Plant Systems Flashcards
What are the three main plant organs?
Roots stems and leaves
What do the epidermis do?
Protects cells below, produces a waxy layer to reduce water loss
What is the palisade mesophyll?
Main site of photosynthesis, palisade cells packed with chloroplasts
What are guard cells
Control the opening and closing of the stomata
What is the role of the xylem and what is its structure?
Transports water and mineral ions from roots to stems and leaves
Hollow tubes
Walls strengthened by lignin
What’s the role of the phloem and what is its structure?
Transports dissolved sugars from leaves to the rest of the plant
Translocation: the movement of food molecules through phloem tissue
Tubes of elongated cells with pores in end walls
Sieve tube element
What are stomata and how do they open/close?
Small opening on the surface of the leaf which, when opened, allow oxygen to diffuse out and carbon dioxide to diffuse in. Then open and close as they’re controlled by guard cells and controls the co2 going in the leaf and the water vapour and oxygen leaving it.
What is transpiration and what are transpiration streams?
The loss of water vapour by diffusion through the stomata.
The constant movement of water molecules through the xylem from the roots to leaves.
What four factors affect the rate of transpiration?
Light intensity, temperature, humidity, air movement
What is a potometer and how does it work?
A device used to estimate the transpiration rate.
Distance moved but an air bubble can me recorded every minute and used to indicate the rate of water uptake by the plant.
