Chapter 36.3, Problem 4CC

Summary Introduction

To determine: The environmental signal used by roots to achieve downward growth.

Introduction: An organism’s response to an external or an internal stimulus is known as its behavior. Plant movement is one of the examples of plant behaviour. Chemical signals which are transported within the body of a plant are known as plant hormones and these assist the plant in responding to the external stimuli. Gravitropism and phototropism are two types of plant movement in which the plant responds to the external sources of light.