How Do Tendrils Actually Curve?
Good question! In general, tendrils are able to curve by employing a process known as “differential growth”. This process involves the stimulation of growth in particular regions of the tendril. In positive thigmotropism, for example, the side of the tendril which is opposite to the side of contact will grow at a faster rate than the contact side. In some cases, the cells on the contact side will actually compress, which enhances the curving response. Therefore, the non-contact side begins to elongate faster than the rest of the tendril, while the contact side actually compresses. This causes the tendril to curve toward the site of contact, as shown below. In addition to differential growth, some tendrils exhibit a type of coiling response which is referred to as “rapid contact-coiling”. This type of response is, as the name suggests, very rapid. It is caused by changes in cell turgor which alter the shape of the tendril, causing it to curve. The cells on the non-contact side of the te
