heliotropic, a. Bot.
(hiːlɪəʊˈtrɒpɪk)
[f. Gr. ἥλιος sun + -τροπος turning + -ic; or ad. F. héliotropique.]
Bending or turning in a particular direction under the influence of light; pertaining to or marked by heliotropism. Said of, or in reference to, growing parts of plants, which may be positively heliotropic, i.e. bend towards the light (the most usual case), or negatively heliotropic (apheliotropic), i.e. bend away from it, or diaheliotropic, q.v.
| 1875 Bennett & Dyer Sachs' Bot. 676 The fact of heliotropic curvature towards the side which receives the most light. Ibid. 677 There are a much smaller number which bend in the opposite direction, i.e. become concave on the shaded side. In order to distinguish between them the former are termed positively, the latter negatively heliotropic. 1880 C. & F. Darwin Movem. Pl. 418 Heliotropic movements are determined by the direction of the light. |
So helioˈtropical a. (rare—0) = prec.; hence helioˈtropically adv.
| 1875 Bennett & Dyer tr. Sachs' Bot. 676 The observation that leaves, some roots, Fungi..etc., curve heliotropically, indicates that their growth is retarded by light. 1891 Athenæum 27 June 832/3 The action of light and gravitation on the protoplasm of heliotropically and geotropically curving cells and hyphæ. |