Chapter 32, Problem 1TY

What feature(s) must be present for a plant to produce wood?

1. a. a type of conducting system in which vascular bundles occur in a ring around pith
2. b. a eustele
3. c. a vascular cambium
4. d. all of the above
5. e. none of the above

Summary Introduction

Introduction: Wood is formed by the combination of cork tissue along with the older vascular bundles. These tissues expand every year by the mechanism of the secondary growth in plants. The secondary growth is the growth along the girth of the tree trunk and it can be observed by the appearance of rings across the trunk. Plants produce two types of rings, namely the spring ring and the autumn ring. The spring ring produced in the summer is wider than the autumn rings.

Answer to Problem 1TY

Correct answer: The features that must be present for a plant to produce wood are “a type of conducting system in which vascular bundles occur in a ring around pith”, “a eustele”, and “a vascular cambium”. Hence, the correct answer is option d.

Explanation of Solution

Reason for correct answer:

The formation of the wood involves the number of features to be present in the plant. The wood is a deposition of the plant secretion in the spaces of the older vascular bundles. These bundles are replaced by new conducting elements by the process of secondary growth. The secondary growth requires the eustele having the arrangement of xylem and phloem. It is initiated by a vascular cambium through the process of redifferentiation of the cambium tissue into meristematic tissue.

Option d is given as “all of the above”.

The plant needs a conducting system with a ring of vascular bundles along the pith arranged in a eustele fashion and a functional vascular cambium for the formation of wood. Hence, the correct answer is option d.

Reasons for incorrect answer:

Option a. is given as, “a type of conducting system in which vascular bundles occur in a ring around pith”.

The vascular bundles help in the formation of the wood as they are the major component of the wood. Plant deposits their secretion in the vascular bundles of xylem tissues and helps in the formation of the wood. However, it is not the only feature that needs to be present in the plant for wood formation. Hence, option a. is incorrect.

Option b. is given as, “a eustele”.

The arrangement of xylem and phloem elements around the pith directly affects the wood formation. Monocots, for example, are not able to form wood because of the absence of eustele. Although eustele is an ideal condition for the expansion and growth of the xylem and woods, it is not the only feature that needs to be present in the plant. Hence, option b. is incorrect.

Option c. is given as, “a vascular cambium”.

The vascular cambium is the initiator of the wood formation by starting the process of redifferentiation in its cells. However it is not the only feature that needs to be present in the plant for wood formation. Hence, option c. is incorrect.

Option e. is given as, “none of the above”.

The plant needs a eustele, a vascular cambium, and a conducting system containing vascular bundles in a ring-like fashion around the pith. Hence, option e. is incorrect.

Hence, the options a., b., c., and e. are incorrect.

Conclusion

Hence, plants need vascular bundles in a ring-like pattern around pith along with a eustele, and the presence of vascular cambium for the production of wood.