6.2 Coordination in Plants

Description

Quick Overview

Plants respond to stimuli through movements that are influenced by growth and other mechanisms despite lacking nervous and muscle tissues.

Standard

This section explores how plants exhibit coordination and responses to environmental stimuli. It distinguishes between rapid movements independent of growth, such as in sensitive plants, and slower, growth-dependent movements like phototropism, emphasizing plant hormones' roles in these processes.

Detailed

Coordination in Plants

Plants lack a nervous system and muscles, yet they exhibit coordination and response to various stimuli through specialized mechanisms. There are two main types of plant movements: immediate responses to stimuli and movements due to growth.

Immediate Response to Stimulus

This kind of movement occurs in response to touch, as seen in sensitive plants, where leaves fold quickly without any growth. The process involves the internal signaling mechanisms that communicate stimuli through chemical and electrical means. Although plants do not have nervous tissues, they can change the shape of their cells by adjusting water content.

Movement Due to Growth

Plants also show directional movements resulting from growth, such as tendrils that curl around supports when they come into contact with something. These movements often appear slow and are responsive to environmental stimuli like light and gravity, termed tropisms. There are two primary types: phototropism, where shoots grow toward light, and geotropism, where roots grow downwards in response to gravity. The coordination of these movements is primarily governed by plant hormones like auxins, which regulate cell elongation on specific sides of the plant in response to stimuli.

Understanding how plants coordinate and respond to their environment helps in comprehending their growth patterns and survival strategies.

Key Concepts

  • Specialized Movement: Plants can move in response to stimuli using internal mechanisms without muscles.

  • Chemical Signaling: Response in plants like the sensitive plant involves shifting water in cells for quick movements.

  • Hormonal Influence: Growth movements are guided by plant hormones, directing development toward stimuli.

Memory Aids

🎵 Rhymes Time

  • In the sun, the plants will bend, to reach their light, their growth won't end.

📖 Fascinating Stories

  • Imagine a tender plant that feels the warmth of the sun and stretches its leaves towards the light, all while roots dig deep into the soil, holding on firmly to the ground.

🧠 Other Memory Gems

  • SHARP: Sensitive plants respond quickly, Hormones guide growth, Auxins elongate cells, Roots grow downward, Phototropism bends towards light.

🎯 Super Acronyms

TROPES

  • Tropisms Reflect Optimal Plant Environmental Sensitivity.

Examples

  • The sensitive plant's leaves fold when touched, demonstrating a quick movement response.

  • A pea plant's tendrils circle around a post to provide support while climbing.

Glossary of Terms

  • Term: Auxins

    Definition:

    Plant hormones that promote growth by elongating cells, especially in response to light.

  • Term: Phototropism

    Definition:

    The growth of a plant towards light.

  • Term: Geotropism

    Definition:

    The growth response of a plant toward gravity.

  • Term: Tropism

    Definition:

    A growth response of a plant to a directional stimulus.