Question

Which of the following tissues is absent in vascular bundles of monocot stem?
(a)Xylem
(b)Phloem
(c)Cambium
(d)All of the above

Answer 1

Hint: It is a tissue layer in plants which provides partially undifferentiated cells for the growth of plants. It is located in the xylem-phloem region. It forms rows of cells in parallel, resulting in secondary tissues.

Complete answer:
Xylem and phloem are arranged in monocots in vascular bundles distributed across the stem. Monocot stems create new vascular bundles for the new tissue as the plant grows. In general, monocot stems have a simpler structure than that found in dicots; only the vascular bundles and the pith that surrounds them are the main elements of the stem.
Cambium in monocot stems is absent and therefore, with a few exceptions, there is no secondary growth. The vascular bundles are arranged in dicots in a ring while they are dispersed in monocots in soil tissue. A sclerenchymatous sheath of the bundle covers each vascular bundle.

Additional Information: Phloem is the vascular tissue responsible for transmitting sugars to sink tissues (e.g. non-photosynthetic root cells or flowers developing) from source tissues (e.g. photosynthetic leaf cells). Phloem also transports other molecules, such as proteins and mRNAs, in the plant.
Xylem One of the two types of transport tissues in vascular plants is Xylem, the other being phloem. Xylem's fundamental function is to carry water from the roots to the stems and leaves, but it also carries nutrients.
So, the correct answer is ‘cambium’.

Note: The vascular cambium is partly meristem primary and partly meristem secondary. Its operation is uninterrupted and constant. It produces two types of secondary xylems, springwood, and autumn wood, due to the seasonal effect. Together, both of these forests form a ring of wood called the annual ring or growth ring.