Question

Phloem transport is described as being from source to sink. Which of the following would most accurately complete this statement about phloem transport as applied to most plants in the late spring? Phloem transports ________ from the ________ source to the ________ sink.
A) amino acids; root; mycorrhizae
B) sugars; leaf; apical meristem
C) nucleic acids; flower; root
D) proteins; root; leaf
E) sugars; stem; root

Answer 1

Answer:

B) sugars; leaf; apical meristem

Explanation:

Phloem is one of the vascular tissues and is mainly involved in the transport of sugars. Phloem sap is the aqueous solution that moves through sieve tubes of phloem. Phloem sap mainly consists of sugars but also carries amino acids, hormones, and minerals. Sucrose is the most prevalent sugar.

Phloem sap moves from sites of sugar production (called sugar sources) to sites of sugar use or storage (called sugar sinks). A sugar sink is an organ that either uses the sugars for energy production and other functions or stores it.

In late spring, the fully grown leaves serve as a source of sugars. Apical meristem is responsible for the growth of stem and root length and serves as a sugar source as it obtains sugars from the leaves and uses them during the growth of shoot and roots.

Answer 2

Answer:

B) sugars; leaf; apical meristem is the correct answer.

Explanation:

• Phloem transports sugars from the leaf source to the apical meristem sink.

• Phloem is a living system that carries and transports the food prepared in the leaves to all parts of the plant.

• Phloem cells are found outside xylem.

Phloem is comprised of

• companion cells

• sieve cells.

• phloem fibers

• phloem parenchyma cells

Phloem transfers food everywhere the plant by this way:

• It performs this by a series of tubes that join source tissues to the sinks tissues.

• The food prepared in the leaves is loaded in the sieve tubes of the phloem and the high pressure produced in the phloem transfer the food to all parts of the plant. Thus mechanism through which sugars are carried is called pressure flow.