8-hydroxyquinoline Citrate Research Articles

A study on the effect of silver nitrate and 8-hydroxyquinoline citrate pulsing solutions on Lilium cut flowers

Lilium is one of the most important cut flowers in commercial markets, giving customers ornamental value. Fresh flowers, a highly perishable item, need more care and proper treatment for their longer post-harvest life and due to this, the end users face the post-harvest losses of cut flowers. Such losses can be minimized by using preservative chemical, which plays an important role in increasing the vase life of flowers. To increase the post-harvest life of lilium cut flowers cv. ‘Pavia’, the present investigation was aimed to study the effect of different combinations and concentrations of silver nitrate at 50, 75 and 100 ppm and 8-hydroquinoline citrate at 100, 150 and 200 ppm pulsing solutions with 20 % sucrose. Three replications were completely randomised with 16 treatments and one control. Silver nitrate showed better results in flower bud opening, flower bud opening to complete flowering, flower size, bloom life, dry weight and dry matter percentage. Among the treatment concentrations, AgNO3 at 50 ppm with 20% sucrose showed the most effective result on enhancing the selected parameters and improved flower quality during post-harvest life. Among the treatment combinations, 8-HQC at 100 ppm + AgNO3 at 75 ppm with 20 % sucrose showed better results. These findings will be useful to researchers, farmers, and end users to retain the ornamental value of lilium cut flowers for longer than usual.

Response of preservative chemicals on the shelf life of cut lilium (Lilium spp.) flower cv. ‘Pavia’

Lilium cut flowers have commercial importance and extending their vase life is vital. An increase in the vase life quality and quantity can directly increase the viability and price realization of commercially important flowers like lilium. Shelf life of cut lilium flower is influenced by using different preservative chemicals and sucrose added in vase solution. Such an extension of vase life can be achieved via chemical treatment. The trial was carried out to examine the effect of various concentration of two chemicals, AgNO3 (silver nitrate) and 8-HQC (8-Hydroxyquinoline citrate) along with sucrose on the shelf life of lilium cut flower cv. ‘Pavia’ (cross between Asiatic and Longiflorum lilies). In the experiment, sucrose (20%), 8-HQC at 3 concentrations (100, 150, 200 ppm) and AgNO3 at 3 concentrations (50, 75, 100 ppm) and water (distilled) as control were tested alone and with combinations. Cut flowers of lilium were treated at one bud opening stage. The trial was carried out in a completely randomized design (CRD) having 16 treatments and one control in three (3) replications. The fresh weight and relative fresh weight of the cut flower spike, opening of all flowers on a spike, vase solution uptake on a day, total vase solution uptake and vase life of lilium cut flower spike showed the best outcome with AgNO3 (50 ppm) and 20% sucrose treatment combination. Out of the two chemicals, silver nitrate showed better results than 8-HQC as a preservative in enhancing the shelf life of cut Lilium flower cv. ‘Pavia’. Analysis of this new and exciting method will be useful to research institutes, commercial producers, wholesalers, retailers, consumers or anyone to choose right chemical and concentration of holding solution to maximize the post-harvest life of lilium cut flowers.

Sucrose + 8-HQC improves the postharvest quality of lily and rose cut flowers by regulating ROS-scavenging systems and ethylene release

The objective of the present investigation was to study the effects of sucrose + 8-hydroxyquinoline citrate (8-HQC) on the reactive oxygen species (ROS)-scavenging systems and ethylene release during the vase life of cut lilies (ethylene-insensitive type) and roses (ethylene-sensitive type). ROS production and the degree of lipid peroxidation increased with the senescence of cut lily and rose flowers. The treatment with sucrose + 8-HQC enhanced ROS-scavenging abilities, decreased Superoxide radical (O2.−) release and mitigated the oxidative damage marked by lower malondialdehyde (MDA) level, although the up-regulated extent of each antioxidant enzyme was not exactly the same in both cut flower species. The treatment of sucrose + 8-HQC decreased the level of proline in cut rose, which suggested water stress of cut rose was alleviated. On the other hand, the increase of proline in cut lily due to sucrose + 8-HQC was elaborated. The preservation effect induced by sucrose + 8-HQC was involved in the regulation of ethylene production in ethylene-sensitive cut flowers, not in ethylene-insensitive cut flowers. From the results of ethylene and proline analysis, it can be found that there are differences in the regulation mechanism of sucrose on the fresh-keeping of the two cut flowers, but the treatment with sucrose and 8-HQC can improve the postharvest quality of cut flowers with different sensitivity to ethylene by enhancing ROS-scavenging activities and alleviating lipid peroxidation.

Effect of silver nano particles and 8-hydroxyquinoline citrate on the longer life of cut Gerbera (Gerbera jamesonii) 'Sunway' flowers

Gerbera is one of the cut flowers with short vase life. In this research, silver nanoparticles (SNP) (0, 5, 15, and 25 mg L−1) and 8-hydroxyquinoline citrate (8-HQC) (0, 100, 200, and 300 mg L−1) as pulse treatment for 24 h in combination with 6% sucrose were used in order to increase the quality and vase life of cut Gerbera 'Sunway’ flowers. The results indicated that the vase life of cut flowers treated with 15 mg L−1 SNP plus 200 mg L−1 of 8-HQC and 6% sucrose was higher than the other treatments (20.68 days). Fresh weight and water uptake of Gerberas were relatively higher than other treatments, and also, this treatment resulted in less protein degradation and lower malondialdehyde, higher carotenoid pigmentation. Treatment with 200 mg L−1 of 8-HQC and 6% sucrose and 15 mg L−1 SNP with 6% sucrose separately showed higher SOD activity than other treatments. The use of nanoparticles and 8- HQC in combination with sucrose in the preservative solution showed the best treatment in delaying senescence and increased the life of cut Gerbera flowers compared to other treatments (Distilled water and sucrose solution).

Pulsing on the postharvest physiology of two cultivars of Polianthes tuberosa L.

Abstract The effect of pulsing on the postharvest behavior of cut tuberose was evaluated in the cultivars ‘Mexican Single’ and ‘The Pearl’. Spikes of both were harvested with 1 or 2 of their basal buds open and treated with 20% sucrose and 200 mg of hydroxyquinoline citrate (sucrose + HQC). Pulsing increased the relative fresh weight of spikes, although water uptake in ‘The Pearl’ was greater regardless. After 5 days, visual quality was scored as ‘excellent’ and ‘good’ in ‘Mexican Single’ and ‘The Pearl’, respectively, and the greatest number of open and of senescent flowers occurred in the latter independent of pulsing. CIE L*C*h values and total sugars increased more noticeably among pulsed florets in ‘The Pearl’, whereas higher rates of respiration occurred in the unpulsed spikes of ‘Mexican Single’. Catalase activity was constant in ‘The Pearl’, although superoxide dismutase and peroxidase activities were higher and similar to, respectively, those of ‘Mexican Single’. These differences in physical, physiological and enzymatic behavior are important to consider when developing postharvest conservation and management strategies that are specific for each variety.

Soluciones hidratantes en dos cultivares de nardo (Polianthes tuberosa): respuestas físicas, fisiológicas y bioquímicas

Espigas de nardo (Polianthes tuberosa) ‘Mexicano’ y ‘Perla’ con 5 ó 1 flores basales abiertas, se trataron con soluciones hidratantes (SH) conteniendo ácido gibérelico (AG3), benciladenina (BA), ácido amino-oxiácetico (AOA), ácido cítrico (AC), sacarosa (Sac) o hidroxiquínoleina citrato (HQC) con el objetivo de evaluar los cambios físicos, quími­cos y fisiológicos durante poscosecha, para posteriormente desarrollar tecnologías que incrementen la vida útil de esta especie ornamental. Se utilizó un experimento completa­mente al azar, la unidad experimental fue una espiga con seis a ocho repeticiones. Los resultados indican que el peso fresco relativo, consumo de agua y número de flores abiertas se incrementó; la respiración y azúcares totales disminuyeron en ambas variedades, cuando se aplicaron SH con AC o BA. La apariencia fue buena por cinco días en ‘Mexicano’ en las espigas hidratadas con AC o BA+ Sac y en ‘Perla’ por siete días en todos los tratamientos donde se aplicó SH. La actividad de peroxidasa, catalasa y superóxido dismutasa fue mayor en las espigas testigo y menor cuando se aplicaron las SH con BA + Sac o AC. En conclusión, la hidratación con AC ó BA mejoran el metabolismo y calidad de las espigas de nardo ‘Mexicano’ y ‘Perla’ en poscosecha.

Effects of Postharvest Treatments with Nanosilver on Senescence of Cut Lisianthus (Eustoma grandiflorum (Raf.) Shinn.) Flowers

Lisianthus is among the most popular cut flowers. Regarding the postharvest losses, these experiments were designed to compare the effects of a nanosilver (NS) based preservative to the standard preservative containing 8-hydroxyquinoline citrate (8-HQC) and sucrose (S). Additionally, the effect of 24 h conditioning in the NS solution on the postharvest longevity and the general condition of lisianthus (Eustoma grandiflorum ‘Mariachi Blue’) was tested. The vase life of flowers on conditioned and non-conditioned stems was extended by the preservatives, more so by NS + S than by 8-HQC + S (44–54% versus 13–23%). Conditioning had no detectable effect on longevity. Daily water uptake showed alternative peaks and drops, with a general tendency of the uptake rate to decrease over time. The highest uptake intensity and the highest transpiration rate were in stems in the NS + S solution while the lowest was in 8-HQC + S. Conditioning negatively affected the average fresh weight of the flowering stems in all holding solutions with stems in preservatives being heavier than those in water. Preservatives did not induce accumulation of the total soluble or reducing sugars in petals; such accumulation was promoted by conditioning, but only in the upper flowers. The free proline content increased in senescing lower flowers on non-conditioned stems; conditioning limited this increase in flowers in preservatives. In the upper flowers, free proline increased in both water controls while the preservatives and conditioning generally reduced the proline contents below the initial level. Conditioning lowered the hydrogen peroxide contents in senescing lower flowers, relative to the initial level and the non-conditioned stems. The catalase activity kept dropping during the vase life in both the lower and upper flowers, in conditioned and non-conditioned stems, with the exception of flowers from water where the activity remained the highest from all three treatments. It appears that the NS preservative with sucrose improves the overall condition of lisianthus flowers and extends their vase life.

Soluciones conservadoras en poscosecha en dos variedades de nardo (Polianthes tuberosa L.) nativas de México: ‘Mexicano’ y ‘Perla’

ntroduction: ‘Perla’ and ‘Mexicano’ are varieties of tuberose grown in Mexico that have potential for commercialization and export; however, no preservative solutions have been evaluated to increase their shelf life. Objective: To determine physical, physiological, and chemical changes that occur in postharvest tuberose when different preservative solutions are applied. Methodology: Tuberose flower spikes of varieties ‘Mexicano’ and Perla, with two open basal flowers, were placed in preservative solutions (Crystal®, sucrose [Sac] + citric acid [CA] + hydroxyquinoline citrate [HQC] and ascorbic acid [AAsc]). A group of tuberose flower spikes was kept as control, and in all cases destructive and non-destructive variables were evaluated during postharvest. Results: Relative fresh weight and water consumption increased with preservative solutions in both varieties. The appearance of the ‘Perla’ variety was excellent for 5 days with Crystal®. The ‘Mexicano’ variety had more open flowers with Crystal® and Sac + AC + HQC, while the ‘Perla’ variety had the same result with AAsc and Crystal®. Respiration in the Mexicano’ variety was high with Sac + AC + HQC, and in the case of ‘Perla’ variety, respiration was low with AAsc. The highest specific superoxide dismutase activity was detected with AAsc and Crystal® for ‘Perla’ variety. Study limitations: The results are valid without previous applications of pulse or hydrating solutions in tuberose varieties evaluated. Originality: This is the first study where the postharvest behavior of two Mexican tuberose varieties is evaluated in preservative solutions. Conclusions: ‘Mexicano’ and ‘Perla’ varieties can use Crystal® and AAsc solutions to maintain the quality for longer time in vase.

EFFECT OF ESSENTIAL OILS ON STORAGE AND KEEPING QUALITY OF GLADIOLUS CUT FLOWERS

A trial was consummated at Postharvest Lab. of Floriculture Res. Dept. Hort. Res. Inst. ARC, Giza, Egypt during 2019 and 2020 seasons to study the influence of essential oils of clove and sage oil in two experiments as preservative solutions, or a spray treatments as well as under long term of storage at low temperatures for three periods on quality and vase life of cut inflorescences of Gladiolus grandiflorus. In the first experiment five holding solutions included, clove oil at 1 and 2 mg/l + 20 g/l sucrose (suc.), sage oil at 1and 2 mg/l + 20 g/l sucrose (suc.), 8-hydroxyquinoline citrate (8-HQC) at 200 pm + 20 g/l sucrose (suc.) and control (distilled water D.W.) were used. In second experiment that used essential oils as spray treatments. The obtained results from the two experiments indicated that, the flowers hold in the preservative solution of sucrose + clove oil (1 mg/l) significantly prolonged vase life, increased flowers fresh weight (%) and water uptake (g), dry weight (%), percentage of opening floret (%) and decreased water loss(g), bacterial counts in the vase solution. Essential oils had a positive effect on total sugar concentrations, level of total indoles and total phenols and total chlorophyll contents of cut flowers. Essential oils as an alternative substitute to chemical compounds had an excellent effect on cut flowers also because of their antimicrobial activities and environmental friendly nature.

Postharvest Treatments Improve Quality of Cut Peony Flowers

Peony is one of the most important ornamental plants in the international flower market, but has a relatively short vase life in water. This study tested the effects of 8-hydroxyquinoline citrate (8-HQC) and nanosilver (NS) in combination with sucrose, as well as two commercial preservatives, on the longevity and some physiological and biochemical aspects of senescence of cut flowers of 14 cultivars. Responses varied both by cultivar and treatment. The preservatives extended the vase life in only five cultivars; however, in nine cultivars, preservatives increased the flower diameter and improved the general flower appearance. Blockages in xylem vessels started to appear soon after harvest. Both NS and 8-HQC with sucrose prevented tylose formation, while bacterial blockages were reduced only by the NS solution. Reduction in stem blockages did not translate into better water balance or flower longevity. The highest carbohydrate accumulation in petals was observed in the NS solution. Preservatives mitigated the rise in free amino acids, including free proline. They did not prevent an increase in H2O2 content but flowers in preservatives generally had higher catalase activity than in the control. As solutions with NS produced comparable or even better results than 8-HQC, we recommend the latter as a component of a preservative for cut peony flowers. However, cultivar-specific responses indicate that postharvest treatments must be individually tailored to each cultivar.

The Effect of Nanosilver on Postharvest Longevity of Thalictrum aquilegifolium L. Foliage

<em>Thalictrum aquilegifolium </em>L. ‘Black Stockings,’ with its interesting foliage, is used as a cut greenery. We tested the postharvest longevity of the foliage after different 24-hr conditioning treatments with nanosilver (0, 5, 10, 15, 20 mg dm<sup>−3</sup>) and 20 g dm<sup>−3</sup> sucrose and compared the results with those obtained using the standard preservative (200 mg dm<sup>−3</sup> 8-hydroxyquinoline citrate + 20 g dm<sup>−3</sup> sucrose) and Floralife 200 Clear. The longevity of the foliage and the content of assimilative pigments were evaluated and the functioning of the photosynthetic apparatus (F<sub>0</sub>, Fm, Fv/Fm) was analyzed. We found that leaf senescence, as determined by chlorophyll <em>a </em>and carotenoid content after 14 days of holding, was most effectively inhibited by the solution containing 5 mg dm<sup>−3</sup> nanosilver and sucrose. This solution increased the maximal quantum efficiency of photosystem II (Fv/Fm) in the leaves.

Nanosilver as a novel biocide for control of senescence in garden cosmos

To prolong their vase life, cut flowers are commonly kept in holding solutions. These must include a biocide to retard bacterial growth. In this study, the effect of nanosilver (NS) on certain aspects of senescence in cut garden cosmos (Cosmos bipinnatus) flowers was compared to that of the commonly used 8-hydroxyquinoline citrate (8-HQC). In combination with sucrose, both biocides prolonged cosmos vase life but did not prevent the occurrence of stem blockages. NS was more effective in limiting a reduction in endogenous soluble carbohydrates. The malondialdehyde (MDA) contents increased in senescing ray florets, both in intact and control cut flowers held in water. Both biocides were comparably effective in limiting this effect. The hydrogen peroxide content tripled in intact flowers but dropped in flowers held in water or the 8-HQC solutions; in flowers kept in NS solutions its increase was moderate. Also, the catalase activity increased in intact flowers but dropped in all cut flowers. Both biocides had similar effects on the enzyme activity, in both pure solutions and with sucrose. Most of these parameters were not significantly correlated with vase life. Overall, the effect of nanosilver on senescence in cut cosmos flowers was similar to that of 8-HQC.

Antimicrobial forcing solution improves recovery of cryopreserved temperate fruit tree dormant buds

Dormant bud cryogenic preservation is a cost- and labor-efficient method of genetic resource backup compared to in vitro derived meristem shoots cryopreservation. While protocols have been developed for cryopreserving apple dormant buds, effective and reproducible protocols are yet to be developed for several temperate fruit and nut species. Dormant bud cryopreservation typically requires material to be grafted to evaluate viability and recover a plant. Forced bud development has been used on a very limited scale for cryostored dormant budwood recovery, however, it provides a labor-efficient alternative viability assessment. To increase the utility of this approach, regrowth must be optimized to allow complete plant recovery. We hypothesized that bacterial attacks are limiting regrowth, thus, an antimicrobial forcing solution can maximize regrowth potential. This study examined the effects of an antimicrobial forcing solution (8-hydroxyquinoline citrate and sucrose, 8-HQC) on the cryosurvival and recovery of dormant buds of fruit (Malus x domestica, Prunus armeniaca, Prunus avium, Prunus persica, Pyrus communis), and nut species (Juglans regia, Juglans nigra, Juglans microcarpa). Recovery and shoot development were significantly improved for all the fruit and one nut species (J. microcarpa) treated with the 8-HQC, compared to standard recovery under high humidity alone (P < 0.001). Additionally, this post cryo recovery approach led to successful in vitro shoot tip establishment across all surviving fruit species. 8-HQC embedded forced bud development method increased viability and efficiency for existing cryostored material and can be used as a benchmark to develop protocols for different crops that could potentially lead to complete plant recovery.

Evaluation Activity of Some Antimicrobial Agents in Reduction Microbial Load and Their Impact on Vase Life of Asparagus aethiopicus L.

The short vase life is a major problem in the Asparagus aethiopicus leafy cut stem industry. The present study showed that several bacterial and fungal species were found to be associated with A. aethiopicus cut wilted stems and their vase life. This included six bacterial species, i.e., Bacillus subtilis, Bacillus sp., Pseudomonas sp., Streptococcus sp., Streptomyces sp. Streptobacillus sp. and also five fungal species, i.e., Alternaria alternata, Fusarium oxysporum, F. solani, Aspergillus flavus and A. niger. However, Pseudomonas sp. and F. oxysporum were the most frequent bacterial and fungal microorganisms. Three tested antimicrobial agents, i.e., 8-hydroxy quinoline citrate (8-HQC), sodium hypochlorite and citric acid significantly reduced number of bacterial and fungal proliferation in the different vase treatments wherestems basal ends were dipped in them and this effect was increased with increasing their concentrations. However, 8-HQC at 200 ppm + oxytetracycline hydrochloride (1000 ppm) showed reduction percentages of 84.29 and 51.72 % of bacterial and fungal numbers, respectively. Also, sodium hypochlorite at 10 ppm + oxytetracycline hydrochloride (1000 ppm) recorded bacterial and fungal reductions that reached 85.25 and 42.44%, respectively. This was followed by citric acid (1000 ppm) + oxytetracycline hydrochloride (1000 ppm) which showed 83.31and 28.32 %, reductions of bacterial and fungal numbers while antimicrobial agents’ treatments without oxytetracycline hydrochloride showed lower reduction effect.All antimicrobial agents’ treatments succeeded to decrease weight loss and enhanced water uptake and vase life of the treated A. aethiopicus cut stems and this effect was increased with increasing their concentrations. Meanwhile, treatment with the mixture of 8-HQC (200ppm) + oxytetracycline (1000 ppm) was the most effective treatment in decreasing cut stem weight loss to be low as 4.05 % compared to 44.37 % for the untreated control. Also, this treatment enhanced water uptake and vase life to be as high of 44.90 g and 14.50 days compared to 16.81 g and 5.44 days of the control treatment in the previous parameters, respectively. This was followed by the mixture of sodium hypochlorite (10 ppm) + oxytetracycline hydrochloride (1000 ppm) and citric acid at (1000 ppm) + oxytetracycline hydrochloride (1000 ppm) treatments.

The Effect of a Sugar-Containing Preservative on Senescence-Related Processes in Cut Clematis Flowers

Clematis is a new species grown as cut flower, whose vase life is variable and cultivar-depended. Little is known about senescence of its cut flowers and their response to flower preservatives. The aim of the study was to evaluate the effect of a preservative (standard preservative SP, 8-hydroxyquinoline citrate plus sucrose) or a biocide solution (8-HQC) on certain senescence-related processes in cut clematis flowers. Analyses were done immediately after harvest and at the end of the vase life when control flowers held in water were wilting. A possible relationship between senescence parameters and the vase life of clematis taxa was also sought. As in most cut flowers, the contents of reducing sugars and soluble proteins in clematis petals decreased during the vase life while the proteolytic activity, including that of the cysteine protease, increased and was accompanied by accumulation of free proline and ammonium. Cut flower longevity in cultivars under study was not associated with the initial levels of reducing sugars, soluble proteins or free proline. Neither was the initial proteolytic activity or its increase during vase life related to the vase life itself: cultivars having comparable life spans differed dramatically in the initial and final proteolytic activities. Both solutions containing 8-HQC significantly affected the senescence-related processes and flowers held in them had more soluble proteins and lower proteolytic activity (total, and that of the cysteine protease) than control flowers held in water. Approximately a twofold increase in reducing sugars was observed in flowers held in SP relative to those held in water or in 8-HQC while the accumulation of free proline and ammonium was limited in their petals. This suggests a regulating action of exogenous sugar in senescence of clematis flowers. However, the delay of senescence produced by the preservative was not always associated with a longer vase life in any given cultivar. Further studies are needed to elucidate the role of sugar in clematis flower senescence.

Improving the Vase Life of Cut Mokara Red Orchid Flower Using Leaf Extracts with Silver Nanoparticles

The major causes of vase life reduction in cut flowers are the microbial proliferation in vase solution and consequently vascular occlusion preventing water uptakes. In order to control microbial proliferation efficiently, silver nanoparticles (Ag-NPs) are used as an enhancer to assess leaf extracts of Psidium guajava and Andrographis paniculata to alleviate xylem blockage in cut Mokara Red orchid flowers. The basal stem of each flower was re-cut and then pulsed with 0, 5 and 10 mg/L Ag-NPs for 24 h. The floral preservative solutions are comprised of control (125 mg/L 8-hydroxyquinoline citrate, 8-HQC) and double combination leaf extracts (DCLE) of P. guajava and A. paniculata, each at 15 mg/L. The preservative solutions of DCLE with 5 mg/L Ag-NPs had higher rates of solution uptake and trace amounts of bacterial suspension, which were responsible for increasing the vase life of cut Mokara Red Orchid flowers for 15.49 ± 0.15 days, compared to the 8-HQC control treatment 8.73 ± 0.16 days. Therefore, leaf extracts of P. guajava and A. paniculata have the potential as a biocide to minimize microbial populations and prolong the vase life of cut flowers. However, the potential activities of specific antimicrobial compounds to extend the vase life need to be tested.

Standardization of rapid multiplication protocol in petaloid male sterile lines of African marigold (Tagetes erecta) through in vitro culture

Marigold (Tagetes erecta L.) is one of the farmer’s first choice for commercial cultivation. It is commonly propagated through seeds, but some ornamentally high valued petaloid and gynomonoecious lines can only be maintained through vegetative propagation. Therefore, the objective of the present investigation was to develop efficient in vitro protocol for mass multiplication of commercially high valued petaloid male sterile cultivars. Nodal segments were chosen as explant from two thermotolerant marigold cultivars, viz. Siracole Orange and Siracole Yellow. Explants were pre-treated with carbendazim (0.2%) + metalaxyl (0.2%) + 8-hydroxy quinoline citrate (200 mg/l) for 60 minfollowed by surface sterilization with 0.1% HgCl2 for 4 min to eliminate the microbial contamination. Highest culture establishment (82.2%) and earliest bud emergence (3.88 days) was recorded in Murashige and Skoog (MS) medium supplemented with BAP (0.5 mg/l) and NAA (0.05 mg/l). Maximum (6, 28, 122 and 404 shoots/explant) proliferation with healthy shoots and free from callus was obtained on MS medium supplemented with 0.5 mg/l BAP + 0.1 mg/l NAA + 2.5 mg/l AgNO3 in 30, 60, 90 and 120 days after culture respectively. Maximum elongation (2.10 cm) wasobserved on MS media devoid of growth regulators (control). Highest rooting percentage (96.50%), maximum number of roots (23.37), rapid root induction (5.25 days) and high ex vitro survival (91.25%) was noted in ½ MS medium supplemented with 0.5 mg/l IBA. Highest plant survival (98.10%) and superior plant growth was observed when rooted plants were shifted to low-cost polypropylene glasses instead of traditional glass bottle system. This protocol is highly useful for mass multiplication of true-to-type, disease free planting material as well as helpful in long termmaintenance of germplasm lines.

Endogenous levels of polyamines during cold storage of bird-ofparadise treated with biocides

This study aimed to analyse the endogenous levels of free polyamines putrescine (Put), spermidine (spd) and spermine (spm) under the effect of 8-HQC (8-hydroxyquinoline citrate) and chlorine during cold storage of bird-of-paradise floral scapes. Flowers were selected, labelled and randomly distributed in recipients for postharvest trials. The base of flower scapes was immersed with pulsing treatments (Control, 100 chlorine, 250 or 500 mg L-1 8-HQC) for 48 h, thereafter, stored at 10.5 °C and 90% relative humidity for a period of 12 days. Flower parts were sampled for polyamines analysis at day 0, 4, 8 and 12 days during storage. All samples had higher Put levels than the control. Treatment with 500 mg L-1 8-HQC showed the highest Spd levels in bracts, while chlorine treatment had the highest Spm levels in stems.

Comprehensive Microbial Study on Biocide Application as Vase Solution Preservatives for Cut ‘Cherry Brandy’ Rose Flower

Disturbance in water relations is the major causes of vase life reduction and senescence in cut flowers This problem is mainly due to microorganism proliferation in the vase solution which leads to vascular occlusion and reduction in solution uptake by cut flowers. Therefore a comprehensive study was conducted to evaluate the biocidal effect of nano silver particles (NSP) and compare it with some previously applied biocides. Roses (cv. Cherry Brandy) were treated in a completely randomized design with: colloid of NSP, citric acid, aluminum sulfate, hydroxyquinoline citrate (HQC), calcium hypochlorite, sodium hypochlorite (NaOCl), tap water, or sterilized distilled water as vase water or solution. Longest vase life was observed in flowers treated with nano silver particles, aluminum sulphate and citric acid, respectively. Nano silver particles, HQC and calcium hypochlorite were the most effective treatments in controlling microbial population followed by aluminum sulfate as the second effective treatment. Nano silver particles, HQC and calcium hypochlorite completely inhibited the microbial growth during the first six days of experiment. Moreover, aluminum sulfate retarded microbial growth, proliferation and growth rate more efficiently than others. Each treatment allowed proliferation of a specific microbe. In general, two yeasts, six fungi, and 26 bacterial colonies were isolated from different vase solutions. Among the isolated fungi, one isolate was Trichoderma harzianum and the five other were different strains of Fusarium solani. Identified bacterial isolates were Bacillus sp., Coccus spp., Streptomyces sp., Pectobacterium sp., Burkholderia sp., and Pseudomonas sp. Bacillus was the most wide spread microorganism in most treatments. Identified Bacillus sp. isolates were B. polymexa, B. subtilis, B. megaterium and B. circulans. Since nano silver significantly improved vase life and effectively controlled microbial proliferation in vase solution, our results suggest that nano silver application could be considered as a biocidal preservative solution for rose cut flowers.

The effect of preservatives on water balance in cut clematis flowers

ABSTRACTA positive water balance is crucial for longevity of cut shoots. When water loss by transpiration exceeds water uptake by cut flowers, wilting symptoms appear. Clematis is a very attractive plant which can be used as a cut flower provided that suitable cultivars are chosen. The vase life of four cultivars tested ranged between 6.7 days and 9.0 days and the standard preservative – 200 mg·dm−3 8-hydroxyquinoline citrate (8HQC) plus 2% sucrose – prolonged it significantly in two cultivars, while 8HQC alone was efficient in only one. The preservatives delayed reduction in fresh weight. An enhancement of water uptake by the preservatives resulted in prolonged vase life of flowers in two cultivars. However, the effect of preservatives on transpiration was not related to longevity. In addition, longevity did not depend on the xylem vessel size: the cultivar with the longest vase life had the lowest average xylem vessel diameter while the cultivar with the largest vessels had an intermediate vase life. Preservatives did not always affect the number of blockages in xylem appearing during vase life. Generally, the effects of preservatives on the elements of water balance in cut shoots of clematis were not directly related to the postharvest longevity.