Question

Root cap in monocots is formed by \(\begin{array}{ll}\text { (a) dermatogen } & \text { (b) calyptrogen } \\\ \text { (c) vascular cambium } & \text { (d) wound cambium. }\end{array}\)

Short answer

The root cap in monocots is formed by calyptrogen.

Step-by-step solution

Identify the Function of Each Option

Start by understanding what each of the options represents in plant tissue. Dermatogen is responsible for epidermis formation. Calyptrogen is involved in the formation of the root cap. Vascular cambium is a layer of tissue that produces vascular tissues (xylem and phloem). Wound cambium forms when a plant is injured and helps in healing.

Determine the Role of Each Tissue in Root Development

Since the question asks which tissue forms the root cap in monocots, determine which of these tissues has the function specifically related to root cap formation.

Select the Correct Option

Calyptrogen is the layer that gives rise to the root cap. Therefore, option (b) is correct.

Key concepts

Calyptrogen

Calyptrogen is a specialized plant tissue found at the tips of roots in monocots, and its primary role is the formation of the root cap. This tissue comprises a group of undifferentiated cells, known as meristematic cells, which have the capability to divide rapidly and give rise to new cells. The root cap formed by the calyptrogen is crucial for the overall root structure as it serves as a protective cover for the delicate apical meristem - the site of active cell division in the root tip.

The root cap protects growing roots from damage as they navigate through the soil. It also facilitates the gravitropic response of roots, directing their growth downward, by perceiving gravity. Moreover, cells of the root cap can secrete a slimy substance called mucigel, which aids in the lubrication of the root as it moves through the soil. It is interesting to note that as the outermost cells of the root cap are worn away or damaged in the soil, new ones take their place thanks to the self-renewing capability of calyptrogen.

Plant Tissue Function

Plant tissues are organized into various systems, each with specific functions that contribute to the plant's overall growth, development, and survival. The major plant tissue types include dermal tissue, vascular tissue, ground tissue, and meristematic tissue.

Dermal Tissue

This outermost layer, epitomized by the dermatogen in the original exercise, acts as a protective cover and is involved in the exchange of matter and gases between the plant and its environment.

Vascular Tissue

Vascular tissue, which includes the vascular cambium, is responsible for the transport of water, nutrients, and the carbohydrates produced by photosynthesis throughout the plant.

Ground Tissue

Ground tissue encompasses various functions including photosynthesis, storage, and support.

Meristematic Tissue

Tissues like calyptrogen and the wound cambium are meristematic, which means they are comprised of cells that can continuously divide and differentiate into other tissue types, enabling growth and healing.

Root Development

Root development is a complex process involving various plant tissues, and it is crucial for anchorage, nourishment, and overall plant health. The main stages of root development include the initiation of root primordia, elongation, and differentiation of the root tissues.

The calyptrogen plays a significant role during the initiation phase, forming the protective root cap. This cap ensures the safety of the apical meristem, a region just behind it, where cells are rapidly dividing to contribute to root lengthening. As the root elongates, its cells differentiate into specialized types, such as the vascular tissues for transport and the epidermal tissues for absorption and interaction with the soil environment.

To fully understand root development, it is necessary to recognize the interplay between the different plant tissues and how each contributes uniquely to the growth and functionality of the root system.