8-hydroxyquinoline Citrate Research Articles

Evaluation of Pre- or Postharvest Application of Some Minerals and Organic Agents on the Growth, Flowering and Vase Life of Rudbeckia hirta, L.

<p>The experiments were carried out during 2014 and 2015 summer seasons at the greenhouses of the Experimental Farm of Faculty of Agriculture, Kafr El-Sheikh University. The experiments were conducted in two phases: First one (pre-harvest): <em>Rudbeckia hirta</em> seedlings were transplanted during the first week of May to 30 cm diameter plastic pots filled with a soil mixture of clay and sand (1:1, v:v). Pots were divided in two equal groups, the first one, plants were foliar sprayed with one of the following:- Distilled water for the control treatment, CaCl<sub>2</sub> (125, 250, 375 mg·L<sup>-1</sup>), NiSO<sub>4</sub> (30, 45, 60 mg·L<sup>-1</sup>), CoCl<sub>2</sub> (50, 75, 100 mg·L<sup>-1</sup>), K<sub>2</sub>SiO<sub>3</sub> (100, 150, 200 mg·L<sup>-1</sup>) and SA (100, 150, 200 mg·L<sup>-1</sup>) at 60, 45, 30 and 15 days before harvest. The second group was without pre-harvest application assay (untreated plants).</p><p>Second phase (postharvest) was conducted in two different methods as follows: First method, flower stems resulted from each pre-harvest treatment were preserved in 250 mL graduated test tube filled with 200 mL of standard holding solution consists of sucrose (4%) + 8-Hydroxyquinoline citrate (250 mg·L<sup>-1</sup>). The second method, flower stems resulted from plants without pre-harvest application preserved in holding solution consists of a constant sucrose (4%) and 8-Hydroxyquinoline citrate (250 mg·L<sup>-1</sup>) beside one of the following additives: Distilled water for the control treatment, CaCl<sub>2</sub> (125, 250, 375 mg·L<sup>-1</sup>), NiSO<sub>4</sub> (30, 45, 60 mg·L<sup>-1</sup>), CoCl<sub>2</sub> (50, 75, 100 mg·L<sup>-1</sup>), K<sub>2</sub>SiO<sub>3</sub> (100, 150, 200 mg·L<sup>-1</sup>) and Salicylic acid (100, 150, 200 mg·L<sup>-1</sup>). Results showed that, pre harvest spraying plants with higher levels of K<sub>2</sub>SiO<sub>3</sub> or CaCl<sub>2</sub> recorded the highest values for all plant vegetation characters. K<sub>2</sub>SiO<sub>3</sub> followed by SA excelled on others in most flowering aspects. At the post harvest stage, SA, K<sub>2</sub>SiO<sub>3</sub> and CaCl<sub>2</sub> exchanged the excellence between them for most vase life measurements. Flowers resulted from plants that preharvest treated was better than those that did not preharvest treated.</p>

Erratum to: The effects of two preservatives on peroxidase activity and total protein content in Strelitzia reginae during cold storage

This study aimed to assess changes in peroxidase activity and total protein content of cut flowers of Strelitzia reginae that were treated with the chemical preservatives 8-hydroxyquinoline citrate (8-HQC) or chlorine during cold storage. The bases of the cut flowers were immersed in 1.5 L of tap water with 48 h pulsing treatments (a control with no chemical preservatives (0 mg·L-1, 100 mg·L-1 chlorine, 250 mg·L-1 8-HQC or 500 mg·L-1 8-HQC) during cold storage at 10.5°C and 90% relative humidity. The solutions were then replaced with tap water and the cut flowers remained in cold storage for 12 days. For biochemical characterization of peroxidase activity and total protein content, tissue samples (sepals, petals, stems, and bracts) were collected and analyzed at 0, 4, 8, and 12 days after treatment. There was an increase in peroxidase activity in petals, stems, and bracts and a decrease in total protein content, regardless of the treatment used. In this experiment, therefore, differences in peroxidase activity and total protein content due to treatments with 8-HQC or chlorine were not identified.

Symptoms of programmed cell death in intact and cut flowers of clematis and the effect of a standard preservative on petal senescence in two cultivars differing in flower longevity

Clematis is visually a very attractive plant which can be used for cut flowers, provided that proper cultivars are chosen. In this study, the phenomenon of programmed cell death (PCD) was compared in petals of clematis blooming on mother plants in the open field and in cut flowers, in two cultivars with different flower longevity. The dynamics of PCD in petals of field grown plants in the two cultivars were different. In the long flower longevity cultivar the first symptoms of PCD were observed in the flower bud, and in the open flower the process was already advanced. On the other hand, PCD in petals of the short flower longevity cultivar was advanced already in the flower bud. In both cultivars the nuclear degradation started early, but the dynamics were different: in the long flower longevity cultivar 18.6% of the nuclei were degraded in the open flower vs. 68.3% of degraded nuclei already in the flower bud in the short flower longevity cultivar. Senescence processes are intensified in cut flowers. In cut flowers of both cultivars kept in water the process of DNA degradation was much faster than in flowers growing on mother plants. It could be slowed down by the addition of preservatives. The standard preservative of 8-hydroxyquinoline citrate (8-HQC) 200mgL−1 with 2% sucrose prolonged the vase life of cut flowers of both cultivars as compared to water, but organelle degradation in petals was delayed only in the shorter-lived cultivar.

Potential of field grown sweet sultan (Centaurea moschata) as cut flower based on vase life

The present study was conducted to evaluate the vase life of sweet sultan (Centaurea moschata L.) in different vase solutions with view to use it as cut flower. Various vase solutions such as sucrose @ 2% and in combination with 8-hydroxyquinoline citrate (8-HQC) @ 200ppm, ethanol @ 2% and plant bio-regulators like aminooxy acetic acid (AOA) @ 0.5 mM, salicylic acid (SA) 150 ppm and benzyl adenine (BA) 50 mg/l, ascorbic acid (200 ppm) were used. Vase life of flowers was found as 4.67 days in control and 6.0 days in treatment with sucrose (2%) alone. However, the vase life was significantly increased in treatments with plant bio regulators namely ascorbic acid, salicylic acid, benzyl adenine and AOA (9.67, 9.33 days and 9 days/respectively). Treatments with 8 HQC and ethanol along with sugar also increased the vase life of the flowers significantly than control. Maximum increase in flower weight (7.80g) was observed in treatment with AOA on 8th day whereas, maximum flower diameter (71.80 mm) was observed in treatment with BA on 10th day. The maximum membrane stability index (57.50%) and total chlorophyll content of bract (1.22 mg/g) were recorded in treatment with ascorbic acid after 9 days of vase life.

Effect of green tea extract powder on the vase-life of fresh-cut rose (Rosa hybrida L.) ‘Carola’ stems

ABSTRACTTo develop an innocuous, easy-to-use, and inexpensive preservative for the cut flower industry, green tea extract (GTE) powder was applied in the fresh-cut rose stem preservation process to exploit its high anti-oxidative and anti-microbial properties. The effects of 2.0 g l−1 GTE powder in the vase solution on the vase-life and flowering profile of cut rose (Rosa hybrida ‘Carola’) stems were investigated. The effectiveness of GTE powder was also compared with other preservatives such as 2% (w/v) sucrose, 200 mg l−1 8-hydroxyquinoline citrate plus 2% (w/v) sucrose, or 0.2 mM silver thiosulphate in the vase solution, with distilled water as a control. The results showed that, compared to the control, the 2.0 g l−1 GTE powder treatment extended the vase-life and reduced the loss in fresh weight in cut rose stems in the vase solution. GTE at 2.0 g l−1 provided the highest anti-bacterial activity (4.2 log10 CFU ml−1 on day-6) and prevented the decline in anthocyanin concentrations compared to that seen in the control stems, suggesting that GTE powder could be used as a preservative to extend the vase-life of fresh-cut rose flowers.

Effect of Floral Preservatives on Vase Life of Gerbera Cut (Gerbera jamesoniiL.) cv. “Dana Allen”

The present study, conducted in the Department of Horticulture, J.A.U., Junagadh (India) was aimed to assess the effect of floral preservatives on the vase life of cut gerbera (Gerbera jamesonii L.) cv. ‘Dana Allen’. The experiment was laid out in a completely randomized design with three replications and nineteen treatment-combination comprising of five floral preservatives viz., sucrose (2 and 3%), 8-HQC [8-hydroxy quinoline citrate] (150 and 200 mg L−1), Al2SO4 (25 and 50 mg L−1), AgNO3 (15 and 25 mg L−1) and Co(NO3)2 (180 and 270 mg L−1) along with an untreated control. The vase solution of 8-HQC @ 200 mg L−1 + 2% sucrose enhanced all the qualitative parameters and improved vase life of gerbera. The vase life could be extended upto 13.6 days of cut gerbera. This treatment improved fresh flower weight by 112.3, 104.2, 88.2, 67.1% on 3, 6, 9 and 12th day of vase, respectively. The treatment of 8-HQC @ 200 mg L−1 + 2% sucrose resulted in maximum total solution uptake (61.26 mL), flower diameter on 3rd day of vase (11.39 cm) and 50% opening of disc florets (7.28 days), 75% opening of disc florets (8.95 days) and 100% opening of disc florets (11.52 days) in gerbera. It may be concluded that holding solution of 8-HQC along with sucrose may help in extending the vase life of gerbera cut flowers.

Pulsing Treatments of Abscisic Acid and Sucrose for Improving Postharvest Quality of Cut Lily Flowers

Abscisic acid (ABA), as a senescence phytohormone, has been proved to be related to flower petal senescence in rose (Mayak and Halevy, 1972; Kumar et al., 2008) and carnation (Nowak and Veen, 1982). Higher ABA concentrations were found in short–lived cultivars compared to long–lived rose cultivars (Halevy and Mayak, 1975). Exogenous application of ABA leads to enhancement of aging–related process in daffodil petals (Hunter et al., 2004). ABA, as one of the preservation agents, was also applied in the fresh–keeping of cut roses (Kohl and Rundle, 1972), Baccara roses (Pompodakis and Joyce, 2003; Pompodakis et al., 2004) and Eustoma flowers (Shimizu–Yumoto and Ichimura, 2009). ABA prolongs the vase life of cut roses with leaves, but shortens the vase life of leafless cut roses (Halevy et al., 1974). ABA can regulate water balance of cut flower through controlling stomata opening, increase the postharvest quality, and extend the vase life of cut flowers (Kohl and Rundle, 1972; Pompodakis and Joyce, 2003; Pompodakis et al., 2004). On the other hand it has been reported that ABA regulates water balance through ways other than stomata opening regulation (Borohov et al., 1976), the application of ABA did not affect the transpiration (Ichimura and Shimizu–Yumoto, 2007). ABA treatment can alleviate the sucrose–induced leaf chlorosis and improve the quality of cut flowers (Pompodakis and Joyce, 2003; Shimizu–Yumoto and Ichimura, 2009). Lilies are the world famous cut flowers with high ornamental value. Yang et al. (1996) indicated that ABA probably is the main factor affecting senescence of cut lilies, because morphology of cut flowers showed senescence symptoms following the peak of ABA, while ethylene can accelerate the aging process only to a certain extent. But Li et al. (2012) indicated that the addition of lower concentrations of ABA with sucrose and 8–hydroxyquinoline citrate (8–HQC) induced the increase of fresh weight, and partly alleviate the sucrose–induced leaf yellowing. Based on the above researches, the preservation mechanism of ABA in cut lilies is still not clear. Lilium ‘Sorbonne’ (Oriental hybrid group) was used as an experimental material in this study to observe the preservation effect of ABA, and to confirm further the preservation mechanism of ABA by determining the physiological indices and ethylene release of cut ‘Sorbonnes’ petals during postharvest.

LONGEVITY AND QUALITY OF HELICONIA PSITTACORUM × H. SPATHOCIRCINATA 'GOLDEN TORCH' TREATED WITH 8-HYDROXYQUINOLINE CITRATE

This study aimed to evaluate the effect of 8-hydroxyquinoline citrate (8-HQC) on the quality and longevity of heliconia ?Golden Torch? inflorescences stored at 23.9±1.8°C and 51±9% RH. The treatments consisted of 0, 100, 200 and 300 mg L-1 8-HQC, evaluated at 0, 2, 4, 6 and 8 days after harvest. The inflorescences were pulsed with 8-HQC for 18 h and subsequently transferred to flasks with distilled water. At every two days, floral appearance, fresh mass, flower opening, chroma and lightness were determined. The floral appearance was influenced by storage time and by the treatment with 8-HQC. However, the values of fresh weight, the flower opening, lightness and chroma were affected only by the number of days in storage. The fresh weight decreased by 1.6% from the first to eighth day after harvest. At the end of the storage time, the inflorescences exhibited two open flowers at the start of expansion. The lightness value increased by 3.4%, while the chroma decreased by almost 4.9% in bracts during storage, indicating the passage of dark orange color to light orange. The 8-HQC did not increase the vase life of inflorescences compared to control. Based on the scale of appearance, the inflorescences treated with 300 mg L-1 of 8-HQC had superior vase life compared with the other treatments, within eight days of evaluation.

Effect of 8-Hydroxyquinoline Citrate, Sucrose and Peroxidase Inhibitors on Vase Life of Lisianthus (EUSTOMA GRANDIFLORUM L.) Cut Flowers

Abstract Cut lisianthus flowers have a short vase life, possibly due to blockage of xylem vessels. The effect of 8-hydroxyquinoline citrate, sucrose and peroxidase inhibitors on delaying senescence and extending vase life of cut lisianthus flowers was tested. The peroxidase inhibitors used in this experiment were catechol (CH) (5, 10, 15 mM) and p-phenylenediamine (PD) (5, 10, 15 mM). All vase solutions contained 200 mg-dm-3 8-hydroxyquinoline citrate (8-HQC) and 3% sucrose. 10 mM CH treatment was the most effective for vase life extension (13.3 days), increasing water uptake, and delaying fresh weight loss. The vase solution containing 10 mM CH significantly increased superoxide dismutase (SOD) and decreased peroxidase (POD) activities. Similarly, 10 mM PD increased anthocyanin content more than the other treat–ments. Protein degradation was significantly delayed by application of 5 mM PD. The malondialdehyde (MDA) accumulation was reduced when CH at 5 mM and PD in 5 and 15 mM were added to the vase solution. Results indicated that peroxidase inhibitors in combination with 8-HQC and sucrose increase vase life of lisianthus by improving water uptake and delaying fresh weight loss.

EFFECT OF NATURAL EXTRACTS ON VASE LIFE OF GYPSOPHILA CUT FLOWERS

The experimental trial was consummated throughout two successive seasons (2012 and 2013) at the Post-Harvest Lab. ofOrnamental Plants and Landscape Gardening Research Dept., Hort. Res. Inst.; Giza, Egypt on Gypsophila paniculata L. “Perfecta” cut flowers. Short postharvest vase life is one of the most important problems on the cut flowers. In this study we investigated the effect of natural plant extracts of thyme (Thymus vulgaris) or moringa (Moringa oleifera Lam), chemical solutions (8-Hydroxyquinoline citrate, salicylic acid and sucrose) as holding solution and storage periods (0 and 7 days at 4°C) on extending the vase life of gypsophila cut flowers. The treatments were: distilled water (D.W.),thyme extract (25%), thyme extract (25%) + sucrose (2%) + salicylic acid (150 mg/l), moringa extract (25%), moringa extract (25%) + sucrose (2%) + salicylic acid (150 mg/l) and 8-Hydroxyquinoline citrate (200 mg/l) + sucrose (2%) + salicylic acid (150 mg/l). Results showed that holding solution containing natural extracts: thyme (25%) + sucrose (2%) + salicylic acid (150 mg/l), moringa (25%), moringa (25%) + sucrose (2%) + salicylic acid (150 mg/l) increased flower longevity followed by the chemical solution of 8- Hydroxyquinoline citrate (200 mg/l) + sucrose (2%) + salicylic acid(150 mg/l) as compared to D.W. The results also revealed that extracts solution (thyme or moringa plus sucrose and salicylic acid) increased fresh weight %, total carbohydrates % and water uptake, but decreased water loss, maintained quality rate, water balance, and decreased number of bacteria in the solution. Concerning the effect of storage period (dry cold storage for 7 days) it has shown favorable effect on vase life and the other studied characters, but 0 day (unstored flowers) significantly surpassed the storage for 7 days. The results of interaction showed that holding solutions containingnatural extracts with storage for 0 days (unstored flowers) had the highest effect on vase life, fresh weight %, total carbohydrates % , water uptake, water loss, water balance and quality rate. It could be concluded that the best treatments were natural extracts: thyme (25%) + sucrose (2%) + salicylic acid (150 mg/l) and moringa (25%) + sucrose (2%) + salicylic acid (150 mg/l) stored 0 day (unstored flowers), which significantly improved the studied characters compared to the other treatments.

Effect of antimicrobial compounds on cut Gerbera flowers: Poor relation between stem bending and numbers of bacteria in the vase water

Gerbera flowers (Gerbera jamesonii) often show stem bending. In four cultivars (Tamara, Liesbeth, Cora, and Mickey), we tested the effects on bending of antimicrobial compounds (chlorine bleach, a slow release chlorine compound, 8-hydroxyquinoline citrate [HQC], silver nitrate, carvacrol and thymol), some combined with sugars. At concentrations used for other cut flowers, inclusion in the vase solution of several of the antimicrobial compounds delayed bending, had no effect, or hastened bending. Hastening of bending was found at higher concentrations. It was accompanied with visible damage on the stem ends. Results with HQC indicated high toxicity as it did not delay bending at any of the concentration tested (100–400mgL−1). At 200mgL−1 HQC induced growth of bacteria that were not found in the controls. The number of bacteria in the vase water showed a low correlation with bending. Visible toxicity on the stem surface was often associated with a high bacteria count. However, at relatively high concentrations of the antimicrobial compounds stem bending was associated with a low count. This indicated an effect other than bacteria. Water uptake was low in stems that bent early. It is hypothesized that material from dead stem cells resulted in a xylem blockage which led to early bending. Sucrose at 15gL−1 in combination with an antimicrobial compound (slow release chlorine, HQC) resulted in the absence of stem damage and produced much less bending than the same concentration of the antimicrobial compounds alone. Sucrose apparently counteracted the toxic effects of the antimicrobial chemicals.

Effect of Pulsing on Postharvest Longevity of Cut Leaves of Lace Fern/Bridal Fern (Asparagus setaceus syn. Plumosus)

Loss of appealing quality characteristics and rapid desiccation within a short period after detaching from mother plants is one of the major problems in cut foliages. Effect of pulsing with benzyl adenine (BA), 8-Hydroxy Quinoline citrate (8-HQC) and sucrose on vase life of cut leaves of Asparagus setaceus syn. Plumosus was investigated. Two durations of pulsing viz., 12 and 24 h were employed. Pulsing for 12 h with BA (25 ppm) + 8-HQC (200 ppm) + 10 % sucrose resulted in higher fresh weight at senescence.The lowest physiological loss in weight was registered by the cut foliages pulsed for 24 h with BA (25 ppm) + 8-HQC (200 ppm) + 10 % sucrose. Pulsing the cut foliages for 24 h with BA (25 ppm) + 8-HQC (200 ppm) + 10 % sucrose resulted in the maximum uptake of water and registered the highest water balance. The lowest transpirational loss of water was found to be associated with foliages pulsed with 10 % sucrose alone for 24 h. The foliages pulsed with BA (25 ppm) + 8-HQC (300 ppm) + 10 % sucrose for 24 h registered lowest ratio between water loss and water uptake. Results suggest that application of 10 % sucrose+BA (25 ppm) + 8-HQC (200 ppm) as a pulse treatment for 24 h can be recommended to prolong the postharvest life (28.50 days) through delayed leaf senescence and thus enhance the marketability of cut leaves of Asparagus setaceus syn. Plumosus.

CALCIUM PROMOTES LONGEVITY AND BUD OPENING IN CUT ROSE FLOWERS

ABSTRACT Calcium applied to cut rose flowers mainly as Ca(NO3)2 (but also as CaCl2) extended longevity and promoted bud opening. The effect was recorded when calcium was applied either alone or together with 2% sucrose (S) and 8-hydroxyquinoline citrate (HQC). Treatments were applied either continuously or as a short-term (20-h) pulse. Longevity extension was observed in the rose cultivars Sonia, Celica, Samantha, and Mercedes. In Ilseta roses, calcium did not extend longevity over that achieved in an HQC + S preservative solution. Mg and K salts had no beneficial effect on the keeping qualities of cut roses. Measurements of 45Ca distribution showed that calcium accumulated in all flower parts, including petals.

TOUGH NUTS TO CRACK: ADVANCES IN MICROPROPAGATION OF WOODY SPECIES

Micropropagation of woody species has proved to be more challenging and difficult than micropropagation of numerous herbaceous species. Castanea spp. and Corylus spp. hybrids have been developed by plant breeders for the purpose of establishment of agroforestry plantations in the Midwestern states of the USA. Many of these hybrids have been developed by The American Chestnut Foundation (TACF), Meadowview, VA and by P.A. Rutter, Badgersett Research Farm, Canton, MN. Difficulties in conventional vegetative propagation approaches (cuttings, grafting) and the heterozygosity of seed populations have led researchers to employ micropropagation to obtain sufficient numbers of clonal plants for establishment of field plantations of such crops. We have utilized a forcing solution containing an anti-microbial chemical (8-hydroxyquinoline citrate, 8-HQC) and sucrose as a technique to obtain softwood outgrowth from cut woody stems that can be used as explant material for micropropagation. Inclusion of gibberellic acid in the forcing solution facilitated breaking bud dormancy of woody species in early to mid-winter, thus making it possible to obtain explants in the off-season for use in micropropagation research. Rooting difficulties have been overcome by use of a bilayer culture of activated charcoal-containing gelled medium overlaying a rooting medium from which light has been excluded. For Corylus, we have determined that a medium based in part on kernel constituents of the nut and higher than normal copper and myo-inositol significantly enhanced shoot proliferation and enabled production of several hundred 75 to 100 cm plants suitable for transplantation to the field.

Manutenção da qualidade de rosas cortadas cv. Vega em soluções conservantes

A rosa é considerada uma das flores de corte mais tradicionais e requisitadas no mercado mundial. Entretanto, após o corte, essas flores tornam-se altamente perecíveis devido à elevada atividade metabólica que conduz aos processos de senescência. Assim, o experimento foi realizado para verificar o efeito do uso de soluções conservantes na fisiologia pós-colheita de rosas vermelhas cortadas cultivar Vega. Utilizou-se o delineamento inteiramente casualizado, em esquema fatorial composto por dois fatores: sete tratamentos pós-colheita e quatro datas de avaliação. As flores permaneceram nas seguintes soluções de manutenção: 1) Água destilada; 2) 8-hidroxiquinolina (200 mg L-1); 3) 8-hidroxiquinolina (200 mg L-1) + Sacarose (20 mg L-1); 4) Ácido cítrico (75 mg L-1); 5) Ácido cítrico (75 mg L-1) + Sacarose (20 mg L-1); 6) 6-benziladenina (60 mg L-1); 7) 6 benziladenina (60 mg L-1) + Sacarose (20 mg L-1). Foram realizadas análises qualitativas e fisiológicas ao longo do período de avaliação. O tratamento com 8-hidroxiquinolina e ácido cítrico revelaram-se mais promissores para manter a qualidade e prolongar a vida de vaso das flores, o que foi evidenciado pela menor perda de massa fresca, atividade respiratória e conteúdo relativo de água; melhor manutenção do conteúdo de carboidratos solúveis e redutores, antocianina e coloração.

Effects of nanosilver and sucrose on vase life of cut Rose flower (Rosa hybrid cv. ‘Royal’)

In cut flowers increasing of quality and duration of storage and minimizing wastes after harvest is very important. Silver thiosulphate (STS) is one of the materials that in this connection is used, but because of environmental pollutant, its application has been limited. Recent study evaluated the possibility of replacing nanosilver instead of STS. In this study, experimental design was factorial with two factors, including sucrose and several types of chemicals such as nanosilver, hydroxyquinoline citrate (HQC), copper nitrate and STS with three replications that were performed on the cut Rose flower cultivar royal using pulsed method. During the experiment, traits such as vase-life of flower, electrolyte leakage (EL), relative water content (RWC), leaf and flower qualitative traits and percentage of flowers opening were evaluated. Analysis of variance showed that between traits among treatments, there are significant differences. Mean comparisons showed that the use of STS in combination with 8 percent sucrose had the most effect on traits, so that vase-life of cut Rose flowers has increased up to 67.15 days. Application of nanosilver using concentration of 5 ppm in combination with 4 percent sucrose also could, to reach the vase-life of flowers to 67.13 days that it seems to bring effective treatment to increase the vase- life of cut Rose flowers. Use of STS in combination with different concentrations of sucrose and 15 ppm nanosilver with 4 percent sucrose had also a significant difference in maintaining of quality and vase-life of flowers other than chemical treatments. Key words: Sucrose, silver thiosulphate (STS), hydroxyquinoline citrate (HQC), copper nitrate, nanosilver, Rose cultivar royal.

Essential oils and silver nanoparticles (SNP) as novel agents to extend vase-life of gerbera ( Gerbera jamesonii cv. ‘Dune’) flowers

The aim of this study was to evaluate the efficacy of silver nanoparticles (SNP) and essential oils as novel antimicrobial agents in extending the vase-life of gerbera ( Gerbera jamesonii cv. ‘Dune’) flowers. The vase-life of flowers held in a solution containing 5 mg L −1 SNP plus 6% sucrose was found to be significantly higher than with 8-HQC (8-hydroxyquinoline citrate) or control treatments. However, the vase-life was not different to that of flowers held in similar concentrations of silver nitrate. All gerbera flowers held in SNP solutions showed significantly higher relative fresh weight than the control. Vase-life of gerbera flowers was extended by addition of either 50 or 100 mg L −1 carvacrol and either 1 or 2 mg L −1 SNP from 8.3 to 16 d. In addition, the relative fresh weight and solution uptake of gerbera flowers were increased by addition of 100 mg L −1 essential oils and 1 or 2 mg L −1 SNP as compared to that of control flowers. Our results suggest the potential application of essential oils or SNP as novel alternatives to common chemicals used in preservative solutions for gerbera flowers.

Postharvest Evaluation of Cut Dahlia, Linaria, Lupine, Poppy, Rudbeckia, Trachelium, and Zinnia

Vase life of ‘Karma Thalia’ dahlia (Dahlia ×hybrida), ‘Lace Violet’ linaria (Linaria maroccana), ‘Sunrise’ lupine (Lupinus hartwegii ssp. cruickshankii), ‘Temptress’ poppy (Papaver nudicaule), ‘Indian Summer’ rudbeckia (Rudbeckia ×hybrida), ‘Jemmy Royal Purple’ trachelium (Trachelium caeruleum), and ‘Benary's Giant Scarlet’ and ‘Sun Gold’ zinnias (Zinnia elegans) was determined after being subjected to postharvest handling procedures. Cut dahlia, lupine, poppy, rudbeckia, trachelium, and ‘Sun Gold’ and ‘Benary's Giant Scarlet’ zinnia flowers could be held in unamended tap or deionized (DI) water with no effect on vase life. Vase life of linaria was longest when placed in DI water with 8-hydroxyquinoline citrate and a solution pH of 3.5. A vase solution of 2% sucrose without foam extended consumer vase lives for linaria, trachelium, and ‘Benary's Giant Scarlet’ zinnia. Floral foam or 2% or 4% sucrose had no effect on the consumer vase life of dahlia, lupine, rudbeckia, and poppy. Trachelium and rudbeckia did not tolerate a 20% sucrose treatment for 24 h, whereas linaria and ‘Benary's Giant Scarlet’ zinnia had a longer vase life with a 10% sucrose pulse than a water-only pulse. For trachelium, the longest (17.5 days) consumer vase life occurred when the Chrysal Professional 2 Processing solution (CP2) was used after pretreatment with DI water. Either of two commercial holding solutions, CP2 or Floralife Professional (FLP), similarly extended the vase life of linaria. The use of FLP or CP2 improved consumer vase life of dahlia, lupine, and poppy compared with DI water. Dahlia, trachelium, and zinnia flowers could not be cold stored at 2 °C. Lupine and poppy could be stored at 2 °C wet or dry for 2 weeks. Linaria and rudbeckia could be cold stored for 3 weeks. Lupine and trachelium were susceptible to 1 μL·L−1 exogenous ethylene, which induced floret abscission in lupine and stopped floret opening in trachelium. 1-Methylcyclopropene and silver thiosulfate similarly suppressed the ethylene effect. Cut linaria, zinnia, dahlia, rudbeckia, and poppy flowers were unaffected by exogenous ethylene.

Postharvest Evaluation of Cut Dahlia, Linaria, Lupine, Poppy, Rudbeckia, Trachelium, and Zinnia

Vase life of ‘Karma Thalia’ dahlia (Dahlia ×hybrida), ‘Lace Violet’ linaria (Linaria maroccana), ‘Sunrise’ lupine (Lupinus hartwegii ssp. cruickshankii), ‘Temptress’ poppy (Papaver nudicaule), ‘Indian Summer’ rudbeckia (Rudbeckia ×hybrida), ‘Jemmy Royal Purple’ trachelium (Trachelium caeruleum), and ‘Benary's Giant Scarlet’ and ‘Sun Gold’ zinnias (Zinnia elegans) was determined after being subjected to postharvest handling procedures. Cut dahlia, lupine, poppy, rudbeckia, trachelium, and ‘Sun Gold’ and ‘Benary's Giant Scarlet’ zinnia flowers could be held in unamended tap or deionized (DI) water with no effect on vase life. Vase life of linaria was longest when placed in DI water with 8-hydroxyquinoline citrate and a solution pH of 3.5. A vase solution of 2% sucrose without foam extended consumer vase lives for linaria, trachelium, and ‘Benary's Giant Scarlet’ zinnia. Floral foam or 2% or 4% sucrose had no effect on the consumer vase life of dahlia, lupine, rudbeckia, and poppy. Trachelium and rudbeckia did not tolerate a 20% sucrose treatment for 24 h, whereas linaria and ‘Benary's Giant Scarlet’ zinnia had a longer vase life with a 10% sucrose pulse than a water-only pulse. For trachelium, the longest (17.5 days) consumer vase life occurred when the Chrysal Professional 2 Processing solution (CP2) was used after pretreatment with DI water. Either of two commercial holding solutions, CP2 or Floralife Professional (FLP), similarly extended the vase life of linaria. The use of FLP or CP2 improved consumer vase life of dahlia, lupine, and poppy compared with DI water. Dahlia, trachelium, and zinnia flowers could not be cold stored at 2 °C. Lupine and poppy could be stored at 2 °C wet or dry for 2 weeks. Linaria and rudbeckia could be cold stored for 3 weeks. Lupine and trachelium were susceptible to 1 μL·L−1 exogenous ethylene, which induced floret abscission in lupine and stopped floret opening in trachelium. 1-Methylcyclopropene and silver thiosulfate similarly suppressed the ethylene effect. Cut linaria, zinnia, dahlia, rudbeckia, and poppy flowers were unaffected by exogenous ethylene.

Longevity of Epidendrum ibaguense flowers as affected by pre-loading treatments and vase solution

SummaryPost-harvest longevity of Epidendrum ibaguense cut flowers was maximum when treated for 6 h with 1 g m–3 Ethylbloc® [0.14% 1-methylcyclopropene; 1-MCP] followed, or not, by pulsing with 200 g l–1 sucrose for 12 h. This extended the vase-life from 5.5 d to at least 11 d. Cut inflorescences pulsed with 2.0 mM silver thiosulphate (STS) had reduced abscission of flowers, similar to the effect of 1-MCP. When inflorescences were pulsed with 200 g l–1 sucrose alone for 12 h, no effect was observed on the vase-life of the flowers. Flowers kept in a vase solution containing 20 g l–1 sucrose, 150 mg l–1 citric acid, and 200 mg l–1 8-hydroxyquinoline citrate did not influence the longevity of 1-MCP or STS pre-treated flowers, but the vase solution had a small influence on retarding abscission compared with flowers kept in distilled water. Adding 0.2 mM STS to the vase solution improved vase-life 1.74- and 1.45-fold compared with the longevity of flowers kept in distilled water or in vase solution alone, respectively. The presence of 0.3 mM AgNO3 alone, or mixed into the vase solution, had no affect on the vase-life of the flowers.