Movimentos vegetais

Pandêmicos

8 Jul 202004:20

Summary

TLDRThis educational video script by Tariq explores the fascinating world of plant movements, distinguishing between tropisms and nastiesm, which are directional growths in response to external stimuli, and tactisms, which involve the movement of organelles, cells, or unicellular organisms towards or away from external agents. Examples include plants growing around objects, water, or sunlight, and the closing of night-blooming flowers in response to light. The script also discusses how certain plants and bacteria move in response to chemicals, oxygen, and light, highlighting the surprising mobility of plants.

Takeaways

🌱 Plants move more than you might think, with movements classified into growth movements and locomotion movements.
📏 Tropisms are directional growths in response to an external stimulus, which can be positive (towards the stimulus) or negative (away from it).
🌿 Thigmotropism is the growth around a solid object, such as in climbing plants or those with tendrils for support.
💧 Hydrotropism is the movement towards water, while geotropism is the movement towards the soil.
☀️ Heliotropism is the tracking of sunlight, as seen in sunflowers following the sun's rays.
🌗 Nasties are movements in response to external stimuli but differ from tropisms as they do not involve directional growth towards the stimulus.
🌜 Nyctinasty is the sleep movement of plants, caused by changes in the turgor of motor cells in the pulvinus at the base of the petiole.
🔍 Tactisms are movements of displacement of an organelle, cell, or unicellular organism in relation to an external agent, which can be positive or negative.
🌼 Chemotactism is the movement in relation to a chemical substance, such as pollen tubes growing towards the female organ in fertilization.
💨 Aerotaxis is the movement based on the chemical element oxygen, like bacteria moving towards oxygen.
🌞 Phototaxis is the movement in relation to sunlight, with chloroplasts moving towards or away from the cell wall in response to light intensity.

Q & A

What are the two main types of plant movements mentioned in the script?
-The two main types of plant movements mentioned are movements of curvature or growth, and movements of locomotion or displacement.
What is tropism and how does it relate to plant growth?
-Tropism is the directional growth of a plant in response to an external stimulus. It can be positive, meaning the plant grows towards the stimulus, or negative, meaning it grows away from the stimulus.
Can you give an example of thigmotropism?
-Thigmotropism occurs when a plant comes into contact with a solid object and starts to grow around it, such as in climbing plants or those with tendrils that coil for support.
What is the difference between hydrotropic and geotropic movements in plants?
-Hydrotropic movement is oriented towards water, while geotropic movement is directed towards the soil.
How does heliotropism affect plant growth?
-Heliotropism is the movement known for tracking sunlight. It causes plants, like sunflowers, to follow the sun.
What are nastic movements and how do they differ from tropisms?
-Nastic movements are responses to external stimuli but differ from tropisms in that the direction of the stimulus does not influence the plant's movement. Examples include nyctinasty and seismonastic movements.
What is nyctinasty and how does it relate to plant movement?
-Nyctinasty is the movement known as 'sleeping' of plants, which occurs due to changes in the turgor of motor cells in the pulvinus at the base of the petiole of a leaf.
What is tactism and how does it relate to plant locomotion?
-Tactism is a type of locomotion oriented towards the displacement of an organelle, cell, or unicellular organism in relation to an external agent. It can be positive or negative depending on the direction relative to the agent.
Can you provide an example of chemotactism in plants?
-Chemotactism is the movement of displacement in relation to a chemical substance. An example is when pollen from a flower's male organ comes into contact with the female organ of another flower, causing the sperm to grow towards the female organ.
What is aerotaxis and how does it relate to plant movement?
-Aerotaxis is the movement based on the chemical element oxygen. For instance, some bacteria move towards oxygen.
How do chloroplasts in plants respond to light through phototaxis?
-Chloroplasts move from the interior of the cell to the part closest to the cell wall in response to sunlight. When the light is too strong, they move away and back into the cell's interior.

Outlines

00:00

🌱 Introduction to Plant Movements

The script begins with an introduction to the topic of plant movements, highlighting that plants are capable of more movement than commonly imagined. The speaker, Tariq, welcomes the audience and sets the stage for a discussion on two main types of plant movements: tropisms, which are directional growths in response to external stimuli, and nastic movements, which are non-directional responses to stimuli. Tropisms can be positive, growing towards a stimulus, or negative, growing away from it. Examples of different tropisms include thigmotropism, idiomotor response to water, geotropism towards the soil, and heliotropism, which involves tracking sunlight, exemplified by sunflowers.

🔍 Exploring Various Tropisms and Nastic Movements

This section delves deeper into the types of tropisms, such as thigmotropism, where plants grow around solid objects, and idiomotor response to water. It also covers geotropism, the growth towards the ground, and heliotropism, the sun-tracking behavior. The script introduces nastic movements, contrasting them with tropisms by explaining that nastic movements are not influenced by the direction of the stimulus but are still responses to external stimuli. Examples given include nyctinasty, the closing of flowers at night, and seismonasty, where tentacles of the sundew plant bend in response to insects, demonstrating both photo- and chemo-nastic movements.

🏃‍♂️ Locomotion in Plants: Tactisms and Other Movements

The script concludes with a discussion on plant locomotion, focusing on tactisms, which are movements of plant organs, cells, or unicellular organisms in relation to external agents. Tactisms can be positive or negative, depending on whether they move towards or away from the stimulus. The script provides examples of chemotactism, where pollen tubes grow towards the female organ of a flower, and aerotaxis, the movement towards oxygen, as seen in some bacteria. Phototaxis is also mentioned, describing the movement of chloroplasts within plant cells in response to light intensity, moving closer to the cell wall when light is less intense and retreating into the cell center when exposed to strong light.

Mindmap

Keywords

💡Plant Movements

Plant Movements refer to the various ways in which plants can change their position or orientation in response to environmental stimuli. In the video, this concept is central as it discusses how plants move more than one might imagine, highlighting the theme of the video.

💡Curvature Movements

Curvature Movements are types of plant movements that involve bending or changing direction in response to stimuli. The video explains that these can be classified into tropisms, which are directional growths in response to external stimuli, and are crucial to understanding how plants interact with their environment.

💡Locomotion Movements

Locomotion Movements, as described in the video, refer to the movement of plant parts from one place to another, such as the movement of cells or unicellular organisms. This concept is important for understanding the dynamic nature of plant life and their adaptation strategies.

💡Tropism

Tropism is a specific type of plant movement characterized by directional growth towards or away from a stimulus. The video provides examples such as phototropism, where plants grow towards light, and gravitropism, where growth is directed towards the ground, illustrating the concept's relevance to the video's theme.

💡Thigmotropism

Thigmotropism is a type of tropism where plants grow in response to touch. The video uses the example of climbing plants and plants with tendrils to explain this concept, showing how it contributes to the overall movement and adaptation of plants.

💡Hydrotropism

Hydrotropism is the movement of plants towards water, as mentioned in the video. This concept is important for understanding how plants seek out essential resources for survival, highlighting the adaptive mechanisms of plants.

💡Gravitropism

Gravitropism is the directional growth of plants in response to gravity, as discussed in the video. It is a key concept for understanding how plants orient themselves in relation to the ground, which is vital for their growth and stability.

💡Heliotropism

Heliotropism is the movement of plants in response to sunlight, specifically the tracking of the sun's rays. The video uses the example of sunflowers to illustrate this concept, showing how plants can move to maximize their exposure to light.

💡Nastic Movements

Nastic Movements are plant movements in response to external stimuli that do not involve directional growth towards the stimulus. The video explains that these are different from tropisms and provides examples like nyctinasty, where plants close at night, to illustrate this concept.

💡Chemotactism

Chemotactism, as described in the video, is the movement of cells or organisms in response to a chemical stimulus. It is an important concept for understanding how plants and other organisms navigate their environment based on chemical cues.

💡Aerotactism

Aerotactism refers to the movement towards oxygen, as mentioned in the video. This concept is relevant to the video's theme as it shows how certain bacteria move in response to oxygen levels, demonstrating the adaptive behaviors of organisms.

💡Phototactism

Phototactism is the movement of plant parts, such as chloroplasts, in response to light. The video explains how chloroplasts move towards or away from light depending on its intensity, illustrating the concept's importance in plant adaptation and movement.

Highlights

Plants move more than you might think, with movements that can be classified into two main types: curvature or growth movements, and locomotion or displacement movements.

Tropisms are directional growths of a plant in response to an external stimulus, either positive (towards the stimulus) or negative (away from the stimulus).

Thigmotropism is when plants grow around solid objects, such as climbing plants or those with tendrils for support.

Hydrotropism is the movement towards water, while geotropism is the movement towards the soil.

Heliotropism is the movement that follows the sun's rays, as seen in sunflowers.

Nastic movements are responses to external stimuli without directional growth towards the stimulus, such as nyctinasty in the evening primrose.

Thigmotropism in the tentacles of the sundew plant (Drosera) is an example of a rapid response to irritation by an insect.

Chemonasty is the directional movement influenced by chemical substances, such as tentacles of sundews bending towards insects.

Nyctinasty is the sleep movement of plants, caused by changes in turgor pressure in the pulvinus at the base of the petiole.

Locomotion in plants involves tactisms, which are movements of organelles, cells, or unicellular organisms in response to external agents.

Chemotactism is the movement towards or away from a chemical substance, such as pollen tubes growing towards the female organ of a flower.

Aerotaxis is the movement based on the chemical element oxygen, like bacteria moving towards oxygen.

Phototaxis is the movement in relation to sunlight, with chloroplasts moving to the side of the cell closest to the light.

Chloroplasts adjust their position within the cell in response to light intensity, moving away from strong light.

Plants exhibit a wide range of movements that are often overlooked, demonstrating a dynamic and responsive nature.

The lecture encourages viewers to appreciate the complexity of plant movements and to subscribe for more biology lessons.