Action Spectra for Chromatic Adaptation in Tolypothrix tenuis

The dark synthesis of biliproteins in the blue-green alga Tolypothrix tenuis is controlled by brief light treatments. Green light potentiates synthesis of phycoerythrin and red light potentiates synthesis of phycocyanin. Red reverses the effect of green and vice versa. Action spectra for the red and green effects were obtained for the wavelength region 320 nanometers to 710 nanometers, at 10-nanometer intervals. The principal action band in the red peaks at 660 nanometers, with a half-band width of 58 nanometers and an accompanying shortwave band at 360 nanometers. The green action band peaks at 550 nanometers, with a half-band width of 76 nanometers, and a shortwave band at 350 nanometers. Chromatic adaptation and another photomorphogenic response in the blue-green algae are discussed in terms of possible regulation by a photoreversible pigment recently isolated from Tolypothrix.     

Action of Near UV and Blue Light on the Photocontrol of Phycobiliprotein Formation; A Complementary Chromatic Adaptation

Action of near UV to blue light on photocontrol of phycoerythrin(PE) and phycocyanin (PC) formation was investigated with non-photobleachedTolypothrix tenuis and Fremyella diplosiphon; this study wasdone to evaluate the proposition of Haury and Bogorad [(1977)Plant Physiol., 60: 835] that near UV to blue light is as effectiveas green and red light for photocontrol of PE and PC formationin blue-green algae and that lack of the blue effect in previousexperiments was due to destruction of blue-absorbing pigment(s)by the photobleaching treatment involved in the experimentalmethod. In our present work, light effect was measured in heterotrophiccultures incubated in darkness following brief exposure to differentwavelengths of light. Results indicated that (1) near UV to blue light was not effectivefor induction of PE formation either in T. tenuis or in F. diplosiphon,and (2) PC formation was induced by near UV light at 360 nmbut not by blue light at 460 nm. These features are identicalwith those previously reported for photobleached cells but notwith those reported by Haury and Bogorad for non-photobleachedcells. We conclude that photobleaching treatment does not haveany influence on the action of near UV to blue light. Actionat 390 and 460 nm observed by Haury and Bogorad probably resultedfrom light effects other than photocontrol, e.g., the actionof photosynthesis. (Received December 18, 1981; Accepted April 8, 1982)     

Some observations on phycobilisomes of Pterocladiella capillacea (Gelidiaceae,Rhodophyta)

ABSTRACT

Phycobilisomes (PBSs) of the red alga Pterocladiella capillacea collected in the field, were characterized both in situ and in vitro by means of a transmission electron microscope (TEM) and an image analyzer. Ultrathin sections of thalli and negatively stained PBSs after isolation revealed hemi-ellipsoidal shapes. In situ PBS dimensions were 38.5 ± 0.2 nm (height) × 38.8 ± 0.2 nm (width) × 22.6 ± 0.2 nm (thickness) in good agreement with the in vitro measurements (mean diameters of 37.6 ± 0.2 nm). These dimensions, especially the width, are smaller than those so far reported for red algae. This could depend either on the ecophysiological conditions of the thalli when harvested and/or on a staggered, symmetrically rotated and compressed disposition of biliprotein rods with respect to the allophycocyanin (APC) core. Hydroxylapatite chromatography of biliproteic extracts and SDS-PAGE electrophoresis revealed that phycoerythrin type R-(λ_max 565 nm>540 nm>498 nm) is formed by α (18.6 kDa), β (19.9 kDa), γ (30.2kDa) and γ′ (33.8 kDa) sub-units. The presence of two γ sub-units suggests that this phycoerythrin is a set of (αβ)₆γ + (αβ)₆γ′ aggregates (R-PE). A spectroscopically distinct form of phycoerythrin with different peak ratios, also found in pure fractions, is thought to be a polydisperse form (the so called r-PE). Similarity of shape and size observed in PBSs both in situ and in vitro, and fluorescence spectral characteristics of PBSs in vitro would indicate a substantial integrity of isolated PBSs. These measurements, if compared with total biliprotein content, would seem to indicate a PE fraction not assembled into PBS. A possible role of phycoerythrin in relation to the ability for a rapid adaptation of this surface species to environmental changes is suggested.     

Photosynthetic enhancement spectra in higher plants

Enhancement spectra for photosynthesis of intact leaves of higherplants were investigated by means of the rate of CO₂ absorptionunder atmospheric conditions. Enhancement spectra for photosystem(system)II measured with a reference beam of 700 nm had twopronounced peaks at about 480 and 650 nm and lower humps at540–600 nm in all of the nine species tested. By the useof a rice mutant which lacks chlorophyll b, it was revealedthat the 650-nm peak and the middle humps in the spectrum canbe attributed mostly to chlorophyll b absorption, whereas the480-nm peak must be due to the absorption of carotenoids andchlorophyll b. Enhancement for system I in wheat had a peakat about 715 nm, and the maximum was much higher than that ofthe enhancement for system II. Enhancement between a red anda farred light for wheat was much greater for the farred lightthan for the red light in the presence of an excess amount ofthe other light. These results demonstrate that the enhancementphenomenon in higher plants is essentially the same as thatin green algae. (Received November 30, 1977; )     

Apical growth of protonemata inAdiantum capillus-veneris

Action spectra for the induction of apical swelling in red-light-grown single-celled protonemata of the fernAdiantum were determined by continuous irradiation with monochromatic light for 5 hr. The resultant action spectra showed a sharp peak at 480 nm with a broad plateau in the region of blue and near ultraviolet light. Wave-lengths longer than 520 nm had no effect. When the tips of filamentous protonemata were irriadiated with a narrow beam (20 μm in width) of blue light for 3 hr, apical swelling and apical growth inhibition obviously took place in all protonemata tested, while no significant effect was observed when any other regions than the tip were irradiated. Polarized blue light vibrating parallel with the developmental axis of protonemata induced apical swelling and also prevented apical growth as effectively as non-polarized light, but that vibrating in a normal direction was significantly less effective.     

Interactions of green or red light with blue light on the dark closure of Albizzia pinnules

The interactions of green or red light with blue light on the dark closing of Albizzia julibrissin Durazz. pinnules have been investigated. Irradiations at 430, 450 and 470 nm progressively delay dark closing with increasing photon fluence rates. Red or green light alone has no effect. However, when the blue fluence rate is low, both red and green light interact with it and increase the delaying effect of the blue light. When the blue fluence rate is high, green light interacts with it to negate some of the effectiveness of the blue light, while red light has no effect. This is similar to results obtained previously with far-red light. It is suggested that the same unidentified photoreceptor is operating in both the far-red and blue regions. The results also indicate the presence of a blue-only absorbing photoreceptor whose action is increased by phytochrome.     

Reversal of blue light-stimulated stomatal opening by green light

Blue light-stimulated stomatal opening in detached epidermis of Vicia faba is reversed by green light. A 30 s green light pulse eliminated the transient opening stimulated by an immediately preceding blue light pulse. Opening was restored by a subsequent blue light pulse. An initial green light pulse did not alter the response to a subsequent blue light pulse. Reversal also occurred under continuous illumination, with or without a saturating red light background. The magnitude of the green light reversal depended on fluence rate, with full reversal observed at a green light fluence rate twice that of the blue light. Continuous green light given alone stimulated a slight stomatal opening, and had no effect on red light-stimulated opening. An action spectrum for the green light effect showed a maximum at 540 nm and minor peaks at 490 and 580 nm. This spectrum is similar to the action spectrum for blue light-stimulated stomatal opening, red-shifted by about 90 nm. The carotenoid zeaxanthin has been implicated as a photoreceptor for the stomatal blue light response. Blue/green reversibility might be explained by a pair of interconvertible zeaxanthin isomers, one absorbing in the blue and the other in the green, with the green absorbing form being the physiologically active one.     

Action Spectra for Conversions of Phycochrome c from Nostoc muscorum

The reversibly photochromic pigment, phycochrome c, was extracted from the blue-green alga Nostoc muscorum strain A. Action spectra were determined for in vitro conversions of the pigment from the short wavelength to the long wavelength form and vice versa. The action peak for the absorbance decrease at 650 nm is at 630 nm. During this decrease there is only a slight increase of the absorbance in the green region. Green and yellow light (maximum efficiency at 580 nm) completely restores absorbance at 650 nm. The observations are explained by the existence of three spectrally different forms of phycochrome c: P^c₆₃₀ and P^c₆₅₀ which equilibrate in darkness and P^c₅₈₀ which is reversibly photoconvertible to P^c₆₃₀. We have also measured the absorbance changes brought about by saturating irradiations with light of various wavelengths (“photostationary state spectrum”). Extreme photostationary states were obtained with about 650 nm and 500 nm light.     

Photosynthetic action spectra and adaptation to spectral light distribution in a benthic cyanobacterial mat

We studied adaptation to spectral light distribution in undisturbed benthic communities of cyanobacterial mats growing in hypersaline ponds at Guerrero Negro, Baja California, Mexico. Microscale measurements of oxygen photosynthesis and action spectra were performed with microelectrodes; spectral radiance was measured with fiber-optic microprobes. The spatial resolution of all measurements was 0.1 mm, and the spectral resolution was 10 to 15 nm. Light attenuation spectra showed absorption predominantly by chlorophyll a (Chl a) (430 and 670 nm), phycocyanin (620 nm), and carotenoids (440 to 500 nm). Blue light (450 nm) was attenuated 10-fold more strongly than red light (600 nm). The action spectra of the surface film of diatoms accordingly showed activity over the whole spectrum, with maxima for Chl a and carotenoids. The underlying dense Microcoleus population showed almost exclusively activity dependent upon light harvesting by phycobilins at 550 to 660 nm. Maximum activity was at 580 and 650 nm, indicating absorption by phycoerythrin and phycocyanin as well as by allophycocyanin. Very little Chl a-dependent activity could be detected in the cyanobacterial action spectrum, even with additional 600-nm light to excite photosystem II. The depth distribution of photosynthesis showed detectable activity down to a depth of 0.8 to 2.5 mm, where the downwelling radiant flux at 600 nm was reduced to 0.2 to 0.6% of the surface flux.     

Photosynthetic action spectra and adaptation to spectral light distribution in a benthic cyanobacterial mat.

We studied adaptation to spectral light distribution in undisturbed benthic communities of cyanobacterial mats growing in hypersaline ponds at Guerrero Negro, Baja California, Mexico. Microscale measurements of oxygen photosynthesis and action spectra were performed with microelectrodes; spectral radiance was measured with fiber-optic microprobes. The spatial resolution of all measurements was 0.1 mm, and the spectral resolution was 10 to 15 nm. Light attenuation spectra showed absorption predominantly by chlorophyll a (Chl a) (430 and 670 nm), phycocyanin (620 nm), and carotenoids (440 to 500 nm). Blue light (450 nm) was attenuated 10-fold more strongly than red light (600 nm). The action spectra of the surface film of diatoms accordingly showed activity over the whole spectrum, with maxima for Chl a and carotenoids. The underlying dense Microcoleus population showed almost exclusively activity dependent upon light harvesting by phycobilins at 550 to 660 nm. Maximum activity was at 580 and 650 nm, indicating absorption by phycoerythrin and phycocyanin as well as by allophycocyanin. Very little Chl a-dependent activity could be detected in the cyanobacterial action spectrum, even with additional 600-nm light to excite photosystem II. The depth distribution of photosynthesis showed detectable activity down to a depth of 0.8 to 2.5 mm, where the downwelling radiant flux at 600 nm was reduced to 0.2 to 0.6% of the surface flux.     

Action Spectra for Phycobiliprotein Synthesis in a Chromatically Adapting Cyanophyte, Fremyella diplosiphon

The action spectra for phycocyanin production by the cyanophyte Fremyella diplosiphon shows maxima at 463 and 641 nm. The action spectrum for phycoerythrin production includes maxima at 387 and 550 nm. The maxima are based on a relative response rate well within the linear ascending portion of the dose response curves; the positions of the maxima are independent of the relative response rates chosen for reference over a 3-fold range although the comparative effectiveness of light at pairs of wavelengths varies with the standard used for comparison. These action spectra differ from those reported previously for Tolypothrix tenuis by Fujita and Hattori (Plant Cell Physiol. 3: 209-220) and by Diakoff and Scheibe (Plant Physiol. 51: 382-385) in that blue light strongly promotes phycobiliprotein synthesis in F. diphosiphon but has been reported to have little or no effect on T. tenuis.     

The photosynthetic action spectrum of the bean plant

The photosynthetic action spectrum of the bean plant leaf, Phaseolus vulgaris L. (variety Red Kidney), has been determined with a diffraction grating illuminated by a 6500-watt xenon arc. An infrared CO₂ analyzer was used to determine the gross photosynthetic rate of the terminal leaflet of the first trifoliate leaf. The rate was measured as a function of the light intensity at steps of 12.5 nanometers which approximates the length of the leaflet used. Twenty-five curves between 400 and 700 nanometers were used to establish the action spectrum. All light curves were some linear function of the incident intensity, and all were extrapolated to zero. The action spectrum shows the following features. (a) there are two peaks (i.e., at about 670 and 630 nanometers) and a shoulder between 600 and 612 nanometers in the red region where the highest rate of photosynthesis is found. Lower peaks in descending order are found in the blue (at about 437 nanometers) and the green (at about 500 nanometers) regions. (b) There are two small minima at about 650 nanometers and between 470 and 480 nanometers, and a broad minimum is found between 540 and 530 nanometers. (c) The photosynthetic rate declines rapidly above 680 nanometers, reaching the lowest value at 700 nanometers. (d) At wave lengths below the blue maximum, the rate decreases progressively to 400 nanometers.     

Wirkungsspektren der Anthocyansynthese in Gewebekulturen und Keimlingen von Haplopappus gracilis

Summary The biosynthesis of anthocyanin in tissue cultures and intact seedlings of Haplopappus gracilis is a light-dependent reaction which can be induced by blue light only. Anthocyanin appeared in all organs of the seedling.Wounding of the plant led to an increase in the content of anthocyanin due to increased anthocyanin synthesis in the cotyledons.The action spectra of anthocyanin formation in tissue cultures and intact seedlings have two peaks, one at 438 nm and the other at 372 nm. The limit of activity in the direction of longer wavelengths lies between 474 and 493 nm. Red light of short and long wavelength is ineffective in the induction of pigment synthesis. The photoreceptor of the light reaction is supposed to be a yellow pigment (flavoprotein or carotinoid). In contrast to the intact plants, isolated cotyledons and wounded seedlings are able to form anthocyanin not only in the blue region but also during irradiation with red light of high intensity. The action spectrum of anthocyanin synthesis in the isolated cotyledons has a marked maximum at about 440 nm and a second one at about 660 nm. A little activity can be observed throughout the visible spectrum. The pigment synthesis induced by red light can be completely suppressed by DCMU, an inhibitor of photosynthesis. This indicates that in the case of the activity in the red light caused by wounding chlorophyll serves as photoreceptor.The anthocyanin synthesis in tissue cultures and seedlings could not be influenced by low energy radiation in the red or in the far red region, even after induction of anthocyanin synthesis by blue light of high intensity. Therefore it seems that the phytochrome system is not involved in anthocyanin synthesis in Haplopappus gracilis.     

Photosynthetic action spectra of marine algae

A polarographic oxygen determination, with tissue in direct contact with a stationary platinum electrode, has been used to measure the photosynthetic response of marine algae. These were exposed to monochromatic light, of equal energy, at some 35 points through the visible spectrum (derived from a monochromator). Ulva and Monostroma (green algae) show action spectra which correspond very closely to their absorption spectra. Coilodesme (a brown alga) shows almost as good correspondence, including the spectral region absorbed by the carotenoid, fucoxanthin. In green and brown algae, light absorbed by both chlorophyll and carotenoids seems photosynthetically effective, although some inactive absorption by carotenoids is indicated. Action spectra for a wide variety of red algae, however, show marked deviations from their corresponding absorption spectra. The photosynthetic rates are high in the spectral regions absorbed by the water-soluble "phycobilin" pigments (phycoerythrin and phycocyanin), while the light absorbed by chlorophyll and carotenoids is poorly utilized for oxygen production. In red algae containing chiefly phycoerythrin, the action spectrum closely resembles that of the water-extracted pigment, with peaks corresponding to its absorption maxima (495, 540, and 565 mµ). Such algae include Delesseria, Schizymenia, and Porphyrella. In the genus Porphyra, there is a series P. nereocystis, P. naiadum, and P. perforata, with increasingly more phycocyanin and less phycoerythrin: the action spectra reflect this, with increasing activity in the orange-red region (600 to 640 mµ) where phycocyanin absorbs. In all these red algae, photosynthesis is almost minimal at 435 mµ and 675 mµ, where chlorophyll shows maximum absorption. Although the chlorophylls (and carotenoids) are present in quantities comparable to the green algae, their function is apparently not that of a primary light absorber; this role is taken over by the phycobilins. In this respect the red algae (Rhodophyta) appear unique among photosynthetic plants.     

Visual behaviors of the migratory grasshopper,Melanoplus sanguinipes F. (Orthoptera: Acrididae)

The visual behavior of adult Melanoplus sanguinipesF. (Orthoptera: Acrididae) was investigated by placing individuals in the center of an arena and recording their orientation responses to visual targets at the perimeter of the arena. Targets that reflected more 540- to 570-nm light were approached more frequently; however, when reflectance in the 540 -to 570-nm region was combined with reflectance in the 400- to 520-nm region, orientation responses were reduced significantly. This suggests that spectral discrimination in M. sanguinipesinvolves at least two classes of photoreceptors, which respond to different regions of the wavelength spectrum. In addition, grasshoppers oriented to vertical, but not horizontal, contrasting stripes. However, when vertical stripes were added to targets reflecting 520- to 650-nm light, responses to verticals on these targets were not enhanced relative to verticals presented against a target background of 400- to 520-nm + 520- to 650-nm light. Thus, spectral discrimination and vertical stripe fixation appear to be two distinct visual behaviors, controlled by outputs from two classes of photoreceptors and a single class of photoreceptors, respectively, and may be used in different physiological or ecological contexts.     

Induction of free radicals in seeds by high intensive flashes and the relevant phosphorus metabolism in the seedling

Influence of high intensive flashes on the yield of free radicals in intact seeds and excised embryonic axis, endosperm, and seed coat, and its resulting effect on seedling growth, total biomass production and phosphorus metabolism in wheat (Triticum aeativum), vetch (Vicia sativa L.) and onion (Allium cepa L.) was studied. Free radicals (f.r.) were formed mainly in seed coat and not in the endosperm. Vetch seeds after irradiation had 20.76 X 10¹³ f.r. g^-1 dry intact seed and 17.30 X 10¹³ f.r. g^-1 dry seed coat. Excised seed coats exposed to irradiation also yielded 17.28 × 10¹³ f.r. g^-1 dry matter. High irradiance “white light” flashes induced more f.r. than a monochromatic one of the same photon content. Red (650 nm), farred (750 nm) and even infra-red (1100 nm) radiation did not initiated f.r. formation but resulted in their decay in samples irradiated earlier by “white”, blue and green parts of the spectrum. Blue irradiation of seeds led to the decrease in the length of shoots and roots in comparison to “white”, green and red irradiation but their biomass increased faster than in the seedlings obtained from non-irradiated or irradiated with “white” and green radiation. The quantity of total acid soluble phosphorus followed a sequence with respect to wavelength of radiation: 436 nm > 650 nm> > 540 nm > non-irradiated > 300–800 nm. Quantity of inorganic phosphorus remained unaffected by different spectral character of radiation. The quantity of organic acid soluble nucleic phosphorus and acid insoluble polyphosphates was higher in samples irradiated with red beams (650 ± 6 nm).     

Effect of Colored Light on Stomatal Opening Rates of Vicia faba L

The average opening rate of Vicia faba L. stomata was determined over an initial 20-minute light period following darkness. Nonsaturating intensities of broad band red and blue light had similar quantum effectiveness for the promotion of opening, whereas broad band green was about 40% and far red about 5% as effective. The opening rates under saturating red, green, and blue light were the same. Net photosynthesis was measured under various intensities of the same red, green, and blue light spectra. Red and blue light were equally efficient in causing photosynthesis, whereas green was 60% as effective. The light compensation points for the three colors were at higher intensities than those which saturated the opening rate response. These data suggest that only a single pigment system, probably the photosynthetic pigments, is responsible for initiating the light-induced opening response in V. faba stomata.     

Comparison of photosynthetic parameters of an aurea mutant (Su/su) of tobacco and the wild-type by the photoacoustic method

Oxygen evolution and energy storage yields in tobacco (Nicotiana tabacum L.) wild-type (cv. John Williams Broadleaf) and a mutant (Su/su) deficient in chlorophyll were compared using the photoacoustic technique. Oxygen-evolution and energy-storage quantum yields in the mutant were higher when measured in red light (640–690 nm) than green or blue light (540 nm and 440 nm, respectively), indicating that carotenoids in this mutant do not transfer energy efficiently to the photochemical reaction centers. It is suggested that carotenoids may play a role in protecting the photosynthetic apparatus against damage by high energy fluxes. In the wild-type, the oxygenevolution yield did not change drastically throughout the visible spectrum. The mutant had a higher quantum yield of oxygen evolution than the wildtype. Similarly maximum rates obtained from saturation curves for the mutant were more than twice higher per leaf area and about five times higher per chlorophyll, as compared to the wild-type.Abbreviation PS photosystem     

Events Surrounding the Early Development of Euglena Chloroplasts: VI. Action Spectra for the Formation of Chlorophyll, Lag Elimination in Chlorophyll Synthesis, and Appearance of TPN-dependent Triose Phosphate Dehydrogenase and Alkaline DNase Activities

Action spectra derived from dose-response curves measured for various processes associated with chloroplast development in Euglena gracilis var. bacillaris are presented. The action spectrum for chlorophyll synthesis during the first 36 hours of continuous illumination of dark-grown resting cells resembles the absorption spectrum of protochlorophyll(ide). The action spectrum for the preillumination phase of potentiation, during which preillumination followed by a dark period brings about lag elimination in chlorophyll synthesis when the cells are subsequently exposed to postilluminating light, shows a high peak in the blue region (at about 433 nm) with a small peak in the yellow-orange region (at about 597 nm); the postillumination phase yields an action spectrum very similar to that obtained for chlorophyll synthesis in continuous light in normal, unpotentiated cells, with peaks at 433 and 631 nm. Alkaline DNase and TPN-linked triose phosphate dehydrogenase, two plastid enzymes which are synthesized outside the chloroplast, yield action spectra which are consistent with protochlorophyll(ide) being the major light receptor. The action spectra which implicate pigments resembling protochlorophyll(ide) holochrome have blue to red peak ratios in the vicinity of 5:1 as does the absorption spectrum of the protochlorophyllide holochrome from beans; the action spectrum is not identical with the holochrome spectrum indicating that the Euglena holochrome may differ from the bean pigment in details of its absorption spectrum. The action spectrum for preillumination, shows a ratio of the blue peak to the red effectiveness of about 24:1. This suggests that preillumination is controlled by a photoreceptor different from the protochlorophyll(ide) holochrome.     

Reversible acidic-alkaline transition of the carbon monoxide complex of cytochrome c peroxidase

The Soret absorption band of the ferrous carbon monoxide (CO) complex of cytochrome c peroxidase exhibited a blue shift from 423.7 to 420 nm upon an increase in pH from 6.5 to 8.5. The spectral change was reversible with an isosbestic point at 422 nm. The pH dependence of this spectral change gave a sigmoidal curve fitted well to a theoretical curve of a cooperative release of two protons with a pK value of 7.5, indicating the existence of the acidic and alkaline forms of the ferrous CO enzyme. Upon irradiation of light flash (100 J of power and 30-microseconds), the heme-bound CO was readily dissociated in both acidic and alkaline forms with a quantum yield of approximately unity. On the other hand, the rate of recombination of the dissociated CO with the heme iron was significantly different between these two forms; the recombination rate constants were 1.1 X 10(3) and 3.0 X 10(4) M-1 S-1 at 25 degrees C for the acidic and alkaline forms, respectively. At intermediate pH values, kinetics of recombination were biphasic, consisting of the slow and fast processes with the appropriate rate constants mentioned above. When the fraction of the fast process was plotted against pH, the pH profile coincided with the spectrophotometric pH titration curve described above. Thus, it was concluded that the acidic and alkaline forms of the enzyme were responsible for the slow and fast processes, respectively. In infrared spectroscopy, the acidic form showed a narrow CO stretching band at 1922 cm-1 with a half-band width of 12.5 cm-1, while the alkaline form exhibited a broad CO-stretching band at 1948 cm-1 with a half-band width of 33 cm-1. Significance of these results are discussed in relation to the structure of the heme vicinity on the CO complex of cytochrome c peroxidase.