Lecture 5 Flashcards
Leaves
Photosynthetic organs with a manufacturing cost
Leaf shape
A) Hight surface area for CO2 absorption (H2O loss) and light exposure, high SA:V
Leaf Shape
B) lower SA:V , less photosynthesis but better H2O conservation
Leaf Shape
C) Lowest SA:V, little SA for gas exchange best H2O conservation
Leaf Shapes
D) High SA, no self shading, must be long to achieve volume = a
Leaf Layer
-Chloroplasts are mainly located in mesophyll cells
Layer from top to bottom
- Cuticle
- Upper epidermis
- Pallsiade Mesophyll Cell
- Bundle Sheath Cell
- Xylem
- Phloem
- Lower Epidermis
- Spungy mesophyll Cells
- Guard cell
- Stoma
- Cuticle
Leaf Fibers
- made from xylem and phloem cells bundled in leaves
- sisal and henequen come from leaves of Agave spp. *Agave sisalana *has sharp spoines that may also be used a needles, “needle and thread” plant
- ropes made from sisal in Africa - can make heavy duty rugs/mats
- has thorns on the side that would be used as a needle
Surface area to volume relationship of different leaf shapes
A) High SA:V = High surface area for CO2 absorption (H2O loss) and light exposure (example: standard broad leaf)
B) Lower SA:V = less photosynthesis but better H2O conservation
C) Lowest SA:V = little SA for gas exchange, best H2O conservation
D) High SA = no self-shading, must be long to achieve volume = a (Example: needle plant)
Chloroplast structure
Chloroplasts are mainly located in mesophyll cells
Mesophyte
- Syringa vulgaris*
- plants that live in medium conditions
Example: lilacs
Xerophyte
- Nerium oleander* (Oleander)
- plants that live in extremely dry conditions
- plants of dry areas
- multiple layers of endodermis with thick cuticle - prevents loss of water molecules
- stomatal crypts
- trichomes within crypts retain moisture near stomata
Stomatal crypts
- where the stomata is sunken into the epidermis like a little cup
- can have trichomes - prevents water loss, creates drags
- reduce moisture loss
- found mostly in Xerophytes
- example: Oleander
Trichomes
DEFINNEEEEE
Hydrophyte
- Nypmphaea* (Water lily)
- stomata on upper surface, or lacking
- lots of air space to conduct O2to submerged portions of plant
- less xylem tissue
- air spaces help move O2 to parts of submerged portions of the plant so they can get oxygen as well
- pants that grow in wet areas, either mud or partially to wholly submerged in water*
Monocot - Zea mays
- mesophyll does not have distinct layers
- conspicuous bundle sheath cells (AKA Kranz antomy) - surrounding vascular bundles, a wreath-like shape
- typical of monocots and grasses
- monocots tend to have parallel leaf veinnation