Question

Plant length is increased by
A. Lateral meristem
B. Apical meristem
C. Primary meristem
D. Secondary meristem

Answer 1

Hint: Throughout their lives, most plants continue to grow. Plants evolve through a combination of cell growth and cell division, much like other multicellular species. Cell growth increases cell size, while the number of cells is increased by cell division (mitosis). As plant cells expand, via cellular differentiation, they also become specialised in various cell types. They can no longer divide until cells separate.

Complete Answer:
Meristem is the secret to continued growing and restoring plant cells. Meristem is a type of plant tissue that can begin to divide and differentiate, consisting of undifferentiated cells.
At the apex, or top, of roots and buds, apical meristems are found, enabling roots and stems to develop in length and to distinguish leaves and flowers.

As the meristem adds tissue behind it, roots and stems expand in length, continuously propelling themselves deeper into the ground (for roots) or air (for stems). The apical meristem of a single branch will also become dominant, decreasing meristem growth on other branches and contributing to the growth of a single trunk. Meristems at the base of the leaf blades in grasses allow for regrowth after herbivores' grazing or lawn mowers' mowing.

The three fundamental types of meristem tissue corresponding to the three types of tissue are differentiated by apical meristems: protoderm produces new epidermis, ground meristem produces ground tissue, and procambium produces new xylem and phloem. These three meristem forms are called primary meristem because they allow length or height growth, which is referred to as primary growth.

Secondary meristems in woody plants allow for diameter (secondary growth) growth. There is no secondary growth of herbaceous plants. The secondary xylem (toward the centre of the stem or root) and phloem (toward the outside of the stem or root) are formed by vascular cambium, adding growth to the plant's diameter. The two types of secondary meristem are both called cambium, meaning "exchange" or "change." This method creates wood and constructs the durable trunks of trees.Cork cambium lies between the epidermis and the phloem, and bark, one layer of which is cork, substitutes the epidermis of the roots and stems.

The correct Answer is option (B) Apical meristem.

Note: Typically, meristematic cells are small and near spherical. They have a large cytoplasm and very few tiny vacuoles (watery saclike enclosures). The meristem is preserved as a continuous source of new cells by some of these cells known as initials, and may undergo mitosis (cell division) several times before differentiating into the particular cells needed for that plant body area.