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In a genus A modified root become aerial...

In a genus A modified root become aerial and grows vertically upwards (negatively geotropic) and ina genus B modified adventitious aerial roots grow vertically downwards (positively geotropic). A and B are respectively

A

Zea mays, Pisum

B

Rhizophora, Ficus

C

Zea mays, Rhizophora

D

Vanda, Rhizophora

Text Solution

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The correct Answer is:
To solve the question, we need to identify the two genera based on the characteristics of their modified roots. Here’s a step-by-step breakdown of the solution: ### Step-by-Step Solution: 1. **Understanding the Characteristics of Genus A**: - Genus A has modified roots that are aerial and grow vertically upwards (negatively geotropic). - This type of root modification is typically found in plants that grow in swampy or marshy areas where the soil is waterlogged and lacks aeration. 2. **Identifying Genus A**: - A well-known example of a plant that exhibits this type of root modification is **Rhizophora**. - The roots of Rhizophora are known as **pneumatophores**, which grow upwards to facilitate respiration in waterlogged soils. 3. **Understanding the Characteristics of Genus B**: - Genus B has modified adventitious aerial roots that grow vertically downwards (positively geotropic). - These roots typically provide support to the plant and are often seen in larger trees. 4. **Identifying Genus B**: - A classic example of this type of root modification is found in the **Banyan tree**, scientifically known as **Ficus benghalensis**. - The roots of the Banyan tree grow downwards from the branches to provide additional support to the massive structure of the tree. 5. **Final Answer**: - Therefore, the two genera are: - Genus A: **Rhizophora** - Genus B: **Ficus**
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