Light-induced formation of fruit-bodies in a basidiomycete, Favolus arcularius (FR.) AMES

fruit-bodies in Favolus arcularius. The effect of light lastedfor about one day after transfer to darkness. The mycelium became sensitive to light about 2.5 days afterinoculation; i.e., at the beginning of the rapid growth phase.The site of fruiting was 2–5 mm inside the edge of colony(actively dividing zone) at the start of illumination. Whenone half of the plate culture was illuminated, fruiting wasrestricted to the illuminated half of the colony ; i.e., theeffect of light was localized. These results suggest that thecells sensitive to light are the actively dividing cells. Under a fixed light intensity, the total irradiation time requiredfor the initiation of fruiting was nearly constant, irrespectiveof the durations of pre-incubation in darkness and the dailyillumination period. With increasing light intensities, up toabout 500 lux, fruiting was promoted, however, a further increasein light intensity was inhibitory. (Received March 27, 1968; )     

Changes in Dormancy and Sensitivity to Vernalization in Axillary Buds of Satsuma Mandarin Examined in vitro During the Annual Cycle

Effect of season and the presence of fruit on bud-endodormancyand the flowering response to low temperature treatments weredetermined using bud cultures of Owari satsuma mandarin (Citrusunshiu Marc). Bud dormancy was deeper in fruiting as comparedto defruited trees. In fruiting trees, the intensity of buddormancy was highest in spring, decreased to a low value byearly Jul. and then increased until early winter. This increasein dormancy during summer and early autumn did not occur innon-fruiting trees. No flowers formed in buds cultured betweenMay and Sep. Both in fruiting and defruited trees, buds becamecompetent to show a vernalization response to chilling by theend of Oct., at the time they also became capable of sproutingin vitro at low temperature (15/10 °C). There was a directeffect of fruit on the buds which persisted long after fruitremoval and resulted in a reduction of the flowering responseto chilling.Copyright 1995, 1999 Academic Press Citrus flowering, Citrus unshiu Marc., dormancy, flower induction, flowering, in vitro flowering, satsuma mandarin, vernalization     

BLUE LIGHT, PHYTOCHROME AND THE FLOWERING OF LEMNA PERPUSILLA 6746

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.     

The Role of Superoxide Dismutase in Regulating the Light Emission of Luminescent Fungi

Luminescent fungi spontaneously emit light during certain stagesof their life cycles. Most of them are luminous during a partof their mycelial stage, but not many of them are luminous whenthey form fruiting bodies. In the case of Panellus stipticus,both the mycelium and the fruiting body can be luminous, andthe emission of light takes place when its luciferin is aerobicallyoxidized in the presence of the superoxide anion (O₂) and acationic surfactant. It is highly likely that the luminescencereactions of all kinds of luminous fungi are basically the sameas that of P. stipticus. In order to determine the factor thatmakes a fungus luminous or non-luminous, we studied the relationsbetween the light emission of fungi at various growth stagesand the contents of luciferin, its precursor, superoxide dismutase(SOD), and catalase, on six species of luminescent fungi: Armillariellamellea, Mycena citricolor, Mycena lux-coeli, Omphlotus olearious,Panellus stipticus, and Pleurotus japonicus. The analysis ofthe data suggested that the fungi generally contain the componentsnecessary for light emission, but also contain very large amountsof SOD which destroy O₂^–. If an appreciable amount ofSOD is distributed at the site of light emission, the luminescencereaction is prevented. For the reaction to take place, it isessential that the SOD activity at the site is sufficientlylow or inhibited, despite the high content of SOD in the wholetissue. Thus, the level of SOD activity at the site of lightemission appears to be a limiting factor in regulating the luminescenceof fungi. Key words: Bioluminescence, chemiluminescence, luminous fungi, superoxide ion, superoxide dismutase     

On the Mechanism of Phase Control by Light in the Rhythm of Carbon Dioxide Output in Leaves of Bryophyllum fedtschenkoi

The induction of phase shifts in the rhythm of CO₂ output inleaves of Bryophyllum fedtschenkoi kept in continuous darknessand a CO₂-free air stream at 15 °C has been investigatedby scanning the circadian cycle with 1-h and 3-h exposures tolow fluence rates of red light. The experiments were designedto test the hypothesis (Wilkins, 1983) that phase-shift inductionwas achieved by the redistribution of malate between the vacuolarand cytoplasmic compartments of the leaf cells due to red lightopening ‘gates’ in the tonoplast through which malatediffusion can take place. The use of red light exposures oftwo different durations enabled the direction of phase shiftsto be established. From 8 h to about 22 h of darkness, whenthe cytoplasm would be expected to have a higher level of malatethan the vacuole, only phase advances were observed, as predictedfrom the hypothesis. At later times in the cycle, phase delaysand then phase advances were induced in a pattern closely similarto that reported for high temperature treatments (Wilkins, 1983).The results are discussed in relation to the tonoplast gatehypothesis which appears to account adequately for every featureof the phase shifts induced by exposing leaves to red light. Key words: Bryophyllum fedtschenkoi, Circadian rhythm, CO² fixation, phase control, red light, malate transport     

Floral Induction of Xanthium strumarium in Long Days

An efficient method of inducing flowering in the normally strictshort-day plant, Xanthium strumarium L., in long days is described.Plants were grown in 16-h long days and subjected to two thermocycleswith a root application of gibberellic acid at the 8th h ofthe light period. A thermocycle was defined as follows. Forthe first 8 h of the 24-h cycle, the temperature was 4 °C;for the remaining 16 h, it was 23 °C. The light was on forthe first 16 h and off for the remaining 8 h. Xanthium strumarium L., floral induction, thermoperiod, gibberellic acid     

Fruiting in Sphaerobolus with Special Reference to Light

Sphaerobolus grows and, provided there is sufficient illumination,fruits readily on oatmeal agar or on malt agar. No effect oflight on vegetative growth can be demonstrated. On the maltmedium, increased fruiting occurs with increase of nutrientup to 4 per cent, malt, but at higher concentrations fruitingis not increased and may be retarded. A chemically defined mediumwith starch as the carbon source allows fruiting, but at a lowlevel. Temperature has a profound effect on basidiocarp development;above 25 C. no fruit-bodies are normally formed although vegetativegrowth is approximately optimal at that temperature. For overallfruit-body production at 20 C, light above 100 lux is necessaryand light remains a limiting factor up to about 1, 000 lux.Under continuous light of suitable intensity, fruit-bodies continueto develop and discharge glebal-masses for many weeks. Thereis a distinct periodicity of discharge with (at 20 C.) about12 days between peaks of activity. This corresponds with thetime taken for basidiocarp initiation and development. A number of developmental stages of the basidiocarp are recognized.The final stage, glebal-mass discharge from stellately openedfruit-bodies, is indifferent to light, but all other stagesare stimulated by light. The light intensity for effective stimulationfalls during development and for the penultimate stage an intensityas low as 1 lux is effective. Only light of wave-length below500 mµ is active in overall basidiocarp development. Inthe sensitive region between 400 mµ and 500 mµ,there appear to be peaks of sensitivity around 440 mµand 480 mµ. In alternating light and darkness, simulating natural conditions,glebal-mass discharge occurs in the light periods. With a regimenof 24 hours light and 24 hours of darkness discharge is mainlyin the dark periods.     

A Physiological Analysis of the Branching Pattern in Sequential Types of Groundnut in Relation to the Fruiting Nodes and the Total Mature Pods Produced

The branching pattern of eight sequential branching types ofgroundnut was studied and the contribution of each node (fruitingpoint) of the n, n+1 and n+2 branches (if present) to the totalnumber of mature pods per plant ascertained. The results indicatedthat n+2 branches were present in several varieties and theircontribution to mature pods was significant in some of them.The first three nodes of the n+1 branches contributed from 50.6per cent (in a variety which had significantly more n+2 branches)to 88 per cent in other varieties. The results also indicatedthat the contribution of the late formed n+1 branches was lowand the total mature pods produced from all nodes decreasedwith each successive (chronologically) n+1 branch in all thevarieties studied. Neither the total number of n+1 branchesnor the number of mature pods per node was related to the podnumber or pod yield, but the total number of fruiting pointsfrom all branches showed a high correlation with pod yield andmature pod number at harvest. The results suggest that for higherpod yield it may be desirable to have only a few n+1 branches(4 or 5) but with more fruiting points on each branch. Arachis hypogaea, branching pattern, sequential types, fruiting points     

Bioluminescence characteristics of the fruiting body of Mycena chlorophos

Bioluminescent fungi are widely distributed on land and most belong to the class Basidomycetes. Light of about 530 nm wavelength maximum is emitted continuously. The molecular basis for the light‐emitting process remains unclear. We investigated the characteristics of the bioluminescence using cultivated fruiting bodies of M. chlorophos. Only fresh fruiting bodies exhibited long‐lasting light emission; rapid decay of light emission was observed with frozen and freeze‐dried samples. Freeze‐dried samples can be stored at room temperature under dry conditions and may be useful for the isolation of luciferin. The light emission of the fresh fruiting bodies was maintained in various buffers at varying pH; it could be stopped with pH 4 acetate buffer and could be recovered at pH 6. The isolation of luciferin from the fresh fruiting bodies might be possible by the control of buffer pH. The effect of temperature on the light emission of fruiting bodies indicated that bioluminescence in M. chlorophos may involve enzymatic reaction(s). The solubilization of bioluminescent components from the fruiting bodies could not be achieved with various surfactants. Copyright © 2011 John Wiley & Sons, Ltd.     

Hardening and Dehardening of Lolium perenne in Response to Fluctuating Temperatures

Hardening and dehardening responses of two contrasting varietiesof Lolium perenne, measured as LT50 estimates, were followedin fluctuating temperature environments. Unhardened seedlingswere exposed to hardening environments for 7, 14, and 21 d inall combinations of 2, 4, 6, 8 and 10 C with either high dayand low night temperatures or low day and high night temperatures.Seedlings hardened for 28 d at 2 C were exposed to dehardeningenvironments in all combinations of 4, 6, 8, 10, and 12 C withhigh day and low night temperatures. A low day, or night, temperature of 2 C in combination withany other temperature increased hardening compared with theconstant higher temperature. For Premo, a hardy variety, thisincrease was 3 C when night temperature was reduced from 10to 2 C in combination with a day temperature of 10 C. Similarly,a low night temperature reduced the dehardening response ofPremo to higher day temperatures. At 12 C this effect on LT60was greater than 2 C. Much smaller responses to daily periodsof low temperature were found for the less hardy variety, GrasslandsRuanui. During each 24-h period, exposures to 2 C of longer than 4h were required to achieve greater hardening than that achievedin continuous 10 C treatments. Hardiness was not improved furtherby exposures longer than 8 h. Responses to diurnal temperature fluctuations were discussedin relation to possible mechanisms and to changes in hardinessduring the winter under different weather systems. Lolium perenne, cold hardening, cold dehardening, diurnal temperature fluctuations, varieties     

Reproductive Biology ofDalbergia miscolobiumBenth. (Leguminosae-Papilionoideae) in SE Brazil: The Effects of Pistillate Sorting on Fruit-set

The breeding system ofDalbergia miscolobiumBenth. was investigatedby means of controlled pollinations and studies of post-pollinationevents in pistils. This species does not have homomorphic self-incompatibility,but crossed flowers always have higher fruit set than selfs,despite the fact that embryo development may be initiated inselfed pistils. It is suggested that deleterious recessive alleles,which lead to abortion of most selfed seeds, together with somematernal resource limitation, result in low fruiting success.Copyright1998 Annals of Botany Company Dalbergia miscolobiumBenth., Leguminosae, breeding system, pistillate sorting, fruiting success, seed set.     

Growth and Dormancy in Lunularia cruciata (L.) Dum.: III. THE WAVELENGTHS OF LIGHT EFFECTIVE IN PHOTOPERIODIC CONTROL

Growth and dormancy in Lunularia are controlled by daylength,short-day promoting active growth, long-day or light-break treatmentinducing dormancy. Light-breaks of red light are highly effectivein inducing dormancy, while irradiation with other wavebandsis much less inhibitory to growth. Far-red light given afterred irradiation causes substantial reversal of the red-lighteffect, suggesting strongly that phytochrome is involved inthe photoperiodic response mechanism of Lunularia. However,even short(15 sec.) exposures to far-red light alone cause significantgrowth inhibition, and it is considered possible that far-redirradiation also leads to the formation of some of the P 730form of phytochrome.     

In Vitro Studies of Floral Induction on Stem Apices of Cuscuta reflexa Roxb. --A Short-day Plant

Stem tips of Cuscuta reflexa, cultured on modified White's medium,were subjected to different light and dark conditions. The culturesflowered when maintained either in continuous darkness or exposedto 14 hours of daily dark period. Thus Cuscuta reflexa behavesas a typically short-day plant. The presence of 5 per cent.sucrose in the medium completely obviates the requirement forhigh-intensity light exposures, otherwise essential for SDP.It appears that the bud itself is sensitive to photoinduction.In spite of the presence of natural tissue-bridge between thehost and the parasite, provided by the haustorial connexions,there is no transportation of flower-forming substance fromone plant to another. The flowering periods of host and parasiteare independent of each other.     

The Spontaneous Formation of Antheridia in Onoclea is not Blocked by Light

Onoclea sensibilis gametophytes were grown from spores on ashedsoil and agar to determine if the spontaneous formation of antheridiacan be blocked by light. Under most conditions, dark-grown gametophytesformed antheridia later than or at the same time as gametophytesgrown in the light. Under no circumstances was there a rapidonset of maleness in the dark. These results contradict thehypothesis that, in Onoclea, antheridiogen is required to inducemaleness because light inhibits the formation of antheridia.In the light, antheridia formed on heart-shaped thalli. In darkness,antheridia formed on filamentous gametophytes. The timing ofonset of maleness was affected by temperature and the presenceof sucrose. The effect of sucrose on the comparison betweenlight and dark treatments depended on both substrate and temperature Onoclea sensibilis, L., sensitive fern, fern gametophytes, sexuality, light-induced block     

Photomorphogenesis of the Gynophore, Pod and Embryo in Peanut, Arachis hypogaea L.

Darkened excized gynophores ceased to elongate after 8–10days in vitro and started to form a pod. Gynophore elongationwas inhibited to a greater extent in total darkness than underlow irradiance, while pod and embryo growth was stimulated indarkness only. Intact gynophores, enclosed in transparent vials containingglass beads, continued to elongate in both light and darkness.In light the elongating gynophores thickened as they penetratedbetween the glass beads, forming a seedless pod at the bottomof the vials. In the dark the elongating gynophores producedsmall pods in which the seeds had started to grow. Excized gynophores elongated in vitro under continuous whitelight at a rate similar to that of intact exposed gynophores.The rate of elongation in vitro, was lower under continuousblue or red-enriched light, than under white light, and wasfurther reduced under continuous far-red irradiation. Pods didnot form during any of the continuous irradiation treatmentsbut only after transfer to darkness, the largest pods formingafter continuous far-red irradiation. As little as 10 min daily exposure to red or far-red irradiancehad the same effect on gynophore elongation as continuous irradiation.Pods formed only when the daily periods of far-red irradiationwere 30 min or less. Reducing the daily exposures to 2 min decreasedthe time to onset of pod formation from 30 to 16 days. Far-redfollowing red irradiation was effective in inhibiting gynophoreelongation stimulated by red irradiation. Pod formation in red/far-redirradiation was only 50 per cent of that observed in far-redirradiation. The involvement of light in continual gynophoreelongation and in the concomitant inhibition of proembryo growthis discussed. Arachis hypogaea L., peanut, gynophore, photomorphogenesis, embryo development, pod development, proembryo     

Protein expression during Flammulina velutipes fruiting body formation

Formation of the Flammulina velutipes fruiting body can be induced by lowering the ambient temperature (first treatment) in complete darkness. Fruiting bodies formed under these conditions elongate without pileus formation (pinhead fruiting body), suggesting that they cannot mature in complete darkness. However, after light treatment of the pinhead fruiting body (second treatment), a pileus develops immediately, and the stipe also thickens and becomes increasingly pigmented. The apical region swells as a result of cell division starting 2 days after light treatment, the pileus–stipe junction fracture and hymenium primordia form on day 4, and gills appear at day 6. Pf1 and Pf3 are specifically expressed after exposure to low temperature without light. The cell wall-associated protein [pileus-specific hydrophobin-like protein (PSH)] is specifically induced in the pileus, but not in the stipe, following the second light treatment to the pinhead fruiting body. These results suggest that Pf1 and Pf3 would be involved in fruiting body induction and that PSH would be involved in pileus formation. These phenomena will aid further histological and molecular biological investigations into the mechanisms behind fruiting body development in F. velutipes.     

Changes of Starch and Sorbitol in Leaves Before and After Removal of Fruits from Peach Trees

Changes in contents of nonstructural carbohydrates in leaves,as well as some characteristics of leaves before and after fruitremoval, were investigated in potted peach (Prunus persica L.)trees. Leaf area and dry mass per unit leaf area (SLW) at thefruit-maturation stage decreased with increasing numbers ofpeaches per tree, whereas the chlorophyll content per unit areain leaves of fruiting trees increased. The chlorophyll contentdecreased more rapidly upon removal of fruit than that in leavesof fruiting trees. The starch content per unit dry mass in leavesof fruiting trees at the fruit-maturation stage was lower thanthat in leaves of non-fruiting trees. Starch accumulated significantlyin leaves within 1 d of removal of fruit during the fruit-maturationstage and continued to increase thereafter. The accumulationof starch after removal of fruit occurred more rapidly thanthe decrease in chlorophyll content. Reducing and non-reducingsugars (total sugars) per unit dry mass in the leaves were higherin fruiting trees than in non-fruiting trees. After fruit removal,the total sugar content of leaves increased temporarily andthen gradually decreased. The sorbitol content per unit freshmass in leaves of fruiting trees during the fruit-maturationstage was slightly higher than that in leaves of non-fruitingtrees. One day after removal of fruit, the sorbitol contentincreased in parallel with the accumulation of starch and remainedhigh. The sucrose content of leaves did not change markedlyupon removal of fruit. Prunus persica L.; peach leaves; nonstructural carbohydrate; starch and sorbitol; fruit removal     

Interactions between temperature and light intensity on growth and photosynthesis of the cyanobacterium Oscillatoria agardhii

Oscillatoria agardhii was grown in turbidostat cultures undera 16/8 h light/dark cycle at various combinations of light intensityand temperature. Temperature was found to influence only themaximal growth rate; this relationship was linear over the temperaturerange studied. An equation was derived describing the growthrate (µ) as a continuous function of light intensity andtemperature. The light harvesting pigments chlorophyll a andC-phycocyanin increased in concentration when growth becamelight limited. The regulation patterns observed did not suggestany influence of temperature on their steady state concentrations.The initial slope of the P versus I curves (     

An Analysis of the Effects of Temperature and Light Integral on the Vegetative Growth of Pansy cv. Universal Violet (Violaxwittrockiana Gams.)

Pansies (Viola xwittrockiana Gams.) cv. Universal Violet weresown on five dates between Jul. and Dec. 1992 and placed insix temperature-controlled glasshouse compartments set to providemean temperatures between 6.5 and 30 °C. Shoot dry weightand leaf number were recorded. A model was constructed, to analysethe effects of light and temperature on dry matter accumulation,which assumed that relative growth rate (RGR) declined linearlywith thermal time accumulated from sowing, reflecting ontogeneticdrift. Furthermore, it assumed that RGR was a semi-ellipsoidfunction of temperature, rising to an optimum of 25.3 °Cand declining thereafter, and a positive linear function oflight integral. When fitted to data collected in this studythe model accounted for 94% of the variance in RGR. Independentvalidation using data from four further crops grown in glasshousecompartments at four different set point temperatures showedthat the model could also be used to predict plant dry weightaccurately (r ²=0.98). The rate of mainstem leaf productionwas also linearly related to both light integral and temperature. Pansy; Viola xwittrockiana ; temperature; light integral; dry weight; relative growth rate; leaf number     

Accumulation of Phenylpropanoids in the Cotyledons of Morning Glory (Pharbitis nil) Seedlings during the Induction of Flowering by Low Temperature Treatment, and the Effect of Precedent Exposure to High-Intensity Light

Extracts from the cotyledons of seedlings of Pharbitis nil strain‘Violet’ cultured at low temperature, which inducestheir flowering even in continuous light, with or without precedentexposure to high-intensity light, which shortens the periodof low temperature required for flowering, were analyzed byHPLC for substances correlating with the flower-inducing process.The content of two phenylpropanoids were found to increase duringthe low-temperature, and were identified as 3-O-feruloylquinicacid and dehydrodiconiferyl alcohol-13-O-ß-D-glucoside.The increase was more rapid in the cotyledons exposed to high-intensitylight before the low-temperature. This suggests that the accumulationof these compounds is correlated to the promotive effect ofhigh-intensity light on the flower-induction by low temperature. (Received March 7, 1994; Accepted April 2, 1994)