Unique Tropisms In Plants By: MMMN Morgan, Meghan, Miles & Noah.

Slides:



Advertisements
Similar presentations
REGULATION OF PLANT GROWTH
Advertisements

Plant Responses 6.L.2.2 Explain how plants respond to external stimuli (including dormancy and forms of tropism) to enhance.
Plant Tropisms.
THE TYPES OF MOVEMENT OBSERVED IN PLANTS
Responses in Plants.
(Or is it physiological)
Movement in Plants continued. Phloem Phloem transport sugars, hormones and other organic molecules throughout the plant. This process is called translocation.
ORIENTATION RESPONSES IN PLANTS.  Plants are autotrophs – making food from photosynthesis.  Apart from reproductive organs (flowers) plant structure.
Plants and External Stimuli
TROPISM NEXT.
Unit Plant Science. Problem Area Managing Plant Growth.
PLANT MOVEMENT Higher plants, being fixed to soil, cannot move from place to place. Really, have you ever seen a tree with legs?! Yikes.
TROPISM NEXT. There are many types of tropisms : Phototropism Geotropism Thigmotropism Hydrotropism Chemotropism Thermotropism 3 main types TROPISM Plant.
Plant Responses How plants move
Plant Control Systems Response to Stimulus. Control systems ► Similar to animals, plants respond to stimuli ► We may respond to a loud noise by covering.
Tropisms.
STIMULI AND RESPONSE IN PLANTS. . Two types of responses: tropism and nastic movement Tropism - Growth response in a particular direction - Occurs slowly,
Tropisms and Turgor Responses
Regulation of Plant Growth
PLANT RESPONSES.
Tropisms.
Hormone Function and Tropisms
Transport of Material in Plants. Internal Transport in Plants Small plants rely on simple diffusion or branching tubules to transport material throughout.
- Negative Tropism = To turn away from a stimulus + Positive Tropism = To turn towards a stimulus.
Plant Hormones Darwin’s idea. Plant hormones are chemical messengers of homeostasis They are: Organic compounds Effective at very low concentration Synthesized.
Tropisms. Plants cannot move from place to place. Usually they are held in position firmly by their roots. They can, however, orientate their stems and.
Plant Tropisms. TROPISM is a biological phenomenon, indicating growth or turning movement of a plant in response to an environmental stimulus.
P LANT R ESPONSES How plants move and communicate.
7.2 Tropic responses.  Plants grow towards or away from stimuli  The growth response is called a tropism gravity light Shoots will grow towards light.
Tropisms To turn toward or away from a stimulus. Toward is positive Away is negative
Movements in Plants Class-10th.
Tropism 6 th Grade Science. Have you ever wondered how seedlings “know” which way to grow? The plant must send its roots down into the soil for minerals.
Plant Respond To Their Environment How many of you have ever been alone in a room watching a movie and the phone rings and you have jumped? You responded.
What are 3 types of tropism?
Tropisms and Photosynthesis. Tropisms Tropism is the growth of a plant towards or away from a stimulus A Stimulus is something that causes change like.
TROPISM NEXT.
Plant Tropisms. What are we talking about? Emergence - An outgrowth, as a projection, on the surface of a plant Force – A push or a pull Turgor Pressure.
How plants move and communicate
What do plants cells have that animal cells do not?
Plant Tropisms A plant’s response to a stimulus is called a tropism.
Plants Move.
Effect of hormones on plant growth
The movement or growth of a plant in response to a stimulus…
9.3 Growth in Plants.
Environmental factors
Plant Tropisms.
Plant Responses.
TROPISM Plant growth or turning in response to an environmental stimulus (a condition that affects a plants growth) (“tropo” – ”turn”) . There are many.
Tropisms and Photosynthesis
TROPISM & Hormones in plants
9.3 Growth in Plants.
Plant Tropisms.
Plant Tropisms.
Chapter Plant Responses.
Tropisms and Photosynthesis
Session 74: 6.L.2.2 Explain how plants respond to external stimuli (including dormancy and forms of tropism) to enhance survival in an environment. Changes.
Plants response to stimulus
Plant Responses.
Plant Tropisms.
Tropism Directional growth of a plant, or part of a plant, in response to an external stimulus such as gravity or light.
Environmental factors
Plants Move.
Tropism We will: Describe the effects of external stimuli on plant growth and development You will: Identify the types of tropisms exhibited by plants.
Growth response of plants
Growth response of plants
Plant Control Systems Topic 9.4.
What do plants cells have that animal cells do not?
TROPISM NEXT.
Tropism Directional growth of a plant, or part of a plant, in response to an external stimulus such as touch, gravity or light.
TROPISM NEXT.
Presentation transcript:

Unique Tropisms In Plants By: MMMN Morgan, Meghan, Miles & Noah

What is a tropism? Definition: A tropism is the turning or bending movement of an organism toward or away from an external stimulus such as light, heat, or gravity. Tropisms are directional movement responses that occur in response to a directional stimulus. The word “tropism” come from the Greek word “trope”, which means “a turning” Tropisms can be positive or negative. One of the most commonly observed tropic responses in plants is phototropism.

Positive and Negative Tropism Positive Tropism  In positive tropism, a plant will bend and grow toward a stimulus.  Ex. Roots of plants exhibit positive gravitropism when growing, because they grow down, toward the direction of gravity. Negative Tropism  In negative tropism, a plant will bend and grow away from a stimulus.  Ex. Shoots of plants show negative gravitropism during growth, because they grow upward, against the force of gravity. Plants are able to alter their growth so they can grow into more favorable conditions. To do this requires a plant’s ability to detect where the conditions are better, and then alter their growth so they can "move" in the appropriate direction. There are many types of tropisms, but only 2 ways that tropism can occur; positively and negatively.

Types of Tropisms There are many types of tropisms, or ways that plants respond to an external stimulus. Some of these types of tropisms are: Phototropism- movement or growth in response to light Gravitropism (or Geotropism)-movement or growth in response to gravity Thermotropism- movement or growth in response to heat/temperature Hydrotropism- movement or growth in response to water Thigmotropism- movement or growth in response to touch or contact Chemotropism- movement or growth in response to chemicals Heliotropism- movement or growth in response to sunlight Host tropism or Cell tropism is a tropism process that determines which cells can become infected by a certain pathogen

Phototropism Phototropism is directional growth in response to a light stimulus. Think: “Photo” means “light” An example of this is “Photosynthesis”, which means “Creation of a new chemical (synthesis) with light” Phototropism can be positive or negative. Positive phototropism is growth toward a light source. Negative phototropism is growth away from a light source. One of the most known plant examples of phototropism is the sunflower.

Phototropism II Most plant shoots exhibit positive phototropism, and roots usually exhibit negative phototropism but gravitropism usually plays a larger part in their behavior and growth. Some vine shoot tips show negative phototropism. This allows them to grow towards dark, solid objects, like tree trunks, and climb them. The reason that phototropism is possible is because of auxins. Auxins are hormones in plants that cause plants and leaves to show a positive response to sunlight. When light shines on one side of the plant, the auxin moves to the shaded side and causes the cells to become longer. This uneven growth makes it possible for the plant to bend to the sunlight. Auxins also control the production of other hormones in plants. In sunflowers, a hormone inside the plant is very important for phototropism. This hormone is called Indole acetic acid. It regulates the entire process. The most important job of IAA is to stimulate cell growth and enlargement wherever it is located.

Gravitropism Gravitropism is the turning or growth movement of a plant or fungus in response to gravity.  Also known as Geotropism  Charles Darwin was one of the first scientists to document that roots show a positive form of gravitropism and stems show a negative form of gravitropism.  Interesting Fact: Plants in a pot can continue to show gravitropism, even when they are turned on their side! Based on the pull of gravity, the roots and stem can orient their growth to the correct position. (Stems move to face upward and roots orient themselves to grow downward.) You can see this in the picture above and in the video.  Auxins also play a part in gravitropism, not just phototropism. During gravitropism, auxins carry signals from the root cap to the zone of elongation. This is an important part of the process of growth response.

Thermotropism Thermotropism is the movement of a plant or part of a plant in response to changes in temperature. AAn example of a thermotropic plant is the rhododendron. It is classified as having thermotropic or temperature-sensitive leaf movements. Charles Darwin fist categorized leaf movements in the year 1880, in his book The Power of Movement in Plants. Darwin said that many plant parts, particularly leaves, move in response to a number of environmental and physiological factors. The most important environmental factors are light intensity (phototropic), light direction (heliotropic), water content (hydrotropic), and temperature (thermotropic). The Rhododendron’s thermotropic leaf movements are unusual because these movements are in response to cold temperatures and the leaves become pendent instead of vertical.

Hydrotropism The prefix “Hydro” means “Water”, so, of course, Hydrotropism is a plant growth response where the direction of growth is determined by a stimulus of ascent/descent in water concentration. o A typical example of hydrotropism is when plant roots grow in humid air. Hydrotropism causes the roots to bend toward a place in the air with a higher humidity level. oThe hydrotropism process is starts with the root cap sensing water and sending a signal to the part of the root which is being made longer. oHydrotropism is hard to observe in roots growing underground, because these roots aren’t very observable. Gravitropism in roots is also usually more of an influence than hydrotropism. oFor these two reasons, most of the research pertaining to root hydrotropism has been conducted on roots growing in humid air, instead of in soil.

Thigmotropism Thigmotropism is a movement or response in which an organism moves or grows as a response to a stimulus of touch or contact.  The prefix “thigmo” comes from the Greek for "touch".  Think: “Thigmotropism” and “Thumb” both start with Th- and you touch things with your thumb. Use this tool to help you remember what thigmotropism is. Thigmotropism occurs most often when plants grow around a surface, like a wall, pot, or trellis. Climbing plants, such as vines, develop tendrils that coil around these supporting objects. Get this!: Auxin is involved in thigmotropism, too! Touched cells produce auxin and transport it to untouched cells. Some untouched cells will then become longer, faster, then cell growth bends around the object. The plant Mimosa pudica is widely known for its rapid plant movement. Its leaves close up and droop when touched, but this is not a form of tropism. It is a nastic movement, which is similar to a tropism, but not the same thing.

Thank you for watching! This slide will self-destruct in…