node Adventitious root Primary root Diagram of a grass crown.

18. Tiller

19. Tillering Tillers arise from axillary buds on crown Tillers arise from axillary buds on crown

20. Tillering Grow upward between enclosing sheath and Grow upward between enclosing sheath and main axis main axis

21. Tillering Tillers arise from axillary buds on crown Tillers arise from axillary buds on crown Grow upward between enclosing sheath and Grow upward between enclosing sheath and main axis main axis Apogeotropic (upwards) growth differs from Apogeotropic (upwards) growth differs from that of stolons and rhizomes that of stolons and rhizomes

22. Tillering Tillers arise from axillary buds on crown Tillers arise from axillary buds on crown Grow upward between enclosing sheath and Grow upward between enclosing sheath and main axis main axis Apogeotropic (upwards) growth differs from Apogeotropic (upwards) growth differs from that of stolons and rhizomes that of stolons and rhizomes Produces an identical daughter plant which Produces an identical daughter plant which becomes independent of mother plants CH 2 O, becomes independent of mother plants CH 2 O, nutrient, and water supply. nutrient, and water supply.

23. Initial Tiller Appearance Factors influencing tiller development : Plant age Plant age Photoperiod Photoperiod Temperature Temperature Management ManagementNutritionMowingIrrigation

24. Tillering in Tall Fescue Cool temperatures: Less than 70 o F Cool temperatures: Less than 70 o F Short days: Less than 12 hours Short days: Less than 12 hours Conditions typical of autumn Conditions typical of autumn

25. Tiller Development Cultural factors that influence tillering: Mowing Decreasing mowing height increases tillering Decreasing mowing height increases tillering

26. Tiller Development Cultural factors that influence tillering: Mowing Decreasing mowing height increases tillering Decreasing mowing height increases tillering Extremely close or frequent mowing will reduce Extremely close or frequent mowing will reduce CH 2 O needed for tiller development CH 2 O needed for tiller development

27. Tiller Development Cultural factors that influence tillering: Mowing Decreasing mowing height increases tillering Decreasing mowing height increases tillering Extremely close or frequent mowing will reduce Extremely close or frequent mowing will reduce CH 2 O needed for tiller development CH 2 O needed for tiller developmentNutrition

28. Tiller Development Cultural factors that influence tillering: Mowing Decreasing mowing height increases tillering Decreasing mowing height increases tillering Extremely close or frequent mowing will reduce Extremely close or frequent mowing will reduce CH 2 O needed for tiller development CH 2 O needed for tiller developmentNutrition N applied to C 3 grasses in fall increases tillering N applied to C 3 grasses in fall increases tillering

29. Tiller Development Cultural factors that influence tillering: Mowing Decreasing mowing height increases tillering Decreasing mowing height increases tillering Extremely close or frequent mowing will reduce Extremely close or frequent mowing will reduce CH 2 O needed for tiller development CH 2 O needed for tiller developmentNutrition N applied to C 3 grasses in fall increases tillering N applied to C 3 grasses in fall increases tillering N applied to C 3 grasses in spring decreases tillers N applied to C 3 grasses in spring decreases tillers

30. Stolon

31. Rhizome and Stolon Development Axillary buds develop into lateral stems Axillary buds develop into lateral stems

32. Rhizome and Stolon Development Axillary buds develop into lateral stems Axillary buds develop into lateral stems Stems break through enclosing leaf sheaths; Stems break through enclosing leaf sheaths; a process termed extravaginal growth a process termed extravaginal growth

33. Rhizome and Stolon Development Axillary buds develop into lateral stems Axillary buds develop into lateral stems Stems break through enclosing leaf sheaths; Stems break through enclosing leaf sheaths; a process termed extravaginal growth a process termed extravaginal growth Process is common to rhizomes and stolons Process is common to rhizomes and stolons

34. Rhizome and Stolon Development Factors influencing rhizome and stolon growth Plant age Plant age Photoperiod Photoperiod Temperature Temperature Management ManagementNutritionMowingIrrigation

35. Photoperiod Favored by long days Favored by long days High irradiance High irradianceTemperature Warm temperatures increase rhizome Warm temperatures increase rhizome development development Rhizome and Stolon Development

36. Cultural factors that influence rhizome & stolon development: Mowing Decreasing mowing height may increase lateral Decreasing mowing height may increase lateral growth of stolons growth of stolons Extremely close or frequent mowing will reduce Extremely close or frequent mowing will reduce CH 2 O needed for rhizome development CH 2 O needed for rhizome development

37. Cultural factors that influence rhizome & stolon development: Nutrition Excessive N impedes rhizome development Excessive N impedes rhizome development Frequent, moderate N applications increase Frequent, moderate N applications increase stolon development stolon development

38. Rhizome and Stolon Development Cool-season grasses Greatest production in late spring to early summer and during fall. Warm-season grasses Greatest production in summer and fall.

39. Apical meristem Primordial leaves Axillary bud Internode Node Adventitious root Primary root Diagram of a grass crown. Leaf formation

40. Shoot Apex Apical meristem Leaf primordia Expanding leaves

41. Senescing leaf Matureleaf Elongatingleaf Immatureenclosedleaf Organization of leaves within the grass shoot showing progression of development from the crown.

42. Upper & lower intercalary meristem. Growing point Leaf primordia Crown Collar Upper intercalary meristem Lower intercalary meristem

43. Apical meristem Primordial leaves Axillary bud Internode Node Adventitious root Primary root Diagram of a grass crown. Rooting

44. Root Growth and Development Anchorage Water absorption Nutrient absorption Soil stabilization/firmness/resiliency

45. Root Growth and Development Root longevity Primary root is short lived Primary root is short lived Adventitious roots of most concern: Adventitious roots of most concern: Arise due to differentiation of cells at nodes Form entire root system in mature turf Exhibit seasonal growth patterns

46. Root cap Apical meristem Zone of cell division Zone of cell elongation Procambium Zone of differentiation Root Anatomy

49. Root Growth and Development Cool-Season Grasses Primarily initiate roots during December to April Primarily initiate roots during December to April

50. Root Growth and Development Cool-Season Grasses Primarily initiate roots during December to April Primarily initiate roots during December to April Minor initiation during cool periods of fall Minor initiation during cool periods of fall

51. Root Growth and Development Cool-Season Grasses Primarily initiate roots during December to April Primarily initiate roots during December to April Minor initiation during cool periods of fall Minor initiation during cool periods of fall Elongation occurs during April to December Elongation occurs during April to December

52. Root Growth and Development Warm-season grasses Primarily initiate roots during summer Primarily initiate roots during summer May totally replace root system annually May totally replace root system annually Replacement usually coincides with spring greenup. Replacement usually coincides with spring greenup.