Anatomy, Morphology, & Growth of Angiosperms – Ch. 5-8

1. Anatomy, Morphology, & Growth of Angiosperms – Ch. 5-8

2. Two plant groups: monocots & dicots

3. Structure Reflects Function http://www.fugu-sg.org/~elia/cambodia/templesfacesweb/pages/A3_Embracing_Roots.htm

4. Structure of a plant determined by: • Genetics • Environment – two time scales: • Long-term: • Short-term: plasticity = wide range of phenotypes for each genotype. Allows plants to adjust to changing environment (ex. Shorter plant in dry year so that it can still reproduce)

5. Muscle cell Cells Tissues Muscle tissue Organs Heart Circulatory system Systems

6. Three organs: Roots, stems, leaves • Roots– • Store food (carbos from photosynthesis) to be used for flowering & fruiting • Covered with root hairs – increased surface area for absorption

7. Fig 35.2

8. Prop roots Aerial strangler roots Modified Roots – Fig 35.4 Sweet Potato – storage root Buttress roots Pneumatophores

9. 2. Stems/shoots • Support, transport • Some photosynthesis • Two types of shoots • Vegetative – • Reproductive – • Two parts of stem: • Node – • Internode – stem segments between nodes

10. Two types of buds • Terminal bud – contains a shoot apical meristem; shoot growth is concentrated here • Axillary buds – Apical dominance = the presence of an apical bud inhibits the growth of axillary buds. -remove or depress apical bud, axillary buds begin to grow.

11. Modified Shoots (stems): • Stolons – • Rhizomes – • Bulbs – swollen underground shoots • Tubers – swollen rhizomes Asexual, vegetative propagation Stores food for later growth

12. Fig 35.5

13. 3. Leaves – main photosynthesis organs http://www.knotweed.co.uk/japknot_Info.htm

14. Modified leaves • Compound, doubly compound – why??

15. Tendrils Fig 35.7 – Modified leaves Spines Succulents

16. Leaf types: Simple leaf = Compound leaf = divided into distinct units called leaflets

17. Four types of leaf arrangement: • Acaulescent – • Alternate – • Opposite – leaves borne across from each other at the same node • Whorled – 3 or more leaves arising from the same node.

19. Three main tissues: Dermal, Vascular, Ground Fig 35.8

20. Dermal tissue or epidermis • Root hairs are specialized epidermal extensions • Secretes waxy cuticle of the leaf

21. 2. Ground Tissue • fills the space between dermal and vascular tissue systems. • Diverse functions: pith In dicots: cortex

22. 3. Vascular Tissue • function in transport between roots & shoots, and structural support of plant • Xylem: • Phloem: Food transported to roots & non-photosynthetic parts such as the flowers

23. The Plant Cell Fig 7.8

24. 5 Differentiated Plant Cell Categories • Parenchyma • Collenchyma • Schlerenchyma • Water-conducting cells of the xylem • Sugar-conducting cells of the phloem

25. 1. Parenchyma • thin and flexible cell walls

26. 2. Collenchyma • Usually grouped in strands to support young parts of plants without restraining growth • Flexible, elongate with growing shoots

27. 3. Schlerenchyma • May be dead at functional maturity – ??? • cell walls left behind as skeleton

29. 4. Water conducting cells of the xylem: • 2 types: tracheids & vessel elements

30. Tracheids • Water flows from cell to cell (laterally) through pits in cell wall • Support function

31. Vessel Elements • End walls are perforated for free flow of water • More efficient as water conductors than tracheids

32. Fig 35.9

33. 5. Sugar-conducting cells of the phloem Sieve-tube members: • Lack a nucleus, ribosomes, vacuole • Cells separated by perforated sieve plates – allow sugar movement

34. Fig 35.9

35. Growth & Development http://www.cneccc.edu.hk/subjects/bio/album/Chapter20/PLANT_GROWTH.html

36. Development =

37. Three processes of development: • Growth = • Cellular differentiation = generation of different cell types • Morphogenesis – creation of body form & organization.

38. 1. Growth • Cell division no expansion

39. Growth • = due to water uptake in the vacuole

40. Fig 35.24

41. Cell division • Occurs in only in meristems!

42. Meristems • = • Two types of meristems: • Apical meristem – • Lateral meristems – extend lengthwise along the axis of the stem & roots. Responsible for growth in girth in older parts of the plant (called secondary growth). Exist only in perennials

43. Fig 35.10

44. Primary Growth of Roots • Root cap – layer of cells that protect the RAM as it pushes through the soil

45. Fig 35.12

46. Arrangement of Primary Tissues in Roots • Epidermis – • Stele – • Ground tissue – mostly parenchyma cells of the cortex – area between the stele & epidermis; stores food & takes up minerals. • Endodermis – single cell layer between cortex & stele. Selective barrier for uptake of soil solution contents into vascular system.

47. Eudicot/Gymnosperm root cross section Epidermis Endodermis Cortex Stele xylem phloem Fig 35.13

48. Primary Growth of Shoots • Bud = cluster of leaf primordia created by meristem. No internodes • Lateral branches arise from axillary buds

49. Fig 35.15

50. Primary tissue arrangement of stems • Ground tissue = pith & cortex