Chapter 22, Problem 32A

Summary Introduction

Introduction :

In plants, the roots growing down, stems growing upward, trees are dropping their leaves, and leaves of some plants trapping an insect are due to responses of plants to their environment. A tropism is the response to an external stimulus by growth of a plant.

Answer to Problem 32A

Correct answer :

The correct answer is option (c) Vascular tissue

Explanation of Solution

Explanation/justification for the correct answer :

Option(C) Vascular tissue. The hormone group called gibberellins causes elongation of the cells, promotes cell division and affects seed growth. Gibberellins are transmitted to vascular tissue. So, the correct answer is option (C).

Explanation for incorrect answer :

Option (A)Cork cambium. The cork cambium forms some bark. The cambium occurs cell division forms cells that become secondary xylem and phloem. So, this is an incorrect answer.

Option (B) Guard cells. A lack of water in the soil triggers abscisic acid to be released. This hormone is transported on guard cells from the root cells to the receptors which in turn lead the guard cells to shut down the stoma to avoid excessive water loss. So, this is an incorrect answer.

Option (D)Apical mersitem. An apical meristem produces auxin inhibiting the growth of side or lateral branches. However, removing apical meristem from a plant reduces the amount of auxin present. This favors side branch growth. So, this is an incorrect answer.