Question

Which of the following is not a monocot?
A. Rose
B. Orchids
C. Palms
D. Banana

Answer 1

Hint: The arrangement of this vascular tissue involves the classification of plants into monocot and dicot. Monocot means presence of single cotyledons and more than one cotyledon is dicot.

Complete Answer:
- A cotyledon within a seed is the embryo part. Often the cotyledons may become the seedlings first leaves when the germination of seed takes place or during the beginning of its growth. Botanists use as classification means the number of cotyledons found in the seed. Monocots are the seeds that have cotyledons and the dicots have two cotyledons. Prior to the germination process the cotyledons formed during embryogenesis with the shoot and the roots of the plants.
- The cotyledons in the dicot plants have photosynthetic functions like leaves. It is the first part that emerged from the ground. Some of the cotyledons last for some days after they come out of the soil and some take a long period of time to grow. The plants like guava, sunflower, papaya, rose, tamarinds, mango, radish, castor, etc are a dicot plant that means they bear two cotyledons.
- Now, the vascular bundles of the monocot stem are irregularly scattered in the ground tissue. The bundles are smaller in the periphery and larger in size towards the center. The smaller bundles are younger, while the larger ones are older. Therefore, the arrangement is described as endarch. Every bundle is covered with bundle sheath that is formed from a layer of sclerenchyma cells.
- The vascular bundle encloses both xylem and phloem. The xylem is present in the inner surface and phloem in the outer surface and cambium is not present in monocot plants. Hence, the vascular bundles in monocot stem are endarch, closed, and collateral. Orchids, palms, and bananas are monocot plants and rose is a dicot plant.

Thus, the correct option is ‘A’. Rose.

Note: In some monocot plants like palm, a secondary growth technique is used that maintains a scattered arrangement of the vascular tissue. The collateral vascular bundle is observed in all dicot plants except the member of Cucurbitaceae.