| 释义 |
photonegative, a.|fəʊtəʊˈnɛgətɪv|
Also with hyphen.
[f. photo- 1 + negative a.]
1. Zool. Of an animal: tending to move away from light.
1914S. O. Mast in Biol. Zentralblatt XXXIV. 662 In place of positively or negatively phototropic, geotropic, etc., we might use photo-, geo-, negative or positive, etc. 1923Jrnl. Exper. Zool. XXVIII. 120 Insects with one eye blinded usually turn, in non-directive light, toward the functional eye if they are photopositive and toward the blinded eye if they are photonegative. 1945T. H. Savory Spiders Brit. Isles (ed. 2) 143 They [sc. harvestmen spiders] are strongly photonegative and collect in the darkest corner of their cage. 1975Nature 25 Dec. 712/2 Flies entering the maze..receive phototactic scores ranging from 1·0 (highly photonegative) to 16·0 (highly photopositive).
2. Physics. Pertaining to or exhibiting a decrease in electrical conductivity when illuminated.
1915Physical Rev. V. 62 For certain regions of the spectrum these cells were photo-negative, while for longer wave-lengths they were photo-positive. 1925H. S. Allen Photo-Electricity (ed. 2) vi. 95 In some instances an apparent rise in resistance has been observed on exposure to light. This type of response is said to be ‘photo-negative’. 1932[see photopositive a. 2].
Hence ˌphotonegaˈtivity.
1962Jrnl. Insect Physiol. VIII. 253 There is a less pronounced shift towards photonegativity in the later instars. 1974Marine Biol. XXV. 313/2 Photokinesis and phototaxis were deliberately confounded in this measure, since there was no way to predict which behavioural element might respond to selection for photonegativity in the tidal pool. |