Lecture 8 Flashcards
Shoot Apical Meristem function
Site for formation of lateral organs (leaves, flowers), replenishes cells
SAM regions (2)
Tunica (2 surface layers that contribute to the epidermis and ground tissue)
- anticlinal division
Corpus (make internal stem tissues)
- anticlinal and periclinal division
SAM zones (3)
Central Zone (large cells/vacuole, slow division, self-renewal cells)
Peripheral Zone (small cells/vacuole, high division, contain cells incorporated into epidermal/peripheral tissues, lateral organs)
Rib Zone (intermediate cells, incorporated into central stem tissue)
SAM cell types (2)
Initials (replace themselves)
Derivatives (differentiate)
SAM ans RAM beginning forming in what embryogenic stage?
Late heart stage
What is stm?
Shootmeristemless
A mutation in Arabidopsis plants that cause them to lack SAM and cotyledon formation during the first heart stage
Where do leaves arise from? What is the function of this structure? What dictates it’s positioning?
Leaf primordia
Protects the apical meristem from drying out
Positioning determined by local zones where plant hormone auxin accumulates
What are axial buds? What do they contain and when are they activated?
Arise from axial cells (in armpit of leaf primordia)
Contain many metabolic organelles that remain dormant unless needed (ex. When attacked/injured)
Leaf parts: simple leaf (3)
Blade (photosynthetic tissue)
Petiole (transport tissue)
Auxiliary bud (becomes lateral shoot)
Leaf parts: compound leaves (2)
Dissected (little leaflets to break up airflow and prevent lead from over-heating/absorption)
Rachis (provides flexibility and displays photosynthetic tissue)
Root Apical Meristem Function
Acts as a reserve for pluripotent cells ready when needed (aren’t particularly actively dividing, only activated when needed)
Root cap
Protects Apical Meristem as Root pushes through soil (as cells are constantly being knocked off as they slide through)
What is hbt?
Hobbit
Mutation in root Apical Meristem that cause Arabidopsis to lack proper root formation
Caused by improper development of suspensor cells causing improper development of hypophysis
Quiescent cent and columella don’t form at all
Root Function (6)
Water uptake
Anchor/support shoot
Stores resources
Mineral nutrient acquisition
Sense environment (nutrient/water availability)
Mutual w fungi/soul bacteria to gather resources
Basic root dicot structure (7)
Epidermis (skin)
Cortex (stores nutrients/carbs)
Endodermis (filters water entering xylem)
Pericycle (where lateral roots/vascular cambium originate)
Phloem (in pace bw xylem poles)
Xylem (in center of vascular cylinder)
Root hairs (single cell outgrowths)