1. Composition: The phloem exudate, also known as sap, primarily consists of sugars, amino acids, hormones, and other organic compounds that are transported throughout the plant. In contrast, xylem sap mainly contains water, minerals, and ions.
2. Transport mechanism: In the phloem, sap is transported in both upward and downward directions through the process of translocation. This movement is facilitated by living cells called sieve elements and companion cells. On the other hand, xylem sap travels only in an upward direction through a process known as transpiration. This process is driven by the evaporation of water from the leaves, creating a negative pressure that pulls the sap upwards.
3. Function: The main function of phloem exudate is to distribute nutrients and sugars produced in photosynthesis to different parts of the plant. It plays a crucial role in growth, development, and storage of energy. In contrast, xylem sap primarily functions in water and mineral transportation. It helps in maintaining turgor pressure, cooling the leaves, and providing mechanical support to the plant.
List three characteristics that differentiate the phloem and xylem exudates
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