2 - plants Flashcards
1
Q
phloem tubes
A
- translocation - transport foods
- pores in walls to allow cell sap to flow through
- transport in both directions UP AND DOWN
1
Q
xylem tubes
A
- transpiration stream - transports water
- only UPWARDS - roots to the stems of leaves
- dead cells and strengthened with lignin
2
Q
epidermal tissue
A
- covers whole plant
- covered in waxy cuticle to reduce water lost by evaporation
3
Q
palisade mesophyll tissue
A
- where photosynthesis happens
- lots of chloroplasts
- top part of leaf to get most light
4
Q
spongy mesophyll tissue
A
air spaces to allow gas to diffuse
5
Q
meristem tissue
A
in the growing tips or roots and shoots and can differentiate into different types of plant cells
6
Q
upper epidermis
A
transparent so light can get through to palisade layer
7
Q
lower epidermis
A
loads of stomata which let co2 diffuse into leaf and controlled by guard cella
8
Q
4 factors affecting the transpiration rate
A
- LIGHT intensity - brighter the greater the transpiration rate
stomata close in dark bc photosynthesis cant happen - when closed little water can escape - TEMP - warmer the faster transpiration rate
- AIR FLOW - better airflow the better the. transpiration rate
- HUMIDITY - the drier the air the faster the transpiration rate
9
Q
guard cells
A
- kidney shape to open and close the stomata
- when the leaf has lots of water it fills the guard cells and they go plump
- this makes stomata open so gases can exchange for photosynthesis
- when the leaf is short of water the guard cells lose water and become flaccid and the stomata close to stop water from escaping
