Search

Immature embryos of Pharbitis nil Chois. were used for the study. They were isolated from previously sterilized fruits and afterwards transferred to Murashige and Skoog (MS) growth medium with 0.8% agar. Immature embryos were cut across their axis. After 6-8 weeks of cultivation in the injury place (hypocotyl-root region) somatic embryos were formed. These embryos were isolated and each of them was transferred into a separate tube containing MS supplemented with naphthaleneacetic acid (NAA; in concentration 0.1 mg•dm-3 ) and gibberellic acid (GA3; in concentration 0.5 mg•dm-3). Under these conditions about 26% of somatic embryos regenerated into complete plants. Two-three weeks after the photoperiodic induction flowers appeared on these plants. A few weeks after pollination normal seeds were developed from these flowers.

The seedlings of Pharbitis nil, a sesitive short-day plant (SDP), were cultivated under special photoperiodic conditions: 72-h-long darkness, 24-h-long white light with low intensity, 24-h-long inductive night. During 24-h-long inductive darkness the total content of gibberellins in cotyledons underwent fluctuations with a maximum at 0 h and 8 h, and a decrease at the end of the dark period. FR light applied at the end of the 24-h-long white-light period inhibited flowering. R light flash and partially exogenous GA3 added on cotyledons could reverse the effect of FR. The seedling growth was not affected by FR and R light irradiation, but was promoted by exogenous GA3 application. The obtained results suggest that gibberellins are involved in photoperiodic control of SDP P. nil flowering. This involvement has nothing in common with participation of gibberellins in the control of the elongation growth of seedlings.

The short-day plant, Pharbitis nil, requires only a single inductive cycle with a 16-hour dark period for flowering. The mitotic activity in the shoot apices was studied directly after the termination of the inductive photoperiod. A pronounced rise in the mitotic index was found in the 2nd and the 8th-14th hours. Control plants grown under noninductive conditions (continuous light, a light interruption in the middle of the dark period) did not flower and did not show an increased mitotic index. The increased mitotic activity in the shoot apices of Pharbitis seems to be causally connected with the phytochrome-controlled entry of the plants into the state of generative induction.

Seedlings of Pharbitis nil cultivated under non-inductive conditions of white light were subjected to generative induction applying one 16-hour-long period of inductive night. During the eighth hour the night was interrupted with 1 min of red light pulse which completely inhibited the flowering. Treating the plants with KCN blocked the inhibiting effect of red light. Because KCN lowers considerably the rate of destruction of labile Pfd in some plant systems, it seems probable that red light night-break irradiation (without KCN), which blocked the flowering, leads also to the accumulation of unknown Pfd destruction products (irreversible phytochrome). It also suggests that it is not the labile PfrI itself but the products of its irreversible transformation that could be active in the photoperiodic control of flowering.

This article draws attention to the shortcomings of modern lighting systems used in greenhouses. Its content focuses on the negative effects of mismatches between the photosynthetic needs of plants and the parameters of artificial light sources. Greenhouse lamps designers often do not have the knowledge of biological cultivation dependencies. Therefore, their cooperation with specialists of plant physiology and gardeners is indispensable. This is important because it can affect the consumer quality of vegetables. Full Text: PDF References M.Kucharczyk, I.Gąsak, Ecological effects of light pollution , III International Conference on Scientific and Technical TRANSEIA, Krynica Zdroj, Poland, 6-8 December 2017. DirectLink T. H. Goldsmith, What Birds See, Scientific American Inc. (2006), CrossRef E.J. Gerl, M.R. Morris, The Causes and Consequences of Color Vision, Springer Science + Business Media, LLC, 2008. CrossRef K. Jaworski, A. Szmidt-Jaworska, J. Kopcewicz, Two calcium dependent protein kinases are differently regulated by light and have different activity patterns during seedling growth in Pharbitis nil, open access at Springerlink.com, Journal: 10725, Article: 9609, 2011. CrossRef K. Jaworski, A. Pawelek, J. Kopcewicz, A. Szmidt-Jaworska, The calcium-dependent protein kinase (PnCDPK1) is involved in Pharbitis nil flowering, Journal of Plant Physiology 169 p. 1578-1585, 2012. CrossRef A. Szmidt-Jaworska, K. Jaworski, J. Kopcewicz, Effect of light on soluble guanylyl cyclase activity in Pharbitis nil seedlings, Journal of Photochemistry and Photobiology B: Biology 93 p. 9-15, 2008. CrossRef Horticulture Lighting Group, Goniophotometer Test Report of the ELITE ECO lamp CrossRef K. Marra, E. P. LaRochelle, M. S. Chapman, P. J. Hoopes, K. Lukovits, E. V. Maytin, T. Hasan, B. W. Pogue, Comparison of Blue and White Lamp Light with Sunlight for Daylight‐Mediated, 5‐ALA Photodynamic Therapy, in vivo, Wiley Online Library, 16 April 2018 CrossRef M. Gilewski, The Ecological Harmfulness of RGB LED Light, International Conference on Energy, Power, Electrical and Environmental Engineering : EPEEE 2018, DEStech Publications, Wuhan, Hong Kong, September 27-28, 2018. CrossRef K. J. McCree, The Action Spectrum, Absorptance and Quantum Yield of Photosynthesis in Crop Plants, Agricultural Meteorology, Elsevier Publishing Company, 9 p. 191-216 , 1972. CrossRef EconoLux Indastries Ltd., What Light do Plants Need, Hong Kong CrossRef I. Ashdown, Photometry and Photosynthesis: From Photometry to PPFD, SunTracker Technologies Ltd CrossRef OSRAM Opto Semiconductors, Horticulture Lighting with LEDs, OS SSL | NR AW CH, November 2016 CrossRef M. Mottus, M. Sulev, F. Baret, R. Lopez-Lozano, A. Reinart, Photosynthetically Active Radiation: Measurement and Modeling CrossRef Heliospectra AB, Full Flexibility ELIXIA grow ligh CrossRef Heliospectra AB, Full Flexibility ELIXIA grow light CrossRef A. Szmidt-Jaworska1, K. Jaworski1, A. Tretyn, J. Kopcewicz, The involvement of cyclic GMP in the photoperiodic flower induction of Pharbitis nil, J. Plant Physiol. 161. p. 277-284, 2004. CrossRef A. Szmidt-Jaworska, K. Jaworski, J. Kopcewicz, The Involvement of Cyclic ADPR in Photoperiodic Flower Induction of Pharbitis nil, J Plant Growth Regul 25: p. 233-244, 2006. CrossRef A. Szmidt-Jaworska, K. Jaworski, A. Zienkiewicz, M. Lenartowska, J. Kopcewicz, Guanylyl cyclase activity during photoperiodic flower induction in Pharbitis nil, Plant Growth Regul 57: p. 173-184, 2009. CrossRef U.J. Blaszczak, D.A. Aziz, L. Gryko, Influence of the spectral composition of LED lighting system on plants cultivation in a darkroom, Proceedings of SPIE, vol. 10445, (2017) 1-9. CrossRef L. Gryko, U. Blaszczak, A.S. Zajac, Colorimetric characterization of the tunable LED-based light source at the output of the homogenizing rod, Proceedings of SPIE, vol. 10808, 2018. CrossRef I.Fryc, T. Dimitrova-Grekow, An automated system for evaluation of the quality of light sources, 6th IEEE Lighting Conference of the Visegrad Countries : LUMEN V4, Karpacz, September 13-16, 2016. CrossRef J. Kusznier, M. Zajkowski, L. Budzynski, D. Tyniecki, Ring optical mixer for LED with truncated surfaces, Proceedings of SPIE, vol. 10325, 2017. CrossRef W. Wojtkowski, LED Power Supply with Thermal Protection for Automotive Application, 7th Lighting Conference of the Visegrad Countries : LUMEN V4, Třebic, September 18-20, 2018. CrossRef W. Wojtkowski, Constant Frequency Operation of the Parallel Loaded Resonant DC/DC Converter for Power LED Lighting, International Conference on Energy, Power, Electrical and Environmental Engineering : EPEEE 2018, DEStech Publications, Wuhan, Hong Kong, September 27-28, 2018. CrossRef Pashiardis S, Kalogirou SA and Pelengaris A. Characteristics of Photosynthetic Active Radiation (PAR) Through Statistical Analysis at Larnaca, Cyprus. SM J Biometrics Biostat. 2(2): 1009, 2017. DirectLink R. Inger, J. Bennie, T. W. Davies, K. J. Gaston, Potential Biological and Ecological Effects of Flickering Artificial Light, PLoS One, vol. 9(5) (2014) PMC4038456 CrossRef C. Dong, Y. Fu, G. Liu, H. Liu, "Growth, photosynthetic characteristics, antioxidant capacity and biomass yield and quality of wheat (Triticum aestivum L.) exposed to LED light sources with different spectra combinations", J Agron Crop Sci, vol. 200, p. 219-230, 2014. CrossRef

MicroRNAs regulate gene expression by guiding the cleavage or attenuating the translation of target mRNAs. In Arabidopsis thaliana, the subset of class II TCP genes (plant-specific group of transcription factors) contains an miR319-binding site. One of them, AtTCP4, regulates negatively leaf growth and positively leaf senescence. In addition, miR319 targeting of TCP4 is critical for petal and stamen development and affects flowering time. The aim of this work was to identify the cDNA of InTCP4 gene and In-miR319 precursor in Ipomoea nil (Pharbitis nil). The cDNA sequence of InTCP4 shows a significant similarity to the cDNA members of the TCP family of other plant species and contains nucleotides complementary to miR319. The identified sequence In-pre-miR319 creates a long hairpin structure and mature miRNA sequence is located in a similar place as in precursors found in other plant species. Accumulation of InTCP4 mRNA and In-pre-miR319 was examined in various organs of I. nil plants. We found that the InTCP4 is strongly expressed in cotyledons of I. nil seedlings while the In-pre-miR319 accumulates mainly in the hypocotyls of seedlings. Moreover, we investigate the role of InTCP4 in the flowering induction, flower development and cotyledon senescence in I. nil. We indicate that the InTCP4 expression is controlled by both light/clock and miR319. Both InTCP4 and InMIR319 probably participate in the regulation of such processes as do their homologues in other plant species, the development of cotyledons, leaves and flower elements. The main function of InMIR319 seems to be the regulation of InTCP4 organ localization.

The aim of this study was to search for potential monoamine oxidase (MAO) inhibitors from Chinese herbal medicine. The organic acid extracts of 34 and the total alkaloidal extracts of 30 traditional Chinese medicines were tested for their MAO inhibitory activities. The results showed that the organic acid extracts of Liquidambar formosana, Pharbitis nil, Punica granatum and alkaloid extracts of Coptis chinensis exhibited the most potent inhibition on MAO and their concentration that inhibited 50% of MAO activity (IC50) values less than 10 μg/mL.

Pharbinilic acid (1), the first naturally occurring allogibberic acid, was isolated from ethanol extracts of morning glory (Pharbitis nil) seeds. Its absolute configuration was determined by NOESY NMR and ECD experiments. Compound 1 showed weak cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cells and weakly inhibited nitric oxide production in lipopolysaccharide-activated BV-2 microglia cells.

Seedlings of the Japanese morning glory (Pharbitis nil, formerly Ipomoea nil) cv. Violet are induced to flower by a single short day treatment, and endogenous levels of 9,10-ketol-octadecadienoic acid (KODA) in cotyledons were found to correlate with this mode of short-day induction. When 100 μM KODA solution was sprayed on 7-day-old seedlings before and after a marginal short-day induction, the seedlings bore approximately 4 flower buds, a one-bud increase compared with control seedlings. In treated seedlings, the second node most commonly bore the first flower bud, one node lower than in the control seedlings. We then used RT-PCR to determine expression levels of 10 genes related to photoperiodic induction of flowering. In the cotyledons, no differences were observed in expression of any genes, including P. nil FLOWERING TIME LOCUS T (PnFT1 and PnFT2), between the KODA-treated and the control seedlings. In the apical buds, P. nil APETALA1 (PnAP1) was expressed earlier in the KODA-treated seedlings than in the control seedlings. A decrease in the expression of P. nil TERMINAL FLOWER1b (PnTFL1b) was also observed in the KODA-treated seedlings. These results suggest that KODA acts as a weak enhancer of flower bud formation.

Many plant species are induced to flower by stress. Stress-induced flowering has been studied mostly in the short-day plant pharbitis (also called Japanese morning glory; Ipomoea nil, formerly Pharbitis nil). In this article, physiological characteristics, the regulation by salicylic acid (SA) and the expression of flowering-related genes in stress-induced flowering in pharbitis are reviewed. Pharbitis flowered under long-days in response to poor nutrition or low temperature. The pharbitis plants induced to flower by stress reached anthesis, fruited and produced fertile seeds. The progeny of the stressed plants developed normally. Grafting experiments indicated that a transmissible flowering stimulus is involved in poor nutrition stress-induced flowering. Aminooxyacetic acid (AOA), a phenylalanine ammonia-lyase (PAL) inhibitor, inhibited the stress-induced flowering, and this inhibition was overcome by SA. Stress induced PAL activity and SA biosynthesis. PnFT2, a pharbitis ortholog of the flowering gene FLOWERING LOCUS T of Arabidopsis thaliana, was expressed when the plants were induced to flower by stress. The overexpression of PnFT2 induced flowering, and PnFT2RNAi inhibited it. AOA inhibited PnFT2 expression induced by stress, and SA eliminated this inhibitory effect. SA enhanced PnFT2 expression under poor nutrition but not under non-stressful conditions. Therefore, stress may induce the production of SA and other unknown factor(s) that may work in combination to induce PnFT2 expression and flowering.

In this study, the first ACC oxidase (PnACO1) cDNA from model short-day plant Pharbitis nil was isolated. The expression pattern of PnACO1 was studied under different conditions (photoperiod and auxin), an adequate balance of which determines P. nil flowering. It was shown that the gene was transcribed in all the examined organs of the 5-day-old seedling and was strongly activated by auxin. Our results also revealed that PnACO1 transcript accumulation in the cotyledons showed diurnal oscillations under both LD and SD conditions. On the basis of presented and previously obtained data, we suggest that flowering inhibition evoked by IAA in P. nil results from its stimulatory effect on both ACC synthase and oxidase gene expression and, consequently, enhances ethylene production.

The role of endogenous gibberellin (GA) in the flowering of the short-day plant, Pharbitis nil, was investigated by using uniconazole, which is a specific inhibitor of GA biosynthesis. Both the endogenous GA level and flowering response decreased with increasing concentration of uniconazole applied via the roots. The strongest inhibition of flowering was observed when uniconazole was applied one day before a 15-h dark treatment. The inhibition by uniconazole was overcome by an application of GAs to the plumules, the order of effectiveness of the endogenous GAs in P. nil being GA1 ≧GA20>GA19≧GA44>GA53»GAH. This is the first report of the correlation between the endogenous GA level and flowering response in P. nil. It was found that endogenous GAs were required for the flowering of P. nil during or just after the dark period.

Plant oxylipins are an important class of signaling molecules in plants. The cyclic adducts of epinephrine or norepinephrine with the naturally occurring oxylipin (12Z,15Z)-9-hydroxy-10-oxo-octadeca-12,15-dienoic acid (KODA, 1) or its synthetic analogues (2-6) have been reported to possess flower-inducing activity toward Lemna paucicostata. By in vivo and in vitro experiments with seedlings of Pharbitis nil cv. Violet carbonyl groups of the alpha-ketols (1 and 3) and the ketones (7 and 9) were enantio-selectively reduced to give their corresponding vicinal diols (2 and 4) and alcohols (8 and 10). The stereochemistry at the oxymethine carbon was determined based on the long range C H coupling constants and the modified Mosher's method. Orientation of the adjacent hydroxyl group in (1 and 3) did not affect the enantio-selectivity, whereas the conversion was slightly affected and higher yields were obtained with the R-enantiomers of the alpha-ketols.

The estimation of participation and density of forage species in several xerothermic communities of the Lublin Upland were carried out in 2004 and 2005. Most plants species visited by bees are grouped in plots of the Brachypodio-Teucrietum and the Adonido-Brachypodietum pinnati communities. The nectariferous and polleniferous taxons are mostly perennials predominated by hemicryptophytes (79%), others are terophytes and geophytes (21%). Successive blooming of the nectariferous and polleniferous species in both associations ensures unbroken food flow from the early spring until the late summer and early autumn. Xerothermic swards make a valuable food potential to be important for the Apoidea before and after blooming of the main forage cultivated crops.

Flowering of plants is controlled by hormones among which both stimulators and inhibitors are present. The role of abscisic acid (ABA) in flower induction of the short day plant Pharbitis nil was shown in our experiments through exogenous applications and endogenous level determination of the hormone in cotyledons of seedlings grown under special light conditions.The application of ABA to cotyledons or shoot apices during the first half of a 24-h long inductive night inhibits flowering. The same compound applied towards the end of or after a 14-h long subinductive night increases the number of flower buds produced by these plants.Exposing P. nil seedlings at the beginning of a 24-h long inductive night to far red light (FR) decreases the level of endogenous abscisic acid in cotyledons and leads to flower inhibition. However, a pulse of red light (R) reversing the inhibitory effect of far red light on the flowering of P. nil increases the ABA content.The results obtained confirm previous observations that ABA may play a dual and an important role in the regulation of floral bud formation in P. nil. The flowering occurs when the level of endogenous abscisic acid is low at the beginning and is high toward the end of the inductive night.

GIGANTEA (GI) is a key regulator of flowering time, which is closely related to the circadian clock function in Arabidopsis. Mutations in the GI gene cause photoperiod-insensitive flowering and altered circadian rhythms. We isolated the GI ortholog PnGI from Pharbitis (Ipomoea) nil, an absolute short-day (SD) plant. PnGI mRNA expression showed diurnal rhythms that peaked at dusk under SD and long-day (LD) conditions, and also showed robust circadian rhythms under continuous dark (DD) and continuous light (LL) conditions. Short irradiation with red light during the flower-inductive dark period did not change PnGI expression levels, suggesting that such a night break does not abolish flowering by affecting the expression of PnGI. In Pharbitis, although a single dusk signal is sufficient to induce expression of the ortholog of FLOWERING LOCUS T (PnFT1), PnGI mRNA expression was not reset by single lights-off signals. Constitutive expression of PnGI (PnGI-OX) in transgenic plants altered period length in leaf-movement rhythms under LL and affected circadian rhythms of PnFT mRNA expression under DD. PnGI-OX plants formed fewer flower buds than the wild type when one-shot darkness was given. In PnGI-OX plants, expression of PnFT1 was down-regulated, suggesting that PnGI functions as a suppressor of flowering, possibly in part through down-regulation of PnFT1.

Induction of some plant organs including tubers and flower buds begins with sensing environmental cues, such as photoperiod and temperature in the leaves. Theobroxide has been shown to induce potato tuberization and flower-bud formation in morning glory under non-inductive photoperiodic conditions, stimulating the activity of lipoxygenase (LOX) and the synthesis of jasmonic acid (JA). In the present study, the ability of theobroxide to overcome the inhibitory effect of unfavorable high temperature on the induction of tubers in potato and flower buds in morning glory was examined. Both tuber induction and flower-bud formation under non-inductive high temperatures were promoted by the application of theobroxide at a high concentration. However, although theobroxide treatment resulted in an increase in fresh weight during potato tuber growth at 30°C, morning glory plants treated with theobroxide at 35°C failed to bloom, implying that theobroxide may assist only in flower-bud formation.

Interactions between methyl jasmonate (JA-Me) and ethylene in the photoperiodic flower induction of short-day plant Pharbitis nil were investigated. Both JA-Me and gaseous ethylene applied during the inductive long night caused a decrease in the number of flower buds generated by P. nil. Application of ethylene did not affected niether the level of endogenous jasmonates in the cotyledons during the 16 h long inductive night, nor the inhibitory effect of JA-Me on the flowering of P. nil accompanied by variations in ethylene production. The application of acetylsalicylic acid (aspirin)—a jasmonate biosynthesis inhibitor—slightly stimulated flowering. Our results have shown that the mechanisms of P. nil flower inhibition by jasmonates and ethylene are independent.

Treatment of the crude ether-insoluble resin glycoside (convolvulin) from seeds of Pharbitis nil (Pharbitis Semen), called pharbitin, with indium(III) chloride in methanol provided seven oligoglycosides of hydroxy fatty acid methyl esters partially acylated by 2-methyl-3-hydroxybutyric (nilic) and 2S-methylbutyric acids. Their structures were elucidated on the basis of NMR and MS data and chemical conversions.

This study was investigated to find a candidate which has an anti-inflammatory activity on RAW 264.7 cells. It was performed by NO assay, RT-PCR and western blot analysis. In the course of screening, it was found that extracts of Pharbitis nil Choisy showed strong activity of anti-inflammation. Therefore, extracts of Pharbitis nil Choisy was sequentially fractionated with hexane, m ethylene chloride, ethyl-acetate, butanol and water. Of the sequential solvent fractions, the ethylacetate fraction inhibited the mRNA and protein expression of LPS-induced iNOS and COX-2. Taken together, these results suggest that extracts of Pharbitis nil Choisy have significant effects on inflammatory factors, and may be a potential antiinflammatory therapeutic plant.

Based on field investigation and statistical analysis, the characteristics of wild herbs in different communities are discussed in this paper. The results showed that there were 32 species and 30 genera of 14 families in the wild herbs of the three communities. Cynanchum chinense R.Br. and Setaria viridis (L.) Beauv are the three community common herbs. Pterocypsela indica (L.) Shih and Cirsium setosum are common to the Cerasus sp. community and Malus micromalus communit. Polygonum, Chenopodium album and Pharbitis nil (Linn.) Choisy are common to the Malus micromalus community and Robinia pseudoacacia L.community.

In this work we studied interactions between auxin and ethylene in the inhibition of photoperiodic flower induction in SDP Pharbitis nil. To this end, PnACS2 was cloned and its expression was studied under various photoperiodic conditions, as well as under the influence of auxin. The full-length PnACS2 cDNA consists of 1,841 bp and encodes for 472 amino acids, with the 80-bp 5′- and the 417-bp 3′-untranslated regions. It was shown that the gene is transcribed in all organs of 5-day-old seedlings and that it is strongly activated by auxin. The maximal transcriptional activity of PnACS2 and the strongest stimulation of its activity by IAA occur in the cotyledons. This confirms the speculation that the inhibitory effect of auxin on P. nil flowering results from its stimulatory effect on ethylene production.

To investigate the role of distinct phytochrome pools in photoperiodic timekeeping, we characterized four phytochrome genes in the short-day plant Pharbitis nil. Each PHY gene had different photosensory properties and sensitivity to night break that inhibits flowering. During extended dark periods, PHYE, PHYB, and PHYC mRNA accumulation exhibited a circadian rhythmicity indicative of control by an endogenous clock. Phylogenetic analysis recovered four clades of angiosperm phytochrome genes, phyA, phyB, phyC, and phyE. All except the phyE clade included sequences from both monocots and eudicots. In addition, phyA is sister to phyC and phyE sister to phyB, with gymnosperm sequences sister to either the phyA-phyC clade or to the phyB-phyE clade. These results suggest that a single duplication occurred in an ancestral seed plant before the divergence of extant gymnosperms from angiosperms and that two subsequent duplications occurred in an ancestral angiosperm before the divergence of monocots from eudicots. Thus in P. nil, a multigene family with different patterns of mRNA abundance in light and darkness contributes to the total phytochrome pool: one pool is light labile (phyA), whereas the other is light stable (phyB and phyE). In addition, PHYC mRNA represents a third phytochrome pool with intermediate photosensory properties.

In previous reports we have reported that theobroxide induces characteristic accumulation of allene oxide cyclase (AOC; EC 5.3.99.6) protein and jasmonic acid (JA) in Pharbitis nil. In the present study, PnAOC, an AOC gene from Pharbitis nil was cloned. Immunofluorescence assays indicated that the AOC protein is located in the chloroplast of vascular bundles in Pharbitis nil leaves. The PnAOC cDNA sequence lacking the chloroplast signal peptide was successfully expressed in Escherichia coli, and a gas chromatography-mass spectrum assay suggested the relative AOC activity of the recombinant PnAOC protein in comparison with Arabidopsis AOC2. Interestingly, a biphasic expression of PnAOC was induced by theobroxide, which is consistent with the accumulation patterns of AOC protein and JA. All these results indicate that AOC is the primary target of theobroxide regulation and suggest that feedback regulation of PnAOC by JA occurs upon theobroxide treatment in Pharbitis nil.

Six new ent-kaurane diterpene glycosides, pharbosides A-F (1-6), and a new ent-gibbane diterpene glycoside, pharboside G (7), together with three known ent-kaurane diterpenoids, 7beta,16beta,17-trihydroxy-ent-kauran-6alpha,19-olide (8), 6beta,7beta,16alpha,17-tetrahydroxy-ent-kauranoic acid (9), and 6beta,7beta,16beta,17-tetrahydroxy-ent-kauranoic acid (10), were isolated from an ethanolic extract of the seeds of Pharbitis nil. The structures of the new compounds were determined by spectroscopic methods including 1D and 2D NMR analysis. The absolute configurations of the compounds were clarified by CD spectroscopic studies. Full NMR data assignments of the three known compounds (8-10) are reported. The isolated compounds were evaluated for their cytotoxic activities against four human cancer cell lines.

The wild-type Japanese morning glory [Ipomoea nil (L.) Roth.] exhibits blue flowers with red stems, and spontaneous r mutants display white flowers with green stems. We have identified two r mutations, r1-1 and r1-2, that are caused by insertions of Tpn1-related DNA transposable elements, Tpn3 (5.6 kb) and Tpn6 (4.7 kb), respectively, into a unique intron of the CHS-D gene, which is responsible for flower and stem pigmentation. Both Tpn3 and Tpn6, which belong to the En/Spm or CACTA superfamily, are nonautonomous elements lacking transposase genes but containing unrelated cellular DNA segments including exons and introns. Interestingly, r1-2 contains an additional 4-bp insertion at the Tpn3 integration site in r1-1, presumably a footprint caused by the excision of Tpn3. The results strengthen the previous notion that Tpn1 and its relatives are major spontaneous mutagens for generating various floriculturally important traits in I. nil. Since I. nil has an extensive history of genetic studies, molecular identification of classical spontaneous mutations would also facilitate reinterpretation of the abundant classical genetic data available.

We previously isolated PnMADS1, a MADS-box transcription factor and member of the functionally diverse StMADS11 clade of the MADS-box family, from Pharbitis nil, which is a typical SD plant. However, its precise function remained unclear. To investigate the biological role of PnMADS1, and especially its involvement in flowering, we constructed transgenic P. nil plants that overexpresses or underexpresses PnMADS1. PnMADS1-RNAi transformants had an increased number of flower buds, whereas overexpression of PnMADS1 led to a decrease in the number of flower buds, although both transgenic plants maintained the photoperiodic responses of flowering. These results suggest that PnMADS1 negatively regulates floral evocation from the vegetative phase to the reproductive phase but it has no essential role in floral induction by photoperiodic signals. Results of yeast two-hybrid experiments revealed that PnMADS1 can interact with itself, suggesting that this protein functions in floral evocation as a homodimer. PnMADS1 also interacts with PnSAH3, an AP1-clade protein, suggesting that PnMADS1 has a functional role in flower formation as a heterodimer with other MADS-box protein(s).

It has been shown that both IAA and ethylene application inhibit flower induction in the short-day plant Pharbitis nil. However application of IAA has elevated ethylene production in this plant, as well. Strong enhancement of ethylene production is also correlated with the night-break effect, which completely inhibits flowering. In order to determine what the role of IAA and ethylene is in the photoperiodic flower induction in Pharbitis nil, we measured changes in their levels during inductive and non-inductive photoperiods, and the effects of ethylene biosynthesis and action inhibitors on inhibition of flowering by IAA. Our results have shown that the inhibitory effect of IAA on Pharbitis nil flowering is not physiological but is connected with its effect on ethylene biosynthesis.

α-Ketol of octadecadienoic acid (KODA, 1 ) has been suggested to play a role in the photoperiod-regulated flowering in Pharbitis nil . The level of 1 in cotyledons is temporarily controlled during short-day conditions. The biosynthesis of 1 is well studied in plants; however, its in vivo conversion is less understood. We have investigated this issue by studying the metabolism of exogenously-applied [U- 13 C]- 1 , [1- 14 C]- 1 , and non-labeled 1 in P. nil seedlings by the spectroscopic methods and identified six major metabolites ( 4 – 9 ). We have also found that the enantiomers of 1 are differentially metabolized in P. nil seedlings.

Elemental concentration in each tissue of Japanese morning-glory (Pharbitis nil) during the growth was analyzed by INAA. Plants were grown in water culture for 4 days under 12-hour light and 12-hour dark condition. During the growth, 10 plants in the same developmental stage were periodically harvested. Then the plants were separated into 9 tissues to determine elemental concentration and water content. There was an elemental specific profile within the plant tissue, for example, Na and K concentrations were high in root whereas Mg and Ca concentrations were high at the upper part of the plants. Among the elements studied, Ca and Mg showed rhythmical change in concentration, increased during the day and decreased during the night. This tendency was especially noted at shoot apex. However, water content in all of the tissue was increased about 6 hours prior to the light period and showed maximum in the middle of the light period. About 6 hour difference of water content movement to those of Ca and Mg concentration suggested that water movement drives more dynamic change of each elemental concentration within a plant.

Seedlings of morning glory (Pharbitis nil) were exposed to blue light-emitting diodes (LEDs) with various peak wavelengths, or mixture lights of blue light and red light to confirm the spectral sensitivity to flowering. Flowering responses to the respective LEDs corresponded to the absorption spectrum of cryptochromes, which is one of blue light receptors. On the other hand, the light qualities consisting of rich blue light had an effective influence on flowering responses. The number of flower buds decreased after being exposed to the red-rich light qualities, a situation under which phytochromes absorb well. From our study, we conclude that cryptochromes, which absorb blue light, effectively act on flowering, whereas phytochromes act on the inhibition of flowering in Pharbitis nil under the normal light/dark cycles.

The short-day plant Pharbitis (Ipomoea) nil has been a model plant in physiological studies of photoperiodic control of floral initiation. However, molecular mechanisms underlying photoperiodic responses, including the induction of flowering in P. nil, are largely unknown. Here we identified and characterized cDNAs whose expression patterns were different in short- and long-day conditions, based on fluorescent differential display and RNA gel blot analysis, to gain insight into the molecular mechanisms of photoperiodic responses in P. nil. The cDNA clones included genes encoding ADP-glucose pyrophosphorylase, a putative protein kinase, eukaryotic initiation factor eIF-4, a putative aldehyde dehydrogenase, subtilisin-like proteinase, crooked neck (crn)-like protein, and cryptochrome 1. The possible roles of these genes in the photoperiodic response, including the control of flowering time in P. nil, are discussed.

Photoperiodic flowering responses are classified into three major types: long day (LD), short day (SD), and day neutral (DN). Arabidopsis is one of the best-characterized LD plants and flowers much earlier under LD than SD conditions. In contrast, SD conditions promote flowering of SD plants such as rice and Pharbitis nil. Recently, molecular genetics of Arabidopsis (LD) and rice (SD) have identified genes that play key roles in the photoperiodic flowering of these plants. A common role of the GIGANTEA (GI)-CONSTANS (CO)-FLOWERING LOCUS T (FT) pathway in Arabidopsis and rice, and a specific role of EARLY HEADING DATE 1 (EHD1) in rice, but not in Arabidopsis, have been demonstrated. The DN response is the most poorly characterized among the three types of photoperiodic flowering responses. In this short review, we discuss how the DN flowering response is achieved in tomato based on recent progress in the analysis of Arabidopsis mutations in the photoperiodic flowering pathway and circadian rhythms.

We present the potential involvement of Mg2+ in the flowering mechanism in the shoot apex of the short-day plant Pharbitis nil (L.). To analyze elemental distribution in shoot apical meristems, fluorescence staining methods with Mag-fluo-4 AM and Fluo-3 AM were used. The former is sensitive to both Mg2+ and Ca2+, and the latter is a specific Ca2+ indicator. When plants were grown under continuous light conditions, some cells with intensive fluorescence of Mg2+ appeared in the top layers of the shoot apical meristem. During growth in the vegetative phase, cells in the center of the top layers accumulated large amounts of Mg2+. Exposure to a single 16 h short-day treatment induced the flowering process and dramatically reduced the fluorescence associated with Mg2+ accumulation in the top layers, suggesting that Mg2+ contributes to the flower induction process. The fluorescence associated with Ca2+ did not show this distribution difference between growth phases. A night-break treatment also influenced the fluorescence pattern. It was suggested for the first time that Mg2+ plays an important role in flower induction.

The effect of the exogenous application of polyamines on the flowering induction of the short-day plant Pharbtis nil was investigated. Putrescine, spermidine and spermine applied on the cotyledons of 4-day seedlings had no significant effect on the flowering of this plant under conditions of full induction caused by a 16-hour-long inductive night. Under the conditions of partial induction caused by a 13-hour-long subinductive night, polyamines inhibit or stimulate flowering, depending on the time of application. Also, inhibitors of the biosynthesis of polyamines influenced the flowering process. Analysis of endogenous polyamines revealed significant fluctuations in their content in cotyledons during an inductive night, as well as under continuous light conditions. Particularly large changes occurred in spermidine and spermine levels. The putrescine level in induced seedlings was lower than in non-induced ones. However, induced seedlings contained a higher level of spermine and spermidine. The highest spermidine and spermine levels were observed at the 8th h of the night, although the total concentration of spermine during photoinduction was always 2–3 times lower than that of spermidine. A break in the inductive night, leading to a complete inhibition of flowering, had caused significant changes in the polyamine level by the end of the night. The results suggest that the flowering induction of Pharbitis nil took place at a low putrescine level and increased spermidine and spermine levels.

The purpose of the study was to determine inhibitory effect of calcium chelator; ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA) on flowering of a short-day (SD) plant Pharbitis nil. It was found that 20 mM solution of EGTA applied on cotyledons of 5-d-old P. nil seedlings four hours before the start of 16-h-long induction night decreased the flowering response by 55% compared to the control plants not treated with this Ca2+ chelator. It also caused a very significant decrease of photosynthesis rate, transpiration rate and stomatal conductance both in light and darkness conditions. The results of this study confirm earlier hypothesis suggesting the effect of Ca2+ and its modulators on P. nil flowering is due to their influence on the stomata.

Most strains harboring the feathered (fe) mutation in the Japanese morning glory (Ipomoea nil or Pharbitis nil) show deformed phenotypes such as upcurled leaves and separated or tubular petals. These phenotypes seem to be caused by loss of abaxial identity in lateral organs. The FE gene was isolated using the inserted transposon as a tag. An En/Spm-related transposable element, Tpn102, inserted in the fourth intron of the FE gene, was responsible for the fe mutation. FE encodes a GARP transcription factor closely related to Arabidopsis KANADI1 (KAN1), which promotes an abaxial cell fate. Genetic analyses and molecular studies, which showed that all fe mutant strains have the same fe allele despite their phenotypic differences, revealed that fe strains with strong phenotypes have additional mutations enhancing the fe phenotype. These findings and historical records of fe phenotypes suggest that these enhancer mutations were accumulated in the fe background during selection for strong phenotypes. The mutant phenotypes and molecular analysis of fe strains suggest that FE regulates the abaxial identity of lateral organs redundantly with modifier genes, as KAN1 does in Arabidopsis. FE, however, affects flower phenotype even in the single mutant unlike KAN1, moreover, modifier mutations affect flower phenotype only in the fe mutant background, suggesting that FE may play a more crucial role in promotion of abaxial cell fate in flowers of the Japanese morning glory.

Cyclic adenosine diphosphate ribose (cADPR) is a potent endogenous calcium-mobilizing agent synthesized from NAD+ by ADP-ribosyl cyclases described for several animal cells. Pharmacological studies suggest that cADPR is an endogenous modulator of Ca2+-induced Ca2+ release channels. There is also information about the sub-micromolar concentration of cADPR in plant cells. Whether cADPR can act as a Ca2+-mobilizing intracellular messenger in plant tissue is an unresolved question. Despite the obvious importance of monitoring cADPR cellular levels under various physiological conditions in plants, its measurement has been technically difficult and requires specialized reagents. In the present study a widely applicable sensitivity assay for cADPR is described. We show that Pharbitis nil tissue from cotyledons contains a certain cADPR level. To explain the possible roles of this second messenger in photoperiodic flower induction, some physiological experiments were also performed. The exogenous applications of cADPR to Pharbitis nil plants, which were exposed to a 12-h-long subinductive night, significantly increased flowering response. Nevertheless 8-Br-cADPR inhibited flowering when these compounds were applied during a 16-h-long inductive night. The effect of ruthenium red, a calcium channel blocker and ryanodine, a calcium channel stimulator, on the photoperiodic induction of flowering was also studied. Ruthenium red, when applied before and during an inductive 16-h dark period, slightly inhibited flowering, whereas ryanodine, when applied before and during a 12-h long subinductive night, stimulated flower bud formation. We also confirmed evidence that Ca2+ ions are involved in the photoperiodic induction of flowering. Thus, the obtained results may suggest the involvement of cyclic ADPR-activated Ca2+ mobilization in the photoperiodic flower induction process in Pharbitis nil.

Summary Theobroxide, a novel active compound isolated from a fungus, has been reported previously to induce potato tuberization and flower bud formation in Pharbitis nil under non-inductive long-day conditions. Up to date, the action mechanism of theobroxide on flower-bud induction of P. nil, however, is still unknown. In the present study, we observed a reduction of the stem length, along with the induction of flower buds, in theobroxide-treated and short-day-grown P. nil plants. Also, the results showed that flower bud formation was delayed markedly in P. nil seedlings with removal of cotyledons or exposure to night break. The suppression effect of night-break and cotyledon-removal, however, was abolished completely by spraying theobroxide. Endogenous gibberellin1/3 contents in P. nil plants treated with theobroxide or grown under short-day conditions were relatively lower, suggesting that gibberellins probably are negatively involved in theobroxide- and short-day-induced flower-bud formation of P. nil.

SUMMARYA cDNA library was constructed from mRNA extracted from plumules including shoot apical meristems, 24 h after a 16 h dark treatment, to clone genes preferentially expressed during flower evo...

Circumnutation and winding in plants are universal growth movements that allow plants to survive despite their sessile nature. However, the detailed molecular mechanisms controlling these phenomena remain unclear. We previously found that a gravitropic mutant of Japanese morning glory ( Pharbitis nil or Ipomoea nil ), Shidare-asagao ( weeping ), is defective not only in circumnutation but also in the winding response. This phenotype is similar to that of the Arabidopsis SCARECROW ( SCR ) mutant. We therefore investigated whether morning glory SCR ( PnSCR ) is involved in the weeping phenotype. We found that one amino acid was inserted into the highly conserved VHIID motif in weeping -type PnSCR; this mutation caused abnormal endodermal differentiation. We introduced either the mutant or WT PnSCR into Arabidopsis scr mutants for complementation tests. PnSCR of the WT, but not of weeping , rescued the shoot gravitropism and circumnutation of scr . These results show that both the abnormal gravitropism and the circumnutation defect in weeping are attributable to a loss of PnSCR function. Thus, our data show that gravisensing endodermal cells are indispensable for shoot circumnutation and the winding response and that PnSCR is responsible for the abnormal phenotypes of weeping .

Theobroxide, a natural product, strongly stimulates the biosynthesis of jasmonic acid (JA) in Pharbitis nil. In this study, we investigated the accumulation of protein by the immunoblot analysis of lipoxygenase (LOX), allene oxide synthase (AOS) and allene oxide cyclase (AOC), key enzymes in JA biosynthesis, and how the endogenous levels of JA in Pharbitis nil are affected by theobroxide. The effect of JA on the accumulations of these proteins was monitored simultaneously. The results show that theobroxide treatment led to a high level accumulation of JA, which is due to high accumulations of LOX, AOS and AOC proteins induced by theobroxide treatment both under short day (SD) and long day (LD) conditions. However, under SD conditions AOS and AOC proteins are not enhanced by JA treatment. Kinetic analysis of protein levels show that a biphasic activation of AOC protein by theobroxide is displayed and the first activation of AOC protein together with elevated JA levels are observed within 30 minutes after treatment. Meanwhile, AOS and LOX proteins are activated by theobroxide later than AOC protein, suggesting that AOC plays an essential role in the initial JA formation induced by theobroxide. Since theobroxide-increased JA levels also show a biphasic manner similar to AOC activation and AOS, LOX proteins are activated later than AOC, and thus we propose a positive JA feedback regulation. Interestingly, AOS protein, which is also the enzyme for the biosynthesis of 9,10-ketol-octadecadienoic acid (KODA, a flowering inducing factor), accumulates markedly due to the simultaneous involvement of theobroxide and SD conditions, suggesting that AOS probably plays a role in flower bud formation in Pharbitis nil.

In this study, exogenous factors affecting the elongation growth in the short day plant, Pharbitis nil, was investigated. Theobroxide inhibited stem elongation in Pharbitis nil both under short day (SD) and long day (LD) conditions. Salicylhydroxamic acid (SHAM), an inhibitor of jasmonic acid (JA) biosynthesis, and GA3 recovered the inhibitory effect of theobroxide on stem elongation. Quantitative analysis of JA showed that the level of endogenous JA increased significantly in theobroxide treated plants, while exogenously applied GA3 and SHAM suppressed JA biosynthesis stimulated by theobroxide. The activity of lipoxygenase (LOX, the key enzyme of JA biosynthesis) also was stimulated by theobroxide and this stimulation was nullified by SHAM and GA3. Quantitative analysis of GA1 showed that theobroxide suppressed GA1 biosynthesis. In non theobroxide treated Pharbitis nil, SD conditions stimulated JA biosynthesis and LOX activity, while GA1 biosynthesis was suppressed. All these results suggest that JA probably is involved negatively in the control of stem elongation, and the balance between JA and gibberellin might determine the stem growth in Pharbitis nil.

To investigate whether night break (i.e., the interruption of the dark period by artificial lighting) controls plant flowering sufficiently with treatment on alternate days, we compared the reproductive responses of seven horticultural crop species under a daily night-break treatment, an alternate-day treatment, and no night-break treatment during the short-daylength season. Longday crops of spinach (Spinacia oleracea), petunia (Petunia×hybrida), and godetia (Godetia cvs.) and short-day crops of cosmos (Cosmos bipinnatus), perilla (Perilla ocymoides), zinnia (Zinnia elegans), and Japanese morning glory (Pharbitis nil) were used. The night-break treatment was supplied for 2 hours starting at midnight using red light-emitting diodes. The effect of the alternate-day treatment was much smaller than the effect of the daily treatment in zinnia and Japanese morning glory; was smaller in spinach, godetia and cosmos; and was only slightly smaller in petunia. Budding in perilla was inhibited by both night-break treatments.