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🥀intro to botany review

Natural hormones

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Natural hormones are chemical messengers produced by plants that regulate various physiological processes, including growth, development, and responses to environmental stimuli. These hormones play crucial roles in plant growth regulators, influencing activities like cell division, elongation, and differentiation.

5 Must Know Facts For Your Next Test

  1. Natural hormones can be classified into different types based on their functions, including auxins, gibberellins, cytokinins, abscisic acid, and ethylene.
  2. These hormones are produced in specific plant tissues and can affect growth and development both locally and systemically within the plant.
  3. Environmental factors such as light, temperature, and water availability can influence the synthesis and action of natural hormones.
  4. Natural hormones often work in concert with each other to coordinate complex growth responses, such as flowering or fruit development.
  5. Some natural hormones can be synthetically produced and used in agriculture to enhance crop yields or modify plant growth patterns.

Review Questions

  • How do natural hormones interact with environmental factors to influence plant growth?
    • Natural hormones respond to environmental cues such as light, temperature, and moisture levels by adjusting the growth processes of plants. For example, auxins are involved in phototropism, where plants grow towards light. When light is detected on one side of a plant, auxins accumulate on the shaded side, causing those cells to elongate more than those on the lighted side. This interaction ensures that plants maximize their exposure to sunlight for photosynthesis.
  • Evaluate the role of gibberellins in seed germination and how this process illustrates the function of natural hormones.
    • Gibberellins play a critical role in seed germination by breaking dormancy and promoting the growth of the embryonic plant. Upon hydration of a seed, gibberellins are released which trigger enzymatic activity to break down stored starches into sugars for energy. This hormonal action is essential for initiating growth processes like root emergence and shoot development. The action of gibberellins exemplifies how natural hormones facilitate key developmental milestones in plants.
  • Assess the implications of using synthetic natural hormone analogs in agricultural practices on ecological balance.
    • The use of synthetic analogs of natural hormones in agriculture can significantly boost crop yields and enhance desirable traits in plants. However, this practice raises concerns regarding ecological balance. Over-reliance on synthetic hormones may disrupt local ecosystems by affecting non-target plant species and their interactions with pollinators or pests. It is essential to assess long-term impacts on biodiversity and soil health when implementing these practices to ensure sustainable agricultural methods that do not compromise environmental integrity.