Question

What is the direction of movement of sugar in phloem
A. Non-multidirectional
B. Upward
C. Downward
D. Bi-directional

Answer 1

The phloem is a vascular tissue which is responsible for transporting sugar to sink tissues, for example, non-photosynthetic root cells of flowers developing from source tissue, for example, photosynthetic leaf cells phloem also transport other molecules such as proteins and mRNA throughout the plant.

Complete step by step answer: The sugar that during photosynthesis is formed by the plant is an essential component of plant nutrition. Like water, the vascular system carries sugar usually in the form of sucrose while glucose is the original photosynthetic product in all parts of the plant. Phloem is the vascular tissue which is responsible for transporting Organic nutrients around the body of the plant which carries nutrient requiring dissolved Sugars from the leaves for the storage sites to other parts of
the plant. Within the phloem, sugar migrates to a region of low osmotic concentration and low water pressure, called sinks, from the areas of high osmotic concentration and high water pressure, which is known as the source.
Source- the sources are called nutrient-rich regions that supply sugar for the remaining portion of
the plant. The leaves, where sugar is generated through photosynthesis, at the sources.
Sinks- sinks such as growing tissues are areas in need of Nutrition. Storage areas such as can roots and
stems serve as things when they are low in supply. The constant of the phloem tubes flow from the Origins to these sinks, where, by active transport, the sugar molecules are separated from the phloem.
Pressure flow: the process by which sugar is transported through the phloem is called pressure flow, from the source to sink. sugar molecules are moved into the sieve elements at the source through
active transport. The direction of the movement of sugar in the phloem is bidirectional as it depends on the source-sink relationship which is variable in the plants.
Thus, the answer is option D- Bi-directional.

Note: In this case, the osmotic concentration refers to the concentration of solute or sugars when the concentration of solute is greatest the osmotic concentration of an refers to the concentration of solutes.