Govt. Exams
Entrance Exams
Bulliform cells are large, vacuolated cells on the adaxial surface of monocot leaves that control leaf rolling to reduce water loss during drought.
The phellogen typically develops from cortical or endodermal cells in dicot stems, occasionally from the epidermis, replacing the original epidermis.
Palisade parenchyma consists of elongated cells arranged perpendicular to the leaf surface, maximizing light capture for photosynthesis.
Succulent plants like cacti have specialized thin-walled parenchymatous tissues that store water. The waxy cuticle reduces water loss, not parenchyma.
Dicot roots typically show tetrarch arrangement (4 xylem groups), while monocot roots show polyarch arrangement. Triarch is less common in roots.
Periderm, consisting of cork, cork cambium, and phelloderm, replaces the epidermis in older stems.
Annual rings result from the difference in growth rate between spring wood (lighter) and autumn wood (darker) formed by secondary xylem.
Secondary growth, mediated by vascular cambium, produces secondary xylem (wood) and secondary phloem (inner bark).
The pericycle, a layer of parenchyma cells inside the endodermis, initiates the formation of lateral roots.
The epidermis is primarily protective and regulatory; photosynthesis is the function of mesophyll cells in the leaf.
