100-word explainer: How plants recognise gravity?

Plants have specialised gravity sensing cells at the root tip that contain ‘amyloplasts’. Amyloplasts are starch-filled structures that are heavier than the other things in the plant cell, so they sink to the bottom. Therefore, plants know that the direction amyloplasts sink is ‘down’ and the opposite way is ‘up’. Plant use this gravity recognition process as a guide to spread the plant growth hormone auxin unevenly inside plant organs. This directs roots towards the ground and shoots towards the sky.

That’s why plant roots always grow ‘down’, and shoots grow ‘up’.  Lights and water also influence plants directional growth.




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  • Ramya Selvi.N 2 years ago

    What is the gene responsible for this???

    • Rupesh Paudyal 2 years ago

      Sorry for a late reply.

      Auxin activates and deactivates several genes that regulate plant growth. The distribution of auxin in plant organs i.e. root is controlled mainly by proteins (such as PIN proteins encoded by PIN genes) that function at the cell membrane.