| 1. |
- Bjorck, S, et al.
(författare)
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Synchronized terrestrial-atmospheric deglacial records around the North Atlantic
- 1996
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Ingår i: SCIENCE. - : AMER ASSOC ADVANCEMENT SCIENCE. - 0036-8075. ; 274:5290, s. 1155-1160
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- On the basis of synchronization of three carbon-14 (C-14)-dated lacustrine sequences from Sweden With tree ring and ice core records, the absolute age of the Younger Dryas-Preboreal climatic shift was determined to be 11,450 to 11,390 +/- 80 years before
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| 2. |
- Björck, S., et al.
(författare)
-
Synchronized terrestrial-atmospheric deglacial records around the North Atlantic.
- 1996
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 274:5290, s. 1155-1160
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Tidskriftsartikel (refereegranskat)abstract
- On the basis of synchronization of three carbon-14 (C-14)-dated lacustrine sequences from Sweden With tree ring and ice core records, the absolute age of the Younger Dryas-Preboreal climatic shift was determined to be 11,450 to 11,390 +/- 80 years before the present. A 150-year-long cooling in the early Preboreal, associated with rising Delta(14)C values, is evident in all records and indicates an ocean ventilation change. This cooling is similar to earlier deglacial coolings, and box-model calculations suggest that they all may have been the result of increased freshwater forcing that inhibited the strength of the North Atlantic heat conveyor, although the Younger Dryas may have begun as an anomalous meltwater event.
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| 3. |
- Hurry, Vaughan, 1960-, et al.
(författare)
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Mitochondria contribute to increased photosynthetic capacity of leaves of winter rye (Secale-Cereale L) following cold-hardening
- 1995
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Ingår i: Plant, Cell and Environment. - 0140-7791 .- 1365-3040. ; 18:1, s. 69-76
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Tidskriftsartikel (refereegranskat)abstract
- Cold-hardening of winter rye (Secale cereale L. cv. Musketeer) increased dark respiration from -2.2 to -3.9 mu mol O-2 m(-2)s(-1) and doubled light- and CO2-saturated photosynthesis at 20 degrees C from 18.1 to 37.0 mu mol O-2 m(-2) s(-1). We added oligomycin at a concentration that specifically inhibits oxidative phosphorylation to see whether the observed increase in dark respiration reflected an increase in respiration in the light, and whether this contributed to the enhanced photosynthesis of cold-hardened leaves, Oligomycin inhibited light- and CO2-saturated rates of photosynthesis in non-hardened and cold-hardened leaves by 14 and 25%, respectively, and decreased photochemical quenching of chlorophyll a fluorescence to a greater degree in cold-hardened than in non-hardened leaves, These data indicate an increase both in the rate of respiration in the light, and in the importance of respiration to photosynthesis following cold-hardening, Analysis of metabolite pools indicated that oligomycin inhibited photosynthesis by limiting regeneration of ribulose-1,5-bisphosphate, This limitation was particularly severe in cold-hardened leaves, and the resulting low 3-phosphoglycerate pools led to a feed-forward inhibition of sucrose-phosphate synthase activity, Thus, it does not appear that oxidative phosphorylation supports the increase in photosynthetic O-2 evolution following cold-hardening by increasing the availability of cytosolic ATP, The data instead support the hypothesis that the mitochondria function in the light by using the reducing equivalents generated by nan-cyclic photosynthetic electron transport.
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