Flowering Response in Relation to C and N Contents of Pharbitis nil Plants Cultured in Nitrogen-Poor Media

Flowering of seedlings of Pharbitis nil, strains Violet andTendan, cultured in modified White's medium, was promoted bymedium dilution, the critical dark period being shortened byabout 15 min. Dilution of the N source alone was enough to causethe medium-dilution effect. Dilution of the culture medium duringthe day before and on the day of exposure to the dark-period(a total of two days) caused the maximum dilution effect. TheC and N contents of the cotyledons and of the shoot apices changedrapidly in response to medium dilution. In 1/2-strength White'smedium with 1/1,000 strength NO₃^– which was most effectivefor flower promotion, the C-N ratio was highest. In 1/2-strengthmodified White's medium, in which flowering was lowest withthe longest critical dark period, the C-N ratio was lowest.Thus, there is a close relation between flowering response andthe C-N ratio in cotyledons or shoot apices of Pharbitis nil. (Received September 14, 1984; Accepted January 26, 1985)     

Accumulation of Phenylpropanoids in Cotyledons of Morning Glory (Pharbitis nil) Seedlings during the Induction of Flowering by Poor Nutrition

Flowering of Pharbitis nil strain Violet is induced in continuouslight under poor nutritional conditions. High-performance liquidchromatography of extracts of the cotyledons revealed that twocompounds in addition to chlorogenic acid accumulate under suchconditions. The compounds were identified as pinoresinol glucosideand p-coumaroylquinic acid. The endogenous levels of these phenylpropanoidswere correlated with the flowering response when nutrition waspoor. However, activation of phenylpropanoid biosynthesis seemednot to be essential for the induction of flowering. (Received May 17, 1993; Accepted July 26, 1993)     

The Presentation Time for Shoot Inversion Release of Apical Dominance in Pharbitis nil

The presentation time for shoot inversion release of apicaldominance in Pharbitis nil is between 1 and 1.5 d. Five to 6d of shoot inversion are required for persistent outgrowth ofthe highest lateral bud. Pharbitis nil, apical dominance, shoot inversion, lateral bud growth, presentation time     

Floral initiation of Pharbitis nil, a short-day plant, under continuous high-intensity light

Pharbitis nil, a short-day plant, initiated floral buds undercontinuous illumination at 23°C, provided that the lightintensity was kept at 16,000 lux or above. Stem elongation ofthe plants was strongly inhibited but leaves developed normallyunder this condition. (Received November 26, 1971; )     

Interaction between L-Pipecolic Acid and Water Extracts of Various Plant Species in Floral Induction of Lemna paucicostata

The flower-inducing activity of L-pipecolic acid was synergisticallyenhanced by simultaneous application of the water extracts ofLemna paucicostata and Pharbitis nil, but suppressed by thewater extracts of all other plants we examined. Simultaneousapplication of the water extract of Lemna enhanced the flower-inducingactivity of all plant water extracts. (Received June 6, 1990; Accepted July 7, 1990)     

Evidence for the Involvement of Calcium Ions in the Photoperiodic Induction of Flowering in Pharbitis nil

The effects of ethyleneglycol-bis-(ß-aminoethyl ether)N,N,N',N'-tetraacetic acid, a specific chelator of Ca²⁺ ions;lanthanum chloride, a calcium channel blocker; and chlorpromazine,a calmodulin antagonist, on the photoperiodic induction of floweringin Pharbitis nil were studied by perfusing the plants with aqueoussolutions of the various compounds. All these compounds inhibitedflowering when applied before an inductive 16-h dark periodbut they did not inhibit flowering when applied after the inductivedark period. The results imply that Ca²⁺ ions are involved inthe photoperiodic induction of flowering in P. nil. (Received August 14, 1992; Accepted November 24, 1992)     

Peroxidase isozymes and their indoleacetate oxidase activity in the Japanese morning glory, Pharbitis nil

Distributions of peroxidase isozymes in various organs of theJapanese morning glory (Pharbitis nil CHOISY) are described.Most peroxidase isozymes had indoleacetate oxidase activity. (Received December 29, 1969; )     

Carbon Dioxide and Flowering in Pharbitis nil Choisy

The effects of photoperiod on floral and vegetative development of Pharbitis nil were modified by atmospheric CO₂ concentrations maintained during plant growth. Short day (SD) photoperiods caused rapid flowering in Pharbitis plants growing in 0.03 or 0.1% CO₂, while plants in long day (LD) conditions remained vegetative. At 1 or 5% CO₂, however, flower buds were developed under both the SD and LD photoperiods. Flowering was earliest in the plants exposed to SD at low CO₂ concentrations which formed floral buds at stem node 3 or 4. At high CO₂ concentrations, floral buds did not form until stem node 6 or 7. Both high CO₂ concentrations and LD photoperiods tended to enhance stem elongation and leaf formation.     

Qualitative analysis by isoelectric focusing of the protein content of Pharbitis nil apices and cotyledons during floral induction

The protein content of apices and cotyledons in Morally inducedor vegetative plants of Pharbitis nilwas examined using isoelectricfocusing. No differences were found in the protein patternsproduced by apical tissue with and without floral induction.Cotyledons, however, repeatedly showed the distinct loss ofa single protein band on floral induction. ¹Current address: Department of Radiation Biology and Biophysics,The University of Rochester School of Medicine and Dentristry,Rochester, N.Y. 14642, U.S.A. (Received March 29, 1976; )     

Enhancement of Flowering by Acetic Acid Bacteria-oxidized Products in Pharbitis Seedlings

When seedlings of Pharbitis nil Chois., strain Shifukurin weregrown in a medium containing acetic acid bacteria-oxidized ethanol(AABOE) or acetic acid bacteria-oxidized methanol (AABOM), 100%flowering was induced by exposure to a single dark period of9.5 to 10.5 hr, while this regime induced little or no floweringin control plants. When the plants were grown in water containingthe freeze-dried substance from an AABOE solution, floweringwas also enhanced. Vegetative growth was considerably suppressedby these fermented alcohols and by the freeze-dried substancefrom an AABOE solution. However, the freeze-dried substancefrom the AABOM solution had no effect on either flowering orvegetative growth. (Received May 13, 1981; Accepted August 21, 1981)     

Production and purification of polyclonal antibodies to Pisum and Avena labile phytochrome which cross-react with phyA from Pharbitis nil

Little work was done so far with phytochrome from Pharbitis nil. Purification of phyA from this plant has been exceptionally difficult. Labile phytochrome was presented in too small amount to obtain either absorption spectra or enough protein to produce antibodies. Monoclonal antibodies mAP5, MAC 50, 52, 198 recognized Pharbitis nil labile phytochrome poorly, so it was necessary to develop independently an antiserum against labile phytochrome. The antiserum was prepared against proteolytically undegraded phytochrome obtained from etiolated Avena and Pisum seedlings using conventional methods. The antiserum to phytochrome from each of the above mentioned plants was prepared by injecting purified phytochrome into rabbits. The newly produced polyclonal antibodies to phyA from Avena and Pisum were used to characterize phytochrome from etiolated seedlings of Pharbitis nil. The cross reaction was tested by immunobloting. Both kinds of PAbs recognised phyA from Pharbitis nil, however IgG against the labile phytochrome from Pisum gave stronger reaction. The recognized peptide had the molecular weight of about 120-kDa.     

Photostimulation of Hydroxypyruvate Reductase Activity in Peroxisomes of Pharbitis nil Seedlings: I. Action Spectrum

Hydroxypyruvate reductase activity in etiolated cotyledons ofPharbitis nil is highly stimulated by white light. The actionspectrum shows three effective regions: blue, red and far red.The main characteristics of this high irradiance reaction responseis a high blue efficiency and a low red efficiency. Experimentswith herbicide-treated plants demonstrated that chlorophyllis not involved in the regulation but suggest that a specificblue-absorbing pigment is involved, in addition to phytochrome. (Received November 22, 1983; Accepted June 20, 1984)     

Establishment of photoperiodic sensitivity by benzyladenine and a brief red irradiation in dark grown seedlings of Pharbitis nil Chois.

Flowering of etiolated seedlings of Pharbitis nil resulted followinga single, brief red irradiation prior to an inductive dark period.Following this irradiation benzyladenine sprayed on the seedlingsenhanced flowering dramatically and this effect was maximalfor concentrations between 44 and 120µM. In the presenceof benzyladenine a brief (4 to 10 sec) low energy red irradiation(2.6 Wm^–2) resulted in flowering and repeated far-redphotoreversal of this red promotion provided clear evidenceof the sole involvement of phytochrome. However, after suchbrief irradiations the critical dark period for flowering waslonger than is normally found in seedlings grown in light whichindicated that additional photoresponses might be importantin natural conditions. An examination of seedling photosynthesisand assimilate transport indicated that the benzyladenine effecton flowering may relate to its promotion of assimilate and floralstimulus transport to the shoot apex. ¹ Present address: Faculty of Agriculture, Mie University, TsuCity, Mie Prefecture, Japan. (Received August 21, 1978; )     

Effects of Aminooxyacetic Acid and Its Derivatives on Flowering in Pharbitis nil

Aminooxyacetic acid (AOA) inhibited photoperiodically inducedflowering in Pharbitis nil. The application of AOA to the plumulejust after an inductive period was the most effective in inhibitingflowering. A correlation between inhibition of flowering andinhibition of glutamic-oxalacetic transaminase activity wasobserved with fifteen aminooxy derivatives. (Received April 18, 1992; Accepted June 25, 1992)     

Sensitivity to Humidity and Temperature in Darkness of the Photoinduction of S-Adenosyl-L-Methionine Decarboxylase Activity in Leaves of Pharbitis nil

The activity of S-adenosyl-L-methionine decarboxylase (SAMD)in leaves of Pharbitis nil increased maximally at "lights-on"after growth in darkness for 16 h at 21 to 25°C and 30%to 40% relative humidity. Under other condition, less SAMD activitywas induced. The photoinduction of SAMD was also observed inleaves of many other plant species. (Received December 14, 1994; Accepted April 6, 1995)     

Inhibition of photoperiodic floral induction in Pharbitis nil by ethylene

Application of ethylene at 100 ppm or higher completely inhibitedflowering in Pharbitis nil when made during an inductive darkperiod. Exposing plants to ethylene before or after the inductivedark period produced only slight or almost no inhibition. Ethylenewas effective when it was applied only to a cotyledon, but wasineffective when applied only to a receptor bud. Ethylene hadno effect on translocation of the floral stimulus. Ethylene-treatedcotyledon did not transfer any flower inhibiting entity. Thus,ethylene is considered to inhibit the induction process(es)in cotyledons. Except for an initial temporary cotyledon epinasty, ethylenetreatment had no effect on the subsequent growth and vigor ofplants. This temporary cotyledon epinasty disappeared withinthe next 24 hr. (Received May 4, 1972; )     

Dark-Induced Accumulation of mRNA for a Homolog of Translationally Controlled Tumor Protein (TCTP) in Pharbitis

A cDNA encoding a homolog of human translationally controlledtumor protein (TCTP) was isolated from cotyledons of the short-dayplant Pharbitis nil cv. Violet. The level of the correspondingmRNA increased gradually during darkness. This increase wasinhibited by end-of-day exposure to far-red light. (Received October 30, 1997; Accepted January 7, 1998)     

Effect of low concentration of hydrogen peroxide on indoleacetate oxidase zymogram in Pharbitis nil

Indoleacetate oxidase activity in Pharbitis nil, Japanese morningglory, was zymographically examined. Some isozymes appearedonly after treatment with a low concentration of hydrogen peroxide.This phenomenon was assumed to be due to the overlapping ofboth isozymes and natural inhibitor substances on the zymograms. ¹Present address: Biological Institute, Department of LiberalArts, Shizuoka University, Ooya 836, Shizuoka, Japan. (Received September 30, 1968; )     

Giant oil cells in the cotyledons ofPharbitis nil and other convolvulacean plants

Suspension of protoplasts (ca. 13–25 μm in diameter) that were isolated from the mesophyll of the cotyledons ofPharbitis nil, strain Violet, contained many large spherical or spheroidal bodies (ca. 100 μm in diameter). Microscopic observation of these bodies and some anatomic studies of the cotyledons during embryogenesis and after germination showed that these bodies are giant cells containing many oil drops stainable with Sudan dyes. Such giant cells were found in four otherPharbitis nil strains, Nepal, Tendan, Africa and Tokyo-kokei, and in six other Convolvulacean plants,Ipomoea batatas, cv. Koukei-14,Calystegia japonica, Calystegia hederacea, Calonyction aculeatum, Quamoclit pennata andCuscuta japonica.     

Flower Induction by Polyamines and Related Compounds in Seedlings of Morning Glory (Pharbitis nil cv. Kidachi)

Putrescine, at 0.5 mM, was found to induce flower buds in 98%of seedlings of Pharbitis nil cv. Kidachi grown hydroponicallyin non-nutrient tap water. Cadaverine and unnatural 1,6-diaminohexanealso induced flowering in 100% of seedlings at 0.5 and 1.0 mM,respectively, and they were found to increase the putrescinecontent in the treated plants concordantly with flower induction.Spermidine was detected in the plant extracts, but a changein its titer was not observed between the treated and untreatedplants. Spermine, 1,3-diaminopropane and cadaverine were notfound. Both the biogenic and non-biogenic diamines were thoughtto drive a common biochemical process to cause flowering. (Received November 16, 1993; Accepted January 27, 1994)