Growth of pollen tube towards ovules during fertilisation is an example of chemotrophism

Chemotropism is a type of tropism in plants that involves the growth or movement of an organism in response to chemical stimuli. It is a vital mechanism for plants to survive and adapt to their environment. Chemotropism can be positive, where the organism moves towards the source of the chemical stimulus, or negative, where it moves away from the stimulus.

Here are some examples of chemotropism:

1. Pollen tube growth towards the ovule:
During plant reproduction, pollen tubes need to grow towards the ovule to reach the egg for fertilization. This process is guided by chemical signals released by the ovule. The pollen tube exhibits positive chemotropism, growing towards the source of the chemical signal to ensure successful fertilization.

2. Root growth towards nutrients:
Plant roots exhibit positive chemotropism by growing towards areas with higher concentrations of essential nutrients, such as nitrogen, phosphorus, and potassium. This allows the roots to maximize nutrient uptake and promote plant growth.

3. Root growth away from toxins:
Plants also display negative chemotropism by growing their roots away from areas with high concentrations of toxins or harmful chemicals. The roots sense and respond to the presence of these substances, redirecting their growth to avoid contact and minimize damage to the plant.

4. Fungal hyphae attraction to plant roots:
Certain beneficial fungi form symbiotic relationships with plant roots, known as mycorrhizae. The fungal hyphae exhibit positive chemotropism, growing towards the roots in response to chemical signals released by the plant. This association enhances nutrient uptake for both the fungus and the plant.

5. Nematode attraction to plant roots:
Some parasitic nematodes exhibit positive chemotropism towards plant roots. They are attracted to chemical signals released by the roots, allowing them to locate and infect the plant. This interaction can lead to plant diseases and damage.

In conclusion, chemotropism plays a significant role in plant growth, reproduction, and survival. Plants utilize chemical signals to guide their growth and movement towards beneficial resources or away from harmful substances. Understanding chemotropism helps scientists and farmers develop strategies to enhance crop yield, protect plants from pathogens, and optimize nutrient uptake.