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Why do cucurbit tendrils coil around supports like springs?

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A pile of freshly harvested pumpkins and gourds in various shapes, with striped patterns in shades of yellow, orange, and green. — Cucurbitales Pumpkins and gourds, order Cucurbitales.

Tendrils in the order Cucurbitales, such as those found in the squash and melon family, function as specialized organs that allow plants to climb and anchor themselves.1

Their ability to coil around supports is driven by thigmotropism, which is a growth response to physical contact. When a tendril brushes against an object, it senses the touch and curves toward the point of contact. If the shape of the object permits, the tendril wraps around it, clinging as long as the stimulation persists.21

Once attached, the tendril undergoes a structural change: it develops strong mechanical tissue known as sclerenchyma. This development renders the coiled structure rigid and durable, providing the necessary strength to support the weight of the climbing plant.1