Exercise 7: Plant Cells and Tissues

• Histology - study of microscopic structure of tissues
• In plants, all the cell types that make up the tissues are differentiated from meristems
• Meristems - embryonic tissue regions that are actively and indefinitely producing new cells
• Apical meristem - produces cells at the tips of the main and lateral shoots and of the roots

  
• Lateral meristem - adds cells inward or outward of the plant body

  
• In the variety of plant tissues, there are three cell types based on morphology. What are they?

  Parenchyma, collenchyma, sclerenchyma
• The plant body consists of three tissue systems which run continuously from root to shoot. What are they?

  Dermal, vascular, ground
• Parenchyma - most common in ground tissue which have thin and uniformly thick primary cell walls
• What is the specialized parenchyma that consists of irregularly shaped cells that bound large airspaces and can be found is x.s. of leaf stalks from canna?

  Aerenchyma
• What is the specialized parenchyma wherein they posses chloroplasts and function in photosynthesis and can be found in s.s. of leaves?

  Chlorenchyma
• What is the specialized parenchyma that line canals and posses large vesicles that contain various substances and can be found in x.s. of pine root, stem or leaf?

  Secretory parenchyma
• Secretory parenchyma can be found lining structures called resin ducts or can also be found in glandular trichomes
• What is the specialized parenchyma that posses leucoplast filled with starch proteins or oil and can be found in potato tubers stained with IKI?

  Storage parenchyma
• Collenchyma - have thick and uneven primary cell walls made of pectin and tissue provides flexible structural support, especially in still growing younger regions and can be bound in x.s. of leaf stalks of Bagasua or Coleus
• Sclerenchyma - posses thick secondary cell walls made of lignin and the tissues are present in ground and vascular tissues
• In the structural support of sclerenchyma, fibers are elongated and flexible and can be found in cotton fibers stained with 18% APGSA
• In the structural support of sclerenchyma, sclereids are short and inflexible and can be observed in coconut shell scrapings with 18% APGSA
• Label the following

  A) Zone of division

  B) Zone of elongation

  C) Root apical meristem

  D) Root cap

  
• Protoderm - outermost layer of cells and gives rise to the dermal tissue system
• Inner to the protoderm is the ground meristem, which has larger cells that give rise to the ground tissue system
• Procambium - inner to the ground meristem; its cells are thin and elongated and have large nuclei
• Label the following

  A) Protoderm

  B) ground meristem

  C) Procambium

  
• Label the following

  A) Protoderm

  B) Procambium

  C) Ground meristem

  D) Shoot apical meristem

  E) Axillary bud

  
• What does the dermal tissue system of a plant comprise of?

  Epidermis
• Uniseriate - composed of single layer
• Multiseriate - composed of more than one layer
• In a corn root x.s., the layer below the uniseriate epidermis which is part of the ground tissue, is called?

  exodermis
• In an orchid root x.s., the alternative name of epidermis composed of multiple layers is called?

  Velamen
• root hairs - projections from some of the epidermal cells
• In the s.s. from the abaxial surface of boat of moses leaf, label the parts

  A) Pavement cells

  B) stomatal complex

  C) stomatal pore

  D) guard cells

  E) subsidiary cells

  
• Where does the ground tissue originate from?

  Ground meristem
• In the ground tissue of root piths, where do they originate?

  procambium
• In the roots and the stems, ground tissue is mostly found where?

  pith

  cortex
• Label the following

  A) Epidermis

  B) Exodermis

  C) Cortex

  D) Endodermis

  
• What is the innermost region of the root?

  pith
• What are the two types of vascular tissues?

  Xylem and phloem
• Phloem tissue can be distinguishable by a pattern of parenchyma cells: sieve tube elements(wider and enucleated) and companion cells(nuclei and denser cytoplasm)
• Xylem tissues is distinguishable as a bundle of sclerenchymatous, water-conducting cells, the tracheary elements: Tracheids and vessels
• Xylem parenchyma originate from where?

  procambium
• Label the following.

  A) Resin duct

  B) secretory parenchyma