Unit 5 plant tissue

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here are the notes about plan and animal tissues

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Unit 5 plant tissue

  1. 1. UNIT 5: PLANT TISSUECampbell and Reece, 2010. Chapter 35 p. 738 – 745 and 750 - 751, Edulink and learning guide notes
  2. 2. PLANT BODY ORGANS Plants have organs that compose of different tissue, which in turn are composed of cells of different types. A tissue is a group of cells with a common function, structure or both. An organ consist of several types of tissues that together carry out particular functions.
  3. 3.  The three basis plant organs are:  Roots,  stems  leaves. SHOOT SYSTEM ROOT SYSTEM The organs are divided into  the root system (roots and mycorhiza)  shoot system (leaves and stems)
  4. 4. ROOTS Anchor plants Root hairs absorb water and minerals. Stores carbohydrates. Eudicots have a taproot system (one main vertical root that give rise to lateral roots) Monocots have an adventitious root system (roots that originate from the stem of a plant)
  5. 5. Fig. 35-4 Roots can be modified to Prop roots Many plants have modified perform different functions: roots “Strangling” aerial roots Storage roots Buttress roots Pneumatophores
  6. 6. STEMS Consist of nodes (where leaves grow) and internodes. The angle between the leave and the stem is called the axillary bud, this can form a lateral shoot. The shoot tip consist of an apical (end) bud. The inhibition of axillary buds by an apical bud is called apical dominance. Stems support the leaves and lateral branches of a plant. Stems keep the plant upright.
  7. 7. Fig. 35-5 Rhizomes Bulbs Storage leaves Many plants Stem have modified stems Stolon Tubers
  8. 8.  Rhizome: Horizontal shoot that grows just below the surface.Vertical shoots emerge from auxillary buds on the rhizome. Stolon: Horizontal shoots that grow along the surface. Reproduce asexually. Tubers: Enlarged ends of rhizome or stolon, specialized to store food. The eyes are clusters of auxillary buds that mark the nodes.
  9. 9. LEAVES Main photosynthetic part of the plant (in most vascular plants). Consist of a flattened blade and a stalk, called a petiole. Monocots have no petiole. Monocots have parallel veins on the leaves and Eudicots have net venation. Leaf shape differs: simple leaves (single leaf) and compound leaves (where the blade consist of smaller leaflets – leaflets have no axillary buds.)
  10. 10. Fig. 35-6 (a) Simple leaf DIFFERENT Petiole LEAF Axillary bud STRUCTURES Leaflet (b) Compound leaf Petiole Axillary bud (c) Doubly compound Leaflet leaf Petiole Axillary bud
  11. 11. Fig. 35-7 TendrilsSome plant species have evolved modified leaves Spines that serve various functions Storage leaves Reproductive leaves Bracts
  12. 12. Tissue categories in plants Each plant organ has:  dermal,  vascular and  ground tissues. Each of these three categories forms a tissue system. The dermal tissue system is the plant’s outer protective covering. In non-woody plants it is a single layer called the epidermis protected by a waxy layer called the cuticle found on stems and leaves. In woody plants, the protective tissue is called periderm.
  13. 13.  Some epidermal cells are modified to form hairs – roothairs on roots and trichomes on leaves and stems. The vascular tissue system carries out transport of materials between the root and the shoot system. The two types are xylem and phloem. Ground tissue are neither dermal or vascular. Internal ground tissue is called the pith. Ground tissue that is external to the vascular tissue is called cortex. Ground tissue includes various cells with specialized functions such as storage, photosynthesis and supports.
  14. 14. MERISTEMATIC TISSUE A flowering plant has the ability to grow its entire life because it possesses meristematic (embryonic) tissue. The apical meristem are located at or near the tips of stems and roots, where they increase the length of their structures by means of mitosis. This increase in length is called primary growth. Monocots also have an intercalary meristem, this allows them to regrow lost parts. (It is found between mature tissues). EXAMPLE: GRASS CUT - GROW
  15. 15. Organization of a plant body MERISTEMATIC TISSUE AT TIP OF STEM MERISTEMATIC TISSUE AT TIP OF ROOTS
  16. 16. APICAL MERISTEM Produces three types of meristems, and these develop into the three types of specialized primary tissues in the body of the plant: SPECIALIZED PRIMARY TISSUES: Protoderm gives rise to the epidermis Ground meristem produced ground tissue Procambium produces vascular tissue
  17. 17. FUNCTIONS OF SPECIALIZED TISSUES Epidermal tissue: forms the outer protective covering of a plant. Ground tissue fills the interior of a plant. Vascular tissue transports water and nutrients in a plant and provides support.
  18. 18. EPIDERMAL TISSUE
  19. 19. EPIDERMAL TISSUE Single layer of closely  Functions: packed, flat, brick - Cuticle minimizes shaped cells, with a water loss (because it large vacuole. has cutin) The aerial parts of the - Protects the plant plant are covered with against bacteria. a cuticle. Longitudinal section Cross section
  20. 20. Leaf contain upper and lower epidermal cells
  21. 21. SPECIALIZE EPIDERMAL CELLS TRICHOMES ROOT HAIR TRICHOMES ROOT HAIRS STOMA OF LEAF CORK CELLS STOMATA CORK OF OLDER STEMS
  22. 22. ROOT HAIRS They are specialized epidermal cells of roots. Unicellular outgrowth of the epidermal cell. Functions: Increase the surface area of the root for absorption of water and minerals. Anchor the plant.
  23. 23. TRICHOMES Specialized epidermal cell of stems and leaves. CUTICLE Multicellular outgrowths MULTICELLULAR of the epidermis of stems and leaves. Functions: Protect the plant from sun Conserve moisture. Protect plant from herbivores, produce toxic substance.
  24. 24. STOMATA Specialized epidermal  FUNCTIONS: cells called guard  Transpiration cells, which are bean shaped, enclose an  Gaseous exchange opening called the take place through the stoma or pore. stomata. The guard cells contain a nucleus and chloroplasts. It has a thick inner membrane and a thin outer membrane. Woody plants have lenticels.
  25. 25. CLOSED- NIGHTOPEN - DAY
  26. 26. GROUND TISSUE •PARENCHYMA •COLLENCHYMA •SCLERENCHYMA
  27. 27. GROUND TISSUES
  28. 28. PARENCHYMA TISSUE Occur in roots, stems and FUNCTIONS: leaves.  If they have Spherical, loosely chloroplasts – packed, big, thin-walled photosynthesis. cells with large vacuoles.  If they have leucoplasts Intercellular airspaces – they store products between cells. of photosynthesis.  They can divide to form more specialized cells
  29. 29. INTERCELLULAR AIR SPACESPARENCHYMA CELLS
  30. 30. COLLENCHYMA TISSUE It is composed of  FUNCTIONS: unevenly thickened  Mechanical primary walls with strengthening and additional cellulose and support to plant organs pectin deposits especially in the corners. Found just beneath the epidermis of young stems. The cells are slightly elongated, tightly packed and overlap each other.
  31. 31. SCLERENCHYMA TISSUE Cell walls have been FUNCTIONS: thickened by impregnation with lignin.  Strengthening, support The cell wall is evenly and protection. thickened and forms a  Found in shell of nuts waterproof barrier and hard parts of fruits impermeable to water.  Fibers give rigidity and In the cell walls are pit flexibility to the plant. canals that serve as channels between cells and to the outside world. The lumen is small. Two types of Sclerenchyma: Stone cells and fibers
  32. 32. VASCULAR TISSUE •XYLEM •PHLOEM
  33. 33. XYLEM Contains 2 types of conducting cells: tracheids and vessel elements (VE). Both cells are hollow and non-living but the VE is larger and has perforated plates in their end walls and are arranged to form a continuous vessel. Tracheids have tapered ends with pits. It also has other tissue: Xylem fibers, and Xylem parenchyma.
  34. 34. FUNCTIONS OF XYLEM  Transports water and minerals from the roots to the leaves.  Support and strengthening.Xylem vessels Xylem tracheids Xylem fibers
  35. 35. PHLOEM Consist of sieve-tubes and companion cells. The sieve-tubes form a continuous tube, they have cytoplasm but no nuclei. They have sieve plates between cells. The companion cell has a nucleus that controls both cells because they are connected by plasmodesmata. It also has other tissue: Phloem fibers and phloem parenchyma
  36. 36. FUNCTIONS OF PHLOEM Transports sucrose and other organic substances, including hormones, from the leaves to the roots. Support and strengthening.
  37. 37. Tissue organization of Leaves P. 750 – 751 (SELF STUDY) KNOW CROSS SECTION THROUGH LEAF

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