LAB: Plant Tissues and Roots

Question 1

3 Tissues Systems of Plants

Answer 1

1. Dermal Tissue
2. Vascular Tissue
3. Ground Tissue

Question 2

Dermal Tissue

Answer 2

• Provides protective covering over plant parts
• Epidermis and Periderm
• Epidermis consists of epidermal cells and guard cells
  
  • Guard cells regulate the opening and closing of the stoma
• Periderm tissue forms the outer bark of woody plants

Question 3

Vascular Tissue

Answer 3

• Xylem and Phloem: tissues designed for transport of materials throughout the plant body
  
  • Xylem - transports water and dissolved minerals from roots to plant body
  • Phloem - transports carb. products (sugar) of photosynthesis throughout the plant

Question 4

Xylem (4 Cell Types)

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Answer 4

1. Vessel elements - non-living, barrel-like cells
2. Tracheids - non-living tapered cells and are the water-conducting cells of xylem tissue
3. Parenchyma cells - storage
4. Fibers - function in support

Question 5

​Phloem (4 Cell Types)

Answer 5

1. Sieve tube members - most unique cells in nature, are long, enucleate (no nucleus) responsible for the transport of food
2. Companion cells - smaller, nucleate cells that assist by loading and unloading sugars into and out of sieve tube members
3. Parenchyma cells - storage
4. Fibers - structural support

Question 6

Ground Tissue

Answer 6

• Parenchyma tissue - most abundant, storage
• Collenchyma tissue - support
• Sclerenchyma tissue - support and strongest (2 cell walls)
  
  • Sclereids - short cubical cells (ex. shells of nuts and pits of fruits)
  • Fibers - elongated, tapered cells often occurring in clumps in stems (wood, inner bark)

Question 7

Overview of Plant Morphology

Answer 7

• 3 basic organs
  
  • root
  • stem
  • leaves
• divided into root system and shoot system

Question 8

Zones of a Root Tip

Answer 8

• Zone of cell division - area at the end of the root tip where cells are mitotically dividing. ​(apical meristem)
• covered by a protective layer of parenchyma cells called the root cap
• the region of elongation is an area where cells increase in volume, lengthening the root
• region of differentiation, an are where cells mature into tissues and root hairs develop
• root hairs are extensions of epidermal cells designed to increase water absorption

Question 9

Introduction to Roots

Answer 9

• the first root that develops from the seed’s embryo is called the primary root
• additional roots are called secondary roots or lateral roots
• roots that develop from leaves or stems are termed adventitious
• Taproot system - large, central primary root with multiple smaller roots (eudicots)
• Fibrous root system - primary root dies and adventitious roots arise from the stem (monocots)

Question 10

Root modifications

Answer 10

• Prop roots - are aerial, adventitious roots that develop from the stem and will eventually penetrate the soil to offer additional support to tall plants
• Storage roots - some taproots are enlarged to store additional water and nutrients (ex. carrots and sweet potatoes)

Question 11

Root Tissues ​(monocot)

Answer 11

• Epidermis - surrounds the cortex
• Cortex - an area of loosely spaced parenchyma cells adapted for starch storage
• Endodermis - interior to the cortex is a single layer of tightly packed cells
• Stele - central core root, vascular cylinder
• inside the endodermis is the pericycle, a layer of cells where secondary roots arise
• in monocots, a pith is typically found in the center of the root
• Surrounded by a ring of alternating bundles of xylem and phloem

Question 12

Root tissues (eudicots)

Answer 12

• center of stele is composed of xlyem cells rather than a pith
• Xylem cells arranged in the shape of a cross or star
• Bundles of Phloem in between the arms of xylem tissues