Responses in Flowering Plants and Growth Regulation

Vocabulary flashcards defining key plant tropisms, growth regulators, anatomical adaptations, and experimental terms from the lecture on plant responses.

Tropism

The growth response of a plant to an external stimulus.

Phototropism

The growth response of a plant to light.

Geotropism

The growth of a plant in response to gravity.

Thigmotropism

The growth response of a plant to touch.

Hydrotropism

The change in the growth of a plant in response to water.

Chemotropism

The growth response of a plant to chemicals.

Growth Regulators

Chemicals that control the growth rate of a plant, produced in meristematic regions and transported mostly in phloem vascular tissue by diffusion.

Growth Promoters

Chemicals such as auxins (like indoleacetic acid, IAA) and gibberellins (like gibberellic acid, GA) that increase the rate of plant growth.

Growth Inhibitors

Chemicals made in stem nodes, ripe fruit, and decaying leaves (such as ethane and abscisic acid) that decrease the rate of growth or stop it completely.

Indoleacetic Acid (IAA)

An auxin produced in shoot and root tips that travels to the shaded side of the plant, causing cells there to elongate faster and bend the plant towards light.

Positively Phototropic

Refers to plant structures, such as stems, that grow towards the light.

Negatively Phototropic

Refers to plant structures, such as roots, that grow away from light.

Positively Geotropic

Refers to plant structures, such as roots, that grow downwards in the direction of gravitational pull.

Negatively Geotropic

Refers to plant structures, such as stems, that grow upwards against the direction of gravitational pull.

Heat Shock Proteins

Stress proteins that help plant proteins fold into the correct shape and navigate to the right place during distress, such as high temperatures.

Serial Dilution

A procedure that produces a range of solutions, each one of which is one-tenth the concentration of the previous solution.

Percentage Stimulation or Inhibition Formula

$$\text{Percentage stimulation or inhibition} = \frac{\text{Average length} - \text{Average length of controls}}{\text{Average length of controls}}$$