Question

Vascular bundles in pinus stem are
a. Radial
b. Collateral and closed
c. Collateral and open
d. Bicollateral

Answer 1

Hint: Here in the question, the main hint is that the vascular bundle is a part of the transport system in vascular plants. Transport mainly happens all by itself. This exists in mainly two forms, xylem, and phloem. These two issues are present in vascular bundles.

Complete answer:
As the pinus mainly belongs to the family of Pinaceae of the gymnosperm and pines are mainly woody and monoecious plants.
The stems of the pinus are very similar in the terms of the structure to the woody dicotyledons except the being a gymnosperm where the xylem is being made up of only the tracheids and with no vessels.
Talking about the vascular bundle of the pinus stem, it is the collateral and the open, and hence the correct option (c) is collateral and open.
The components are arranged separately in the radial vascular bundles.
The vascular bundles which are collaterally closed have xylem towards the inner side and phloem towards the outer side.
Bicollateral vascular bundles have phloem both the external and xylem to the internal.

Hence, The correct answer is option (B).

Additional information:
In the stem of the pinus, mainly the general arrangement of the various tissues taken from the circumference to the center is the same.
But also it differs from the dicot stem by having a large number of resins. These ducts are mainly found to be generally distributed almost throughout the stem.
The epidermis has mainly an irregular outline structure. Endodermis and the pericycle are like those the dicotyledonous like stem.
But mainly the pericycle does contains no sclerenchyma. The vascular system does not resemble the wedge-shaped as like the dicotyledons.

Note: The conjoint vascular bundles are mainly seen in the stem and leaves. A type of conjoint vascular bundle where the xylem is arranged towards the adaxial or can be said to the interior and the phloem arranged to the abaxial or can be said to the exterior.
It consists of a single layer of cells and has a very large and thick cuticle. It also consists of a single layer which is internal to the cortex called endodermis.