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Author Lumsden, P. J., & Furuya, M.
Title (up) Evidence for Two Actions of Light in the Photoperiodic Induction of Flowering in <italic>Pharbitis nil</italic> Type Journal Article
Year 1986 Publication Plant and Cell Physiology Abbreviated Journal
Volume Issue Pages
Keywords Plants
Abstract Using one-day-old light-grown seedlings of Pharbitis nil we have shown that there are two distinct responses to light during the inductive dark period. The first is the classic night-break, which inhibits flowering at a specific stage of the circadian rhythm (assumed to be the basis of dark time measurement). The second action is to control the phase of this rhythm. The two responses were compared at the 6th and 8th hour of darkness. They differed in their dose responses, and by using very short exposures it was possible to achieve one response without the other. The response of the rhythm to light displayed characteristics of other circadian rhythms; the direction and sensitivity of the phase shift changed between the 6th and 8th h, the rhythm was reset by longer exposures to light, and with one critical light treatment at the appropriate phase, the rhythm was apparently abolished. These results offer direct support for an external coincidence model in the photoperiodic control of floral induction.
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Language Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 1471-9053 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ intern @ Serial 2375
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Author Myers, L.; Christian, K.; Kirchner, R.
Title (up) Flowering responses of 48 lines of oilseed rape (Brassica spp.) to vernalization and daylength Type Journal Article
Year 1982 Publication Australian Journal of Agricultural Research Abbreviated Journal Aust. J. Agric. Res.
Volume 33 Issue 6 Pages 927
Keywords Plants
Abstract Forty-eight lines of Brassica spp, of diverse origins were grown in the glasshouse either under natural daylengths or daylengths extended to 16 h by artificial illumination. Plants were either unvernalized or had been subjected to 6 weeks at 8¦C day and 6¦C night temperatures as seedlings. Lines could be classified into two major groups, according to whether or not vernalization or long photoperiods were essential for 50% flowering within 21 weeks. In six lines, both vernalization and long days were essential for prompt flowering, while only five lines did not respond to either treatment. Strong interactions between lines and treatments were found in the number of leaves and subtended buds at flowering. The results show that a wide range of responses is obtainable from material currently available, offering considerabk, scope for adaptation to different environments.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0004-9409 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ intern @ Serial 2369
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Author Lang, M.; Lichtenthaler, H.K.; Sowinska, M.; Heisel, F.; Miehé, J.A.
Title (up) Fluorescence Imaging of Water and Temperature Stress in Plant Leaves Type Journal Article
Year 1996 Publication Journal of Plant Physiology Abbreviated Journal Journal of Plant Physiology
Volume 148 Issue 5 Pages 613-621
Keywords Plants
Abstract
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Language Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 0176-1617 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ kagoburian @ Serial 656
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Author Haag, C.R.; Riek, M.; Hottinger, J.W.; Pajunen, V.I.; Ebert, D.
Title (up) Genetic diversity and genetic differentiation in Daphnia metapopulations with subpopulations of known age Type Journal Article
Year 2005 Publication Genetics Abbreviated Journal Genetics
Volume 170 Issue 4 Pages 1809-1820
Keywords Plants; Aging; Animals; Daphnia/*genetics/*physiology; *Genetic Variation; *Genetics, Population
Abstract If colonization of empty habitat patches causes genetic bottlenecks, freshly founded, young populations should be genetically less diverse than older ones that may have experienced successive rounds of immigration. This can be studied in metapopulations with subpopulations of known age. We studied allozyme variation in metapopulations of two species of water fleas (Daphnia) in the skerry archipelago of southern Finland. These populations have been monitored since 1982. Screening 49 populations of D. longispina and 77 populations of D. magna, separated by distances of 1.5-2180 m, we found that local genetic diversity increased with population age whereas pairwise differentiation among pools decreased with population age. These patterns persisted even after controlling for several potentially confounding ecological variables, indicating that extinction and recolonization dynamics decrease local genetic diversity and increase genetic differentiation in these metapopulations by causing genetic bottlenecks during colonization. We suggest that the effect of these bottlenecks may be twofold, namely decreasing genetic diversity by random sampling and leading to population-wide inbreeding. Subsequent immigration then may not only introduce new genetic material, but also lead to the production of noninbred hybrids, selection for which may cause immigrant alleles to increase in frequency, thus leading to increased genetic diversity in older populations.
Address Unite d'Ecologie et d'Evolution, Departement de Biologie, Universite de Fribourg, CH-1700 Fribourg, Switzerland. christoph.haag@ed.ac.uk
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0016-6731 ISBN Medium
Area Expedition Conference
Notes PMID:15937138; PMCID:PMC1449778 Approved no
Call Number LoNNe @ kagoburian @ Serial 660
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Author Arnott, J. T.
Title (up) Growth Response of White and Englemann Spruce Seedlings to Extended Photoperiod Using Three Light Intensities Type Report
Year 1982 Publication Technical Report: Pacific Forestry Centre Abbreviated Journal
Volume Issue Pages
Keywords Plants
Abstract Four seedlots of white spruce (Picea glauca (Moench) Voss) and three of Engelmann spruce (Picea engelmannii Parry), covering a range of 10 degrees of latitude and a range of altitudes, were sown in BC/ CFS Styroblocks and grown in a heated greenhouse and an unheated shadehouse, using incandescent light to provide a 19-h photoperiod. Four intensities of lighting were used: 0, 100,200, and 400 Ix. A second experiment with the same seedlots was conducted in growth rooms that were programmed to evaluate the effect of low night temperature on seedling shoot growth when the photoperiod was extended to 19 h, using a light intensity of 200 Ix.

Shoot length of white and Engelmann spruce seedlings grown under an extended daylength of 100 Ix were significantly taller than the control (0 Ix). There were no significant differences in shoot length or weight among the three intensities of light used to extend the photoperiod for all seedlots except the southern latitude-low elevation population of Engelmann spruce. The more northern populations of white spruce and the high altitude populations of Engelmann spruce did not require light intensities higher than 100 Ix to maintain apical growth. Low night temperature (7°C) did produce significantly smaller seedlings than the warm night (1SoC) regime. However, terminal resting buds of seedlings grown under the cool night regime did not form any sooner than on those seedlings grown under warm nights.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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Area Expedition Conference
Notes Approved no
Call Number IDA @ intern @ Serial 2372
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