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1.
Lemna perpusilla 6746 was grown on HUTNER'S medium with sucroseunder light schedules combining red, blue and far-red light.As shown earlier, brief red exposures added to a continuousblue schedule inhibit flowering although either schedule alonepermits it; hence red and blue act together in establishinga long day (flower inhibiting) condition. However, the red exposurerequired to inhibit flowering is greater with high intensitythan with low intensity continuous blue, suggesting in additiona blue-red antagonism. Blue light reverses the effects of abrief red exposure closing a blue or far-red main photoperiod,but it also reverses the effects of a brief far-red exposureclosing a red photoperiod. Thus, blue can act either like redor like far-red, depending on the situation. All effects ofblue light on the flowering of L. perpusilla 6746 are consistentwith the notion that it establishes a Pfr level intermediatebetween those established by red and far-red light; the postulationof an additional photoreaction to explain the effects of blueseems unnecessary.
1Research carried out at Brookhaven National Laboratory underthe auspices of the U. S. Atomic Energy Commission. 相似文献
2.
Effects of Blue Light on the Vertical Colonization of Space by White Clover and their Consequences for Dry Matter Distribution 总被引:5,自引:0,他引:5
The morphology of white clover is very sensitive to the lightenvironment, especially to the ratio of red:far-red light andto photon irradiance. However, less is known about the effectsof blue light on clover morphogenesis. Cuttings of white cloverwere grown for 56 d in two controlled chambers receiving lightwith similar photosynthetic efficiency and phytochrome photoequilibriumstate but different levels of blue light: some plants were grownunder orange light (very low blue light, 0.02 µmol m-2s-1)or under white light containing blue light (83 µmol m-2s-1).Other plants were switched from white light to orange lightorvice versa,after 30 d. The absence of blue light modifiedthe growth habit of clover and raised the laminae in the upperlayer of the canopy by increasing petiole length, and petioleangle from the horizontal, and by raising stolons above theground surface. Moreover, the absence of blue light had no effecton total leaf area and total dry weight per plant, but increasedthe leaf area and biomass of petioles of the main axis. Largerpetioles and laminae were associated with the allocation ofmore dry weight to the petiole at the same petiole thicknessbut with thinner laminae. These results indicate that a decreasein blue light is involved in the perception of, and adaptationto, shading by the plant.Copyright 1997 Annals of Botany Company Biomass allocation; blue light; growth habit; leaf area; light quality; photomorphogenesis; Trifolium repensL.; white clover 相似文献
3.
Haustoria of Cuscuta japonica, a Holoparasitic Flowering Plant, Are Induced by the Cooperative Effects of Far-Red Light and Tactile Stimuli 总被引:2,自引:0,他引:2
When seedlings of Cuscuta japonica were grown with Vigna radiata(the host plant) in a flower pot for 6 d under white light andthen irradiated with far-red or blue light (ca. 6 µmolphotons m2 s1), the seedlings parasitized V. radiata.However, no parasitism of the seedlings was observed under redor white light or in darkness. The parasitic behavior of seedlingsof C. japonica was observed even if an acrylic rod was usedas a substitute for the host plant. Upon incubation under far-redlight, the seedling twined tightly around the rod and developedhaustoria towards it. Haustoria also developed when apical andsubapical regions of seedlings were held between two glass platesthat were about 0.7 mm apart and were irradiated with far-redlight. However, no haustoria were induced by either the holdor irradiation alone. These results indicate that parasitismof Cuscuta japonica is controlled by the cooperative effectsof two physical signals, far-red light and appropriate tactilepressure. Our findings suggest that parasitism by the genusCuscuta involves a novel strategy. (Received April 10, 1996; Accepted August 21, 1996) 相似文献
4.
Green Light Drives CO2 Fixation Deep within Leaves 总被引:5,自引:0,他引:5
Maximal l4CO2-fixation in spinach occurs in the middle of thepalisade mesophyll [Nishio et al. (1993) Plant Cell 5: 953],however, ninety percent of the blue and red light is attenuatedin the upper twenty percent of a spinach leaf [Cui et al. (1991)Plant Cell Environ. 14: 493]. In this report, we showed thatgreen light drives 14CO2-fixation deep within spinach leavescompared to red and blue light. Blue light caused fixation mainlyin the palisade mesophyll of the leaf, whereas red light drovefixation slightly deeper into the leaf than did blue light.14CO2-fixation measured under green light resulted in less fixationin the upper epidermal layer (guard cells) and upper most palisademesophyll compared to red and blue light, but led to more fixationdeeper in the leaf than that caused by either red or blue light.Saturating white, red, or green light resulted in similar maximal14CO2-fixation rates, whereas under the highest irradiance ofblue light given, carbon fixation was not saturated, but itasymptotically approached the maximal 14CO2-fixation rates attainedunder the other types of light. The importance of green lightin photosynthesis is discussed.
1Supported in part by grants from Competitive Research GrantsOffice, U.S. Department of Agriculture (Nos. 91-37100-6672 and93-37100-8855). 相似文献
5.
1) With Chlorella ellipsoidea cells, in the presence of 5x106M DSPD, or in its absence, the amounts of 14CO2 incorporatedin P-esters, serine-plus-glycine and alanine were larger underred light than under blue light, whereas blue light specificallyincreased 14CO2-incorporation in aspartate, glutamate, malateand fumarate (blue light effect). The amount of total 14C fixedunder blue or red light was greatly decreased by the additionof DSPD. When the concentration of DSPD was raised to 5x104M, practically no radioactivity was found, under blue or redlight, in aspartate, glutamate and fumarate. Radioactivity inalanine was greatly increased. Effects of higher concentrationof DSPD are explained as due to the inhibition of PEP carboxylaseactivity in Chlorella cells. 2) The percentage incorporation of 14C into aspartate and theother compounds mentioned above, under near infra-red illuminationwas significantly smaller than that under blue light and wasalmost equal to that under red light. These results along withthe effect of 5x106 M DSPD, exclude the possibility thatcyclic photophosphorylation is involved in the "blue light effect"mechanism. (Received December 12, 1969; ) 相似文献
6.
SPECTRAL SENSITIVITY OF SEED GERMINATION IN ARTEMISIA MONOSPERMA 总被引:2,自引:0,他引:2
The absolute requirement for light in the germination of achenesof Artemisia monosperma is as satisfied by radiant energy inthe blue, green, yellow, red and far-red regions of the visiblespectrum, as by unfiltered white light. The same stimulationwas obtained by a short irradiation as by an uninterrupted one.Phytochrome seems to be either absent, or masked by a differentpigment which absorbs light in the entire visible spectrum andthus initiates germination.
1 This study was supported by grant FG-Is-115 from the UnitedStates Department of Agriculture. 相似文献
7.
Effects of night-interruption on the aerial tuber formationof Begonia evansiana Andr. were investigated. Among coloredlights tested, red light was most effective to reduce the photoperiodicresponse. It inhibited tuberization almost completely at lowintensities. The red lightaction was partially reversed by subsequentblue or far-red irradiation under the 12-hour daylength, andthe relation between the red and the blue or far-red lightswas reversible. No reversal, however, was observed under the8-hour daylength. The inhibitory action of red light remainedunchanged on irradiating with red, blue or far-red light beforethe night periods.
1Present address: Department of Horticulture, Purdue University,Lafayette, Indiana, USA 相似文献
8.
Chlorella cells incubated in the dark longer than 12 hr showedpronounced blue light-induced 14CO2 fixation into aspartate,glutamate, malate and fumarate (blue light effect), whereasthose kept under continuous light showed only a slight bluelight effect, if any. 2) During dark incubation of Chlorellacells, phosphoenolpyruvate carboxylase activity and the capacityfor dark 14CO2 fixation decreased significantly, whereas ribulose-1,5-diphosphatecarboxylase activity and the capacity for photosynthetic 14CO2fixation (measured under illumination of white light at a highlight intensity) did not decrease. 3) In cells preincubatedin the dark, intracellular levels of phosphoenolpyruvate and3-phosphoglycerate determined during illumination with bluelight were practically equal to levels determined during illuminationwith red light. 4) The blue light effect was not observed incells incubated widi chloramphenicol, indicating that blue light-inducedprotein synthesis is involved in the mechanism of the effect. (Received April 9, 1971; ) 相似文献
9.
- Effect of light on ion absorption and resting potential of theinternodal cell of Nitella flexilis was investigated under variousconditions.
- On illumination, the resting potential increasedby about 30mVin 104 M KCl and by about 60 mV in 104M NaClsolution. A similar photoelectric response was also observedin 103 M KCl, 102 M CaCl2 and 5 x 102 MCaCl2 solutions, but not at all in 102 M KCl solution.
- Absorption of ions by the cell took place in parallel withthelight-induced change in resting potential.
- Red and bluelights were very effective in increasing the restingpotential,while green light was almost ineffective. These differenteffectsof color lights were in good agreement with their effectsinincreasing the osmotic value of the cell.
- The photoelectricresponse was not affected by phenylurethane,which, on the otherhand, strongly inhibited the light-inducedion absorption.
- Theuptake of ions by the cell from the external medium intothevacuole is assumed to proceed in two different steps: thefirstis the process involving the ion movements across theoutermostplasmalemma, and the second is that involved in thetransportof ions through the cytoplasmic layer and tonoplast.The formerprocess is considered to be influenced by the increasein restingpotential probably caused by the light absorbed bychlorophyll.The process was, however, suggested to be independentof photosynthesis.On the other hand, the latter process issupposed to be relatedto photosynthesis. A discussion was madealong this line.
10.
By direct somatic embryogenesis in vitro a clone of asepticplantlets can be raised from a single immature embryo of Trifoliumrepens (white clover) within about 6 weeks of pollination. Embryoidsare induced directly from intact zygotic embryonic tissue ona culture medium containing 0·025 or 0·05 mg 11BAP and 1·0 g 11 yeast extract. Similar directsomatic embryogenesis has also been achieved for Trifolium pratense(red clover) and Medicago sativa (lucerne). Applications ofembryo propagation by direct somatic embryogenesis are discussed,particularly in relation to multiple screening of host genotypesfor analysis of host/pathogen and legume/Rhizobium interactions. Trifolium repens L., Trifolium pratense L., Medicago sativa L., clover, lucerne, tissue culture, embryoid, somatic embryogenesis, legumes 相似文献
11.
Calcium-calmodulin signalling is involved in light-induced acidification by epidermal leaf cells of pea, Pisum sativum L. 总被引:2,自引:0,他引:2
Elzenga J. Theo M.; Staal Marten; Prins Hidde B.A. 《Journal of experimental botany》1997,48(12):2055-2061
Pathways of signal transduction of red and blue light-dependentacidification by leaf epidermal cells were studied using epidermalstrips of the Argenteum mutant of Pisum sativum. In these preparationsthe contribution of guard cells to the acidification is minimal.The hydroxypyridine nifedipine, a Ca2+-channel blocker, partlyinhibited the response to both blue and red light, while thephenylalkylamine, verapamil, a Ca2+-channel blocker that hasbeen shown in plant cells also to block K+-channels, causednearly complete inhibition. The Ca2+-channel activator S()BayK 8644 induced acidification when added in the dark and diminishedthe light-induced lowering of the extracellular pH. The Ca2+-ionophores,ionomycin and A23187
[GenBank]
, also reduced the light response. Furthermore,the light-induced acidification was inhibited by the calmodulinantagonists W-7 and trifluoperazine, but not by W-5. These calmodulininhibitors completely inhibited the red light-induced acidification,but inhibited the response to blue light by only 6070%.In general, inhibition by compounds affecting Ca-calmodulinsignalling was always stronger on the red light response thanthat on the blue light response (with the exception of verapamilthat blocked both the red and blue light responses equally well).This differential effect on red and blue light-induced responsesindicates a role for Ca2+-CaM signalling in both the red andblue light responses, while a second process, independent ofCa2+ is activated by blue light. Key words: Signal transduction, light-induced acidification, epidermal cells, pea 相似文献
12.
Protoplasts were successfully isolated from internodal callustissues of both Oxalis glaucifolia and O. rhombeo-ovata whenthey were digested in a solution containing 0.1% (w/v) MacerozymeR-10, 0.5% (w/v) cellulase Onozuka R-10 and 0.3 mmol m3sucrose. Protoplasts proliferated to give cell colonies on Gamborget al.'s B5 medium supplemented with 0.3 mmol m3 mannitol,0.5 mg dm32, 4-D, and 2.0 mg dm3 kinetin. Calluswas produced upon transfer of cell colonies to Murashige andSkoog medium containing 2.0 mg dm3 l-naphthaleneaceticacid (NAA) and 0.1 mg dm3 kinetin for O. glaucifolia,or with 5.0 mg dm3 NAA and 0.5 mg dm3 6-benzylaminopurine,for O. rhombeo-ovata. Plants were regenerated from O. glaucifoliaprotoplasts on a medium containing 0.1 mg dm3 NAA, 1.0mg dm3 kinetin and 1.0 mg dm3 gibberellic acid,but only vascular nodules were differentiated by O. rhombeo-ovataprotoplast-derived calli. Key words: Tissue culture, protoplasts, plant regeneration, Oxalis spp 相似文献
13.
Lemna paucicostata, normally a short-day plant, can be inducedto flower under long-day conditions by providing a cytokininin a medium containing a high level of ferric citrate (5 x 104M).Interestingly, when a cytokinin and EDDHA are present togetherin the medium, flowering is induced even at low levels of iron(105 and 5 x 105M ferric citrate). However, inthe absence of a cytokinin, flowering takes place only undershort days. (Received September 30, 1968; ) 相似文献
14.
- It has been demonstrated previously that when Chlorella protothecoidesis grown in a medium rich in glucose and poor in nitrogen source(urea), chlorophyll-less cells with markedly degenerated plastidscalled "glucose-bleached" cellsare produced eitherin the light or in darkness. When the glucose-bleached cellsare incubated in a medium enriched with the nitrogen sourcebut without added glucose, normal green cells with fully organizedchloroplasts are obtained in the light, and pale green cellswith partially organized chloroplasts in darkness. During theseprocesses of chloroplast development in the glucose-bleachedcells, there occurs, after a certain lag period, an active DNAformation followed by a more or less synchronous cellular division.In the present study the effects of light on the DNA formationand cellular division were investigated in the presence of CMUor under aeration of CO2-free air to exclude the interveninginfluence of photosynthetic process.
- It was revealed thatlight severely suppresses the DNA formationand cellular divisionof the glucose-bleached cells while enhancingremarkably theirgreening. The suppression was saturated atthe light intensityof about 1,000 lux. Blue light was mosteffective, being followedby green, yellow and red light inthe order of decreasing effectiveness.
- Further experiments unveiled that light exerts two apparentlyopposing effects on the DNA formation depending upon the timeof application during the incubation of algal cells. When thealgal cells were illuminated only during the lag period beforethe active DNA synthesis, there occurred an enhancement of theDNA synthesis occurring during the subsequent dark incubation.When, on the other hand, the cells were transferred to the lightfrom darkness at or after the start of the DNA synthesis, itcaused an almost complete abolition of the subsequent synthesisof DNA in the algal cells. No such effects of light were observedwith RNA and protein (total)
- These findings were discussedin relation to the process ofchlorophyll formation occurringconcurrently in the algal cells.
15.
A marked accumulation of chlorophyll was observed in calluscells of Nicotiana glutinosa when they were grown under bluelight, while under strong red light no chlorophyll accumulated.This blue light effect saturated at an intensity of about 500mW.m2. The effects of white, blue and red light on the transformationof protochlorophyll (ide) (Pchl) accumulated in dark-grown calluscells were studied by following the changes in the intensityof fluorescence emitted by Pchl and different forms of chlorophyll(ide) (Chi). Pchl with a fluorescence maximum at 633 nm (absorptionmaximum: 630 nm) decreased slowly, concomitant with an increasein Chl having a fluorescence maximum at 677 nm (absorption maximum:675 nm), which was subsequently transformed, independently oflight, to Chi with a fluorescence maximum at 683 nm (absorptionmaximum: 680 nm). Both blue and red light of low intensitieswere effective for the phototransformation, while red light,but not blue light, of high intensities caused significant destructionof Pchl. An action spectrum for this photodestruction showedthat the maximum destruction took place at 630 nm. White lightof high intensities was effective for the photoreduction withonly slight destruction of Pchl, suggesting that blue lightcounteracts the destructive effect of red light. At low temperatures,however, blue light as well as red light of low intensitiescaused photodestruction of Pchl. It was inferred that blue lightenhances a certain step or steps involved in the productionof a reductant required for the photoreduction of Pchl to Chl. (Received July 3, 1981; Accepted November 11, 1981) 相似文献
16.
Red light-emitting diodes (LEDs) are a potential light sourcefor growing plants in spaceflight systems because of their safety,small mass and volume, wavelength specificity, and longevity.Despite these attractive features, red LEDs must satisfy requirementsfor plant photosynthesis and photomorphogenesis for successfulgrowth and seed yield. To determine the influence of galliumaluminium arsenide (GaAIAs) red LEDs on wheat photomorphogenesis,photosynthesis, and seed yield, wheat (Triticum aestivum L.,cv. USU-Super Dwarf) plants were grown under redLEDs and compared to plants grown under daylight fluorescent(white) lamps and red LEDs supplemented with either 1% or 10%blue light from blue fluorescent (BF) lamps. Compared to whitelight-grown plants, wheat grown under red LEDs alone demonstratedless main culm development during vegetative growth throughpreanthesis, while showing a longer flag leaf at 40 DAP andgreater main culm length at final harvest (70 DAP). As supplementalBF light was increased with red LEDs, shoot dry matter and netleaf photosynthesis rate increased. At final harvest, wheatgrown under red LEDs alone displayed fewer subtillers and alower seed yield compared to plants grown under white light.Wheat grown under red LEDs+10% BF light had comparable shootdry matter accumulation and seed yield relative to wheat grownunder white light. These results indicate that wheat can completeits life cycle under red LEDs alone, but larger plants and greateramounts of seed are produced in the presence of red LEDs supplementedwith a quantity of blue light. Key words: Triticum aestivum L., red light, blue light, subtillering, bioregenerative advanced life support 相似文献
17.
SPECTRAL CHANGE OF LIGHT WITH DEPTH IN SOME LAKES AND ITS SIGNIFICANCE TO THE PHOTOSYNTHESIS OF PHYTOPLANKTON 总被引:2,自引:0,他引:2
- A linear relation was found between the relative light intensityat 5 in depth and the mean chlorophyll a content of the euphoticzone, when they were plotted on logarithmic scales. The intensitiesof underwater lights of different wave lengths were measuredby a photocell with various colored filters. It was recognizedthat with the increase in chlorophyll a content the proportionof blue light fraction became reduced and that of red lightincreased. A similar relation was also found in the sea.
- Thephotosynthetic rate.light relation was investigated withthesuspension of cultured Chlorella and Tabellaria. At lowlightintensities, the photosynthetic rate for red light waslargerthan those for blue and green lights. The photosyntheticrateunder the mixed light of red and blue was equal to thesum ofthe rates in the individual lights, so far as the intensityof each light was low. But when the intensity of red light wassufficiently high, the addition of blue light brought no furtherincrease in photosynthesis.
- The photosynthetic rate-depthrelations were investigated bythe surface and underwater exposuremethods. Good agreementswere found between the results obtainedby these two differentmethods. However, there are some discrepanciesbetween the resultsof in situ exposure experiments and thoseobtained by the twomethods.
18.
Red and blue light-stimulated proton efflux by epidermal leaf cells of the Argenteum mutant of Pisum sativum 总被引:1,自引:0,他引:1
Staal Marten; Elzenga J. Theo M.; van Elk Alette G.; Prins Hidde B.A.; Van Volkenburgh Elizabeth 《Journal of experimental botany》1994,45(9):1213-1218
Light stimulates leaf expansion in dicotyledons by increasingapoplastic acidification, cell wall loosening and solute accumulationfor turgor maintenance. Red and blue light enhance growth viadifferent photo-systems, but the cellular location and modesof action of these systems is not known. Here, the effect of red and blue light was studied on transportprocesses in epidermal cells of expanding leaves of the Argenteummutant of Pisum satlvum. Both red and blue light caused extraceiiuiaracidification by isolated epidermal tissue, which was stimulatedby extracellular K+ and inhibited by DCCD at 0.1 mol m3.Acidification induced by red compared with blue light showeddifferent saturating kinetics in fluence rate-response curves.Under near saturating light conditions the effects of red andblue light were additive. The red light-induced acidificationwas inhibited by far-red light while the blue light-inducedacidification was not. Light caused a hyperpoianzation of themembrane potential in epidermal strips, and stimulated 86Rb+uptake by epidermal protoplasts. These results show that phytochromeand an additional blue light-photoreceptor function in isolatedepidermal cells to promote proton efflux, hyperpolarization,and cation uptake. Key words: Pisum sativum, light-induced acidification, ion transport, epidermis, photoreceptor 相似文献
19.
Irradiation of spores of the fern Mohria caffrorum Sw. witheither red light (67.4 µW cm2) or far-red light(63.2 µW cm2) for a period of 24 h induced maximumlevels of germination. Brief irradiations with blue light (127.6µW cm2) administered before or after photoinductioncompletely nullified the effects of red or far-red light; however,with prolonged exposure to blue light, germination levels roseto near maximum. The similar effects of red and far-red lightin promoting spore germination makes the involvement of phytochromein this process questionable. Based on energy requirements,the promotive and inhibitory phases of blue light appear toinvolve independent modes of action. Mohria caffrorum, ferns, spore germination, photoinduction, phytochrome 相似文献
20.
Callus cultures of Nardostachys jatamansi DC. maintained onMurashige and Skoog's medium containing 3.0 mg 11 of-naphthaleneacetic acid and 0.25 mg 11 of kinetin whenshifted to medium containing 0.251.0 mg 11 ofindole-3-acetic acid or indole-3-butync acid showed profuserhizogenesis. The callus-regenerated roots when transferredto medium containing 2.06.0 mg 11 of kinetin producedshoot buds. The de novo shoot bud regeneration took place eitherdirectly from cortical cells or from the inner stelar region.In addition, direct, concomitant root-shoot development wasalso observed. Nardostachys jatamansi, organogenesis, root-buds 相似文献