Differences between phototropism, geotropism, hydrotropism, and thigmotropism:
| Aspect | Phototropism ☀️ | Geotropism 🌍 | Hydrotropism 💧 | Thigmotropism 🤲 |
|---|---|---|---|---|
| Stimulus | Light | Gravity | Water | Touch or physical contact |
| Response | Plant grows towards (positive) or away (negative) from light. | Roots grow downward (positive); stems grow upward (negative). | Roots grow towards water or moisture. | Plant parts like tendrils or vines wrap around or move away from objects. |
| Example | Sunflowers 🌻 turning towards the sun. | Roots of plants growing into the soil, and shoots growing upwards. | Roots seeking water in dry conditions. | Tendrils of pea plants wrapping around a stick or support. |
| Direction of Growth | Towards/away from the light source. | Upward or downward in response to gravity. | Towards the source of water. | Towards or away from the object touched. |
| Hormone Involved | Mainly auxins regulating uneven growth. | Auxins accumulate on the lower side of roots/shoots. | Involves auxins and other growth hormones. | Triggered by touch-sensitive cells and hormones like auxins. |
These movements help plants adapt to their environment by directing their growth towards favorable stimuli or away from harmful ones!
