Test: The Stem (NCERT) - NEET MCQ

Hydrophytes are plants adapted for growing in waterlogged soil or on a substrate that becomes inundated on a regular basis. In hydrophytes, roots are of secondary importance so they are poorly developed.

The stem plays a crucial role in plants by spreading out branches that bear leaves, flowers, and fruits. It is responsible for conducting water, minerals, and photosynthates (sugars produced during photosynthesis) throughout the plant. This function is vital for the plant's overall growth and development, as it ensures that all parts of the plant receive the necessary nutrients and energy to thrive.

A tuber is a modified stem that serves the purpose of storing food. It is an adaptation that allows plants, such as potatoes, to store nutrients in underground stems. This not only helps in vegetative propagation but also acts as an organ of perennation, enabling the plant to survive unfavorable growth conditions.

The rhizome is the part of the ginger plant responsible for vegetative propagation. It grows horizontally below the soil surface and bears nodes, internodes, and buds. This adaptation allows the plant to spread and reproduce asexually, ensuring the survival and proliferation of the species.

Stem tuber is an oval or spherical underground swollen stem structure which does not bear adventitious roots, e.g., potato (Solanum tuberosum), Jerusalem artichoke (Helianthus tuberosus). Food reserve is starch in potato and inulin in artichoke.

Bougainvilea is one of many plants that fall into the scamblers category. These plants have long, fleible, curved stem thorns which help them in gripping neighbouring stems and clombing.

Offsets are one internode long, thick, small runner bearing a cluster of leaves in rosette manner at the water or ground level and adventitious roots beow the water or ground level arising from all nodes, e.g., Pistia (water letiuce), Eichhomia crassipes, etc.

Stem tendrils are slender, spirally coiled structures that develop from axillary buds. Their primary function is to help plants climb towards sunlight by attaching to surrounding structures. This adaptation is particularly beneficial for plants like cucumber and grapevines, enabling them to grow in environments where direct access to sunlight is competitive.

The assertion is correct because the stem indeed plays a crucial role in transporting nutrients and water throughout the plant. The reasoning accurately explains this function by mentioning xylem and phloem, the plant's vascular tissues responsible for this transport mechanism.

In potato, the stem nature is evident by the presence of eyes on its brownishy corky surfaces. Each sye is a pit like structure and represents the node. At the rim of the eye, scale leaf scar is seen.Buds are situated in the pit of the eye.

The assertion correctly identifies tubers and rhizomes as underground stem modifications. The reasoning provides a correct explanation, highlighting their roles in nutrient storage and vegetative propagation, which are key functions of these modifications.

Sucker is a special non-green slender stem  branch which arises from underground base of  an erect shoot or crown. It grows  horizontally in soil and ultimately comes out to  form a new aerial shoot or crown. The process  is repeated. Each sucker has one or more  nodes with scale leaves and axillary buds. e.g.  Chrysanthemum. Curcuma domestica and  Zingiber officinale both are the examples of  rhizomes.

The assertion is true as phylloclades are indeed modified stems that carry out photosynthesis, especially in plants from arid regions. The reasoning correctly explains this adaptation, noting the reduction in leaf size to minimize water loss and the stem's assumption of the photosynthetic function.

The assertion is true as stems can indeed modify into tendrils to help plants climb by attaching to surrounding structures. However, the reasoning is false because tendrils can be modified stems or leaves, depending on the plant species. In this context, the focus is on stem modifications.

Onion (Allium cepa) is a bulb. It is a short, modified, underground stem surrounded by usually fleshy modified leaves that contain stored food for the shoot within. Therefore edible part of onion is fleshy leaves.