Economics of Carnation Cut Flower Production in Kathmandu Valley, Nepal

Comparison of petal senescence between cut and intact carnation flowers using potted plants

Carnation is an important cut flower commercially traded in Kathmandu Valley. It has high demand of floriculture market in the Kathmandu Valley due to its physical characteristics and also its suitability to be used singly or in combination with other flowers in different floriculture products. So, the study has attempted to analyze the market of carnation cut flower in Kathmandu Valley. Data were collected from sample of carnation producers, wholesalers, retailers, and consumers of the Kathmandu Valley. Simple random sampling technique was employed to select the respondents. Information from the respondents was generated through semi-structured interview schedule. Key informants were also interviewed for in-depth and related information. Data collected through personal interview and secondary sources was analyzed by applying descriptive statistical tools. Data analysis focused mainly on the market structure, conduct of marketing agents, and performance of carnation cut flower in the market in terms of returns to the marketing agents, present problems in marketing, and future prospects of carnation in Kathmandu Valley. Findings reveal that the market structure was well integrated and the conduct of the marketing actors was so far competitive to the large extent. The performance of the carnation cut flower in terms of price and profit seems satisfactory and sustainable. However, there were ample areas of improvements in the marketing system. Given the high degree of demand in the valley and increasing trend of imports of carnation cut flowers from other districts of the country as well as from foreign countries, concerted efforts must be made to reverse the situation and make the Valley self-reliant in fulfilling its demand alongside exporting to other districts and countries in the future.

Two full‐length cDNAs encoding alcohol dehydrogenase (ADH, EC 1.1.1.1) and pyruvate decarboxylase (PDC, EC 4.1.1.1), named Dcadh1 and Dcpdc1, respectively, were cloned from the petals of cut carnation flowers exposed to hypoxia (1.5% O2). Dcadh1 and Dcpdc1 transcripts were accumulated in large amounts in the petals of carnation flowers 2 and 3 h after the exposure of the flowers to hypoxia and anoxia, respectively. The accumulation of the transcripts was accompanied by subsequent increases in the ADH and PDC activities in the petals. The rapid and massive induction of Dcadh1 and Dcpdc1 expression and their enzymatic activities make these genes useful molecular markers for the early events of hypoxic adaptation in cut carnation flowers. The long‐term objective of this research is to induce a hypoxia‐like response in cut carnation flowers maintained under normoxic conditions in order to extend their vase life. Cut carnation flowers represent a good model system to study the molecular triggering of the hypoxic response.

The effect of cis-propenylphosphonic acid (PPOH), a structural analoge of ethylene, on flower wilting and ethylene production was investigated using cut carnation flowers which are very sensitive to ethylene. Wilting (petal in-rolling) of the flowers was delayed by continuously immersing the stems in a 5–20 mM PPOH solution. In addition, the continuous treatment with PPOH markedly reduced autocatalytic ethylene production of the petals accompanying senescence. This reduction of autocatalytic ethylene production was considered responsible for the inhibitory effect of PPOH on flower wilting. The inhibitory activity of trans-propenylphosphonic acid (trans-PPOH), on both flower wilting and the autocatalytic ethylene production accompanying senescence was markedly lower than that of PPOH, suggesting that PPOH action is stereoselective. PPOH may be of interest as a new, water-soluble inhibitor of wilting and autocatalytic ethylene production in cut carnation flowers.

Transient water stress in cut carnation flowers: effects of cycloheximide

Carnation (Dianthus caryophyllus L.) holds great significance as a cut flower, and its vase life plays a crucial role in determining its quality and market appeal. However, the extended transportation distances from the production location to consumer markets can have an unfavourable impact on the vase life and overall quality of cut flowers. The first experiment demonstrated that exposing cut carnation flowers to simulated vibrational stress (SVS) led to a decline in vase life and overall quality. Notably, the application of Nano Silver (NS; 25 and 50 μM) and melatonin (MT; 100 and 200 μM) into the holding solution proved effective in counteracting these negative effects, and extended the vase life by promoting cut flower water relations. In the second experiment, the optimal concentrations of NS and MT into the holding solution (25 and 100 μM, respectively) effectively reduced chlorophyll degradation, electrolyte leakage, and lipid peroxidation by enhancing the activity of catalase and peroxidase enzymes. As a result, it appears that the application of NS and MT in the holding solution has successfully prolonged vase life by both improving water balance and boosting antioxidant activity, while mitigating the negative effects of SVS.

The effect of calcium nitrate addition to α-aminoisobutyric acid (AIB) on the vase life of cut carnation flowers (Dianthus caryophyllus L.) in continuous treatment and pretreatment was investigated. In the continuous treatment, the addition of 2.5 mM calcium nitrate to 10 mM AIB significantly prolonged the vase life of 'Soana' cut flowers, relative to the control or 10 mM AIB or 2.5 mM calcium nitrate alone. This combination treatment was as effective as 20 mM AIB solution in extending vase life of carnations. In the pretreatment trials, an exposure to 60 mM AIB for 21 or 24 hours significantly extended the vase life of 'Nora', relative to the control. Exposure of cut flowers to 60 mM AIB+10 mM calcium nitrate solution for 21 or 24 hours enhanced the vase life by 20% or 14%, respectively over 60 mM AIB alone, but the calcium nitrate effect was not significant. The results of this study suggest that the addition of calcium nitrate to AIB promotes the AIB uptake in cut carnation flowers.

In Dianthus caryophyllus L. (carnation), floral scent emission declines more rapidly after cutting than when plants remain in the ground. Treatment using exogenous sucrose or l-phenylalanine (Phe) increases scent emission from cut flowers of some ornamental plants; however, carnations have not been studied in this context. This study aimed to evaluate the effects of exogenous sucrose and Phe on scent emission in cut carnation flowers. Sucrose, a substrate for benzenoids/phenylpropanoids (BPs), terpenoids, and fatty acid derivatives, increased emissions of all these compounds. However, Phe, a BP precursor, increased BP emissions only selectively. In addition to acting as scent biosynthetic substrates, both inhibited senescence, delaying β-caryophyllene increase and aligning daily scent composition more closely with that of intact flowers. Thus, the physiological effects of sucrose and Phe also contribute to scent regulation. These compounds show potential as scent-preserving agents for cut carnations; however, the scent enhancement effects in more cultivars and Phe-induced leaf yellowing must be confirmed for practical use.

A low concentration of benzyladenine (4.44 × 10-5 M) accelerated the senescense of cut carnation flowers. This effect could be reversed by STS-treatment but not by keeping the flowers in a holding solution containing 4% ethanol. This appears to be the first report indicating that cytokinins at a specific level may actually enhance flower senescense. The higher levels tested (1.11 × 10-4 and 2.22 × 10-4 M) retarded senescense, being in agreement with published results. The applied cytokynin was metabolized slowly in the petals to a compound(s) which co-chromatographed with ribosylbenzyladenine when separated by TLC and when fractionated by HPLC. In the experiments applying (14C) benzyladenine to the petals, a small degree of transport of the 14C was detected in naturally senescing (control) cut flowers and when treated with ethrel. The transported 14C was detected in both the ovaries and in the stems and co-chromatographed with benzyladenine. Where flower senescense was delayed (ethanol or STS) no movement from the petals was detected. This suggests that the cytokinin moved within the assimilate stream, along with sugars.

A biological method for synthesising silver nanoparticles (AgNPs) was developed using the callus extracts from Artemisia annua L. under sunlight at 25,000 lx. The AgNPs were characterised using transmission electron microscopy, atomic force microscope, X-ray diffraction and Fourier transform infrared spectroscopy. The AgNPs were mostly spherical with the size of 2.1 to 45.2 nm (average 10.9 nm). Pulse treatments of AgNPs at 125, 250 and 500 mg/l for 1 h extended vase life of cut carnation (Dianthus caryophyllus cv. Green Land) flowers. Four dominant bacteria strains Arthrobacter arilaitensis, Kocuria sp., Staphylococcus equorum and Microbacterium oxydans were isolated from the stem-ends of cut D. caryophyllus flowers. AgNP pulse inhibited significantly bacterial growth in vase solution and cut stem ends during all of the vase period. The bacteria related blockage in the stem-ends was significantly alleviated by AgNP pulse because of its higher antibacterial efficacy against the dominant bacteria. In addition, ethylene release of cut carnation flowers was inhibited in response to AgNP pulse. This is the first time that the biologically synthesised AgNPs could be applied as a promising preservative agent for cut carnation flowers.

Effects of hypoxia on respiration and the onset of senescence in cut carnation flowers (Dianthus caryophyllus L.)

Temperature, an environmental factor affecting cut flowers' physiological state, is expected to affect scent emission. We investigated scent emission from carnation cut flowers of two scent types (Dianthus caryophyllus L.), exhibiting fruity (because of methyl benzoate) and spicy (because of eugenol) scents, at various temperatures (10°C, 15°C, 23°C, and 28°C). Cut flowers harvested on the day of flower opening were used for analysis. Scent emission was significantly higher at 23°C and 28°C than at 10°C and 15°C until 1 or 2 days but was significantly lower at 8 and 10 days postharvest. Methyl benzoate emissions decreased faster than eugenol emissions. Considering the lower limit of noticeable scent, as per previous sensory evaluations of carnations, scent lasted the longest at 10°C and 15°C. After ~5 days of pretreatment at 10°C, scent emission was slightly improved at 23°C than at 23°C. Such cut flower management at 10°C before sale may contribute to the persistence of scent at room temperature in consumers' homes after sale. Various factors, including the suppression of scent substrate consumption, regulation of scent emission from the cuticle, and influence on the expression of scent emission–related genes, may affect the retention of scent emission because of low temperature.

Cut flowers of carnation were treated with Salicylic acid (0,1.5, 3 mM) and sucrose (0, 3%).The effects of Salicylic acid on the ACC-oxidase activity, bacteria populations in vase flower preservative solution, anthocyanin leakage, Membrane stability, malondialdehyde and ACCoxidase activity of cut flowers of carnations (Dianthus caryophyllus L. cv.White) were investigated. The experimental results showed that SA treatment cause descrease MDA content and ACC-oxidase activity, reduced the membrane permeability and peroxidation of lipids.also, Results showed that The best treatment involved 1.5 mM SA+ sucrose 3% . The vase solution containing 1.5 mM Salicylic acid + sucrose 3% significantly descreased MDA content, ACCoxidase activity and bacteria populations in vase flower preservative solution and increased the vase life and membrane stability of carnation cut flower compared to the control. Results suggested that Salicylic acid increases membrane stability by descrease MDA content and ACC-oxidaseactivity, bacteria populations in vase flower preservative solution of the carnation cut flowers.

The effect of 1-MCP on extending the vase life of chrysanthemum and carnation cut flowers was studied. The flowering stems of both flowers were terminated to 50 cm. in height. Then, the flowers were pre-treated with 1-MCP at 0.3, 0.5 and 0.7g/m3 for 3 hours or 6 hours. The control flowers were placed in ambient air during the treatment. After the period of treatments the flowers were aerated then put in glass vials contained tap water. The vase life determination was conducted in a vase life evaluation room at 22 ± 1°C. Fresh weight determinations of the flowers were made just before the immersion of the flowers into the glasses of water and were repeated on the day when the vase life of the control flowers was terminated. The treatment of 1-MCP at 0.5g/m3 for 6 hours was the most effective treatment of chrysanthemum and carnation cut flowers.

This study investigated the influence of different degrees of cross-linking of β-cyclodextrin-based nanosponges (β-CD-NSs) on the activity of the incorporated 1-methylcyclopropene (1-MCP) to extend the postharvest longevity of carnation cut flowers. The polymeric β-CD-NSs were synthesized from cyclodextrins at three varying reticulations, β-CD-NS 1:2, β-CD-NS 1:4, and β-CD-NS 1:8. These carriers were supplied to carry the nonvolatile formulations of 1-MCP at two different concentrations (0.25 and 0.5 μL L−1, ai) through stem and tissues of cut flowers of Dianthus caryophyllus L. ‘Idra di Muraglia’, both sprayed and in vase suspension. Treated cut flowers were compared to those receiving like concentrations of commercially prepared gaseous 1-MCP and to neat β-CD-NS 1:2, β-CD-NS 1:4, and β-CD-NS 1:8. Visual checks for symptoms of senescence alteration (VS), petal color variation, and endogenous ethylene production were registered daily. The β-CD-NS 1:2, β-CD-NS 1:4, and β-CD-NS 1:8 complexes favored decorative value maintenance in carnation cut flowers. In particular, the lowest suspended concentration (0.25 μL L−1) of the β-CD-NS 1:8 complex proved best for maintaining cut flower ornamental quality. β-CD-NS 1:8 treated flowers also appeared longer-lived than those treated with both doses of commercial gaseous 1-MCP. Data on petal color variation and endogenous ethylene production were strictly correlated with VS results. The potential for the formulated 1-MCP-loaded β-CD-NS suspension to induce prolonged vase life was demonstrated. Its use could yield benefits, such as a reduction in total dose and frequency of administration.