Question

Bordered pits are more common in
A)Monocots
B)Dicots
C)Gymnosperms
D)All the above

Answer 1

Bordered pits is a primitive structure which is developed into lateral pits through the course of evolution. Developed plants do not have bordered pits.

Complete answer:
In the kingdom Plantae vascular system was first seen in pteridophytes. But, pteridophytes didn’t have that well-developed vascular system. After pteridophytes, there was more evolution of the vascular system in gymnosperms. Gymnosperms have xylem and phloem in their vascular system. Xylem (water-conducting tissue) and phloem (food conducting tissue). Tracheids are the main water-conducting part of xylem in gymnosperms. Most of the parts of vascular tissue are dead because if they were living then their cells would have taken space which leads to narrowing of space in tissue for the transportation of food, water, and nutrients. Tracheary elements are dead tissue covered with the cell walls. All living elements (cytoplasm, nucleus, cell organelles, etc) inside it degenerates. These tracheids are elongated tubes inside the stem and other parts of plants for transporting the water and nutrients.
During cell wall thickening, lignin is deposited on the whole primary cell wall except some places termed as bordered pit-pairs. This bordered pit-pairs represents regions of an un-lignified primary wall from two adjacent cells, where there is the formation of lateral walls around the pit aperture. These lateral walls serve as a border around the pit, so-called bordered pits. There is middle-lamella between the cells enclosed in pits. Bordered pits are the primitive structure which are developed into lateral pits in angiosperms.

So, the correct answer is “bordered pits are more common In gymnosperms”.

Note: Gymnosperms do not have xylem vessels in their xylem tissue. Except for three genera that are Ephedra, Gnetum, and Welwitschia.