Which part of a plant is involved in Translocation?

Appeared in: HSSC Staff Nurse - 2015

Explanation

Translocation is the specific term for the transport of soluble organic food materials, primarily sucrose, from the leaves (source) to other parts of the plant (sink).
Phloem is the complex vascular tissue responsible for carrying out translocation.
This transport occurs through living cells (sieve tubes and companion cells) and is an active, bidirectional process, allowing nutrients to be moved wherever they are needed.

Option B: Xylem transports water and dissolved minerals, not the sugary food (photosynthates) produced during photosynthesis.
Option C: The cortex is a layer of ground tissue, not vascular tissue. Its primary functions are storage and providing structural support, not long-distance transport.
Option D: Pith is the central core of ground tissue found in stems. Like the cortex, its main function is storage, not the long-distance movement of nutrients.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Transport systems in plants as background academic context rather than a clinical decision trigger.
Understanding translocation is crucial in agriculture for practices like grafting, where the phloem of the scion and rootstock must align for the graft to be successful.
The 'girdling' or 'ringing' experiment, where a ring of bark including the phloem is removed, demonstrates the role of phloem in downward food transport, as sugars accumulate above the ring, causing it to swell.
What if? If a plant is infested with aphids, which have specialized mouthparts to pierce phloem tubes and feed on the sugary sap, the plant's energy reserves are depleted. This starves the roots and other sink tissues, leading to stunted growth and reduced crop yield.

How to Approach the Question

First, identify the key process in the question: 'Translocation'.
Recall the definition of translocation in a botanical context: the movement of food (sugars) made during photosynthesis.
Differentiate between the two main transport tissues in plants. A simple mnemonic is: Xylem transports water and minerals 'up' from the roots, while Phloem allows food to 'flow' all around the plant.
Based on this, associate 'translocation' of food with 'phloem'.
Evaluate the other options. Cortex and Pith are ground tissues primarily for storage, not long-distance transport, which confirms Phloem is the correct choice.

Concept Tested & Keywords

Qd_3eeEKhUAWSYzxIVIgut

Practise the full HSSC Staff Nurse - 2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.