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Agrociencia

On-line version ISSN 2521-9766Print version ISSN 1405-3195

Agrociencia vol.52 n.7 México Oct./Nov. 2018

 

Biotechnology

Sucrosesucrose and citric acid in preservative solutions with nano silver particles in the vase life of rosa

Columba Vicencio-Salas Solís1 

Araceli Zavaleta-Mancera1  * 

Ma. de Lourdes Arévalo Galarza2 

Luis M. Carrillo-López1 

Mario Luna Cavazos3 

1 Botánica. Campus Montecillo. Colegio de Postgraduados. 56230. Montecillo, Estado de México.

2 Fruticultura. Campus Montecillo. Colegio de Postgraduados. 56230. Montecillo, Estado de México.

3 Facultad de Zootecnia y Ecología, Universidad Autónoma de Chihuahua, Periférico Francisco R. Almada Km 1, 33820. Chihuahua.


Abstract

The silver nanoparticles (Ag NPs) in the vase solutions are antimicrobial agents and ethylene inhibitors in some species for cut flowers, but the combined effect of sucrosesucrose and citric acid remains uninvestigated. The biosynthesis of Ag NPs with plant extracts is an efficient and ecologically friendly method. The objective of the present study was to evaluate the effect of sucrosesucrose and citric acid in combination with 1 ppm NPs of Ag in the vase life of Rosa hybrida cv. Freedom. The NPs were synthesized with Camelia sinensis extract and characterized them with UV-Vis spectrometry and Transmission Electron Microscopy. The design was completely randomized and the treatments were: 1) 1 ppm Ag NPs; 2) 1 ppm Ag NPs + 2% sucrosesucrose (pH 6); 3) 1 ppm Ag NPs + citric acid (pH 3), d) 1 ppm Ag NPs + citric acid + 2% sucrosesucrose; 4) control (distilled water, pH 6). The experimental unit was a floral stem with 15 replicates per treatment. The treatment 1 ppm NPs + citric acid generated the longest vase life (7.3 d), the highest water consumption (147.08 mL) and the highest relative fresh weight (89.50%). The treatments with AgNPs alone and AgNPs + citric acid delayed the maximum floral opening (5.33 d and 6.80 d) with respect to the control (3.13 d); variable related to the longevity of the flower. The presence of AgNPs in the solution inhibited bacterial growth but the citric acid increased the water consumption and the fresh weight of the floral stem. The presence of sucrosesucrose in the solution reduced the vase life, the consumption of water and increased the bacterial count but the acidification of the medium with citric acid partially reversed the negative effect of sucrosesucrose.

Keywords: Rosa hybrida; silver nanoparticles; vase solution; sucrosesucrose; citric acid

Resumen

Las nano partículas de plata (NPs de Ag) en las soluciones florero son agentes antimicrobianos e inhibidores de etileno en algunas especies de flor para corte, pero el efecto combinado de sacarosa y el ácido cítrico no se ha investigado. La biosíntesis de NPs de Ag con extractos vegetales es un método eficiente y ecológicamente amigable. El objetivo del presente estudio fue evaluar el efecto de sacarosa y ácido cítrico en combinación con 1 ppm NPs de Ag, en la vida florero de Rosa hybrida cv. Freedom. Las NPs se sintetizaron con extracto de Camelia sinensis y se caracterizaron con espectrometría UV-Vis y Microscopía Electrónica de Transmisión. El diseño fue completamente al azar y los tratamientos fueron: 1) 1 ppm NPs de Ag; 2) 1 ppm NPs de Ag + 2 % sacarosa (pH 6); 3) 1 ppm NPs de Ag +ácido cítrico (pH 3), d) 1 ppm NPs Ag + ácido cítrico + 2 % sacarosa; 4) testigo (agua destilada, pH 6). La unidad experimental fue un tallo floral con 15 repeticiones por tratamiento. El tratamiento 1 ppm NPs + ácido cítrico generó la mayor vida de florero (7.3 d) y el mayor consumo de agua (147.08 mL) y el mayor peso fresco relativo (89.50 %). Los tratamientos con solo NPs de Ag y NPs + ácido cítrico retrasaron la apertura floral máxima (5.33 d y 6.80 d) con respecto al testigo (3.13 d); variable relacionada con la longevidad de la flor. La presencia de NPs de Ag en la solución inhibió el crecimiento bacteriano pero el ácido cítrico aumentó el consumo de agua y el peso fresco del tallo floral. La presencia de sacarosa en la solución redujo la vida florero, el consumo de agua y aumentó el conteo bacteriano pero la acidificación del medio con ácido cítrico revirtió parcialmente el efecto negativo de la sacarosa.

Palabras clave: Rosa hybrida; nanopartículas de plata; solución florero; sacarosa; ácido cítrico

Introduction

Mexico is a country with a wide potential for the production and export of cut flowers and pot plants; it has satisfactory climates for the cultivation of different species, has good labour offer, a large market and proximity to the great consumer, the United States of America (Tejeda and Arévalo, 2012, Hernández, 2007, van Vliet, 2004). However, the country's potential is diminished by technological backwardness, lack of organization, poor working conditions in the country and low exports (Tejeda-Sartorius and Arévalo-Galarza, 2012, van Vliet, 2004).

In cut flowers, the common causes of senescence are the inhibition of water absorption, dehydration due to poor management, low carbohydrate supply to sustain respiration, the presence of ethylene and other associated metabolic events (Halevy and Mayak, 1981). Microbial contamination at the base of the stems is the main cause of the blockage of the xylem vessels, which reduces water absorption and consequently the longevity of the flower stems (Zagory and Reid, 1986).

Some requirements necessary for the survival of the cut flowers are the quality and acidity (pH 3-5) of the water, which affect the microbial growth (Hayat et al., 2012). The vase solutions contribute to lengthen the life of cut flowers. These solutions have several functions: to reduce the synthesis of ethylene; inhibit the development of pathogenic microorganisms; maintain water and respiratory balance; contribute to the conservation of colour and induce the opening of flower buds (Halevy and Mayak, 1981).

Silver (Ag+) is used in preservative solutions such as silver thiosulfate or silver nitrate, due to its antimicrobial properties and to inhibit ethylene production in cut flowers and thus prolonging vase life; but the disposal of these solutions by the flower packers is a potential damage to the environment, so we must find alternatives to reduce their use. The nanostructured materials have at least one dimension in nanometric scale (1-100 nm) among which we can find nanoparticles, nanobars, nanowires and thin films (Cao and Wang, 2011).

When the particle size decreases there is an increase in the volume fraction of the boundaries of the particle or interfaces and triple bonds, with an increase in the density of defects; the atoms in the particle boundaries and triple bonds begin to compare with those residing in the nuclei (Murty et al., 2013). Due to the high surface/volume ratio, among other chemical and physical properties, nanoparticles are efficient by contact with microorganisms, which makes them very effective as germicides (Monge, 2009); therefore, silver concentrations are much lower when nanoparticles are used instead of silver salts. In addition, the biosynthesis of nanoparticles consists of the production of NPs using biological systems, which is based on the reductive property of biomolecules. This synthesis method is considered eco-friendly (Sadowski, 2010) since the reagents for synthesis (plant extract) are not toxic nor require stabilizing substances, unlike chemical and physical methods (Iravani, 2014). Several aqueous extracts of plants are used in the reduction of Ag NPs, such as Phlomis sp. (Allafchian et al., 2016), Pteris tripartita (Baskaran et al., 2016), Acacia leucophloea (Murugan et al., 2014) and Opuntia ficus-indica (Rico-Moctezuma et al., 2010) for the biosynthesis of Ag NPs.

The size and morphology of the nanostructures depends on the interaction of the biomolecules with the metal ions (Makarov et al., 2014; Shiv Shankar et al., 2004). Phenolic compounds such as flavonoids and anthocyanins contain hydroxyl groups that have a strong ability to bind silver ions and involve them in the biosynthesis of nanoparticles and function as a reducing agent of silver ions (Ag+) to Ag NPs (Ag0) (Jain et al., 2009; Solgi and Taghizadeh, 2012).

The Ag NPs originated with chemical methods are used in vase or pulse solutions in experiments. The biocidal effect of Ag NPs on vase and pulse solutions (Nemati et al., 2013, Solgi et al., 2009) is frequently the object of research, but little is known about the effect of sucrosesucrose and citric acid in vase solutions prepared with Ag NPs as a microbicidal agent.

The objective of the present research was to study the effect of sucrosesucrose and citric acid in preservative solutions added with Ag NPs synthesized with extracts of Camellia sinensis in the vase life, bacterial population, floral opening, perspiration and water relations of Rosa hybrida cultivar Freedom.

Materials and Methods

Biosynthesis of silver nanoparticles

We obtained the vegetal extract by boiling (95 °C) for 5 min 2 g of Lagg® green tea (Camellia sinensis) in 100 mL of deionized water, cooled to 22 °C and filtered with Whatman No. 4 paper. From a 10 mM solution of AgNO3 (Sigma Aldrich from Mexico, ACS ≥ 99.0%) prepared with deionized water, we took 5 mL, added 3 mL of aqueous extract of Camellia sinensis, and then adjusted the solution to 15 mL with deionized water (modification by Carrillo, 2014 and Nakhjavani et al., 2017) and exposed to sunlight for 5 minutes.

Characterization of Ag NPs

We evaluated the formation of the NPs with spectroscopy (UV-vis) in an HP 845x UV-visible System Spectrophotometer in a range of 350 to 700 nm, to verify the presence of the surface plasmon resonance (SPR). The stability over time of NPs was verified at 1 h, 2 h, 3 h, 4 h, 5 h, 24 h, 48 h, 72 h, 5 d, 12 d, 30 d, 60 d, 90 d, 130 d, 160 d, 200 d, and 9, 10, 11, 12, 13 and 14 months. We studied the morphology and dimensions of the Ag NPs with an Electronic Transmission Microscope (MET, Tecnai 2 Spirit, Thermo Fisher Scientific-Fei Copany), in bright field mode, at 150000 and x300,000 magnifications and 120 kV.) The largest (DMa) and smallest (DMe) diameters were measured in 251 particles with the TIA 4.7 SP3 image processor (Tecnai: Imagining & Analysis, USA) to obtain the average diameter and the roundness index (IR = DMa/DMe).

Biological material and establishment of the experiment

We obtained stems of Rosa hybrida cv. Freedom from the commercial greenhouse of the company “Flores Selectas of Tequexquinahuac”, S. de P. R. de R. L. (19° 28' 51.26" N, 98° 50' 23.03" W), in Tequexquinahuac, Texcoco, State of Mexico. The floral stems were cut the same day, with a harvest index of 2, according to De la Cruz et al., (2015) and they were used without receiving any postharvest treatment. We adjusted the stem lengths to 35 cm ± 2 and 6 leaves.

In a preliminary study, the concentration of 1 ppm NPs appeared to be the most efficient in reducing vascular tissue obstruction and the bacterial population in the preservative solution, so we used this concentration for the present study. We prepared the solutions with distilled water from a solution with 1 ppm of Ag NPs, with and without sucrosesucrose (2%) and two pH (5.8 and 3.4) by the addition of citric acid. The control treatment was distilled water pH 5.6.

Experimental design and statistical analysis

The experimental design was completely randomized with the following treatments: 1) 1 ppm Ag NPs, 2) 1 ppm Ag NPs + 2% sucrosesucrose (pH 6), 3) 1 ppm Ag NPs + citric acid (pH 3), 4) 1 ppm Ag NPs + citric acid + 2% sucrosesucrose and 5) control (distilled water, pH 6). The experimental unit was a floral stem in a vase (250 mL) with 200 mL of preservative solution, with 15 replicates per treatment. The stems were placed in a room at 25 ± 2 °C and 60% relative humidity, and 2 cm were cut at the base on days 4 and 9. The vases were covered with parafilm to avoid evaporation. Results were analysed with ANOVA and the treatment means were compared with the Tukey test (p ≤ 0.05) using the SAS System 9.0 software.

Variables evaluated

We measured water consumption every day with a digital balance (Setra, S1-2000, USA), to calculate the volume (mL) of water consumed by the stem. We estimated the change in fresh weight from the difference between the initial fresh weight (PF0) and the fresh weight at 24 h (PF1) x 100 until the end of the vase life. The vase life (d) or longevity was measured at the beginning of the experiment until the senescence of the stems, which was determined considering the presence of any of the following characteristics: wilting of the petals, darkening of ≥ 30% of the edge of external petals, neck bending and relative weight of 85% (Hernández et al., 2009). We evaluated the floral opening and the maximum floral opening by daily measuring the diameter of the button (mm) with a digital vernier scale (Trupper, Mexico). The bacterial count (Log 10 CFU mL-1) in the preservative solution was measured on the third and seventh days in 5 vases per treatment per date, for which we used 3MTM PetrifilmTM plates (3M MEXICO S.A. DE C.V.); on this account, we placed 1 mL of vase solution per plate and incubated it at 22 °C for 24 h, under aseptic conditions. In cases of excessive bacterial colonies, we diluted 1:10 and 1:20 the solution with distilled water, depending on the case.

Results and Discussion

Characterization of nanoparticles

Brahmachari et al. (2014) suggest that in Oncimum sanctum eugenol is the predominant chemical compound, so under solar radiation the phenolic OH bond undergoes homolytic cleavage to form a radical that eventually transfers its electron to the silver ion (Ag+) to form Ag NPs. The UV-Vis absorption spectra provide information on the optical properties dependent on the size, distribution and surface properties of metallic NPs (Ider et al., 2016).

With the biosynthesis method with 5 mL of 10 mM AgNO3 + 3 mL of Camellia sinensis aqueous extract, the absorption peak was 436.8 ± 2.154 nm from the first hour of reaction, which increased in time, and the highest absorbance was obtained at month 14 (Figure 1). This indicates an increase of Ag NPs synthesized over time (Carrillo et al., 2014). The amplitude of the plasmon peak depends on the size distribution of NPs (Pastoriza et al., 2002). Vilchis-Nestor et al. (2008) observed that in the solutions with AgNO3, 10 mM and aqueous extract of C. sinensis from 1 to 10 mL the reduction of silver ions and the formation of stable NPs occurred within the first 4 h of reaction. The wavelengths of the maximum absorption of Ag NPs at 4 h (440, 445 and 430 nm) were similar to those obtained by Hussain and Khan (2014), Kamal et al. (2010) and Vilchis-Nestor et al. (2008). The maximum absorbance (20.89 u.a.) was higher in our study compared with those already mentioned. The experiment with black tea (C. sinensis) conducted by Begum et al. (2009) shows a similar maximum absorbance (460 nm) to that reported. The maximum absorbances increased over time. At 60 min (1 h) the maximum absorbance was 11.99 u.a. (λ of 433 nm), but at 14 months the absorbance increased to 31.06 u.a. (λ 446 nm). The SPR were symmetric, indicating the stability of the system over time (Ider et al., 2016; Carrillo et al., 2014). The symmetric shape of the PSR peak indicates the existence of spherical-shaped Ag NPs and a uniform distribution (Ider et al., 2016).

Figure 1 Spectra of absorption (SPR) of silver nanoparticles synthesized with 10 mM AgNO3 (5 mL) and aqueous extract of C. sinensis (3 mL) at 24 °C taken at different times. 

A greater absorption registered in the peak of the SPR reflects a greater reduction of silver ions and, in turn, a higher concentration of Ag NPs (Ider et al., 2016; Carrillo et al., 2014).

Eighty percent of the Ag NPs synthesized and stored for 14 months at 4 °C showed diameters between 10-40 nm and a quasi-spherical shape (roundness index 0.893 ± 0.006) (Figure 2).

Figure 2 Transmission Electron Microscopy of Ag NPs synthesized with + 5 mL 10 mM AgNO3 + 3 mL of C. sinensis extract. A and B, morphology and distribution. D, measurement of the largest and smallest diameter for roundness index. Tecnai 2G Spirit, at 120 kV. 

The Ag NPs produced had an average size of 21.509 ± 0.634 nm and 81.6% were less than 30 nm. The size intervals with the highest frequency were 10 to 20 and 20 to 30 (Figure 3). Hussain and Khan (2014) obtained nanodiscs 47 nm long and 10 nm wide, synthesized with 1 mM AgNO3 and 4% extract with catechins; and Sun et al. (2014) synthesized NPs of 20-90 nm with 10 mM AgNO3 and with different concentrations of tea extract. In addition, Rastogi and Arunachalam (2011) obtained spherical Ag NPs of 7.3 ± 4.4 nm by exposing a solution of [Ag (NH3) 2] + 0.1 M with extract of Allium sativum (garlic) to sunlight for 15 min.

Figure 3 Size distribution of Ag NPs synthesized with 5 mL of 10 mM AgNO3 + 3 mL of aqueous extract of C. sinensis and 5 min of exposure to sunlight (n = 251). 

The roundness index (IR) was high, 0.893 ± 0.006, and indicated a quasi-spherical shape.

Changes in fresh weight and water consumption

In the treatment with citric acid (pH 3) we obtained the highest relative fresh weight (PFR) (104.77%) on the third day and during the whole experiment it was significantly higher than the control (pH 6) (PFR, 86.24%), which was reflected in a reduction of the vase life. Safa et al. (2015), Liu et al. (2012) and et al. (2010) observed that the use of Ag NPs in vase solutions significantly decreases the loss of PFR in stems of Gerbera jamesonii cv. 'Balance', Acacia holasericea and R. hybrida cv. 'Movie Star'. In all these tests, the PFR was significantly lower in the control treatment. The reduction of pH by the addition of citric acid to a solution with NPs improved the preservative effect of the Ag NPs and allowed a greater absorption of water by the stem. The treatment of Ag NPs with sucrosesucrose (pH 6) had an accelerated loss of PF from day 4. The treatments of Ag NPs without sucrosesucrose caused gain of PF until day 3, and later they lost weight progressively (Figure 4).

Table 1 Effect of sucrosesucrose and citric acid on solutions with 1 ppm of Ag NPs on the relative fresh weight of stems of Rosa hybrida cv. Freedom. 

Tratamientos Peso fresco relativo (%)
Día 1 Día 3 Día 5 Día 7 M.A.F (días)
Testigo (agua) 104.44 a 82.41 c 67.86 c 57.68 b 3.13 c
NPs de Ag 102.97 ab 96.56 ab 92.48 a 82.12 a 5.33 ab
NPs de Ag + sacarosa 98.45 b 92.05 bc 80.41 b 66.82 b 3.87 bc
NPs de Ag + Ác. cítrico 104.15 a 100.40 a 96.30 a 89.50 a 6.80 a
NPs de Ag + Ác. cítrico + sacarosa 99.33 b 97.05 ab 93.02 a 85.67 a 4.73 bc
C.V. (%) 7.43 10.23 12.73 16.69 38.31

MAF: Days at the maximum floral opening. Different letters in columns indicate significant statistical differences (Tukey; p ≤ 0.05, n=15).

Figure 4 Stems of Rosa hybrida cv. Freedom after ten days of evaluation. T-1: Water; T-2: 1 ppm of Ag NPs; T-3: 1 ppm Ag NPs + sacchrose; T-4: 1 ppm of Ag NPs + citric acid, and T-5: 1 ppm of Ag NPs + citric acid + sacchrose. 

The water balance results from the difference between water consumption and water loss in the stem (Ried and Jiang, 2012). The absorption of water stops during dry management due to the phenomenon of embolism, in which the water column in the xylem does no longer flow due to a bacterial occlusion or formation of tampons by tyloses, and gels in the vessels (Van Doorn and Reid, 1995). The control and treatments with Ag NPs without sucrosesucrose registered higher water consumption during the first 2 d (54.16 mL) (Table 2). The treatment with Ag NPs + citric acid had the highest cumulative consumption (147.08 mL) on day 8. According to Nazemi and Ramezanian (2013), treatments with Ag NPs increase the rate of water absorption in Rosa cv. Avalanche, but in the present study we corroborated the positive effect of acidification of the medium on water absorption due to the reduction of vascular blockage (Reid and Jiang, 2012, Reid and Kofranek, 1980).

Table 2 Effect of sucrosesucrose and citric acid on solutions with Ag NPs in the accumulated water consumption of R. hybrida cv. Freedom. 

Tratamientos Consumo de agua acumulado (mL)
Día 2 Día 4 Día 6 Día 8
Testigo (agua) 54.16 a 77.96 bc 88.78 bc 96.88 cd
NPs de Ag 50.67 ab 89.10 ab 110.03 ab 126.40 ab
NPs de Ag + sacarosa 39.42 b 67.22 c 78.45 c 86.29 d
NPs de Ag + ác. cítrico 54.94 a 98.73 a 128.04 a 147.08 a
NPs de Ag + ác. cítrico + sacarosa 44.07 ab 79.33 abc 98.19 bc 116.86 bc
C.V. (%) 26.33 24.27 22.31 21.78

Different letters in a column indicate significant statistical differences (Tukey, p ≤ 0.05; n = 15).

The control and sucrosesucrose treatments had less accumulated water consumption. This variable related to vase life, and stems with a lower water consumption showed early wilting, loss of color and neck bending (Figure 5). The Ag NPs + citric acid treatment favored longer vase life, increased water consumption, and obtained greater fresh weight and better vase life quality (Figure 5). Ethylene is a phytohormone that has negative effects on the floral longevity of species sensitive to this molecule, but this effect can be inhibited by the Ag + ion (Reid and Jiang, 2012).

Figure 5 Effect of Ag NPs with sacchrose and citric acid in the vase life of stems of Rosa hybrida cv. Freedom. Different letters indicate significant differences (Tukey, p ≤ 0.05, n=15). 

In the present study there were no significant differences between treatments regarding the diameter of the maximum floral opening, but we did detect them in the floral opening speed which was delayed in the solution with citric acid + 1 ppm of Ag NPs (Figure 5), variable related to the longevity of the flower.

Vase life

The longest vase life treatment was NPs + citric acid (7.3 d). In Gerbera jamesonii we obtained the maximum vase life only with the addition of Ag NPs to the vase solution (Geshnizjany et al., 2014). In the experiment with the cv. of Rosa Freedom, the addition of sucrosesucrose to the vase solutions with 1 ppm of Ag NPs decreased the vase life, in contrast to the sole presence of Ag NPs (Figure 5). The use of sucrosesucrose in the vase solutions has benefits: longer vase life and relative fresh weight in stems, improvement in floral opening, pigmentation, reduction of sensitivity to ethylene and improved water relations (Asgari et al., 2013; and Jiang, 2012; Hayat et al., 2012; et al., 2010). Yet in the present study, sucrosesucrose had an adverse effect on solutions with Ag NPs, which increased the bacterial count in the solution and reduced the flower vase life. This adverse effect was counteracted by citric acid, which decreased the adverse effects of sucrosesucrose by acidifying the solution (Figure 7). The decrease of pH limits the proliferation of microorganisms (Hayat et al., 2012; Jowkar et al., 2012), related to vessel obstruction and lower water absorption (Macnish et al., 2008; Van Doorn, 1997).

Bacterial count of the solution

In this study, the addition of sucrosesucrose in the preservative solution with AG NPs promoted bacterial growth in the solution on the third day, but on the seventh day the control (water) recorded the highest bacterial count (Table 3). The treatment with the lowest bacterial count (CFU mL-1 0.85) was that of Ag NPs + citric acid (pH3). The treatments with citric acid, with pH 3, had lower CFU mL-1 than the other treatments, with pH 6, so the acidification of the solutions contributed to the inhibition of bacterial growth.

Table 3 Bacterial count in the solution (Log 10 CFU mL-1) per treatment 

Tratamientos Log 10 UFC mL-1
Día 3 Día 7
Control (agua) 2.42 a 3.51 a
NPs de Ag 1.85 ab 2.36 ab
NPs de Ag + sacarosa 2.60 a 2.91 a
NPs de Ag + ác. cítrico 0.17 c 0.85 b
NPs de Ag + ác. cítrico + sacarosa 0.64 bc 1.26 b
C.V. (%) 42.34 33.95

Different letters in a column indicate significant statistical differences (Tukey; p ≤ 0.05; n=5).

The number of CFUs increased over time, the same as in the experiment by Liu et al. (2009, 2012), who did not find significant differences between the control treatment (distilled water) and the treatment with Ag NPs (5 mg L-1), in pulse solutions. According to Okafor et al. (2013), concentrations of 4 ppm of Ag NPs synthesized with plant extracts (aloe, geranium, magnolia and black cohosh) and 3-9 nm in size, inhibited the bacterial growth of E. coli.

In a previous study all the treatments presented bacterial growth in the solution, but the treatments with 1, 5 and 10 ppm of Ag NPs (21.5 nm) synthesized with aqueous extract of C. sinensis had an antimicrobial activity that prevented the occlusion of a large number of xylem vessels. Okafor et al. (2013) observed that Ag NPs synthesized with aloe extract had the highest antibacterial activity compared to treatments with 2 and 4 ppm of Ag NPs (3-9 nm) synthesized with extracts of geranium, magnolia and black cohosh. According to Jowkar et al. (2013), there was no microbial growth in vase solutions treated with 1, 2.5 and 5% of Ag NPs, but these concentrations are higher than those of our study. However, Carrillo et al. (2016) reported that vase solutions with 0.01, 0.05, 0.1, 0.5, 1 and 5 mM of Ag NPs (10.3 nm) had no CFU in the solution. Reid and Jiang (2012) mentioned that reducing the pH of the solution, either with citric acid or Al2 (SO4) 3, helps to reduce bacterial growth, but it is insufficient in itself because acidophilic yeasts and bacteria can quickly colonize the vase solution.

It follows that not all species of microorganisms affect vase life in the same way. Zagory and Reid (1986) observed that an unidentified yeast caused more damage in the vase life of carnation (Dianthus caryophyllus) with an inoculum of 103 CFU mL-1 than Pseudomonas sp. with an inoculum of 106 CFU mL-1.

Conclusions

The addition of aqueous extract of Camellia sinensis in a solution of AgNO3, with exposure to sunlight, produced Ag NPs of quasi-spherical forms, with uniform size distribution. The NPs obtained were stable for 14 months stored at 4°C, which was corroborated with the presence of the SPR in the solutions with Ag NPs. The Ag NPs did not cause the total elimination of mesophilic aerobic bacteria in the vase solutions, but the increase in CFUs between the first and second counting was lower in the solutions with Ag NPs than in the control.

The sucrosesucrose treatments showed a higher number of CFU in the solution and shorter vase life. The addition of Ag NPs and citric acid to the vase solutions improved the quality of the stems; the opening period lengthened, and there was greater water absorption by the stem and vase life.

A low concentration of Ag NPs allowed to improve the quality of the vase life of stems of Rosa hybrida cv. Freedom. But it is necessary to formulate alternatives for the use of Ag NPs in vase solutions based on drinking water, as it is the one used by local farmers and final consumers. However, the concentration of 1 ppm of Ag NPs is low and more studies are required to evaluate the impact of these nanoparticles on the environment.

Literatura Citada

Allafchian, A. R., S. Z. Mirahmadi-Zare, S. A. H. Jalali, S. S. Hashemi, and M. R. Vahabi. 2016. Green synthesis of silver nanoparticles using phlomis leaf extract and investigation of their antibacterial activity. J. Nanostruct. Chem. 6: 129-135. [ Links ]

Asgari, M., M. H. Azimi, Z. Hamzehi, S. N. Mortazavi, and F. Khodabandelu. 2013. Effect of nano-silver and sucrose on vase life of Tuberose (Polianthes tuberosa cv. peril) cut flowers. Intl. J. Agron. Plant Prod. 4: 680-687. [ Links ]

Baskaran, X., A. V. Geo V., T. Parimelazhagan, D. Muralidhara-Rao, and S. Zhang. 2016. Biosynthesis, characterization, and evaluation of bioactivities of leaf extract-mediated biocompatible silver nanoparticles from an early tracheophyte, Pteris tripartita Sw. Int. J. Nanomedicine 11: 5789-5806. [ Links ]

Begum, A. A., S. Mondal, S. Basu, R. A., and Mandal Debabrata. 2009. Biogenic synthesis of Au and Ag nanoparticles using aqueous solutions of black tea leaf extracts. Colloids Surf B Biointerfaces 71: 113-118. [ Links ]

Boruah, S. K., P. K. Boruah, P. Sarma, C. Medhi, and O. K. Medhi. 2012. Green synthesis of gold nanoparticles using Camellia sinensis and kinetics of the reaction. Adv. Mat. Lett. 3: 481-486. [ Links ]

Brahmachari, G., S. Sarkar, R. Ghosh, S. Barman, N. C. Mandal, S. K. Jash, B. Banerjee, and R. Roy. 2014. Sunlight-induced rapid and efficient biogenic synthesis of silver nanoparticles using aqueous leaf extract of Ocimum sanctum Linn. with enhanced antibacterial activity. Org. Med. Chem. Lett. 4:18. [ Links ]

Cao, G., and Y. Wang. 2011. Nanostructures and nanomaterials: synthesis, properties, and applications. World Scientific. Singapore. 581 p. [ Links ]

Carrillo L., L. M., A. Morgado G., and A. Morgado G. 2016. Biosynthesized silver nanoparticles used in preservative solutions for Chrysanthemum cv. Puma. J. Nanomater 2016. https://doi.org/10.1155/2016/1769250 [ Links ]

Carrillo L., L. M., H. A. Zavaleta M., A. Vilchis N., R. M. Soto H., J. Arenas A., L. I. Trejo T., and F. Gómez M. 2014. Biosynthesis of silver nanoparticles using Chenopodium ambrosioides. J Nanomater 2014. https://doi.org/10.1155/2014/951746 [ Links ]

De la Cruz G., G. H., M. L. Arévalo G., C. B. Peña V., A. M. Castillo G., M. T. Colinas L., y M. Mandujano P. 2015. Influencia del índice de cosecha en la vida de florero de siete cultivares de Rosa hybrida. Agroproductividad 8: 3 - 11. [ Links ]

Geshnizjany, N., A. Ramezanian, and M. Khosh-khui. 2014. Postharvest life of cut gerbera (Gerbera jamesonii) as affected by nano-silver particles and calcium chloride. Int. J. Hort. Sci. Technol. 1: 171-180. [ Links ]

Halevy, A. H., and S. Mayak. 1981. Senescence and postharvest physiology of cut flowers-part 2. In: Jules, J. (ed). Horticultural Reviews. John Wiley & Sons. pp: 59-143. [ Links ]

Hayat, S., N. U. Amin, M. A. Khan, T. M. A. Soliman, M. Nan, K. Hayat, I. Ahmad, M. R. Kabir, and L. J. Zhao. 2012. Impact of silver thiosulfate and sucrose solution on the vase life of rose cut flower cv. cardinal. Adv. Environ. Biol. 6: 1643-1649. [ Links ]

Hernández H., F., M. L. Arévalo G., M. T. Colinas L. , H. A. Zavaleta M., y J. Valdes C. 2009. Diferencias anatómicas y uso de soluciones de pulso en dos cultivares de rosa (Rosa sp.). Rev. Chapingo Ser. Hortic. 15:11-16. [ Links ]

Hussain, S., and Z. Khan. 2014. Epigallocatechin-3-gallate-capped Ag nanoparticles: preparation and characterization. Bioprocess Biosyst. Eng. 37: 1221-1231. [ Links ]

Jain, D., H. K. Daima, S. Kachhwaha, and S. L. Kothari. 2009. Synthesis of plant-mediated silver nanoparticles using papaya fruit extract and evaluation of their anti-microbial activities. Dig. J. Nanomater Biostruct. 4: 723-727. [ Links ]

Jowkar, M. M., M. Kafi, A. Khalighi, and N. Hasanzadeh. 2012. Reconsideration in using citric acid as vase solution preservative for cut rose flowers. Curr. Res. J. Biol. Sci. 4: 427-436. [ Links ]

Jowkar, M. M., A. Khalighi, M. Kaf,i and N. Hassanzadeh. 2013. Nano silver application impact as vase solution biocide on postharvest microbial and physiological properties of “Cherry Brandy”. JFAE 11: 1045-1050. [ Links ]

Kamal, S. S. K., P. K. Sahoo, J. Vimala, M. Premkumar, S. Ram, and L. Durai. 2010. A novel green chemical route for synthesis of silver nanoparticles using Camellia sinensis. Acta Chim. Slov. 57: 808-812. [ Links ]

Iravani, S., H. Korbekandi, S.V. Mirmohammadi, and B. Zolfaghari. 2014. Synthesis of silver nanoparticles: chemical, physical and biological methods. Res. Pharm. Sci. 9: 385-406. [ Links ]

Ider M., K. Abderrafi, A. Eddahbi, S. Ouaskit, and A. Kassiba. 2016. Rapid synthesis of silver nanoparticles by microwave-polyol method with the assistance of latex copolymer. J. Clust. Sci. DOI 10.1007/s10876-016-1096-6. [ Links ]

Liu, J., S. He, Z. Zhang, J. Cao, P. Lv, S. He, G. Cheng, and D. C. Joyce. 2009. Nano-silver pulse treatments inhibit stem-end bacteria on cut gerbera cv. Ruikou flowers. Postharvest Biol. Technol. 54: 59-62. doi: 10.1016/j.postharvbio.2009.05.004 [ Links ]

Liu, J., K. Ratnayake, D. C. Joyce, S. He, and Z. Zhang. 2012. Effects of three different nano-silver formulations on cut Acacia holosericea vase life. Postharvest Biol. Technol. 66: 8-15. doi.org/10.1016/j.postharvbio.2011.11.005. [ Links ]

Loo, Y. Y., B. W. Chieng, M. Nishibuchi, and S. Radu. 2012. Synthesis of silver nanoparticles by using tea leaf extract from Camellia sinensis. Int. J. Nanomedicine 7: 4263-4267. [ Links ]

Lü, P., J. Cao., S. He, J. Liu, H. Li, G. Cheng, Y. Ding, and D. C. Joyce. 2010. Nano-silver pulse treatments improve water relations of cut rose cv. Movie Star flowers. Postharvest Biol. Technol. 57: 196-202. doi:10.1016/j.postharvbio.2010.04.003 [ Links ]

Macnish, A. J., R. T. Leonard and T. A. Nell. 2008. Treatment with chlorine dioxide extends the vase life of selected cut flowers. Postharvest Biol. Technol. 50: 197-207. doi: 10.1016/j.postharvbio.2008.04.008 [ Links ]

Monge, M. 2009. Nanopartículas de plata : métodos de síntesis en disolución y propiedades bactericidas. An. Quím. 105: 33-41. [ Links ]

Murugan K., B. Senthilkumar, D. Senbagam, and S. Al-Sohaibani. 2014. Biosynthesis of silver nanoparticles using Acacia leucophloea extract and their antibacterial activity. Int. J. Nanomedicine 9: 2431-2438. [ Links ]

Nakhjavani, M., V. Nikkhah, M. M. Sarafraz, S. Shoja, and M. Sarafraz. 2017. Green synthesis of silver nanoparticles using green tea leaves: Experimental study on the morphological, rheological and antibacterial behaviour. Heat Mass Transfer. DOI 10.1007/s00231-017-2065-9 [ Links ]

Murty, B. S., P. Shankar, B. Raj, B. B. Rath, and J. Murday. 2013. Textbook of Nanoscience and Nanotechnology. Springer-Verlag Berlin Heidelberg. Berlin. 244 p. [ Links ]

Nemati, S. H., A. Tehranifar, B. Esfandiari, and A. Rezaei. 2013. Improvement of vase life and postharvest factors of Lilium orientalis “bouquet” by silver nano particles. Not Sci. Biol. 5: 490-493. [ Links ]

Okafor, F., A. Janen, T. Kukhtareva, V. Edwards, and M. Curley. 2013. Green synthesis of silver nanoparticles, their characterization, application and antibacterial activity. Int. J. Environ. Res. Public Health 10: 5221-5238. [ Links ]

Pastoriza S., I., and L. M. Liz M. 2002. Formation of PVP-protected metal nanoparticles in DMF. Langmuir 18: 2888-2894. [ Links ]

Rafi, Z. N., and A. Ramezanian. 2013. Vase life of cut rose cultivars ‘Avalanche’ and ‘Fiesta’ as affected by Nano-Silver and S-carvone treatments. S. African J. Bot. 86: 68-72. [ Links ]

Rastogi, L., and J. Arunachalam. 2011. Sunlight based irradiation strategy for rapid green synthesis of highly stable silver nanoparticles using aqueous garlic (Allium sativum) extract and their antibacterial potential. Mater. Chem. Phys. 129: 558-563. [ Links ]

Reid, M., and A. Kofranek. 1980. Postharvest physiology of cut flowers. Chronica Horticulturae 20: 25-27. [ Links ]

Reid, M. S., and C. Z. Jiang. 2012. Postharvest biology and technology of cut flowers and potted plants. In: Janick, J. (ed). Horticultural Reviews. John Wiley & Sons. pp: 1-54. [ Links ]

Rico M., A., A. R. Vilchis N., V. Sánchez M., M. Avalos B., and M. A. Camacho L. 2010. Biosíntesis de nanopartículas de oro mediante el extracto de Opuntia ficus-indica. Superficies y Vacío 23: 94-97. [ Links ]

Sadowski, Z. 2010. Biosynthesis and application of silver and gold nanoparticles. In: Pozo P., D. (ed). Silver Nanoparticles. CC BY-NC-SA. pp: 257-277. [ Links ]

Safa, Z., D. Hashemabadi, B. Kaviani, N. Nikchi, and M. Zarchini. 2015. Studies on quality and vase life of cut Gerbera jamesonii cv. “Balance” flowers by silver nanoparticles and chlorophenol. J. Environ. Biol. 36: 425-431. [ Links ]

Shankar, S. S., A. Rai, A. Ahmad, and M. Sastry. 2004. Rapid synthesis of Au, Ag, and bimetallic Au core-Ag shell nanoparticles using neem (Azadirachta indica) leaf broth. J. Colloid Interface Sci. 275: 496-502. [ Links ]

Solgi, M., and M. Taghizadeh. 2012. Silver nanoparticles ecofriendly synthesis by two medicinal plants. Int. J. Nanomater and Biostructures 2: 60-64. doi: 10.1016/j.postharvbio.2009.04.003 [ Links ]

Solgi, M., M. Kafi, T. S. Taghavi, and R. Naderi. 2009. Essential oils and silver nanoparticles (SNP) as novel agents to extend vase-life of gerbera (Gerbera jamesonii cv. “Dune”) flowers. Postharvest Biol. Technol. 53: 155-158. [ Links ]

Sun, Q., X. Cai, J. Li, M. Zheng, Z. Chen, and C. P. Yu. 2014. Green synthesis of silver nanoparticles using tea leaf extract and evaluation of their stability and antibacterial activity. Colloids Surf A Physicochem. Eng. Asp. 444: 226-231. [ Links ]

Tejeda S., O., y M. L. Arévalo G. La floricultura, una opción económica rentable para el minifundio mexicano. Agroproductividad 5: 11-19. [ Links ]

van Doorn, W. G. 1997. Water Relations of Cut Flowers. Jules, J. (ed). John Wiley & Sons. pp:1-85. [ Links ]

van Doorn, W. G., and M. S. Reid. 1995. Vascular occlusion in stems of cut rose flowers exposed to air: role of xylem anatomy and rates of transpiration. Physiol. Plant. 93: 624-629. [ Links ]

van Vliet, C. 2004. Mexican growers start to apply heat in US. FlowerTECH 7: 6-9. [ Links ]

Vilchis, N., A. R., V. Sánchez M., M. A. Camacho L., R. M. Gómez E., M. A. Camacho L., and J. A. Arenas A. 2008. Solventless synthesis and optical properties of Au and Ag nanoparticles using Camellia sinensis extract. Materials Lett. 62: 3103-3105. [ Links ]

Zagory, D., and M. S. Reid. 1986. Role of vase solution microorganisms in the life of cut flowers. J. Am. Soc. Hortic. Sci. 111: 154-158. [ Links ]

Received: September 2017; Accepted: July 2018

* Author for correspondence: arazavaleta@colpos.com.mx

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