Transpiration And Translocation Flashcards
What are phloem tubes primarily made of?
Columns of elongated living cells with small pores in the end walls
Phloem tubes transport food substances, mainly dissolved sugars, made in the leaves.
What is the main function of phloem tubes?
Transport food substances from the leaves to the rest of the plant for immediate use or storage
This process is called translocation.
What are xylem tubes made of?
Dead cells joined end to end with no end walls between them
Xylem tubes are strengthened with a material called lignin.
What do xylem tubes transport?
Water and mineral ions from the roots to the stem and leaves
The movement of water through the xylem is called the transpiration stream.
What is transpiration?
The loss of water from the plant caused by evaporation and diffusion
Most transpiration occurs at the leaves.
How does transpiration affect water movement in plants?
Creates a slight shortage of water in the leaf, drawing more water up from the roots
This establishes a constant transpiration stream of water through the plant.
What role do stomata play in transpiration?
Allow gases to be exchanged, facilitating water escape from leaves
Water escapes by diffusion due to higher moisture inside the plant compared to the air outside.
True or False: Phloem transports substances only in one direction.
False
Phloem can transport substances in both directions, while xylem only transports upwards.
What environmental factors affect the rate of transpiration?
Light intensity, temperature, air flow, and humidity
Changes in these factors influence the rate at which water evaporates from the leaves.
Fill in the blank: The process of water movement from the roots, through the xylem, and out of the leaves is called the _______.
transpiration stream
What are guard cells?
Cells that surround stomata and regulate their opening and closing
They help control water loss and gas exchange in the leaves.
