Govt. Exams
Entrance Exams
Monocots lack a functional vascular cambium, which is essential for secondary growth, hence they remain herbaceous throughout life.
Vascular cambium produces secondary xylem and phloem, while cork cambium produces cork and secondary cortex, together contributing to secondary growth.
Collenchyma provides mechanical support with flexibility but does not transport water and minerals; that function belongs to xylem.
The spongy mesophyll contains intercellular spaces and is located below the palisade layer, facilitating gas exchange through stomata.
Companion cells are specialized parenchymatous cells that remain alive and are attached to sieve tube elements in the phloem.
Dicot stems have vascular bundles arranged in a ring or eustele pattern, whereas monocots have scattered bundles.
Xylem is a vascular tissue that transports water and minerals from roots to shoots through tracheids and vessels.
The middle lamella is composed mainly of pectin and calcium pectate, which acts as a cement holding adjacent cells together.
Xylem transports water and minerals (inorganic nutrients) from roots to all parts of the plant in an upward direction.
The endodermis contains Casparian strips—bands of suberin and lignin that prevent lateral movement of water and minerals, forcing them through the cell.
