3.3 Transport in plants Flashcards
How does water enter the plant?
Through the root hair cell by osmosis. It moves across the cortex, through the endodermis, to the xylem. Minerals are also actively transported the same way.
What are the 3 pathways water can take?
Symplastic pathway, Apoplastic pathway, Vacuolar pathway.
What is the symplastic pathway?
Movement of water through the cytoplasm of adjacent cells.
What is the apoplastic pathway?
Movement of water through spaces between the cell wall and plasma membrane of adjacent cells, and in spaces between cells.
What is the vacuolar pathway?
Movement of water through the cytoplasm and vacuoles of adjacent cells.
What can water not pass?
The Casparian strip because it is made of waterproof suberin.
How does water move up the stem?
Water moves up the xylem in a transpiration stream held together by cohesion and adhesion.
What is the cohesion-tension theory?
The cohesion-tension theory explains how water is transported in plants through the xylem.
It involves water being pushed up by root pressure and pulled up by transpiration.
What are some plant adaptations?
Waxy cuticle, rolled leaf, leaf hairs, stomata sunk in pits
What are xerophytes?
Xerophytes are plants that are adapted to live in habitats with little available water - like deserts and the extreme cold.
Example: cacti and marram grass.
What are some adaptations of xerophytes?
Conserve water by storing water in stems or leaves. Prevent loss of water by having coiled leaves, sunken stomata, and small hairs to catch water droplets. This increases the water vapour potential around the stomata and lowers the water vapour potential gradient, decreasing transpiration.
What are hydrophytes?
Hydrophytes are plants that live in water or water-logged areas.
e.g. water lilies.
What is one adaptation of hydrophytes?
Many large air spaces in the leaf to keep leaves afloat.
Where are the stomata located in hydrophytes?
The stomata are on the upper epidermis.
Why are the stomata on the upper epidermis in hydrophytes?
So that they are exposed to the air, allowing gaseous exchange and transpiration of water.
