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排序方式: 共有107条查询结果,搜索用时 31 毫秒
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Phytochrome Control of Anthocyanin Biosynthesis in Tomato Seedlings: Analysis Using Photomorphogenic Mutants 总被引:5,自引:0,他引:5
L. H. J. Kerckhoffs M. E. L. Schreuder A. Van Tuinen M. Koornneef R. E. Kendrick 《Photochemistry and photobiology》1997,65(2):374-381
Anthocyanin biosynthesis has been studied in hypocotyls and whole seedlings of tomato (Lycoperskon esculentum Mill.) wild types (WTs) and photomorphogenic mutants. In white light (WL)/dark (D) cycles the fri1 mutant, deficient in phytochrome A (phyA), shows an enhancement of anthocyanin accumulation, whereas the tri1 mutant, deficient in phytochrome Bl (phyBl) has a WT level of anthocyanin. Under pulses of red light (R) or R followed by far-red light (FR) given every 4 h, phyA is responsible for the non-R/FR reversible response, whereas phyBl is partially responsible for the R/FR reversible response. From R and blue light (B) pretreatment studies, B is most effective in increasing phytochrome responsiveness, whereas under R itself it appears to be dependent on the presence of phyBl. Anthocyanin biosynthesis during a 24 h period of monochromatic irradiation at different flu-ence rates of 4 day-old D-grown seedlings has been studied. At 660 nm the fluence rate-response relationships for induction of anthocyanin in the WT are similar, yet complex, showing a low fluence rate response (LFRR) and a fluence rate-dependent high irradiance response (HIR). The high-pigment-1 (hp-1) mutant exhibits a strong amplification of both the LFRR and HIR. The fri1 mutant lacks the LFRR while retaining a normal HIR. In contrast, a transgenic tomato line overexpressing the oat PHYA3 gene shows a dramatic amplification of the LFRR. The tri1 mutant, retains the LFRR but lacks the HIR, whereas the fri1, tri1 double mutant lacks both components. Only an LFRR is seen at 729 nm in WT; however, an appreciable HIR is observed at 704 nm, which is retained in the tri1 mutant and is absent in the fri1 mutant, indicating the labile phyA pool regulates this response component. 相似文献
3.
Paulien Adamse Janny L. Peters † Patricia A. P. M. Jaspers Ageeth VAN Tuinen Maarten Koornneef Richard E. Kendrick 《Photochemistry and photobiology》1989,50(1):107-111
The photocontrol of anthocyanin synthesis in dark-grown seedlings of tomato (Lycopersicon esculentum Mill.) has been studied in an aurea (au) mutant which is deficient in the labile type of phytochrome, a high pigment (hp) mutant which has the wild-type level of phytochrome and the double mutant au/hp , as well as the wild type. The hp mutant demonstrates phytochrome control of anthocyanin synthesis in response to a single red light (RL) pulse, whereas there is no measurable response in the wild type and au mutant. After pretreatment with 12 h blue light (BL) the phytochrome regulation of anthocyanin synthesis is 10-fold higher in the hp mutant than in the wild type, whilst no anthocyanin is detectable in the au mutant, thus suggesting that it is the labile pool of phytochrome which regulates anthocyanin synthesis. The au/hp double mutant exhibits a small (3% of that in the hp mutant) RL/far-red light (FR)-reversible regulation of anthocyanin synthesis following a BL pretreatment. It is proposed that the hp mutant is hypersensitive to the FR-absorbing form of phytochrome (Pfr ) and that this (hypersensitivity) establishes response to the low level of Pfl . (below detection limits in phytochrome assays) in the au/hp double mutant. 相似文献
4.
Helen S. J. Lee Richard E. Kendrick Daphne Vince-Prue 《Photochemistry and photobiology》1985,42(6):625-632
Abstract— An examination has been made of the involvement of phytochrome in the circadian rhythm of flowering in Pharbitis nil Chois. The peak position of Pfr absorption changes with time after a red light pulse. The shortest absorption wavelength of Pfr occurs at the same time as flowering is inhibited by red light in dark grown, red light pretreated plants. Pelletable and supernatant phytochrome show a similar trend with lowest values found at the time of flower inhibition. Neither phototransformation kinetics nor intermediates of phytochrome which accumulate in white light show such a relationship to the circadian rhythm found in flowering of dark grown P. nil. 相似文献
5.
Abstract— The kinetics of the far-red absorbing form of phytochrome (Pfr) appearance from intermediates in the pathway from the red absorbing form of phytochrome (Pr) to Pfr that accumulate under high fluence rate white light have been investigated in 3-day old dark grown Amaranthus caudatus seedlings. The appearance of P(r after a 5 s white light pulse was measured over the temperature range -8 to 25°C in samples flushed with O2 or N2. Over the whole temperature range under anaerobic conditions the kinetics of the slowest component of Pfr appearance are faster than in the presence of O2. Arrhenius plots are linear over this temperature range and indicate the activation energy for the slowest component of Pfr appearance is 44.05 ± 1.97 kJ mol?1 for O2 and 53.69 ± 4.86 kJ mol?1 for N2. 相似文献
6.
Abstract— In epicotyl tissue of Pisum , irradiation of Pr at – 196°C forms a stable product P698 , whereas Pfr forms a stable product P650 . On warming P698 , dark transformation to Pr predominates. On warming P650 to – 70°C an intermediate P690 is formed which bleaches on further warming to –10°C. When tissue is cooled to –196°C during actinic irradiation, difference spectra for subsequent warming to –10°C indicate that Pr , Pfr and an intermediate P710 are formed from weakly absorbing intermediates. Complete photoconversion of Pr to Pfr is not possible at temperatures below –5°C. As the temperature is reduced, the amount of Pfr produced from Pr decreases, while P710 increases. P710 can be photoconverted at –20°C and above, ultimately forming Pr , but in contrast to Pfr it is not photoconvertible at –196°C. 相似文献
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ABSTRACT Copolymers of 1,5-dioxepan-2-one (DXO) and e-caprolactone (?-CL), δ-valerolactone (δ-VL) or L-lactide (LLA) have been synthesized and characterized. High molecular weight copolymers were obtained using stannous-2-ethyl hexanoate as catalyst in bulk. Reactivity ratios for the copolymerization of DXO and δ-VL were determined at 110°C as rVL=0.5 and rDXO=2.3. At high conversion, depolymerization of δ-VL occurred, resulting in lower molecular weight and variations in the copolymer composition. Physical properties, such as crystallinity and melting temperature of the DXO-copolymers proved to be strongly dependent on the choice of comonomer and on the molar composition of the copolymers. DXO appears to be incorporated into the poly-?-caprolactone (PCL) crystals and to some extent into the poly-δ-valerolactone (PVL) crystals, resulting in a more gradual decrease in crystallinity with increasing amount of DXO. 相似文献
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Kendrick BK 《The Journal of chemical physics》2004,121(6):2471-2482
The quantum hydrodynamic equations associated with the de Broglie-Bohm formulation of quantum mechanics are solved using a new methodology which gives an accurate, unitary, and stable propagation of a time dependent quantum wave packet [B. K. Kendrick, J. Chem. Phys. 119, 5805 (2003)]. The methodology is applied to an N-dimensional model chemical reaction with an activation barrier. A parallel version of the methodology is presented which is designed to run on massively parallel supercomputers. The computational scaling properties of the parallel code are investigated both as a function of the number of processors and the dimension N. A decoupling scheme is introduced which decouples the multidimensional quantum hydrodynamic equations into a set of uncoupled one-dimensional problems. The decoupling scheme dramatically reduces the computation time and is highly parallelizable. Furthermore, the computation time is shown to scale linearly with respect to the dimension N=2,...,100. 相似文献