Plant Tissue, Organs and Organ Systems Flashcards
What are plants made up of?
Organs like stems or roots
What is the Epidermal tissue?
Tissue that covers the whole pant
What is Palisade mesophyll tissue?
Part of the leaf where most photosynthesis occurs
What is the Spongy mesophyll tissue?
In the leaf, contains big air spaces which allow gases to diffuse in/out of cells.
What is the Meristem tissue?
Allows the plant to grow, differentiates cells into different types (found at growing tips of shoots/roots)
What is epidermal tissue covered with?
A waxy cuticle, which helps prevent water loss
Why is the upper epidermis transparent?
So that light can pass through it to the palisade layer.
What does the Palisade layer have a lot of?
Chloroplasts - which is where photosynthesis takes place
At top of the leaf so they get the most light
How are the tissues of leaves adapted for gas exchange?
- Air spaces in Spongy mesophyll tissue increase rate of diffusion
- Lower epidermis is full of stomata, which let CO2 diffuse directly into the leaf.
What do Phloem Tubes transport?
Food substances made in the leaves to the rest of the plants.
Transport can go in both directions
What is the process in Phloem Tubes called?
Translocation
What are Phloem Tubes made up of?
Elongated cells with small pores that allow cell sap to flow through.
What do the Xylem tubes carry?
Water and mineral ions from the roots to the stem and leaves.
What is the Xylem made up of?
Dead cells joined end to end with no end walls between them and a hole down the middle
What material strengthens Xylem Tubes?
Lignin
What is meant by the process Transpiration Stream?
Movement of water from the roots, through the Xylem and out of the leaves.
What is meant by the process Transpiration?
The loss of water from leaves by evaporation through the stomata.
What does Transpiration cause?
The shortage of water in the leaf causes more water to be drawn up by Xylem vessels causing a constant Transpiration Stream.
How does light intensity affect the Transpiration rate?
1) The brighter the light the greater the transpiration rate
2) When dark very little water lost as Stomata don’t open
How does Temperature affect Transpiration rate?
1) Warmer it is the faster it is
2) Warm water particles cause more energy to evaporate and diffuse out of stomata
How does Air Flow affect Transpiration rate?
1) Better the airflow the better the transpiration rate
2) Poor airflow causes a high concentration of particles outside the leave which makes diffusion from stomata slower
How does Humidity affect Transpiration rate?
1) Drier the air the faster transpiration
