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Pbl Presentation Plant Physiology


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Pbl Presentation Plant Physiology

  2. 2. <ul><li>NURUL SYUHADA BT. ISHAK </li></ul><ul><li>D20091034862 </li></ul><ul><li>PUI WAN TING </li></ul><ul><li>D20091034840 </li></ul><ul><li>NORAZLIN BT. SALAHUDDIN ABDUL AZIZ </li></ul><ul><li>D20091034847 </li></ul><ul><li>NUR IZZAH BT. IBRAHIM </li></ul><ul><li>D20091034874 </li></ul>GROUP MEMBERS
  3. 3. WHAT IS PLANT GROWTH? <ul><li>Plant growth is the process by which a plant increases in the number ,size and length of leaves, stems, roots and tubers. </li></ul>
  4. 4. WHAT IS PLANT DEVELOPMENT? <ul><li>Plant development by which plant structures originate </li></ul><ul><li>and mature as a plant grows. </li></ul>
  6. 6. LEAVES
  7. 7. WHAT ARE THE FUNCTIONS OF LEAVES? <ul><li>Absorb sunlight to manufacture plant sugars through a process called photosynthesis. </li></ul><ul><li>The cuticle is part of the epidermis. </li></ul><ul><li>It produces a waxy layer called cutin, which protects the leaf from dehydration and disease. </li></ul><ul><li>Special epidermal cells called guard cells regulate the passage of water, oxygen, and carbon dioxide into and out of the leaf through tiny openings called stomata. </li></ul>
  8. 8. The Growth and Development of Leaves <ul><li>The first leaves to develop are the unifoliolate leaves. </li></ul><ul><li>Two of these single leaves appear directly opposite one another above the cotyledons. </li></ul><ul><li>All subsequent leaves are </li></ul><ul><li>trifoliolates </li></ul><ul><li>comprised of </li></ul><ul><li>3 leaflets. </li></ul>
  9. 9. THE GROWTH AND DEVELOPMENT OF RICE LEAVES <ul><li>A leaf primordium is differentiated from a little below the shoot apical meristem (SAM).  </li></ul><ul><li>As it develops, it elongates and forms a cone-shaped structure around the SAM.  </li></ul><ul><li>Soon after, smaller veins start to form on both sides of its base, and later in between larger veins.  </li></ul>
  10. 10. <ul><li>When the primordium has grown to about 8 mm, a cavity develops at its base. </li></ul><ul><li>The auricles and the ligule will be differentiated from this location, which will be differentiated into the collar. </li></ul><ul><li>The collar separates the blade and the sheath. </li></ul><ul><li>After the cavity has formed, the meristem that is responsible for elongation is activated and the blade starts to elongate. </li></ul>
  11. 13. <ul><li>Now the blade has grown to its full size, and its cells have stopped dividing, the blade is ready to emerge. </li></ul><ul><li>As the blade emerges,  it unrolls from its tip down to the base. </li></ul><ul><li>As it unrolls, cells in the blade expand to reach a larger size.  </li></ul>
  12. 14.   The figure on the left is a cross section of a young rice shoot showing a rolled-up leaf blade being enclosed by an older leaf sheath.  The figure on the right demonstrates the location of the sheath &quot;1&quot; and the young blade &quot;2&quot;.
  13. 15. <ul><li>This is why an older leaf is wider and longer that a newly emerged leaf not because it has more cells, but because its cells have grown larger. </li></ul><ul><li>As soon as the blade starts to expand, the leaf sheath starts to elongate.  </li></ul><ul><li>The sheath completes its elongation when the blade has fully expanded.   </li></ul>
  14. 16. ROOTS
  15. 17. WHAT ARE THE FUNCTIONS OF ROOT <ul><li>Anchor the plant in the soil. </li></ul><ul><li>Store food. </li></ul><ul><li>Absorb water and mineral salts </li></ul><ul><li>from the soil. </li></ul><ul><li>Form a passage way for water and dissolved substances from the root into the stem and also for foods from the stem down into the root. </li></ul>
  16. 18. The Growth and Development of Root <ul><li>Early root growth is one of the functions of the apical meristem located near the tip of the root. </li></ul><ul><li>The meristem cells more or less continuously divide, producing more meristem, root cap cells and undifferentiated root cells. </li></ul>
  17. 19. <ul><li>The latter become the primary tissues of the root, first undergoing elongation, a process that pushes the root tip forward in the growing medium. </li></ul><ul><li>Gradually these cells differentiate and mature into specialized cells of the root tissues. </li></ul>
  18. 20. <ul><li>Growth from apical meristems is known as primary growth, which encompasses all elongation. </li></ul><ul><li>Secondary growth encompasses all growth in diameter, a major component of woody plant tissues and many nonwoody plants. </li></ul><ul><li>For example, storage roots of sweet potato have secondary growth but are not woody. </li></ul><ul><li>Secondary growth occurs at the lateral meristems, namely the vascular cambium and cork cambium. </li></ul>
  19. 21. THE GROWTH AND DEVELOPMENT OF SOYBEN ROOT <ul><li>As soybean seed takes on the water and swells, the radical is the first part of embryo to penetrate the seed coat . </li></ul><ul><li>It develops rapidly into a root which must become firmly anchored for seedling to develop enough leverage to force its way to the soil surface. </li></ul>
  20. 22. <ul><li>Lateral roots are formed soon after the radical or primary root begins to elongate. </li></ul><ul><li>Root hair appear on the primary root within 4 or 5 days after germination and on the lateral roots soon after they are formed . </li></ul><ul><li>These hair are the main absorbing surface of the root system. </li></ul><ul><li>They are very small nearly invisible without a lens and might be extensions of single epidermal cells. </li></ul><ul><li>They are actively growing part of the root just behind the growing point. </li></ul>
  21. 23. What condition did root grow? <ul><li>Roots will generally grow in any direction where the correct environment of air, mineral nutrients and water exists to meet the plant's needs. </li></ul><ul><li>Roots will not grow in dry soil. </li></ul><ul><li>At germination, roots grow downward due to gravitropism. </li></ul>
  22. 25. What are the functions of stem ? <ul><li>serves as mechanical support for leaves and buds. </li></ul><ul><li>Water and food storage. </li></ul><ul><li>Reproduction </li></ul><ul><li>Photosynthesis </li></ul><ul><li>New growth </li></ul>
  23. 26. Types of growth and development in stem <ul><li>Primary stem growth :- </li></ul><ul><ul><li>begins at the tip of the terminal bud in the area called the apical meristem. </li></ul></ul><ul><ul><li>The cell divisions on the apical meristem are responsible for the stem's growth in length. </li></ul></ul><ul><li>Secondary stem growth :- </li></ul><ul><ul><li>Also known as secondary thickening or lateral growth arises from secondary meristems. </li></ul></ul><ul><ul><li>Secondary xylem and secondary phloem are formed. </li></ul></ul><ul><ul><li>Stems are tend to thickening. </li></ul></ul><ul><ul><li>Cambium is developed at the outer part of the stem. </li></ul></ul><ul><ul><li>More stronger than primary stem. </li></ul></ul>
  24. 28. Stem terminology <ul><li>Shoot (a young stem [1 years old or less] with leaves) </li></ul><ul><li> twig (A young stem [1 year old or less] that is in the dormant winter stage with no leaves.) </li></ul><ul><li> branch (A stem that is more than 1 year old, typically with lateral stems radiating from it) </li></ul>(A woody plant's main stem) trunk
  25. 29. Types of stems: <ul><li>Specialize above ground stems: </li></ul><ul><ul><li>Crowns ( strawberries) </li></ul></ul><ul><ul><li>Spurs (apple, cherry trees) </li></ul></ul><ul><ul><li>Stolons ( strawberry runners) </li></ul></ul>
  26. 30. <ul><li>Specialized below-ground stems </li></ul><ul><ul><li>Rhizome </li></ul></ul><ul><ul><li>Bulb </li></ul></ul><ul><ul><ul><li>Tunicate - thin, papery covering; protection to the bulb from damaging and drying during digged out from the soil. </li></ul></ul></ul><ul><ul><ul><li>Nontunicate – do not have papery cover. </li></ul></ul></ul><ul><ul><li>Corm </li></ul></ul><ul><ul><li>Tuberous stem </li></ul></ul>
  27. 33. What are the functions of tubers? <ul><li>food storage </li></ul><ul><li>reproduction </li></ul>
  28. 34. Types of growth and development in tubers <ul><li>Stem tubers </li></ul><ul><ul><li>are formed from the thickening of rhizomes or stolons. </li></ul></ul><ul><ul><li>Exp:- potato tubers are developed from thickened stolons or known as propagation. </li></ul></ul><ul><li>Root tubers </li></ul><ul><ul><li>Enlargement of modified lateral roots and budding. </li></ul></ul>
  29. 35. Types of tubers: <ul><li>There are 2 types of tubers: </li></ul><ul><ul><li>Stem tubers </li></ul></ul><ul><ul><li>Root tubers </li></ul></ul>
  30. 38. MECHANISM OF GROWTH <ul><li>Seed germination </li></ul><ul><li>Photosynthesis </li></ul><ul><li>Plant hormones </li></ul>
  32. 40. SEED GERMINATION <ul><li>Germination is the process in which a plant or fungus emerges from a seed or spore and begins growth. </li></ul><ul><li>example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. </li></ul><ul><li>of a sporeling from a spore, for example the growth of hyphae from fungal spores, is also germination. </li></ul>
  34. 43. PHOTOSYNTHESIS <ul><li>a process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. </li></ul><ul><li>the process always begins when energy from light is absorbed by proteins called photosynthetic reaction centers that contain chlorophylls. </li></ul>
  36. 45. <ul><li>also known as plant growth regulators (PGRs) or phytohormones, </li></ul><ul><li>are chemicals that regulate plant growth. </li></ul><ul><li>Plant hormones are often not transported to other parts of the plant and production is not limited to specific locations. </li></ul><ul><li>occur in extremely low concentrations </li></ul><ul><li>Plants lack glands that produce and secrete hormones, instead each cell is capable of producing hormones. </li></ul><ul><li>affect gene expression and transcription levels, cellular division, and growth. </li></ul>
  37. 46. <ul><li>Auxin (IAA) </li></ul><ul><li>Cytokinins </li></ul><ul><li>Gibberellins </li></ul><ul><li>Brassinosteroids </li></ul><ul><li>Abscisic Acid (ABA) </li></ul><ul><li>Ethylene </li></ul>
  38. 47. Auxin (IAA) <ul><li>are class of plant growth substance and morphology (often called phytohormone or plant hormone) </li></ul><ul><li>On the molecular level, auxins have an aromatic ring and a carboxylic acid group </li></ul>
  39. 48. Function: <ul><li>Primary site of synthesis in shoot apical meristem and young leaves. </li></ul><ul><li>influence cell enlargement, bud formation and root initiation. </li></ul><ul><li>in conjunction with cytokinins, they control the growth of stems, roots, and fruits, and convert stems into flowers. </li></ul><ul><li>Stimulate stem elongation and promotes the formation of lateral and adventitious roots. </li></ul><ul><li>Regulates development of fruit. </li></ul>
  40. 49. Cytokinins <ul><li>Synthesized primarily in the roots and transported to other organs. </li></ul><ul><li>-promote cell division and organ development, but impede senescence. </li></ul><ul><li>influence cell division and shoot formation. </li></ul><ul><li>Modify apical dominance and promote lateral bud growth. </li></ul><ul><li>Promote movement of nutrients into sink tissues. </li></ul><ul><li>Stimulate seed germination. </li></ul><ul><li>Delay leaf senescence. </li></ul>
  41. 50. Gibberellins <ul><li>Site for production in meristems of apical buds and roots, young leaves and developing seeds. </li></ul><ul><li>Stimulates stem elongation, pollen development, pollen tube growth, fruit growth, and seed development and germination. </li></ul><ul><li>Regulate sex determination and the transition from juvenile to adult phases. </li></ul><ul><li>control cell expansion, </li></ul>
  42. 51. Brassinosteroids <ul><li>Present in all plant tissue at different intermediates predominate in different organs. </li></ul><ul><li>Promotes cell expansion and cell division in shoot, at low concentration promote root growth. </li></ul><ul><li>Promote xylem differentiation but inhibit phloem differentiation. </li></ul><ul><li>Promote seed germination and pollen tube elongation . </li></ul>
  43. 52. Abscisic Acid (ABA) <ul><li>Almost all plant cell can synthesize ABA. </li></ul><ul><li>Inhibit growth. </li></ul><ul><li>Promotes stomatal closure during drought stress. </li></ul><ul><li>Promotes seed dormancy and inhibit early germination. </li></ul><ul><li>Promotes leaf senescence and desiccation tolerence . </li></ul>
  44. 53. Ethylene <ul><li>Can be produce by almost all plant parts. </li></ul><ul><li>Promotes ripening of many types of fruit, leaf abscission and the triple response in seedlings (inhibition of stem elongation, promotion of lateral expansion and horizontal growth). </li></ul><ul><li>Enhances the rate of senescence. </li></ul><ul><li>Promotes root and root hair formation. </li></ul>
  46. 55. THANK <ul><li>YOU </li></ul>