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1.
William C. LeNoir Jr. 《American journal of botany》1967,54(7):876-887
First internodes of light-grown bean seedlings exposed to supplementary red and far-red light and those of dark-grown seedlings were sectioned and studied to determine the effects of irradiation on the cellular components of polarized growth. Cell counts and measurements of epidermis, cortex, and pith are given. Increased length of internodes of far-red-treated plants was caused by both increased rate and increased duration of cell elongation. The effect of far-red light is interpreted as a reversal of the accelerating effect of light upon cell maturation. It is suggested that investigations of the mechanism of the red, far-red response of stems be concerned with the processes involved in cell elongation. In darkness, rate and duration of cell division as well as rate and duration of cell elongation were greater than in any of the irradiated plants, indicating that only part of the photocontrol of stem elongation is mediated through the red, far-red system. 相似文献
2.
The elongation of fern protonemata is controlled by red andfar-red light in an atypical fashion. Red light promotes theelongation of young plants but inhibits the elongation of olderplants. Far-red light promotes elongation regardless of filamentage, and the maximum promotion by far-red is greater than thepromotion which red light causes in young filaments. The elongationof rhizoids is under typical red, far-red control. Red lightpromotes elongation, and a period of far-red illumination followingred light treatment negates the promotive effects of red light.
1 Present address of the authors: Dept. of Bacteriology andBotany, Syracuse University, Syracuse, New York, U. S. A. (Received November 5, 1962; ) 相似文献
3.
Nine-day-old Pinto bean seedlings, Phaseolus vulgaris L., were treated daily for 12 days with supplementary red or far-red radiation following daily exposure to 8 hr of daylight. Stem elongation was nearly exponential from the 4th to the 12th day of treatment and was about 2.9 times greater under far-red radiation. Cell division and cell elongation were promoted essentially equally by far-red radiation. There was virtually no difference in either the rate of leaf initiation or the duration of growth of internodes under the supplementary radiation. 相似文献
4.
Thomson , Betty F., and Pauline Monz Miller . (Connecticut Coll., New London.) Growth patterns of pea seedlings in darkness and in red and white light. Amer. Jour. Bot. 48(3): 256–261. Illus. 1961.—Seedlings of peas were grown in vermiculite at 22°C. and exposed 16 hr. daily to red or white light or kept in darkness. Others were grown in soil in the greenhouse. Samples harvested daily to 16 days were dissected, the length of each internode and leaf measured and the total number of leaves and leaf primordia counted. The form of the stem apex and youngest primordia and interrodes is the same in light as in darkness. Leaf production is accelerated very slightly and the growth of leaves and internodes is decidedly accelerated by light. Leaf-leaf, leaf-internode and internode-internode correlations indicate that the morphogenetic effect of light is limited to later stages of organ growth. Dry weight is consumed more rapidly in light than in darkness, probably because of more rapid growth and slightly greater amounts of respiring tissue in light-grown plants. 相似文献
5.
Photocontrol of stem elongation in plant neighbourhoods: effects of photon fluence rate under natural conditions of radiation 总被引:11,自引:4,他引:7
Abstract. We investigated the effects of photon fluence rate on internode elongation in fully de-etiolated plants growing under sunlight. Our goal was to find out whether perception by the stems of fluence rate changes related to canopy density may be involved in the modulation of internode growth in canopies formed by plants of similar stature (e.g. crop stands). Using Datura ferox L. and Sinapis alba L. seedlings growing under natural radiation, we found that internode elongation is promoted by localized shading. This effect was observed with internodes receiving light with a high (>0.9) or a low (0.3) red (R) to far-red (FR) photon ratio. Selective removal of the different wavebands from the light impinging on the internodes showed that part of the response to fluence rate is due to photons in the R + FR range. The blue (B) component, most likely acting through a specific photoreceptor, also inhibited elongation. However, changes in the fluence rate of B light did not have detectable effects on the response of the internodes to R:FR ratio. Fibre-optic studies and measurements with integrating-cylinder sensors in even-aged populations of seedlings showed that both the quality and quantity of radiation received by the stems are profoundly influenced by changes in canopy density. When density is very low (leaf area index = LAI ≥ 1) only the R:FR ratio is reduced, due to FR reflected from nearby leaves. In the LAI range of 1 to 2, though a large proportion of the leaf area is still receiving full sunlight, the photon fluence rate at the stem level drops dramatically. These results suggest that in even-aged populations of LAI > 1 elongation growth is promoted by the low R:FR ratio and the reduced fluence rate. Perception of these two factors at the stem level may elicit morphological adaptations in the canopy before the onset of severe competition among neighbours for the resource of light. 相似文献
6.
PHYTOCHROME ACTION IN ORYZA SATIVA L.: I. GROWTH RESPONSES OF ETIOLATED COLEOPTILES TO RED, FAR-RED AND BLUE LIGHT 总被引:3,自引:0,他引:3
- Under continuous irradiation, the growth of intact rice coleoptilewas strongly inhibited by red light, and somewhat preventedby blue and far-red light. The inhibitory effect of red lighton coleoptile elongation was caused by a low-energy brief irradiation,and a single exposure of 1.5 kiloergs cm2 incidentenergy of red light brought about the 50% inhibition. This photoinhibitionof growth was observed only after the coleoptile had elongatedto about 10 mm or longer. The red light-induced effect was reversedby an immediately following brief exposure to far-red light,and the photoresponses to red and far-red light were repeatedlyreversible. The escape reaction of red lightinduced effect tookplace at a rate so that 50% of the initial reversibility waslost within 9 hr in darkness at 27. The inhibition by bluelight and reversal by far-red irradiation was also achievedrepeatedly with successive treatments of the coleoptiles. Theevidence for a low intensity red far-red reversible controlof coleoptile growth, indicative of control by phytochrome,seems clearly established in etiolated intact seedlings.
- Incontrast, the elongation of apically excised rice coleoptilesegments was promoted by a brief exposure to red light in 0.02M phosphate buffer, pH 7, and the effect was almost completelynullified by an immediately subsequent exposure to far-red light.It becomes evident that the growth of intact coleoptiles wasinhibited by a exposure to red light, while that of excisedsegments in a buffer was rather promoted by red irradiation.The direction of red light induced responses, either promotiveor inhibitory, depends upon the method of bioassay using intactcoleoptiles or their excised segments.
7.
J. L. STODDART 《The Annals of applied biology》1960,48(4):800-810
The response of seedling and first harvest year plants of red clover ( Trifolium pratense L.) to treatment with gibberellic acid (GA) at various growth stages is described.
Seedlings sprayed before the seventh leaf stage developed into single-stemmed plants; treatment with GA at the third- or fourth-tiller stage resulted in final stem numbers similar to those of controls. Emergence was earliest, and the number of heads per plant greatest where sprayings were delayed until the third- or fourth-tiller stage.
In first harvest year plants significant increases in the number of heads per stem were obtained with certain treatments, especially those which had two applications of 0.5 mg. GA per plant during the elongation of the first four internodes. This was related in all treatment groups to modifications of the branching pattern, and also to the increased incidence of multiple heading. Earlier emergence resulted from treatment at all growth stages, the effect being maximal where three well-spaced sprayings were applied during active stem extension. 相似文献
Seedlings sprayed before the seventh leaf stage developed into single-stemmed plants; treatment with GA at the third- or fourth-tiller stage resulted in final stem numbers similar to those of controls. Emergence was earliest, and the number of heads per plant greatest where sprayings were delayed until the third- or fourth-tiller stage.
In first harvest year plants significant increases in the number of heads per stem were obtained with certain treatments, especially those which had two applications of 0.5 mg. GA per plant during the elongation of the first four internodes. This was related in all treatment groups to modifications of the branching pattern, and also to the increased incidence of multiple heading. Earlier emergence resulted from treatment at all growth stages, the effect being maximal where three well-spaced sprayings were applied during active stem extension. 相似文献
8.
Third internodes or whole stems of 7-days old etiolated pea plants were extracted and the content of gibberellin-like substances and inhibitors has been determined. Extracts were found to contain four or five different gibberellin-like substances, some of which are chromatographically similar to GA3. The content of gibberellins has been high in young internodes and decreased along with the internodes elongation. Brief red light irradiation brings about quantitative changes in gibberellin content, depending also on the length of internodes. The extracts contain acidic and neutral inhibitors which interfere with the response to GA3. The content of the inhibitors does not seem to be affected by the ageing of internodes or by the light treatment. 相似文献
9.
D. Vince-Prue 《Planta》1977,133(2):149-156
Stems of the caulescent long-day plant, Fuchsia hybrida cv Lord Byron, showed 2 types of response to light. In one, internode length was increased by far-red irradiation given at the end of an 8 h photoperiod: the response was no greater with prolonged exposure and was less when the start of far-red was delayed. The effect of far-red was reversible by a subsequent exposure to red light. Internode length was inversely proportional to the Pfr/P ratio established before entry to darkness and there was no evidence for loss of Pfr during a 16 h dark period. The inhibitory effect of Pfr acted at a relatively late stage of internode growth. With the development of successive internodes a second response appeared in which stems lengthened following prolonged daily exposures to red or far-red light, or mixtures of the two, or to brief breaks with red or white light. In these later internodes, a short exposure to far-red near the middle of the night was not reversible by red because red alone promoted elongation at this time. Internode length increased with increase in the daily duration of light and, when light was given throughout an otherwise dark period of 16 h, with increase in illuminance to a saturation value of 200 lx from tungsten lamps. Elongation increased as a linear function of decrease in photostationary state of phytochrome down to Pfr/P0.3; however, internodes were shorter in far-red light than in 25% red/red+far-red. It was concluded that stem length is a net response to two modes of phytochrome action. An inductive effect of Pfr inhibits a late stage in internode expansion, and a phytochrome reaction which operates only in light (and may involve pigment cycling) promotes an early stage of internode development. Stem elongation is thus a function both of the daily duration of light and its red/red+far-red content. The outgrowth of axillary buds was controlled by the first type of phytochrome action only.Abbreviations and symbols FR
far red light
- R
red light
- P
phytochrome
- Pfr
phytochrome in the far-red light absorbing form
- SD
8 h short days
- LDP
long-day plant
- SDP
short-day plant 相似文献
10.
Sunflower (Helianthus annuus L.) stems showed increased elongation under two types of vegetative shade: canopy shade (low red to far red [R/FR] ratio)
and neighbouring proximity shade (FR enrichment). Hypocotyls also elongated more under narrow-band FR light than under narrow-band
R light. Ethylene levels were determined in actively elongating 7-day-old hypocotyls and 17-day-old internodes under three
R/FR ratios. Ethylene levels were lower in both sunflower hypocotyls and internodes when the R/FR ratio was reduced. Both
FR enrichment of normal R/FR ratio and narrow-band FR light with very low light irradiance resulted in reduction in ethylene
levels in 7-day-old hypocotyls. Further, in application experiments, sunflower stems grown under low R/FR ratio were more
sensitive to ethephon and less sensitive to aminoethoxyvinylglycine (AVG) than stems grown under high R/FR ratio. Low R/FR
ratio appears to initiate reduction in ethylene levels in sunflower seedlings, allowing maximum stem elongation. These results,
and findings of other authors, suggest that various plant species may have developed different ways of regulating stem elongation
and ethylene levels in response to low R/FR ratio. 相似文献
11.
Effects of white, blue, red and far-red lights on the elongationgrowth of intact primary roots in rice seedlings were investigated.White light inhibited elongation of root cells. Blue light inhibitedboth cell elongation and cell multiplication, but red lightinhibited only cell elongation. The effect of far-red lightwas almost the same as that of the red. The lights exerted;the same effects on the growth of primary roots irrespectiveof age of the seedlings. The inhibitory effects of the lightswere also observed when the root of the deshooted seedlingswas irradiated, but not when only the shoot of the seedlingswas irradiated. It was inferred that it is not the shoot butthe root which responds to the light in this phenomenon. DCMUhardly affected root growth at a concentration so high as toinhibit strongly photosynthesis in the shoot. The possibilitythat photosynthesis participates directly in the photoinhibitionof root growth in rice seedlings was excluded.
1 Present address: Tohoku National Agricultural Experiment Station,Morioka 相似文献
12.
Germinating spores of the fern Onoclea sensibilis L. were grown in darkness, so that they developed as filaments (protonemata). Brief daily exposure of the filaments to red, far-red or blue light increased the rate of filament elongation. Filament elongation was also promoted by indoleacetic acid. When filament elongation was promoted with both indoleacetic acid and exposure to light, the growth promotions caused by red and far-red light were additive to auxin-induced growth. Blue light promoted elongation only at sub-optimal concentrations of auxin. Elongation induced by guanine was additive to red- and far-red-induced elongation. Gibberellic acid had no effect on elongation under any condition. Blue-light-induced elongation resembled auxin-induced elongation in its requirement for exogenous sucrose and sensitivity to inhibition by parachlorophenoxyisobutyric acid. Red and far-red light were active regardless of the presence or absence of sucrose and promoted elongation at a concentration of parachlorophenoxyisobutyric acid which completely inhibited blue-light-induced elongation. 相似文献
13.
This paper shows that the hypothetical yellow-light-absorbingpigment P580 is an unnecessary postulate for describing thephotobiology of fern filaments. The existence of P580 was originallypredicted on the basis of action and response spectra that assumedthat filament elongation is the growth parameter subject todirect photocontrol. The present work supports an alternativeconcept, that the cross-sectional area at the base of the apicaldome is the photocontrolled parameter. Far-red irradiation reversesthe effects of both red and yellow light, and dose-responsecurves for yellow light parallel but lag behind the curves forred light. These observations indicate that the responses offern filaments to the entire long wavelength spectral region(yellow to far-red) can be attributed to absorption of lightby phytochrome alone. 相似文献
14.
Temperature-dependent internode elongation in vegetative plants of Arabidopsis thaliana lacking phytochrome B and cryptochrome 1 总被引:1,自引:0,他引:1
Vegetative plants of Arabidopsis thaliana (L.) Heynh. form a compact rosette of leaves in which internode growth is virtually arrested. Rapid extension of the internodes
occurs after flower buds are present in the reproductive apex. Under natural radiation, continuous light from fluorescent
lamps, or short photoperiods of light from fluorescent lamps, plants of the phyB cry1 double mutant (lacking both phytochrome B and cryptochrome 1) did not form normal rosettes because all the internodes showed
some degree of elongation. Internode elongation was weak in the phyB single mutant and absent in the cry1 mutant, indicating redundancy between phytochrome B and cryptochrome 1. The absence of phytochrome A caused no effects. The
failure to form normal rosettes was conditional because internode elongation was arrested at low temperatures in all the mutant
combinations. In contrast, the temperature dependence of phytochrome B and cryptochrome 1 effects on hypocotyl growth was
weak. The elongation of the internodes in phyB cry1 was not accompanied by early flowering as showed by the lack of effects on the final number of leaves. Apex dissection indicated
that in phyB cry1 double mutants internode elongation anticipated the transition from the vegetative to the reproductive stage. Thus, stem
growth in Arabidopsis thaliana is not fully dependent on the program of reproductive development.
Received: 2 June 1999 / Accepted: 13 August 1999 相似文献
15.
16.
Klaus Lüning 《Journal of phycology》1992,28(6):794-803
Growth rates in terms of area increase per 30 min were measured in flat thalli of several seaweed, species by means of computer-assisted image analysis, at 12 h light per day and a photon fluence rate of 20 μmol · m-2· s?1. Light fields included white fluorescent, imitated underwater, blue, green, and red light. In the green alga Ulva pseudocurvata Koeman et Hoek, blue light caused an immediate reduction of thallus area and growth rate after the onset of light, whereas green light and red light resulted in an initial peak in growth rate followed by inhibition 60 min after the onset of light. More growth was observed in darkness than in blue light in U. pseudocurvata. All brown and red algae tested, with Laminaria saccharina (L.) Lamour. and Palmaria palmata Stackh. as the main investigated species, grew faster during the day than during the night, irrespective of light quality during the main light phase. The upper intertidal red alga Porphyra umbilicalis (L.) J. Ag. achieved most of its thallus expansion per 24 h during the first 3 h of the light phase, with maximum growth rates of 2–3% increase in area per hour. Maximal growth rates were 0.7% for juvenile laminarian sporophytes and were lower than this in Palmaria palmata and other perennial red algae. The temporary growth inhibition by light in Ulva pseudocurvata suggests photomorphogenetic events, similar to the kinetics of stem elongation in higher plant seedlings after blue or red light pulses in darkness. 相似文献
17.
Protonemata of Onoclea sensibilis and Diyopteris filix-mas elongate in response to both red and far-red light. The promotion caused by far-red is larger than that caused by red light. This phenomenon differs from a typical response to phytochrome, the photoreceptor pigment immediately suggested by the activity of red and far-red light. The phenomenon has been explained by two different hypotheses, one of which holds that phytochrome is solely responsible for the response, whereas the other postulates an interaction between phytochrome and P580, a yellow-green light absorbing pigment, to account for the response. The hypothesis that phytochrome is the sole photoreceptor leads to some specific predictions concerning the shapes of the dose-response curves for light-induced protonema elongation. These predictions were tested with both continuous and short-term irradiation. In all instances saturating far-red light caused greater elongation than did saturating red light, and no dose of red light duplicated the activity of saturating far-red light. Other experiments tested the interactions of red and far-red light and the effects of different doses of yellow-green light on protonema elongation. The results of many of the experiments were not in agreement with the hypothesis that phytochrome is the sole photoreceptor, whereas they were in agreement with the assumption that filament elongation is controlled by both phytochrome and P580. 相似文献
18.
研究重点针对雨生红球藻绿色游动细胞的增殖培养阶段,分析了在利于细胞增殖的红光条件下,几种培养方式的调整对增殖过程和细胞活力的影响。结果显示:(1)在红光下,增殖平台期维持时间长,细胞活力稳定,细胞中性脂无累积,但进入平台期前,细胞中性脂有规律波动,进入平台期后相对稳定;通过更新率为20%的半连续培养,细胞数产出较批次培养提高57%;半连续培养中细胞呈现胁迫调节的时间较批次培养晚。随着培养时间增加,半连续培养下细胞营养盐吸收能力降低。(2)初始接种密度与细胞增殖速率及细胞光合活力呈负相关:初始密度低的细胞增殖速率较高,细胞光合作用活力高。(3)在培养过程中添加CO2时,最大密度均有提高,达6.0105 cells/mL,较无添加组提高54%;细胞分裂速率均有提高,但红光下较白光下增殖速率高(分别为0.223/d和0.198/d);添加CO2降低培养液pH,利于维持适宜增殖的pH环境。叶绿素荧光参数以及细胞粒径在红光和白光下有显著差异:红光下,Fv/Fm显著高于白光下;红光下补充CO2显著减小细胞粒径,而白光下粒径无显著变化。研究结果显示,在红光下,采用间断式半连续培养补充CO2培养绿色游动细胞,有利于提升细胞活力与产出。 相似文献
19.
Blockage by gibberellic Acid of phytochrome effects on growth, auxin responses, and flavonoid synthesis in etiolated pea internodes 总被引:5,自引:3,他引:2
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Red light inhibits the growth of etiolated pea internodes, causes a shift toward higher indoleacetic acid (IAA) concentrations in the IAA dose-response curve of excised sections, and promotes the synthesis in intact internodes of kaempferol-3-triglucoside. Gibberellic acid (GA3) prevents all 3 effects, the first effect substantially and the last 2 completely. This suggests GA3 blockage of an early or basic event initiated by the active form of phytochrome. The red light-induced shift in the IAA dose-response curve of excised sections is consistent with a light-induced increase in the activity of an IAA destruction system, since the magnitude of the red light inhibition varied with IAA concentration. The red light and GA3 effects on growth and on flavonoid synthesis are consistent with the view that phytochrome may control growth by regulating the synthesis of phenolic compounds which act as cofactors in an IAA-oxidase system. GA3 reversal of the red light-induced shift in the IAA dose-response curve involves both growth promotion and inhibition by GA3 at different IAA concentrations and this, together with the GA3 reversal of light-induced flavonoid synthesis, supports the suggested regulatory role of phenolic compounds in growth. 相似文献
20.
Glenn T. Howe Gary Gardner Wesley P. Hackett Glenn R. Furnier 《Physiologia plantarum》1996,97(1):95-103
In trees and other woody perennial plants, short days (SDs) typically induce growth cessation, the initiation of cold acclimation, the formation of a terminal bud and bud dormancy. Phytochrome control of SD-induced bud set was investigated in two northern clones of black cottonwood (Populus trichocarpa Torr. & Gray) by using night breaks with red light (R) and far-red light (FR). For both clones (BC-1 and BC-2), SD-induced bud set was prevented when R night breaks as short as 2 min were given in the middle of the night. When night breaks with 2 min of R were immediately followed by 2 min of FR, substantial reversibility of bud set was observed for BC-1 but not for BC-2. By comparing the effects of the R night breaks on bud set and the length of specific internodes, we determined that the R night breaks influenced internode elongation in two opposing ways. First, the addition of a R night break to the SD treatment prevented the cessation of internode elongation that is associated with bud set. Those internodes that would not have elongated under SDs (and would have been found within the terminal bud) elongated in the R treatment. Second, the R night breaks decreased internode length relative to the long-day (LD) control. In contrast to the clonal differences in reversibility that we observed for bud set, the decrease in internode length (i.e. the second effect of R) was R/FR reversible in both clones. Based on these results, we conclude that internode elongation is influenced by two distinct types of phytochrome-mediated response. The first response is a typical response to photpperiod, whereas the second response is a typical “end-of-day” response to light quality. Our results demonstrate that SD-induced bud set in black cottonwood is controlled by phytochrome but that clonal differences have an important influence on the R/FR reversibility of this response. The availability of an experimental system in which SD-induced bud set is R/FR reversible will be valuable for studying the physiological genetics of photoperiodism in trees. 相似文献