Intercalary meristem occur between mature tissues and is the separated region of apical meristem.It is found between the plant organs. By the activity of this meristem , length of the plant organ increase.

The length of different internodes in a culm of sugarcane is variable because of the intercalary meristem.

Intercalary meristem is a type of meristem found between regions of primary growth. It is responsible for the elongation of internodes in plants. In sugarcane, the length of different internodes in a culm is variable because of the presence of intercalary meristem. The intercalary meristem is located at the base of each internode and is responsible for the elongation of the internode.

Explanation:

1. Intercalary Meristem:
Intercalary meristem is a specialized tissue found in certain plants, including sugarcane. It is located at the base of each internode, between the regions of primary growth. Unlike the shoot apical meristem, which is responsible for the overall growth of the plant, the intercalary meristem specifically controls the elongation of internodes.

2. Elongation of Internodes:
Internodes are the segments of the stem between two nodes. In sugarcane, the length of different internodes in a culm can vary. This variation is primarily due to the activity of the intercalary meristem. The intercalary meristem undergoes cell division and elongation, resulting in the elongation of the internode. The rate of cell division and elongation in the intercalary meristem determines the length of the internode.

3. Factors Influencing Intercalary Meristem Activity:
The activity of the intercalary meristem can be influenced by various factors, including:

- Shoot Apical Meristem: The shoot apical meristem is the primary meristem located at the tip of the shoot. It produces hormones, such as auxins, which can influence the activity of the intercalary meristem and, consequently, the elongation of internodes.

- Position of Axillary Buds: Axillary buds are present in the leaf axils, which are located at the base of each leaf. The position of these axillary buds can affect the activity of the intercalary meristem. If the axillary buds are actively growing, they may compete with the intercalary meristem for resources, leading to reduced internode elongation.

- Size of Leaf Lamina: The leaf lamina is the flat, expanded part of the leaf. The size of the leaf lamina at the node below each internode can also influence the activity of the intercalary meristem. A larger leaf lamina may provide more resources for the intercalary meristem, promoting internode elongation.

Conclusion:
In conclusion, the length of different internodes in a culm of sugarcane is variable because of the intercalary meristem. The intercalary meristem, located at the base of each internode, is responsible for the elongation of the internode. Factors such as the shoot apical meristem, position of axillary buds, and size of leaf lamina can influence the activity of the intercalary meristem and, consequently, the length of the internode.