| 释义 |
photoperiod Biol.|ˈfəʊtəʊpɪərɪəd|
[f. photo- 1 + period n.]
The period of daily illumination which an organism receives; also, the value of this period which optimally stimulates reproduction or some other function.
1920Garner & Allard in Jrnl. Agric. Res. XVIII. 603 The term photoperiod is suggested to designate the favorable length of day for each organism, and photoperiodism is suggested to designate the response of the organism to the relative length of day and night. 1932Fuller & Conard tr. Braun-Blanquet's Plant Sociol. v. 102 Photoperiod affects growth as well as flowering of plants. 1937Ann. Reg. 1936 58 The photoperiod of a plant can be modified by temperature. 1957New Biol. XXIII. 10 The profound importance which the daily photoperiod may have in controlling the time of transition from vegetative growth to flowering was discovered more than forty years ago. 1972Sci. Amer. Aug. 27/1 It is likely..that temperature rather than photoperiod directly influences the duration of incubation [of mallard eggs]. 1976Nature 1–8 Jan. 41/1 The fish were maintained in aquaria at 22–24°C, on a light–dark (LD) 12:12 photoperiod.
Hence ˌphotoperiˈodic a., of, pertaining to, or influenced by photoperiods; ˌphotoperiˈodically adv., by means of or with regard to photoperiods; ˌphotoperioˈdicity = photoperiodism (see quot. 19451).
1923Jrnl. Agric. Res. XXIII. 873 The wide extent and great variety in form of the photoperiodic response verifies..the modern view..that environment through its action on internal conditions governs the form of expression in the plant. 1936Q. Rev. Biol. XI. 373/2 It is open to question whether they are true cases of sexual photoperiodicity. 1940Bot. Gaz. CI. 815 These differences..indicated that young leaves were photoperiodically more effective than old ones. 1945Science 6 Apr. 353/2 Botanists refer to this phenomenon as ‘photoperiodism’, while most zoologists use the term ‘photoperiodicity’. Ibid. 354/1 ‘Photoperiodicity’..has now come to include any periodic or rhythmic process controlled by photoperiods. It is not only reproduction controlled photoperiodically, but includes pelt cycles, plumage cycles in birds and migrations also. 1971Canad. Jrnl. Zool. XLIX. 109 Two morphological variations of Davainea tetraoensis were found... Changes in diet and changes in photoperiodicity do not seem to effect any change from one form to the other. 1972Country Life 16 Mar. 630/4 Wild rock doves are photoperiodic..and cease to breed when day lengths become shortened in winter. 1974Nature 10 May 183/2 The data showed that different strains produced F1 hybrids photoperiodically intermediate between the parents. 1976Sci. Amer. Feb. 114/2 It has..been demonstrated that the insect's eye is not involved in its photoperiodic response. |