Food (mainly in the form of sugars) is transported in plants through the phloem via a process called translocation:
- Movement from source to sink: Sugars are produced in the leaves (source) and transported to other parts of the plant (sink) such as roots, stems, and fruits.
- Pressure flow mechanism: Sucrose is loaded into sieve tube elements at the source, creating high osmotic pressure. Water follows by osmosis, creating pressure that drives the flow of sap to the sink where the sucrose is unloaded.
MCQs Based on the above question
Question 1: How is food primarily transported in plants?
A) By diffusion through cell walls
B) Through specialized tubes called xylem
C) Through specialized tubes called phloem
D) By active transport through root cells
Answer: C) Through specialized tubes called phloem
Question 2: What is the main source of sugars in plants for transport to other parts?
A) Roots
B) Stems
C) Leaves
D) Flowers
Answer: C) Leaves
Question 3: What mechanism explains the movement of sucrose from the source to the sink in plants?
A) Diffusion gradient mechanism
B) Capillary action mechanism
C) Pressure flow mechanism
D) Active transport mechanism
Answer: C) Pressure flow mechanism
Question 4: Why does water follow sucrose into the sieve tube elements during the pressure flow mechanism?
A) Due to active transport of water molecules
B) Due to the evaporation of water in the leaves
C) Due to high osmotic pressure created by the loaded sucrose
D) Due to gravitational pull
Answer: C) Due to high osmotic pressure created by the loaded sucrose