DENDROLOGY

TREE PHYSIOLOGY

RESPIRATION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Glucose travels ____ the plant, through the ____
A
up, phloem
B
down, phloem
C
up, xylem
D
down, xylem
Explanation: 

Detailed explanation-1: -Sugars produced in sources, such as leaves, need to be delivered to growing parts of the plant via the phloem in a process called translocation, or movement of sugar. The points of sugar delivery, such as roots, young shoots, and developing seeds, are called sinks.

Detailed explanation-2: -The mechanism by which sugars are transported through the phloem, from sources to sinks, is called pressure flow. At the sources (usually the leaves), sugar molecules are moved into the sieve elements (phloem cells) through active transport.

Detailed explanation-3: -In plants, sugars are produced through photosynthesis in leaves. The synthesized sugar molecules are transported to different tissues and organelles through a class of specialized cellular uptake transporters called SWEETs (Sugars Will Eventually Be Exported Transporters).

Detailed explanation-4: -Food and other organic substances (e.g., some plant hormones and even messenger RNAs) manufactured in the cells of the plant are transported in the phloem. Sugars (usually sucrose), amino acids and other organic molecules enter the sieve elements through plasmodesmata connecting them to adjacent companion cells.

Detailed explanation-5: -Phloem are tissues that look like tubes. They transport sugars throughout the plant and supply it to tissues like roots, flowers and fruits that depend on this sugar to grow. Think of them like the veins in our body that move blood. Moving sugars from cells in the leaves to cells in the phloem is difficult for plants.

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