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An R2R3-MYB transcription factor, CmMYB9a, activates floral coloration in chrysanthemum by positively regulating CmCHS, CmDFR and CmFNS, but inhibiting the expression of CmFLS. Chrysanthemum is one of the most popular ornamental plants worldwide. Flavonoids, such as anthocyanins, flavones, and flavonols, are important secondary metabolites for coloration and are involved in many biological processes in plants, like petunia, snapdragon, Gerbera hybrida, as well as chrysanthemum. However, the metabolic regulation of flavonoids contributing to chrysanthemum floral coloration remains largely unexplored. Here, an R2R3-MYB transcription factor, CmMYB9a, was found to be involved in flavonoid biosynthesis. Phylogenetic analysis and amino acid sequence analysis suggested that CmMYB9a belonged to subgroup 7. Transient overexpression of CmMYB9a in flowers of chrysanthemum cultivar 'Anastasia Pink' upregulated the anthocyanin-related and flavone-related genes and downregulated CmFLS, which led to the accumulation of anthocyanins and flavones. We further demonstrated that CmMYB9a independently activates the expression of CmCHS, CmDFR and CmFNS, but inhibits the expression of CmFLS. Overexpression of CmMYB9a in tobacco resulted in increased anthocyanins and decreased flavonols in the petals by upregulating NtDFR and downregulating NtFLS. These results suggest that CmMYB9a facilitates metabolic flux into anthocyanin and flavone biosynthesis. Taken together, this study functionally characterizes the role of CmMYB9a in regulating the branched pathways of flavonoids in chrysanthemum flowers.

In the Netherlands recirculation of the nutrient solution is statutory required in soilless culture systems. The goal is to achieve a zero liquid discharge, it means no solution with fertilizers, pesticides and/or cleansing products are allowed to be discharged to surface or ground water or the sewage system. It also means that products added to the system should be taken up by the plants or broken down. The objectives of this research were to investigate i) if frequently used cleansing products accumulate in the nutrient solution and may harm growth of the plants, and ii) if the used concentrations of cleansing products were able to eliminate pathogens in the circulating nutrient solution. Gerbera was used as a pilot crop. The research was divided in four steps. As a first step growers and consultants were inquired (1) about the use of cleansing products additional to the traditional disinfection methods. It was followed by laboratory experiments (2) to test a few cleansing products in various concentrations against plant pathogens. A next step was a greenhouse experiment in which gerbera plants were infected with Fusarium oxysporum (3). Finally sampling at commercial farms (4) was performed to investigate if accumulation did really appear. The inquiry showed that nearly all growers were using, additional to UV or heat treatment for disinfection, cleansing products such as hydrogen peroxide, bleach, chlorine dioxide or ECA water. They were mainly used for cleaning of the pipework. From the laboratory experiments it appeared that the concentration to eliminate the pathogen was much higher as the concentration used to clean the pipe work. In the greenhouse experiment two cleansing products (hydrogen peroxide, chlorine dioxide) were added in five concentrations with two replicates and compared with a control. All treatments were infested with F. oxysporum, except for the control. During the short growing cycle there were no symptoms of F. oxysporum at the plants. However, it appeared that the higher the concentration of added cleansing products the worse the state of the plants, decreasing plant growth. Additionally, bleach showed high sodium concentrations, while the iron chelate was broken down by the hydrogen peroxide. Looking to the cleansing products at commercial farms hardly any accumulation could be measured. It was concluded that the low concentrations applied in commercial practice do not accumulate to toxic levels while a side effect of cleansing products against pathogens cannot be expected.

This work aimed to investigate the interaction between salt stress and the application of silicon dioxide-nanoparticles. In this study, gerbera plants grown in soilless culture were supplied with nutrient solutions with different NaCl concentrations (0, 5, 10, 20 and 30 mM) in combination with SiO2-NPs spray (0, 25 and 50 mg · L−1). Exposure of gerbera to salinity increased sodium concentration but decreased potassium and calcium concentrations in leaf as well as stem length/diameter, fresh/dry weight, leaf/flower number, flower diameter and leaf area. It also increased the activities of antioxidant enzymes and electrolyte leakage. Results indicated that SiO2-NPs could improve growth, biochemical and physiological traits. It increased stem thickness but slightly affected stem length. Flower diameter was not affected by salinity rates up to 10 mM of NaCl. However, a significant difference was observed between controls and plants treated with 30 mM of NaCl. Salinity increased the electrolyte leakage (32.5%), malondialdehyde (83.8%), hydrogen peroxide (113.5%), and the antioxidant enzyme activities such as ascorbate peroxidase (3.4-fold) and guaiacol peroxidase (6-fold) where SiO2-NPs activated them more, except for superoxide dismutase. Under salinity (30 mM), the increase in SiO2-NPs (especially at 25 mg · L−1) led to the increase in the uptake of Ca2+ (25.3%) as well as K+ (27.1%) and decreased absorption of Na+ (6.3%). SiO2-NPs has potential in improving salinity tolerance in gerbera. It seems that the sensitivity threshold of gerbera to the salinity was 10 mM and the use of SiO2-NPs is also effective in non-saline conditions.

Silica nanoparticles and calcium are necessary for improving plant yield and decreasing stem bending in gerbera flower (Gerbera Jamesonii L.). In order to determine the optimal concentrations of silica nanoparticles and calcium in gerberas (Gerbera Jamesonii L.), a factorial experiment in the form of completely randomized design with two factors was conducted. The first factor was the concentration of silica nanoparticles (Nanoparticle-SiO2) at four rates (0, 20, 40, and 80 mg L-1) and the second factor was the concentration of calcium chelate (Ca-Chelate) at four rates (0, 60, 120, and 240 mg L-1) which were applied as nutrient solutions. After harvest, characteristics such as stem bending, cellulose content, phenyl alanine ammonia-lyase enzyme activity in leaves, and stem histological characteristics were measured. Results indicated that the lowest stem bending (deviation angle of 8.78°) was observed with applying 20 mg L-1 Nanoparticle-SiO2 and 240 mg L-1 Ca-Chelate. Comparing with control, applying 80 mg L-1 Nanoparticle-SiO2 and 240 mg L-1 Ca-Chelate increased lignin and cellulose contents by 33 and 15%, respectively. The highest amount of phenylalanine ammonia-lyase (2.87 units per mg of fresh leaf) was obtained by using 60 mg L-1 calcium chelate. According to nutrient concentrations, the change patterns of xylem and stem lignification were different, which is in line with the results of the physiological studies conducted on the effects of applying silica nanoparticle and calcium in nutrient solution. Under the epidermis, there was a hypodermis (sclerenchyma) which strengthens stem tissue. Silica nanoparticles and calcium chelate due to increasing phenylalanine ammonia-lyase content and its effect on the production cycles of cellulose and lignin and increasing stem sclerenchyma, led to stems strength and lignification, which eventually decreased stem bending. According to study results, applying 40 mg L-1 Nanoparticle-SiO2 and 60 mg L-1 Ca-Chelate in hydroponic nutrient solution is recommended for growing gerbera flowers. Resumo Nanopartículas de sílica e cálcio são necessárias para melhorar a produtividade das plantas e diminuir a curvatura da haste em gérbera (Gerbera jamesonii L.). Para determinar as concentrações ótimas de nanopartículas de sílica e cálcio na gérbera (Gerbera jamesonii L.), foi realizado um experimento fatorial na forma de delineamento inteiramente casualizado com dois fatores. O primeiro fator foi a concentração de nanopartículas de sílica (Nanopartícula-SiO2) em quatro doses (0, 20, 40 e 80 mg L-1) e o segundo fator foi a concentração de quelato de cálcio (Ca-Quelato) em quatro doses (0 , 60, 120 e 240 mg L-1), as quais foram aplicados como soluções nutritivas. Após a colheita, características como curvatura da haste, conteúdo de celulose, atividade da enzima fenil alanina amonia-liase nas folhas e características histológicas do caule foram determinados. Os resultados indicaram que a menor curvatura da haste (ângulo de desvio de 8,78°) foi observada com a aplicação de 20 mg L-1 de Nanopartícula-SiO2 e 240 mg L-1 de quelato de Ca. Em comparação com o controle, a aplicação de 80 mg L-1 de nanopartícula-SiO2 e 240 mg L-1 de quelato de Ca aumentou os teores de lignina e celulose em 33% e 15%, respectivamente. A maior quantidade de fenilalanina amania-liase (2,87 unidades por mg de folha fresca) foi obtida com o uso de quelato de cálcio 60 mg L-1. De acordo com as concentrações de nutrientes, os padrões de alteração do xilema e da lignificação do caule foram diferentes, o que está de acordo com os resultados dos estudos fisiológicos realizados sobre os efeitos da aplicação de nanopartículas de sílica e cálcio em soluções nutritivas. Sob a epiderme, havia uma hipoderme (esclerênquima) que fortalece o tecido do caule. Nanopartículas de sílica e quelato de cálcio decorrente do aumento do conteúdo de fenilalanina amonia-liase e seu efeito nos ciclos de produção de celulose e lignina e ao aumento do esclerênquima do caule, levaram à resistência e lignificação da haste, o que acabou diminuindo a curvatura do caule. De acordo com os resultados do estudo, a aplicação de 40 mg L-1 de Nanopartícula-SiO2 e 60 mg L-1 de quelato de Ca em solução nutritiva hidropônica é recomendada para o cultivo de flores de gérbera.

Aims: The effects of exogenously applied salicylic acid (SA) on gas exchange characteristics, photosynthetic pigments and chloroplast ultrastructure were investigated in gerbera at their reproductive stage under salt-stressed conditions. Methodology: A pot experiment was conducted under glasshouse conditions at the Zhejiang University, Hangzhou, China, (30° N/120° E) between February 2008 and March 2009.Plants, pretreated with foliar applications of 0, 0.5, and 1.0 mmoldm-3 SA at the onset of flower initiation were irrigated with 100 mmoldm-3NaCl(aq) for two weeks, starting after three days from the SA pretreatment. Control did not receive either NaCl or SA.Photosynthetic rate, gas exchange, photosynthetic pigments content and chloroplast ultrastructure were investigated against treatments. All data were subjected to analysis of variance (ANOVA) and Generalized Linear Model (GLM) using SAS statistical software. Pearson’s correlation test was carried out to study the relationships among the parameters. The means were compared using Duncan’s multiple range test (DMRT). For all the tests, P< .05 was considered statistically significant. Results: Salt stress adversely affected the gas exchange characteristics, photosynthetic pigment contents and chloroplast ultrastructure. SA application significantly increased the net photosynthesis, stomatal conductivity, intra-cellular CO2 content and transpiration rate but decreased the stomatal limitation, compared to those of untreated salt-stressed plants. Further, the enhanced photosynthetic pigment contents and notably undamaged chloroplast ultrastructure were evident of the ameliorative effects of SA on photosynthetic system under salt stress. Of the two concentrations tested, 0.5 mmoldm-3 SA concentration seemed to have greater effect throughout the experiment showing no significant variation from control in some attributes (chlorophyll contents and chloroplast ultrastructure). Conclusion: Responses of plants pretreated with SA spraying and significant correlation among them plausibly suggest SA-induced enhancement of photosynthetic system as another target for conferring salt tolerance in crop plants.

Interaction of plants with beneficial microbes is one of the strategies for increasing growth and resistance under environmental stresses. In this study, the effects of a fungus, Piriformospora indica, on growth and salt resistance in gerbera (Gerbera jamesonii L.) seedlings were investigated. After co-cultivation with P. indica, the gerbera roots were colonized by the mature chlamydospores of P. indica. A large increase in plant biomass and enhanced photosynthesis were observed in the P. indica-colonized seedlings. Moreover, these seedlings also exhibited a strong tolerance to salt stress after the colonization. The wilting symptoms, the impairments in chlorophyll, carotenoids, and photosynthesis, and anthocyanin accumulation, that can be caused by salt stress, were alleviated in the P. indica-colonized plants. The malondialdehyde and hydrogen peroxide levels were lower in P. indica-colonized plants than in non-colonized plants under salt treatment, whereas both enzymatic and non-enzymatic antioxidants were not increased by P. indica colonization. Differential expressions of sodium transporter genes and aquaporin genes were found in gerbera plants after P. indica colonization. The P. indica colonization positively regulated the transcription level of genes involved in ionic homeostasis, such as NHX2 and SOS1, while most aquaporin genes were not induced in P. indica-colonized gerbera seedlings exposed to salt stress, except for NIP6;1 gene. These results demonstrate a strategy through plant–microbe interaction to promote Gerbera jamesonii performance under salt stress.

Bend neck of scape and short vase life are the most important problems of cut gerbera flowers in postharvest stage. Inhibitors of laccase enzyme influence lignin formation at cut stem end of flower...

A factorial experiment, in the form of completely randomized design with two factors, was conducted in four replicates to investigate the effects of silica nanoparticles (nanoparticle-SiO2) and cal...

A study on performance of gerbera cultivars for different levels of silicic acid application was carried out under protected condition. The results revealed that among all seven cultivars, ‘Marinilla’ recorded with higher number of flowers (15.11) and lower number of flowers observed with cultivar ‘Vilassar’ (13.11). Cultivars ‘Vilassar’ and ‘Amelie’ recorded with higher flower diameter (11.88 mm) than ‘Natasha’ (10.47 mm). Stalk length was recorded higher with cultivar ‘Marinilla’ (70.16 cm) and lower stalk length was observed in cultivar ‘Nijela’ (64.16 cm) after fourth spray. Flowers of cultivars ‘Vilassar’ and ‘Amlet’ was recorded with higher vase life (13.88 days) compared to other cultivars. Silicic acid spray showed better results with respect to number of flowers, flower diameter, stalk length and vase life of flower. Foliar spray of silicic acid 2 ml/L of water was recorded with higher vase life of flower (14.33 days). Treatment without silicic acid (0 ml/L) recorded with lower vase life (12.76 days).

A study was conducted to find out the effect of nano silver particles (NSPs) on vase life of gerbera cut flower at Post harvest laboratory, College of Horticulture, Dr. YSRHU, Anantharajupeta. The treatment T11- Nano silver @ 10 ppm + sucrose @ 2% is found be significantly superior over other treatments and control. It recorded maximum cumulative water uptake (96.60 g), transpirational loss of water (95.06 g), water balance (1.54 g), fresh weight of flower (15.77 g), vase life (19.77 days) and the lowest bacterial count in vase solution (1.03 X 106 CFU ml-1) was observed at the end of the vase life in 10 ppm nano silver whereas the flowers held in distilled water (control) recorded minimum water uptake (21.93 g), transpirational loss of water (28.23 g), water balance (-6.30 g), fresh weight of flower (10.80 g), vase life (19.77 days) and highest bacterial count (9.18 X 106 CFU ml-1).

The objective of this study was to assess the influence of different foliar gibberellic acid (GA 3 ) levels (0, 10, 50, and 200 mg L -1 ) and application timing on the growth, physiology (chlorophyll and gas exchange) and flower quality of gerbera ( Gerbera jamesonii cvs. Beaudine and Palm Beach) and Asiatic lily ( Lilium × elegans cvs. Fangio and Eldivo). The application of GA 3 (50 mg L -1 ) increased ( p < 0.05) gerbera shoot height (30%), pedicel length (20%), and vase life (12.5%) and decreased the number of days to flowering (7%) compared to the control. GA 3 application at the seedling stage increased pedicel length and flower diameter compared to GA 3 treatment at the flower initiation stage. However, the chlorophyll content index, photosynthesis ( Pn ), stomatal conductance ( gs ) and transpiration ( E ) were similar across the study period. For Asiatic lily, 10 and 50 mg L -1 were the best GA 3 levels in terms of leaf gs , E and flower diameter. Compared to 0, 10 and 50 mg L -1 -GA 3 , 200 mg L -1 -GA 3 decreased the number of days to flowering. Overall, the application of 50 mg L -1 -GA 3 to gerbera and lily cultivars at the seedling stage can potentially improve flower quality and shorten the number of days to flowering.

The pot experiment was conducted during the two consecutive seasons of 2016 and 2017 in plastic house at Horticulture Research Station, Mansoura, Dakahlia Governorate, Egypt as pre-harvest treatments. The main objective of the first experiment was to study the effect of two rates of adenosine triphosphate(0.0 and 7.0 g/l) alone or combined with potassium nitrate at the dose of 2.5, 5.0, 7.5 and 10.0 g/pot, on vegetative growth, flowering and chemical constituents of gerbera (Gerbera jamesonii). The highest values of plant height, number of leaves per plant, leaf area, number of flowers per plant, flower diameter, stalk length as well as the contents of total chlorophyll, carbohydrates, N, P, and K in plants were achieved with adenosine triphosphate(ATP) at 7 g/l as weekly foliar spray with significant difference compared to control. Also, increasing potassium nitrate from 2.5 up to 10.0 g/pot gradually increased the above mentioned parameters during both seasons. Furthermore, using the highest doses of potassium (7.5 and 10.0 g/pot) in interaction with ATP at 7 g/l significantly increased gerbera growth, flowering and chemical constituents compared to untreated plants and the other interaction treatments. From the first experiment the best interaction treatments were 7.5 and 10.0 g potassium nitrate/pot plus1 7 g ATP/l, these treatments were in the second experiment to study the effect of different pulsing solutions on flower vase life, solution uptake and flower fresh weight of gerbera. The obtained results revealed that, the longest vase life of gerbera and the highest quality cut flowers were obtained by using the combination treatments between (7.5 g potassium nitrate/pot + 7 g ATP/l) combined with 3% sucrose + 8-HQS at 200 ppm as holding solution. By studying simple correlation coefficients, gerbera cut flowers vase life exhibited strong positive relationship with each of water uptake and flower fresh weight which, indicated that the increase in these parameters was accompanied by increasing vase life of gerbera cut flowers under the effect of interaction treatments of pre and postharvest.

Ninety five bacterial strains were isolated from the rhizosphere and soils of flower crops, specifically gerbera, carnation and tuberose, were preliminarily screened against Fusarium oxysporum f. sp. gerberae in vitro along with five elite strains Bbv 57, EPCO 16, EPC 5, EPC 8 and Pf 1 obtained from Department of Plant Pathology, TNAU, Coimbatore, India. The results revealed that the strain Bbv 57 had highest inhibition of 50.00% and showed the maximum value for the assays that is siderophore, hydrogen cyanide, IAA, GA3 and salicylic acid production (3.68 O.D. value; 14.05 µg ml-1; 44.40 µg ml-1; 25.28 µg ml-1 and 19.25 µg ml-1 respectively). It also showed resistance to antibiotics namely ampicillin, erythromycin, clindamycin. The highest exopolysaccharides, biofilm production was observed and had lowest protease production clearly indicated that it is non - pathogenic to plants. Further, the polymerase chain reaction using16S rRNA intervening sequencing showed 100% homology to Bacillus subtilis (KF718836) and showed positive for quorum sensing regulator genes of aiiA and comQ. Additionally, the culture filtrate assay also produced significant reduction in egg hatching capacity and juvenile mortality of root-knot nematode Meloidogyne incognita. Further, the HPLC study showed 91.69 µg µl-1 of surfactin with the retention time of 2.304 min and 0.453 µg µl-1 of Iturin with the retention time of 8.739 min at 205 nm. Whereas, GCMS analysis has detected the aliphatic hydrocarbons responsible for antifungal, antibacterial and nematicidal activity.

Capitulum wilting and neck bending are the two important complications that impair the post-harvest quality and vase life of the gerbera cut flowers. The present study investigates the effects of pre- and post-harvest treatments of spermine (SPER), γ-aminobutyric acid (GABA) and β-aminobutyric acid (BABA) on the vase life, qualitative features and enzyme activity of gerbera cut flowers ‘Stanza’. The pre-harvest treatments (1 mM doses) were applied by foliar spraying, and the post-harvest were by pulse treatment (5 mM doses). The flowers kept their quality longer in pre and post SPER and GABA treatments. The longest vase life was recorded in pre-SPER (14 days) and pre-GABA (13 days) compared to BABA treatments and controls (9 days). Neck bending was observed more frequently in controls whereas SPER and GABA showed a lower neck bending rate at 9 days after harvest. The highest vase solution uptake, total soluble solids, total flavonoid, total protein, the activities of catalase, peroxidase, superoxide dismutase, phenylalanine ammonia-lyase, and ascorbate peroxidase, besides the lowest neck bending, electrolyte leakage, malondialdehyde, H2O2 and polyphenol oxidase activity were observed in pre-SPER treatment and subsequently in pre-GABA. Pre- and post-harvest treatments with β-Aminobutyric acid (BABA) had no significant effects on cut flowers compared to SPER and GABA, although showed slightly better effects than water control. It is therefore suggested that pre-harvest treatment using SPER and GABA can improve the vase life and quality of gerbera cut flowers. Resumo O murchamento do capítulo e a flexão do pescoço são as duas complicações importantes que prejudicam a qualidade pós-colheita e a vida de vaso de flores cortadas de gérbera. O presente estudo investigou os efeitos dos tratamentos pré e pós-colheita de espermina (SPER), ácido γ-aminobutírico (GABA) e ácido β-aminobutírico (BABA) na vida de vaso, nas características qualitativas e atividade enzimática de flores de gerbera 'Estrofe'. Os tratamentos pré-colheita (doses de 1 mM) foram aplicados por pulverização foliar e os pós-colheita foram realizados por tratamento de pulso (doses de 5 mM). As flores mantiveram sua qualidade por mais tempo nos tratamentos pré e pós aplicação com SPER e GABA. A maior vida útil do vaso foi registrada no pré-SPER (14 dias) e no pré-GABA (13 dias) em comparação com os tratamentos e controles BABA (9 dias). A flexão do pescoço foi observada com mais frequência nos controles, enquanto SPER e GABA apresentaram menor taxa de flexão do pescoço aos 9 dias após a colheita. Maior absorção de solução em vaso, sólidos solúveis totais, flavonoides totais, proteína total, atividades de catalase, peroxidase, superóxido dismutase, fenilalanina amônia-liase e ascorbato peroxidase, além da menor flexão do pescoço, vazamento de eletrólitos, malondialdeído, H2O2 e polifenol oxidase atividade foi observada no tratamento pré-SPER e subsequentemente no pré-GABA. Os tratamentos pré e pós-colheita com ácido β-aminobutírico (BABA) não tiveram efeitos significativos nas flores cortadas em comparação ao uso de SPER e GABA, embora tenham mostrado efeitos ligeiramente melhores que o controle da água. Portanto, sugere-se o uso de tratamento pré-colheita com SPER e GABA para melhorar a vida do vaso e a qualidade das flores cortadas com gérbera.

The present research was conducted in the greenhouse of the Experimental Station of Horticultural Research Station in Mansoura, Horticultural Research Institute, Agricultural Research Center during the two successive seasons of 2016 and 2017 from February 21 to June 27. One month oldgerbera plants were obtained from a commercial nursery in Mansoura, planted in 20 cm pots. This investigation aimed to improve some plant growth, flowering parameters and chemical constituents of gerbera (Gerbera jamensonii L.) plants, by using foliar application with some amino acids (glycine, arginine, asparagine, alanine, tryptophan, and a mixture from all of them) at concentrations of 100 ppm plus the control (tap water). Application of amino acid treatments began 30 days after transplanting then repeated after 14 days intervals. The results showed that spraying gerbera plants with a mixture of amino acids at 100ppm gave the highest values of leaves and roots fresh and dry weights, total leaf area, leaf area/ plant, number of leaves/ plant, chlorophyll (A, B and total), total carbohydrates, N, P and K contents in the leaves and biggest flowers diameters (11.23 and 11.83 cm), followed by plants treated with glycine then tryptophan in the two seasons, respectively. Glycine at 100ppm recorded pronounced significant values in flowers stem length and number of flowers (7.66 and 8.00 flowers/ plant) in both seasons respectively, followed by the tryptophan treatment (7.00 and 7.33 flowers/ plant), the third highest was that of the mixture treatment. The lowest values were obtained when plants treated with tap water (control) in both seasons, respectively.

Each species cultured in vitro has specific nutritional requirements on the culture medium. The use of silicon in culture can provide benefits to plants, such as increase of tolerance to water stress, increase of photosynthetic capacity and reduction in transpiration. These effects may be quite relevant for in vitro growth and development of plant and during acclimatization. However, the effectiveness of this nutrient may vary depending on the used sources. The aim of this study was to verify the ideal concentration of the MS culture medium and to evaluate the to evaluate the different sources as well as the function of silicon for in vitro development and acclimatization of gerbera plantlets. Shoots (4–6 cm) of gerbera (Gerbera jamesonii cv. Jaguar Cream) cultured in vitro were inoculated in MS medium with different concentrations of salts (MS ¼, MS ½, MS ¾, MS) supplemented with different silicon sources (potassium silicate, sodium silicate, calcium silicate and silicic acid) at concentrations of 0 (control), 0.25, 0.5, 0.75, and 1 mg L−1. The use of MS ¼ medium and the supplementation of 0.25 g L−1 calcium silicate provided better shoot development. The acclimatization rate was not affected by the origin of plants treated in vitro by different silicon sources, their concentrations, and the used culture medium. Thus, the use of silicon is beneficial for in vitro development of gerberas, however, the effectiveness depends on the used source. In vitro shoots of Gerbera jamesonii cv. Jaguar Cream regenerate better, shoots are taller and healthier, and root more effectively when are cultured on MS 1/4 supplemented with 0.25 mg L−1 calcium silicate.

Background Gerbera jamesonii Bolus ex Hooker f. (African daisy) is listed among the top five most important ornamental plants in the global floricultural industry. To satisfy its demand, the floriculture industry relies on reproducible and effective propagation protocol while retaining the genetic uniformity of G. jamesonii. The present study, for the first time, reports the potential of picloram for enhanced induction of organogenic calli from leaves of G. jamesonii and its high-frequency indirect regeneration. Results The fastest induction of calli with maximum fresh and dry weight was recorded in the Murashige and Skoog (MS) semisolid medium supplemented with 1 mg/l picloram. In addition, callus induction was observed in 2,4-dichlorophenoxy acetic acid- and α-napthaleneaceticacid-supplemented media but with delayed response and reduced fresh and dry weight. The proliferated calli were transferred to shoot induction media containing MS salt and 0.5–1 mg/l N6-benzylaminopurine, kinetin, or thidiazuron. A mean number of ~6 shoots per callus were developed after 5 days of culture in the MS medium supplemented with 1 mg/l kinetin, with a mean length of 5.2 cm. Successful rooting of shoots was achieved in the MS medium fortified with 1.5 mg/l indole-3-acetic acid, wherein the earliest root initiation (~5 days), as well as the maximum number (~9) and length (~4.8 cm) of roots, were recorded. Complete plantlets were primarily acclimatized in sand before being transferred to a mixed substrate (of soil, sand, tea leaf waste, and cow urine) that secured >90% survival and further growth of the plantlets. Eventually, clonal fidelity of the in vitro regenerants assessed via inter-simple sequence repeats (ISSR) primers exhibited a monomorphic banding patterns that suggested genetic integrity within the plantlets as well as with their mother plant. Conclusions The results of the present study should be of interest for commercial propagation and mutagenesis- as well as genetic transformation-related research.

Vegetative tissue analyses might help to diagnose nutritional status of a crop. Foliage diagnosis is an effective method to set up balanced fertilization procedures. The current work aims to evaluate nutrient contents of two gerbera leaf sampling periods as a cut flower cultivated in pots with different doses of nitrogen (N) and calcium (Ca) under greenhouse conditions. The experiment was carried out in a protected environment, shelter type, in a container containing substrate in a 3x3+1 factorial scheme. Three doses of N (0.07, 0.15 or 0.2 g L-1) or three doses of Ca (0.02, 0.03 or 0.04 g L-1) were applied every 15 days. Control plants did receive neither N nor Ca. The substrate was analyzed before and after cultivation, and at the end of production years, as well as completely expanded leaves were collected for nutrient analyses. There was not significant interaction between N and Ca doses. Regarding the sampling period or doses of N and Ca, the determined macronutrient concentrations were in the following order of N>K>Ca>P>S>Mg. The micronutrient concentrations were in the following order of Fe>Mn>B>Zn>Cu. Except for K, all the other nutrient concentrations were in the recommended range for gerberas production. Resumo A análise química do tecido vegetal serve como forma de diagnosticar o estado nutricional da cultura. Neste sentido, o diagnóstico foliar torna-se uma ferramenta para se estabelecer programas racionais de adubação. O objetivo do trabalho foi avaliar o teor foliar de nutrientes, ao término do primeiro e segundo ano de produção, de gérbera de corte cultivada com diferentes doses de nitrogênio (N) e cálcio (Ca). O experimento foi conduzido em ambiente protegido, tipo abrigo, em recipiente contendo substrato em esquema fatorial 3x3+1, sendo três doses de N (0,07; 0,15 e 0,2 g L-1) e de três doses de Ca (0,02; 0,03 e 0,04 g L-1), aplicadas a cada 15 dias, além do controle, sem adubação com N e Ca. O substrato foi analisado antes e após o cultivo, e ao término dos anos de produção, realizou-se a coleta de folhas completamente expandidas para análise nutricional. Não houve efeito significativo da interação entre as doses de N e Ca. O teor foliar de potássio (K) encontrou-se abaixo do sugerido na literatura. Independente do período de coleta das folhas e das diferentes doses de N e de Ca, a concentração dos macronutrientes seguiu a ordem decrescente: N>K>Ca>P>S>Mg, e para os micronutrientes: Fe>Mn>B>Zn>Cu. Os teores foliares dos macronutrientes, com exceção do K, e os teores foliares dos micronutrientes, ao término do primeiro e segundo ano de produção, estão de acordo com o recomendado na literatura para gérbera de corte.

An energy-saving light emitting diode (LED) system allows for adjustment of light quality, which affects plant development and metabolic processes in in vitro cultures. The study investigated the content of endogenous carbohydrates and the condition of the photosynthetic apparatus of Gerbera jamesonii Bolus ex Hook. f. Our aim was to analyze the effects of different LED light qualities—100% red light (R LED), 100% blue (B LED), a mixture of red and blue (7:3) (RB LED), and a fluorescent lamp as a control (Fl)—during the multiplication of axillary shoots. After 40 days, the culture measurements were performed using a non-invasive pulse amplitude modulation (PAM) fluorimeter. Sugar content was assessed with high performance liquid chromatography (HPLC). Two forms of free monosaccharides (glucose and fructose), two sugar alcohol derivatives (inositol and glycerol), and seven forms of free oligosaccharides were identified. Of those, glucose content was the highest. LEDs did not disturb the sugar metabolism in multiplied shoots. Their monosaccharides were three times more abundant than oligosaccharides, the same results were found in plants grown under control light. R light depleted the performance of the photosynthetic apparatus and caused its permanent damage. The RB LED spectrum ensured the most efficient non-photochemical quenching of the photosystem II (PS II) excitation state and high shoot quality.

Short vase life, capitulum wilting, neck bending, and postharvest chilling injury (CI) are major disorders have negative impact on quality and marketing of gerbera cut flowers. Low storage temperatures prolonging the vase life, but on the other hand leads serious CI which decreases the quality and consumer preferences. Spermine (SPER) and γ-aminobutyric acid (GABA) were identified as anti-aging factors delay the senescence and elevate the chilling tolerance in many species. Greenhouse-grown gerbera cv. ‘Stanza’ sprayed with 2 mM SPER and 1 mM GABA twice (2 T) or thrice (3 T). Cut flowers were stored at 1.5 °C and 8 °C postharvest to study the effects of GABA and SPER on senescence and CI. Vase life, CI and quality of cut flowers were improved by GABA and SPER treatments. No CI was observed in GABA-treated flowers at 1.5 °C; while, flowers sprayed with water showed severe CI. GABA treatments efficiently prolonged the vase life for 6–7 days more than the control (15 days). GABA and SPER increased the fresh weight, solution uptake, protein and proline contents, catalase, peroxidase, and superoxide dismutase activities, while decreased the electrolyte leakage, H2O2, and malondialdehyde contents, polyphenol oxidase, lipoxygenase, and phospholipase D activities. GABA and SPER significantly prolonged the vase life and prevented degradation of proteins and chilling damage and increased capacity of detoxifying and scavenging of H2O2 and reactive oxygen species (ROS), led to alleviate the negative consequences of the senescence and CI.

Gerbera in vitro shoots were irradiated using three types of ion beams with different line energy transfers (LETs) to investigate the effective LET and absorbed doses for mutagenesis. Furthermore, genomic mutation analyses were conducted on the obtained mutants. Survival rate analysis showed a lower lethal dose 50% (LD50) with ion beams with higher LETs. Trait/morphological mutations exhibited changes in the color and shape of petals and male sterility. Irradiation conditions with the highest growth change and trait/morphological mutation rates in each ion were C irradiation at 10 Gy, Ar irradiation at 5 Gy, and Fe irradiation at 5 Gy, with a range of absorbed dose of around LD50 to about 10 Gy lower. The highest trait/morphological mutation rate was 14.1% with Ar irradiation at 5 Gy, which was one of the criteria for ion beam irradiation of gerbera in vitro shoots. Furthermore, the genomic mutation in the flower color, petal shape, and male sterile mutants were confirmed by genotype analysis using Genotyping by Random Amplicon Sequencing-Direct technology. This is the first study to report the efficient production of gerbera mutants that could be analyzed. Our findings may lead to more efficient gerbera mutant production and analysis technology.

Gerbera is a flowering species with relevance to the cut flower market. Understanding nutritional requirements of the species is important to improve fertilization procedures. In the present work, our objective was to evaluate the influence of different doses of nitrogen (N) and calcium (Ca) on the growth and development of gerbera cultivated in pots as a cut flower. The experiment was conducted in a protected environment in a bifactorial design, with an additional treatment consisting of the combination of three N (0.07, 0.15 and 0.2 g L-1 substrate) and Ca (0.02, 0.03 and 0.04 g L-1 substrate) doses applied every 15 days. Control plants were not supplemented with either N or Ca. No significant interaction between N and Ca doses was observed. The highest number of flower stalks was obtained with 0.15 g N L-1 substrate and 0.04 g Ca L-1 substrate. Flower diameter, plant leaf area and total chlorophyll contents were at a maximum of 0.14 g N L-1 substrate and 0.04 g Ca L-1 substrate. N and Ca doses influenced in an independent manner the growth and development of gerberas as a cut flower cultivated in pots, and we determined that its fertilization should occur every 15 days with 0.34 g N L-1 substrate and 0.04 g Ca L-1 substrate. RESUMO A gérbera é uma das espécies floríferas com destaque no mercado de flores de corte. Conhecer suas necessidades nutricionais torna-se importante para melhorar a eficiência da adubação. O objetivo do presente trabalho foi avaliar a influência de diferentes doses de nitrogênio (N) e cálcio (Ca) no crescimento e desenvolvimento de plantas de gérbera de corte cultivadas em recipientes. O experimento foi conduzido em ambiente protegido, tipo abrigo, em esquema bifatorial com tratamento adicional, que consistiu da combinação de três doses de N L-1 de substrato (0,07, 0,15 e 0,2 g) e de três doses de Ca L-1 de substrato (0,02, 0,03 e 0,04 g), aplicadas a cada 15 dias, além da testemunha, sem adubação com N e Ca. Não houve efeito significativo da interação entre as doses de N e Ca. A maior produção de hastes florais planta-1 foi obtida com as doses de 0,15 g de N L-1 de substrato e 0,04 g de Ca L-1 de substrato. O diâmetro do capítulo, a área foliar planta-1 e o teor de clorofila total planta-1 foram máximos com as doses de 0,14 g de N L-1 de substrato e 0,04 g de Ca L-1 de substrato. As diferentes doses de nitrogênio e cálcio influenciam, de maneira independente, o crescimento e o desenvolvimento de plantas de gérbera de corte cultivadas em recipientes, e recomenda-se o uso, a cada 15 dias, de 0,14 g de N L-1 de substrato e de 0,04 g de Ca L-1 de substrato.

Made available in DSpace on 2020-12-12T02:35:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-07-01. Added 1 bitstream(s) on 2021-07-15T15:26:09Z : No. of bitstreams: 1 S2447-536X2019000300238.pdf: 2038154 bytes, checksum: 3e2c714386730ba113f1898e3334a19d (MD5) Several authors report that potassium (K) is the nutrient absorbed in greater amounts by gerbera plants. Thus, objective of determining the concentration of Kin the solution of substrates for growing potted gerbera, quantified by the Cardy Horiba C-131 and an atomic absorption spectrophotometer, correlating them with each other and with the plant leaf content. The experiment was carried out in a greenhouse. The experimental design was in randomized complete blocks usinga 5x2 factorial scheme (5 substrates/2 cultivars) and four replications. Cherry and Red gerbera cultivar seedlings with four final leaves were transplanted into pots, filled with the substrates and acclimated for 30 days. After acclimation,the K content in the substrate solution extracted by the PourThru methodology was evaluated every two weeks using the Cardy Horiba C-131 portable ion meter and an atomic absorption spectrophotometer, as well as the K content in the leaves of gerbera plants. The solution of the commercial substrate had higher concentrations of K in relation to theothers in the two forms of measurement, which is directly related to the high initial contents of the nutrient in this substrate. This is directly related to the high initial K contents in the substrate. Greater values of K were obtained for the cultivar Red, both in the solution and in the leaves. The K concentration of the substrate solution cultured with gerbera plants quantified by the Cardy Horiba C-131 and atomic absorption spectrophotometry correlated significantly with each other and showed a low correlation with the content of this nutrient in the plant tissue. Universidade Estadual do Rio Grande do Sul (UERGS) Unidade em Santa Cruz do Sul FCA/UNESP Departamento de Solos e Recursos Ambientais Centro de Citricultura Sylvio Moreira-APTA Universidade Federal de Santa Maria FCA/UNESP Departamento de Solos e Recursos Ambientais

With the objective of identifying an ecologically sustainable substrate for commercial gerbera production, we conducted an experiment to assess the effects of super absorbent polymer and organic vermi-products on the physico-chemical properties of the growing media, and plant growth and flower yield in gerbera cv. Yosemite. CPV (Cocopeat: Perlite: Vermiculite) and soil amended with vermicompost (VC, 20%), Pusa hydrogel (PHG, 0.25%) and horn bio-manure (HBM, 1%) had significant positive effects on growth and flowering of gerbera. The lowest (0.29 ± 0.02 g cm−3) bulk density was recorded in CPV + PHG + HBM while the maximum (59.75 ± 0.63%) water holding capacity was observed in CPV + PHG + VC substrate. The maximum electric conductivity (0.99 ± 0.06 dS m−1) and pH (7.90 ± 0.04) were recorded in Soil + PHG + VC. Plants grown on CPV + PHG + VC media and sprayed with 20% of vermiwash produced the highest number of leaves during the entire period (31 ± 0.58), maximum leaf length (30.18 ± 0.18 cm) and width (8.30 ± 0.16 cm), maximum number of primary roots (42 ± 1.53), highest flowers per plant (19.67 ± 0.33), stalk length (41.08 ± 0.10 cm) and flower head diameter (10.11 ± 0.03 cm). Flowers produced on this medium also had an extended attractive appearance (20.33 ± 0.33 days) and longer vase life (14.33 ± 0.33 days). Water requirement of gerbera (litre/crop season) on CPV + PHG + VC medium, with or without Vermiwash spray was also considerably lower than other treatments. Overall results suggest that CPV amended with PHG and VC coupled with Vermiwash spray provide congenial conditions for gerbera plant growth and flower production while also simultaneously reducing irrigation water use considerably.

Background Gerbera hybrida is one of the most popular cut flowers in the world; however, stem bending, which always happens when gerbera flower harvested from the field, greatly limits its vase life. To date the molecular mechanisms underlying stem bending remain poorly understood. Results In this study, we performed high-throughput transcriptome sequencing of gerbera during stem bending using the Illumina sequencing technology. Three cDNA libraries constructed from mRNAs of gerbera stem at stem bending stage 0, 2 and 4 were sequenced. More than 300 million high-quality reads were generated and assembled into 96,492 unigenes. Among them, 34,166 unigenes were functionally annotated based on similarity search with known protein. Sequences derived from plants at different stem bending stages were mapped to the assembled transcriptome, and 9,406 differentially expressed genes (DEGs) were identified. Through Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, specific pathways were identified during the stem bending process, such as phenylpropanoid biosynthesis pathway, phenylalanine metabolism pathway, starch and sucrose metabolism pathway, and plant hormone signal transduction pathway. A total of 211 transcription factors (TFs), including TF families involved in plant senescence, such as NAC, MYB, WRKY, and AP2/ERF members, as well as TFs related to water stress tolerance, were shown to be regulated during stem bending. Gene Onotology (GO) functional enrichment analysis indicated that key genes involved in responses to osmotic and oxidative stresses were also varied in expression during this process. Furthermore, analysis of DEGs involved in the hormone signaling pathways and determination of endogenous abscisic acid (ABA) content showed that stem bending may be an ethylene-independent process, but regulated by ABA. In short, our findings suggested that the stem bending of cut gerbera may be caused by the involvement of water stress and regulation of ABA during the postharvest life. Conclusions The transcriptome sequences provide a valuable resource in revealing the molecular mechanism underlying stem bending of cut flower and offer novel genes that can be used to guide future studies for ornamental plant breeding. Electronic supplementary material The online version of this article (10.1186/s12864-019-5961-1) contains supplementary material, which is available to authorized users.

A fertigation experiment during 2009-2011 was conducted to investigate the quality parameters of Gerbera (Gerbera jamesonii Bolus ex Hooker F. 'Palm Beach') in different fertigation schedules under Shevaroy hills condition at three levels i.e., 125, 100, 75% of recommended dose of fertilizer along with foliar spray of micronutrient mixture (0.004%) and humic acid (0.2%). Application of 100% RDF + 0.004% micronutrient mixture + 0.2% humic acid was most effective for improved flowering parameters like flower yield m(‑2), flower yield 1000 m(‑2), highest vase life and benefit:cost ratio.

Ethanol and citric acid can increase longevity in some cut flowers. However, its use must be extremely careful, with application methods and specific concentrations for each type of cut flower. Thus, the objective was to examine the physico-chemical and physiological changes in Gerbera cv. Mistique cut flowers treated with ethanol (Et) and/or citric acid (CA). Stem were selected and standardized to a length of 35 cm and maintained at 20 ± 2 ºC and RH 65 ± 2%, under continuous lighting. The flowers were subjected to two application methods (pulsing for 48 h and maintenance), using different concentrations of Et (4%, 6%, and 8%) and/or CA (100 and 200 mg L-1) and distilled water (control). A visual assessment and analyses of longevity, stem bending, fresh mass, relative water content, electrolyte leakage, and peroxidase and polyphenol oxidase enzyme activities were performed at every two days. The Et (4%) + CA (100 mg L-1) solution provided the greatest longevity, regardless of the application method. These results were the basis for a third experiment, in which the stems were immersed in pulsing solutions of Et (4%) and/or CA (100 mg L-1) and distilled water (control). The Gerbera flowers under Et + CA solution showed lower fresh mass loss and electrolyte leakage, higher relative water content and a slower increase in polyphenol oxidase and peroxidase activities. This allowed for delayed stem bending and better appearance, resulting in greater longevity compared to the other solutions.

This research was carried out to determine the effect of gibberellic acid (GA3) and benzyladenine (BA) application on yield and quality components (multiplication ratio, flower stem length, flower diameter, vase life, flower stem diameter,) of gerbera. Three different levels of GA3 (125, 250, 500 ppm) and BA (100, 200, 400 ppm) were applied by foliar spray. Compared to BA application, GA3 applications gave good results on yield and quality parameters. The maximum yield was obtained by 125 ppm of GA3 application. It was found that 500 ppm of GA3 application most effective on stem length and flower diameter. On the other hand, it's determined that 400 ppm BA application significantly increased stem diameter and multiplication ratio. Its concluded that, the GA3 and BA demonstration interference in growth characteristics of gerbera plant.

To improve keeping quality of gerbera cv. Marleen cut flowers this work was conducted at the laboratories of Hort. Dept., Agric. Fac., Mansoura Univ., Egypt during January to February months of 2016 and 2017 seasons. This, by using pulsing and holding solutions and cold storage periods for different durations as well as their interaction treatments, besides, studying these treatments affects on cut flowers vase life, water balance, anthocyanin content and total sugars percentage of gerbera flowers. The used pulsing solution treatments were control as distilled water (DW), 5% sucrose (S) + 200 ppm 8-hydroxy quinolene sulphate (8-HQS) for 16 hours, 15 ppm kinitin (Kin) + 5 % S + 200 ppm 8-HQS for 16 hours, silver thiosulphate (STS) 1:4 mM for 20 minutes then placed in 5 % S + 200 ppm 8-HQS for 16 hours and 1:4 mM STS for 20 minutes then placed in 25 ppm Kin + 5 % S + 200 ppm 8-HQS for 16 hours. Moreover, cut flowers of gerbera were stored at 5±1˚C for 0, 6 and 12 days. In addition, holding solution treatments used after cold storage periods were controlas distilled water (DW) and 5% sucrose (S) + 200 ppm 8-HQS + 200 ppm ascorbic acid (AA), besides to the interaction treatments between them. The obtained results referred to that, the longest vase life of gerbera cut flowers were achieved by STS+S + 8-HQS for 16 hours as pulsing solution and storage at 5±1˚C for 0-time which followed by 6 days and holding solution under study compared to the other interactions. Also, the highest values of water balance were obtained with the same treatment at 0-time storage. Finally, the best data regard anthocyanin content and total sugars percentage were observed with pulsing solutions and storage at 6 days plus 5% S + 200 ppm 8-HQS + 200 ppm AA as holding solution.

Gerbera (Gerbera jamesonii) is an important commercial species of cut flowers all around the world. Stem bending is a major disorder in cut gerbera flowers caused mainly by the lack of mechanical support in the flower stem. Lignin is the component of plant cell walls that provides strength. Three major enzymes comprise the pathway of lignin anabolism including peroxidase (POD), cinnamyl alcohol dehydrogenase (CAD), and cinnamoyl-CoA reductase (CCR). In this study, three overexpressed mutants for each of these major genes were generated and analyzed for their role in stem bending. Comparing the pod transgenic plants with ccr and cad mutants indicated that pod plants had the highest lignin content. Compared to wild-type (WT) plants, the highest vase life, membrane stability and solution uptake were obtained in gerbera pod mutants. Therefore, it appears that higher lignin contents can decrease stem bending and improve cell wall rigidity of cut gerbera flowers. These results also suggest that POD is a key gene in the biosynthesis of lignin in gerbera.

The postharvest longevity of gerbera (Gerbera jamesonii) flowers has a critical importance in determining their commercial value; and therefore, there is a commercial demand for prolonging their vase life (VL). Here, we tested the efficacy of salicylic acid (SA, 150 µM) preservative in extending longevity of cut flower of two gerbera cultivars, namely the ‘Sunway’ and ‘Bayadere’, of which water-held ‘Bayadere’ has longer VL than water-held ‘Sunway’. The results indicated that exogenous SA could significantly prolong the VL of cut flowers of both ‘Sunway’ and ‘Bayadere’ cultivars, with better preservative effect being observed on ‘Sunway’. SA preservative was more effective in ameliorating relative water uptake and relative fresh weight in ‘Sunway’ than in ‘Bayadere’, which was accompanied by a greater decrease in proline accumulation. Application of SA prolonged the VL of two cut gerbera flower cultivars by inhibiting the activity of polyphenol oxidase involved in browning reaction, and decreasing oxidative stress through improving reactive oxygen species-scavenging antioxidant capacity, which included accumulation of total phenolic compounds and total flavonoids, and enhancement of enzymatic antioxidant activities. As a result, membrane lipid peroxidation levels were reduced in cut flowers of both cultivars, with higher reduction level being observed in ‘Sunway’ than in ‘Bayadere’. Additionally, SA preservative was more efficient in maintaining a greater content of total soluble proteins in ‘Sunway’ than in ‘Bayadere’. These findings clearly demonstrated that SA has higher preservative effects on extending VL of ‘Sunway’ than that of ‘Bayadere’. Taken together, SA can be recommended to farmers for postharvest treatments to maintain quality and delay senescence of gerbera flowers.

Filamentous structures were observed in purified extracts from chrysanthemum, gerbera, sunflower and zinnia. When purified filament proteins were subjected to SDS-PAGE, the major protein associated with filaments from all three species has an apparent molecular mass of ≈25 kDa. Protein bands from chrysanthemum, gerbera, and zinnia were subjected to N-terminal protein sequencing while proteins from sunflower were sequenced by CID MS/MS. All of the sequences shared highest similarity to the kunitz trypsin inhibitor family. The sequencing results indicated that the proteins lacked the signal sequences. We tested the gerbera filament protein for glycosylation and found that it was a glycoprotein. Together these results indicate that the filaments are composed of mature KTI protein. This is the first report of a KTI assembling into filaments and the first report of a filament forming Asteraceae enzyme.

Non-thermal plasma (NTP) appears a promising strategy for supporting crop protection, in-creasing yield and quality, and promoting environmental safety through a decrease in chemical use. However, very few NTP applications on containerized crops are reported under operational growing conditions and in combination with eco-friendly growing media and fertigation man-agement. In this work, the NTP technology was applied on the nutrient solution used for the production of gerbera plants grown on peat or green compost, as an alternative substrate to peat, and with standard or low fertilization. NTP treatment promoted fresh leaf and flower bi-omass production in plants grown on peat and nutrient adsorption in those grown on both sub-strates, except for Fe, while decreased plant dry matter. However, it caused a decrease in leaf and flower biomasses of plants grown on compost, showing a substrate-dependent effect highlighted under a low fertilization regime. In general, the penalty on compost was probably caused by the high substrate alkalinisation that commonly interferes with gerbera growth. Under low fertili-zation, a reduction in the photosynthetic capacity further penalized plant growth on compost. The lower level of fertilization also decreased gerbera quality anyway highlighting that Ca, Mg, Mn, and Fe could be reduced respect the standard fertilization.

The experiment evaluated the influence of different light qualities and 6-benzyladenine (BA) concentration in a medium on the leaf response of multiplied Gerbera jamesonii Bolus ex Hook. f.&lsquo, Big Apple&rsquo, shoots. Three different light-emitting diode (LED) spectra&mdash, 100% blue (B), 100% red (R) and red and blue mixture (7:3, RB)&mdash, were used, and a fluorescent lamp was used as a control (Fl). Concentrations of BA in Murashige and Skoog (MS) medium were 1, 2.5 and 5 &micro, M. Leaves developed under 100% blue light had a lower frequency of stomata and a smaller area as compared with those from plants exposed to light with red in spectrum. Under 100% red light, the leaf area and the frequency of stomata increased along with growing concentration of BA in the medium. The thickest mesophyll was spotted in the cross-section of leaves exposed to the blue LED light. Leaves developed under the 100% red light had the thinnest mesophyll layers. Increasing concentration of BA in the medium resulted in enhanced leaf blade thickness. The cross-section of leaf vascular bundles was only half of that in petioles. The leaves under the LED combinations had larger vascular bundles than those under fluorescent light. The highest level of photosynthetic pigments was noticed in the leaves grown under LED R and RB lights. Our study demonstrated that 2.5 &micro, M BA and a mixture of blue and red light provided by LED improved leaf quality during multiplication of gerbera shoots.

Anthocyanins and flavonols have vital roles in flower coloration, plant development, and defense. Because anthocyanins and flavonols share the same subcellular localization and common biosynthetic substrates, these pathways may compete for substrates. However, the mechanism regulating this potential competition remains unclear. Here, we identified GhMYB1a, an R2R3-MYB transcription factor involved in the regulation of anthocyanin and flavonol accumulation in gerbera (Gerberahybrida). GhMYB1a shares high sequence similarity with that of other characterized regulators of flavonol biosynthesis. In addition, GhMYB1a is also phylogenetically grouped with these proteins. The overexpression of GhMYB1a in gerbera and tobacco (Nicotianatabacum) resulted in decreased anthocyanin accumulation and increased accumulation of flavonols by upregulating the structural genes involved in flavonol biosynthesis. We further found that GhMYB1a functions as a homodimer instead of interacting with basic helix-loop-helix cofactors. These results suggest that GhMYB1a is involved in regulating the anthocyanin and flavonol metabolic pathways through precise regulation of gene expression. The functional characterization of GhMYB1a provides insight into the biosynthesis and regulation of flavonols and anthocyanins.

To achieve a zero emission of water with nutrients and plant protection products, recirculation of water in the greenhouse system is obligatory and discharge should be minimized. In this study it was investigated if applied cleaning products may accumulate to harmful concentrations and hamper plant growth. An enquiry amongst growers gave insights in the use of various products. This enquiry showed that most products are used in low concentrations to remove biofilm from piping. Laboratory tests have been executed to investigate if a side effect could be seen to eliminate pathogens. It appeared that the applied, low, concentrations to clean the pipework had no side effect in eliminating of pathogens. In a greenhouse experiment it appeared that sodium, chloride and chlorate can potentially accumulate, while chelates are partly broken down. Measurements at commercial gerbera farms showed that no accumulation took place to harmful concentrations. Steeds minder lozing van drainwater in de glastuinbouw is toegestaan om uiteindelijk te komen tot nul-emissie van nutriënten en gewasbeschermingsmiddelen naar oppervlaktewater en riool. In deze studie is de potentiële ophoping van reinigingsproducten in recirculatiewater onderzocht als er niet meer wordt geloosd (nul-emissie). Via een enquête is inzicht verkregen in gebruik van diverse producten. Hieruit bleek dat producten meestal in lage concentraties worden gebruikt met als doel om vorming van biofilm in leidingen te voorkomen. In laboratoriumproeven is onderzocht bij welke concentraties een additioneel effect is te verwachten op de afdoding van pathogenen. Reinigingsmiddelen worden gedoseerd bij veel lagere concentraties dan wanneer doding van pathogenen optreed. In een korte teeltproef is onderzocht of er ophoping optrad. Duidelijk werd dat natrium, chloride en chloraat potentieel snel kunnen ophopen met zichtbare symptomen in het gewas, terwijl chelaten deels worden afgebroken. Praktijkmetingen bij gerberagewassen lieten geen ophoping zien van reinigingsmiddelen tot schadelijke concentraties.

Gerbera flowers are positioned amongst the most marketed cut flowers worldwide due to their attractive appearance. Their shelf-life is typically short (7-12 days) owing to stem bending that determines its commercial value. Postharvest treatments based on vase solutions with calcium compounds (e. g., CaO, Ca (OH)2, CaCO3, CaCl2) are applied to avoid stem bending. The aim of this research was to evaluate the effectiveness of vase solutions based on calcium oxide nanoparticles (CaO-NP) on the postharvest quality of gerbera (Gerbera jamesonii L. cv. 'Forza'). The treatments consisted in distilled water (negative control), 2000 mg·L−1 calcium chloride (positive control, CaCl2, 0.2 %), 0.1 % glycerol, and 50, 100 and 150 mg·L−1 of CaO-NP; glycerol (0.1 %) was applied to maintain the CaO-NP dispersed. Results indicated positive effects of CaO-NP on stem firmness, decreasing stem bending, as well as reducing the weight loss and preserving the diameter of the gerbera flowers. Moreover, gerberas treated with CaO-NP preserved their visual quality, and chlorophylls content. The action of CaO-NP did not modify phenolic compounds and antioxidant capacity. Thus, the application of CaO-NP can be considered as an efficient alternative vase solution to preserve gerbera flowers during postharvest.

The relation between bacteria numbers in vase water and vase life of gerbera cut flowers has recently been challenged because of reported negative effects of bactericidal compounds. This relation is investigated using two types of experiments that do not rely on antimicrobial compounds. The first type controls vase water temperature (4, 15, 22 or 28 °C) independently from air temperature (15, 22 or 28 °C) to investigate whether fresh weight behavior for two mini gerbera cultivars (‘Okidoki’ and ‘Kimsey’) is affected by bacterial growth and leaking of soluble sugars in the vase water, or by senescence of the flower head. Fresh weight loss, when compared at constant water temperatures, was higher at higher air temperatures. At higher water temperatures and constant air temperatures fresh weight loss was not higher, although bacterial levels were high enough to expect water uptake issues. Also sugar consumption in the vase water depended on water temperature. This indicates that senescence was the main reason for the decline in fresh weight for these flowers, not bacterial growth. The second type of experiments was based on adding predetermined levels of bacteria (0, 103 or 105 CFU mL−1) and sugars (0.1% glucose or 0.2% sucrose) into vase water of flowers of three large-bloomed (‘Carambole’, ‘Candela’ and ‘Iceberg’) cultivars harvested with closed stem-ends and had their scapes sterilized before the start of vase life. When bacteria were added varying types of responses were observed. ‘Carambole’ flowers showed lower water uptake and lower transpiration and, early scape bending. Petal wilting was observed for ‘Candela’ flowers. ‘Carambole’ flowers showed higher scape sugar leakage levels in the vase water while ‘Candela’ flowers had higher scape firmness. ‘Iceberg’ flowers were also affected by bacteria, resulting in early scape bending, although sugar levels in the vase water were low. Furthermore, adding sucrose and/or bacteria in the vase water of one ‘Iceberg’ and one ‘Carambole’ flower in the same flask resulted in later scape bending for ‘Iceberg’ flowers compared to having two ‘Carambole’ or two ‘Iceberg’ flowers. The results indicate that bacteria interactions with gerbera flowers depend strongly on genotype.

Micropropagation techniques changed the production of clonal plantlets in the world. However, the high costs of micropropagated plantlets continue as the main constraint for the expansion of the technique. This paper aimed to test the use of the chemical sterilization of culture medium using chlorine dioxide (ClO2) for in vitro cultivation of gerbera. There was used gerbera in vitro shoots in the stage of rooting for these experiments, using 0.0035%, 0.0070% and 0.0105% of chlorine dioxide in the culture medium. Also, peracetic acid was tested previously for sterilization, but resulted in microbial contamination. Chemical sterilization of the culture medium was successfully using ClO2 at 0.0035% to 0.0105% (100% decontamination) at rooting and elongation stage of gerbera with production of plantlets with similar (number of leaves, total and root fresh weight) or higher quality (mainly aerial part) at rooting/elongation stage, compared with autoclaved culture medium. The increase of concentration of ClO2 also resulted in increasing of height and fresh weight of aerial part of gerberas. The ClO2 could replace the autoclaving with production of sterilized culture medium without phytotoxic problems to gerbera in vitro cultivation.

The objective of the present work was to evaluate the effect of nitrogen (N) and calcium (Ca), complementary to the complete fertilization established, on production, quality and postharvest shelf life of floral stems of gerbera as cut flower harvested 117 days after transplant. The experiment consisted of a combination of three doses of N.L−1 substrate (0.07 g, 0.15 g and 0.2 g) and three doses of Ca.L−1 substrate (0.02 g; 0.03 g and 0.04 g) and was conducted in a greenhouse in a bifactorial arrangement with an additional control treatment. Control plants were not supplemented with N or Ca. Both elements were diluted in water and applied manually every 15 days. Highest flower yields were obtained with application 0.2 g de N.L−1 substrate and 0.04 g Ca.L−1 substrate. Stem length, stem diameter, flower diameter, and longevity, relative fresh weight and solution uptake were highest in gerbera fertilized with 0.2 g de N.L−1 substrate and 0.04 g Ca.L−1 substrate. Applying every 15 days, 0.2 g of N.L−1 substrate and 0.04 g of Ca.L−1 substrate resulted in higher yields, better quality and postharvest shelf life of floral stems of gerbera as cut flower harvested 117 days after transplant. Resumo O objetivo do trabalho foi avaliar o efeito de diferentes doses de nitrogênio (N) e cálcio (Ca) na produção, qualidade e pós-colheita de hastes florais de gérbera de corte colhidas aos 117 dias após o transplante. O experimento foi conduzido em ambiente protegido, tipo abrigo, em esquema bifatorial com tratamento adicional, que consistiu da combinação de três doses de N.L−1 de substrato (0,07 g, 0,15 g e 0,2 g) e de três doses de Ca.L−1 de substrato (0,02 g, 0,03 g e 0,04 g), aplicadas a cada 15 dias, além da testemunha, sem adubação com N e Ca. Não houve interação significativa entre as doses de N e de Ca. A maior produção de hastes florais foi obtida com o uso de 0,2 g de N.L−1 de substrato e de 0,04 g de Ca.L−1 de substrato, sendo que sem aplicação de N e de Ca não houve produção de hastes. Para o comprimento e diâmetro da haste; diâmetro do capítulo; longevidade; massa fresca relativa e absorção de solução, a aplicação de 0,2 g de N.L−1 de substrato e 0,04 g de Ca.L−1 de substrato apresentou os melhores resultados. Utilizando-se, a cada 15 dias, 0,2 g de N.L−1 de substrato e 0,04 g de Ca.L−1 de substrato ocorre uma maior produção, qualidade e longevidade pós-colheita de hastes florais de gérbera de corte colhidas aos 117 dias após o transplante.

This study was conducted to evaluate the chemical composition of asafoetida (Ferula assa-foetida) essential oil (FAEO) and Shirazi thyme (Zataria multiflora) EO (ZMEO) and their impact on vase life of gerbera cut flowers (Gerbera jamesonii cv. Rosalyn). Five concentrations of both, ZMEO and FAEO including 0, 100, 200, 300 and 400 mg L−1 used as continuous vase solution for gerbera cut flowers. EOs used in this study were extracted by hydrodistillation method using Clevenger apparatus. They were analyzed by GC and GC–MS for determination of the active compounds. Thirty five compounds were identified in ZMEO, mainly including thymol (40.1%), p-cymene (15.5%) and carvacrol (6.5%). Also, thirty compounds were identified in FAEO. The main components were trans propenyl sec-butyl disulfide (21.7%), eudesmol (10-epu-γ) (19.2%) and cis propenyl sec-butyl disulfide (10.2%). The results showed that both ZMEO and FAEO at all concentrations could act as an effective antibacterial compounds and this property increased by increasing their concentration. The results of this research showed that ZMEO increased the vase life at all concentrations but high concentrations of FAEO increased mortality percentage and reduced the vase life of cut flowers. The relative fresh weight and vase solution uptake of gerbera cut flowers increased by the applied EOs treatments. ZMEO at 400 mg L− 1 and FAEO at 300 and 400 mg L− 1 resulted the least stem color change. Overall, 200 mg L− 1 ZMEO and 100 mg L− 1 FAEO were the best treatments for maintenance of gerbera cut flowers quality during vase life.

Paclobutrazol substrate drenches at 0, 1, 2, 3, or 4 ppm were compared to a 2,500 ppm daminozide foliar spray standard in two finishing seasons (fall 2015 and spring 2016) and at two application stages for plant size control and improved market quality of ‘Bright Red with Light Eye' Gerbera daisy (Gerbera jamesonii Hook. f. ‘Bright Red with Light Eye') in 12.7cm (5 in) pots. Stage 1 was when the majority of plants had roots to the bottom of the substrate, and stage 2 was 2 weeks later. A consumer preference survey assessed purchasing preference when plants had two or three open flowers. Plant size index, foliage height, peduncle length, flower diameter, and quality rating at first flower decreased linearly while days to first flower increased quadratically with increasing paclobutrazol concentration, regardless of stage or season. Paclobutrazol applications delayed flowering, and decreased flower diameter and flower and bud counts, but these differences were small and not considered of practical importance. Based on quality rating at first flower and survey results, a 1 or 2 ppm paclobutrazol drench produced the most marketable plants in fall, and 0, 1, 2, or 3 ppm produced the most marketable plants in spring.Index words: plant growth retardant, B-Nine, Bonzi, greenhouse productionChemicals used in this study: B-Nine (daminozide) [butanedioic acid mono (2,2- dimethylhydrazide)] and Bonzi (paclobutrazol) [(±)-(R*,R*)-β-[(4-Chlorophenyl)methyl]-α-(1,1- dimethylethyl)-lH-1,2,4-triazole-1-ethanol]Species used in this study: ‘Bright Red with Light Eye' Gerbera daisy (Gerbera jamesonii Hook. f. ‘Bright Red with Light Eye')

The objective of this study was to evaluate the acclimatization efficiency of Gerbera shoots, in vitro rooted under LED lights. For the experiment, Gerbera jamesonii 'Big Apple' shoots were rooted on a MS medium with 1 µM IAA, 30 g dm-3 sucrose and 5 g dm-3 BioAgar, pH 5.7. Three different LED lights were tested (B - blue, R - red, RB - blue and red mixture 70/30) and fluorescent light (Philips TL-D 36W/54) as a control. PPFD was 35 µM m-2 s-1. After 6 weeks, all shoots formed adventitious roots and they were prepared for acclimatization. The agar remains were washed off and the plants were immersed in a 0.1% Topsin M 500 SC and planted in containers filled with TS2 substrate (Klasmann-Deilmann). The plantings were covered with a polypropylene transparent film and were kept in a greenhouse at a temperature of 19/22°C. After 10 days, the boxes were gradually uncovered to reduce humidity, while the light intensity was increased. At the end of the acclimatization, biometrical observation and analyses, the dry mass of the leaves and roots, and the stomata features of the acclimatized plants were recorded. After 6-week ex vitro culture, all gerbera plants were 100% acclimatized. The longest shoots had plants rooted under red light, while those rooted under monochromatic blue light had the highest number of leaves and the leaf blades had the largest surface. The control plants showed the lowest number of roots when compared to the plants rooted under all LED combinations. The shortest roots after acclimatization were observed in gerbera rooted under RB, while the highest dry mass was recorded in those rooted under monochromatic light. There were no differences in the stomata frequency in acclimatized plants rooted under different light spectra. Stomata and their pores of plants rooted on RB light were shortest and had the smallest area.

Gerbera jamesonii cv. Dura is a well-known and economically important ornamental crop that is produced using micropropagation. This study aimed to evaluate the effect of various light wavelengths in six different light emitting diode (LED) treatments on biometric attributes and photosynthetic pigment content in gerbera plants grown in vitro. The LED treatments were B (100% blue), RB1 (50% red and 50% blue), RB2 (70% red and 30% blue), RBW (40% red, 40% blue, and 20% white), RBfR (49% red, 49% blue, and 2% far red), and R (100% red). Light quality was seen to significantly affect plant growth and development. The highest shoot multiplication rate was observed in plants grown under both RB1 and RB2. Plantlets grown under R displayed the greatest shoot elongation, and their petioles were three times longer than those grown under B. Both B and R resulted in reduced leaf blade area. Rooting of shoots was observed in plants grown under all light treatments; however, R stimulated adventitious root formation. The average number of roots produced by plants under all light treatments was calculated and found to match that produced under RB2. The RBfR treatment caused a reduction in leaf dry weight compared to that produced under B, which represented the highest leaf dry weight. Control fluorescent lighting, supplied by Philips TL-D 36W/54 lamps, had a positive effect on root dry weight. Photosynthetic pigment content was higher in the leaves of rooted plants compared to that in plants at the multiplication stage. RB2 resulted in higher concentrations of chlorophyll a and b and carotenoids, whereas lower accumulation of photosynthetic pigments was observed under R. These results demonstrate that light wavelength manipulation through LEDs can be strategically used for the rapid and large-scale propagation of gerbera. The outcomes of this study offer potential to improve micropropagation efficiency and reduce the costs of in vitro plant production.

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).