Entrance Exams
Govt. Exams
Xerophytes have a thick, waxy cuticle and stomata sunken in pits (crypts), which reduces direct exposure to air and decreases transpiration rate.
The mestome sheath, composed of sclerenchyma fibers, surrounds the vascular bundle and provides mechanical strength to the leaf structure.
Tracheids lack perforation plates, have oblique overlapping end walls with bordered pits, and are found in both gymnosperms and angiosperms, conducting water more slowly than vessel elements.
Dicot petioles typically have multiple vascular bundles arranged in a ring or scattered pattern, while monocots have scattered bundles throughout.
The Casparian strip is an impermeable band of suberin and lignin that prevents lateral movement of water and minerals, forcing them through the endoderm symplastically.
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.
According to the histogen theory, the calyptrogen (root cap mother region) produces the root cap, while dermatogen produces epidermis, periblem produces cortex, and plerome produces stele.
Insectivorous plants have anatomically modified leaves (pitchers, traps) with specialized glandular and digestive tissues to trap and digest insects.
The stele consists of pericycle, vascular tissues, and endodermis. The cortex lies outside the endodermis and is not part of the stele.