WHAT HAPPENS TO SEEDLINGS IN THE SCATTERED LIGHT IN AUXIN DISTRIBUTION
In the scattered light, the distribution of auxin (a plant hormone responsible for growth and development) in seedlings can be affected.
Auxin plays a crucial role in various aspects of plant growth, including cell elongation, root development, and phototropism (response to light). In normal conditions, auxin is distributed asymmetrically within the seedling, with higher concentrations on the darker side of the plant, away from the light source.
When seedlings are exposed to scattered light, the distribution of auxin can become more uniform. This happens because scattered light does not have a specific direction or intensity, making it difficult for the plant to accurately determine the light source. As a result, there is less asymmetry in auxin distribution, and it becomes more evenly spread throughout the seedling.
This change in auxin distribution can have several effects on the seedling's growth. It may lead to reduced elongation of cells, which could affect the overall plant height. It can also impact the development of roots, as auxin is important for root formation and branching.
Overall, the scattered light can disrupt the normal distribution of auxin in seedlings, which can have negative consequences on their growth and development.
When seedlings are exposed to scattered light, there are specific effects on auxin distribution. Here are the step-by-step processes that occur:
1. Perception of light: Seedlings have photoreceptors known as phototropins that sense light direction and intensity. When scattered light is present, these photoreceptors detect the changes in light intensity and direction.
2. Asymmetric light distribution: Scattered light leads to an uneven distribution, causing different light intensities on different sides of the seedling. This creates a light gradient across the seedling.
3. Auxin transport: Auxin is a hormone responsible for the growth and development of plants. It is transported from the shoot apex (tip) downward through the stem. There are two transport processes: polar auxin transport (PAT) and lateral auxin transport (LAT).
4. Polar auxin transport (PAT): PAT involves the movement of auxin in a unidirectional manner, from the shoot apex downward, mainly through the vascular tissue of the stem. This transport is influenced by the auxin efflux carrier proteins, which can be biased by light cues.
5. Lateral auxin transport (LAT): LAT occurs horizontally within the tissues of the seedling. It helps in the redistribution of auxin, contributing to the overall auxin distribution patterns within the plant.
6. Differential auxin distribution: Scattered light affects the PAT and LAT processes, causing alterations in auxin distribution within the seedling. The areas receiving higher light intensity have a lower concentration of auxin, while areas with lower light intensity have a higher concentration.
7. Phototropic response: The differential auxin distribution resulting from scattered light can trigger a phototropic response in the seedling. Phototropism is the growth or movement response of a plant towards or away from light. In this case, the seedling grows towards the area with higher auxin concentration, which is away from the scattered light source.
Overall, in the presence of scattered light, the uneven light distribution affects auxin transport and leads to differential auxin distribution, ultimately influencing the phototropic response of the seedling.