Plant organisation&Bioenergetics Flashcards
What tissues in the leaf help it carry out its function?
epidermal, mesophyll, xylem and phloem tissues
What does the upper epidermis do?
The upper epidermis is transparent so light can pass through it (speed up photosynthesis)
What do epidermal tissues do?
They are covered in a waxy cuticle to reduce water loss (evaporation)
What does the palisade layer do?
It has many chloroplasts (where photosynthesis takes place) and they are located at the top of the leaf where they can get the most light
What Xylem and Phloem tissues do?
deliver water and other nutrients to the leaf as well as taking away glucose produced in photosynthesis
How is the lower epidermis adapted?
Full of stomata for more efficient gas exchange. Also has guard cells which control the opening and closing of the stomata.
What are stomata and what do they do?
They are tiny holes in the under side of a leaf and they let CO2 diffuse directly into the leaf.
What does spongy mesophyll do?
Contains air spaces which increase the rate of diffusion.
What does meristem tissue do?
found at growing tips of shoots and roots and is able to differentiate into different types of plant cell allowing the plant to grow.
What do phloem tubes do?
Transports food (mainly dissolved sugars) that were made om the leaves to the rest of plant for storage or immediate use.
What do xylem tubes do?
carry water and minerals ions from roots to the stem and leaves.
What is transpiration?
The loss of water from the Plant
Describe the structure of xylem
made up of dead cells joined together with no walls between them and a hole down the middle. It is strengthened by lignin.
What 4 things is the transpiration rate affected by?
Light intensity, Air flow, humidity and temperature.
How are guard cells adapted?
They have a kidney shape which opens ad closes the stomata.
When the plant has lots of water they go plump and turgid so stomata open and gases can be exchanged for photosynthesis
When short of water cells become flaccid and close.
Sensitive to light so close at night to save water without losing out on photosynthesis.
