What is the primary role of the chemical signal Auxin in the formation of leaves?
Trigger cell division at shoot apical meristem, forming leaf primordium
The opening and closing of stomata are regulated by changes in water pressure within the guard cells. What triggers these pressure changes?
Influx and efflux of K+ followed by osmosis of water
What is the primary cause of photorespiration, an inefficient process that occurs in C3 plants?
Rubisco, acting as an oxygenase, binds O2 instead of CO2
The leaves of C4 plants exhibit Kranz anatomy. What is the functional significance of this structure?
Separates intial capture of CO2 from Calvin cycle, minimizing photorespiration
In the C4 photosynthetic pathway, what happens to the 4-carbon compound (e.g., malate) after it diffuses from the mesophyll cells into the bundle sheath cells?
It releases CO2, which is then fixed by Rubisco in Calvin cycle
What is an adaptation commonly found in shade plants?
Larger surface area than leaves found in full sun
Some plants, like onion and lily, have fleshy leaves that store large amounts of carbohydrates. What is the primary purpose of this storage?
Provide energy for rapid growth early in next growing season
What are bracts?
Floral leaves located at base of flowers that often become large and colourful to attract pollinators
