L13- Development-morphology and anatomy

Question 1

STUDY FROM SLIDES

Question 2

Tissues

Answer 2

• Develop into cell types grouped into tissues
- dermal (Closely packed, protection)
• Ground (Bulk of primary plant body)
• Vascular (Transport function)

Question 3

Dermal System

Answer 3

Outside covering of plant
• Determines water loss
• Pathogen susceptibility/defense
• Resistance to penetration of chemicals
• Protects against chem injury
• Protects against temperature stress
• Facilitates gas exchange (Oxygen in, Carbon dioxide out)

Question 4

Elements found in dermal system

Answer 4

• Epidermis
• Cuticular membrane
• Trichomes
• Stomata
• Lenticels

Question 5

Epidermis

Answer 5

• Single layer
• Elongated tightly arranged cells
Epidermal cells/Pavement
• Points of interruption occur
Facilitate gas/moisture exchange

Question 6

Cuticular Membrane

Answer 6

• Extracellular structure of cutin and waxes
• Protects against water loss, pathogens, and chemicals
Cutin ->C16 - C18 fatty acids hydroxylated to each other and glycerol
-Cuticular wax ->Lipids of very long chain fatty acids (C20-C34)

Question 7

Two sections of cuticular membrane

Answer 7

1. Cuticular Layer
   - Embedded polysaccharides
   - Pathogen defense
2. Cuticular proper (on top)
   - Intracuticular wax
   - Epicuticular wax forming film (shiny)
   - Epicuticular wax crystals (dull)
   - Water loss – Wax composition moreimportant than amount

Question 8

Trichomes

Answer 8

• Single-celled, or multicellular appendages
found on stems, and some fruits, such as
peach and kiwifruit.
• May be branched or unbranched to help
prevent water loss
• Storage of volatile compounds (essential
oils)

Question 9

Stomata

Answer 9

• Present in leaves mostly
predominantly in epidermis of abaxial side
(bottom)
but also in adaxial side (top) of leaves, fruit
surfaces, stems of herbaceous plants
• Great variation between species and
organs

Question 10

Opening and closing of stomata

Answer 10

• Two guard cells that for the pore
• Regulate exchange of O2(out) and CO2 (in)
• Opening, closing regulated by turgor
Swell by water intake: kidney shape, pore
Shrink by water outlet, reverses shape,
closure
• Respond to ABA and desiccation

*swelled stomata due to osmosis and turgor pressure

Question 11

Lenticels

Answer 11

• Found on epidermis (stem, petiole, fruit)
• Parenchymatous cells that are pores that are always open
• Visible on fruit surfaces, mango, apple, avocado
• In fruit, often derived from no longer functioning stomata
• Permit gas exchange between environment and internal tissue space of the organs (stems, and some fruit)
• Oxygen/CO2 exchange
• In apple, lenticels account up to 21% of transpiration