Mention one significant difference between mesogamy and porogamy.

Explanation

### Step-by-Step Solution:

1. **Definition of Mesogamy**: Mesogamy is a type of fertilization where the pollen tube enters the ovule through its middle part or through the integuments of the ovule.

2. **Example of Mesogamy**: This type of fertilization is observed in cucurbit plants such as pumpkin, ridge gourd, and bitter gourd.

3. **Definition of Porogamy**: Porogamy is another type of fertilization where the pollen tube enters the ovule through the micropyle, which is the opening at one end of the ovule.

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