According to pressure flow hypothesis in phloem transport, organic solutes flows from the regions of

Options

A. Low turgor pressure
B. High turgor pressure
C. Low osmotic pressure
D. Low diffusion pressure

Answer

**Step-by-Step Solution:**

1. **Understanding the Pressure Flow Hypothesis**: The pressure flow hypothesis explains how organic solutes, primarily sugars, are transported through the phloem in plants. This process is driven by differences in turgor pressure between source and sink regions.

2. **Identifying Source and Sink**: In the context of phloem transport, the "source" refers to the regions of the plant where organic solutes are produced or stored, such as leaves (where photosynthesis occurs). The "sink" refers to regions where these solutes are utilized or stored, such as roots, fruits, and growing tissues.

3. **Mechanism of Transport**: According to the pressure flow hypothesis, organic solutes move from areas of high turgor pressure (sources) to areas of low turgor pressure (sinks). This movement occurs through a process called facilitated diffusion, where solutes move from regions of higher concentration to lower concentration.

4. **Role of Turgor Pressure**: The turgor pressure in the source (e.g., leaves) is high due to the accumulation of solutes, which draws water into the phloem through osmosis. This creates a pressure gradient that pushes the sap (which contains the organic solutes) towards the sink regions where the turgor pressure is lower.

5. **Conclusion**: Therefore, according to the pressure flow hypothesis, organic solutes flow from regions of **high turgor pressure** (sources) to regions of **low turgor pressure** (sinks).

**Final Answer**: Organic solutes flow from regions of **high turgor pressure** to regions of **low turgor pressure**.

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