Designation (also claws, curls, noodles, gussets, nooks and crannies) for the fastening organs of the vine. This belongs to the group of climbing plants, whose natural supports are other plants, slender upright woody plants but also hanging climbing plants (lianas). The tendrils are a transformed grape stem framework, the panicle of the inflorescence (clusters or later grapes). They are also closely related to the flowering plants. This can be seen in the occurrence of mixed forms, because side arms of the tendril can have some flowers and those of the appendages can have tendrils. At the node of the shoot they are always opposite the leaf. In the European varieties (species Vitis vinifera) the tendril sequence is discontinuous (with spatial interruptions). This means that in the node sequence on the shoot, after two tendril-bearing nodes, a node without tendril follows. They are forked with two to four branches.
The curved forked ends of the young tendrils carry out a nutation (circular movement) during growth. On contact with a support, the tip usually winds very quickly in the same direction in a helix around the base and attaches the shoot to it. Later, the fork-free part of the tendril branch contracts into a two-part helical spring contracting in the opposite direction, so that the shoot is pulled closer to the tendril base. The tendril then becomes woody, but remains elastic. In certain grape varieties they are particularly strong and long, as is the case with Chasselas, Muscat Ottonel and Welschriesling, for example. The Grüner Veltliner, Silvaner or Traminer varieties, on the other hand, have short or weakly developed tendrils. Often the tendrils are also only partially functional and fall off after some time without contact with a support. See also under vines.
Graphic: taken from Bauer/Regner/Schildberger, viticulture,
ISBN: 978-3-70402284-4, Cadmos Verlag GmbH